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Biological Inventory for the Conservation of Great Lakes Islands: Year 2001 Progress Report

Authors:
  • Affiliated with Niswander Environmental in Brighton Michigan
Biological Inventory for Conservation of Great Lakes
Islands: Year 2001 Progress Report
Prepared by:
Michael R. Penskar, Jennifer A. Olson, Michael A. Kost, John J. Paskus,
David L. Cuthrell, Rebecca L. Boehm, Edward H. Schools, Michael T. Fashoway
Michigan Natural Features Inventory
P.O. Box 30444
Lansing, MI 48909-7944
For:
Michigan Coastal Management Program
Land and Water Management Division
Coastal Management Program Grant #01-309-10
Submitted September 30, 2002
Report Number 2002-21
Great Lakes Islands 2001 Page-i
Executive Summary
In 1998, Michigan Natural Features Inventory
(MNFI) initiated a multi-year project to conduct
biological inventories for the conservation of Great
Lakes islands. The fundamental goal of this project is
to systematically examine selected Great Lakes islands,
compile comprehensive information on natural features
and significant biodiversity areas, and then convey this
information in the most useful form for landowner
education and conservation planning purposes. The
first year of the project focused on several biological
inventories in the Beaver Island archipelago and a
selective floristic survey of several islands within the
Garden Peninsula group. In 1999, we continued
inventories within the Beaver Island archipelago and
also conducted inventory work in northern Lake Huron,
focusing on Bois Blanc Island, selected islands within
the Les Cheneaux chain, and portions of Drummond
Island. In addition, a prototype conservation planning
workshop was held on Beaver Island for residents and
other island stakeholders. In 2000, the third year of the
study, inventories were continued in northern Lake
Huron, highlighting Bois Blanc Island, Drummond
Island, and selected islands within Potagannissing Bay.
Preliminary work was also completed for preparation
of a conservation planning workshop to be held in
2001 for Drummond Island. Analysis of the work
completed to date was conducted to assess the status of
the project and its future direction.
In 2001, the fourth year of this study, we conducted
inventories on Drummond Island, the second largest
island in Michigan. In addition to biological invento-
ries for natural communities, rare plants, and rare
animals, all natural features data for Drummond Island
were digitized for management within the Michigan
Natural Features Inventory (MNFI) GIS systems. A
conservation outreach workshop was also held with
residents and stakeholders following the field season,
following preliminary work completed in 2000 and
building upon the format used for an initial island
workshop on Beaver Island.
Animal Surveys: Inventories were conducted to
complete a two-year census of migratory and breeding
birds, and a targeted insect survey was performed for
the federal and state endangered Hines emerald
dragonfly. For the bird survey, 113 species were
recorded overall, with 94 species observed during
spring migration and 97 species observed during the
summer breeding season. Forty-four species were
classified as long distance migrants, 50 were classified
as short distance migrants, and 19 species were consid-
ered residents. Mean bird abundance and species
richness were calculated and compared during migra-
tion and breeding season. Mean bird abundance during
migration was 8.3 birds per station, whereas species
richness was 6.4 species per station. During the
breeding season, mean bird abundance was 9.9 birds
per station, and species richness was 7.3 birds per
station. A qualitative assessment of habitat use by
birds was conducted, comparing shoreline sites, inland
sites, and inland water sites during both the migration
and breeding seasons. Five important bird migration
sites and six important bird breeding sites were identi-
fied. Nine new rare bird occurrences and two known
rare bird occurrences were documented during surveys.
For insect surveys, four sites identified during 2000
surveys were searched for Hines emerald dragonfly.
No Drummond Island locations could be documented,
and it was concluded that the potential is low for this
species, though there may be additional habitat of merit
for further surveys, which may also identify other listed
dragonflies.
Plant Surveys: Rare plant surveys were conducted
in conjunction with all natural community surveys.
Comprehensive inventory was conducted in the Maxton
Plains complex, on Marblehead, and in selected areas
along and near the southern coast. Nine new plant
occurrences were documented from a total of six sites,
and 18 previously known occurrences from a total of
seven sites were located and updated.
Natural Community Surveys: Natural community
surveys resulted in the identification of one new high
quality occurrence for alvar and significant updated
information for six previously known communities.
Data were gathered highlighting ecological processes,
natural and artificial disturbance, the presence of
invasive exotic species, and spatial extent of communi-
ties. Site summaries were prepared for significant
survey targets.
Digitization of Island Data: Digitizing was
completed for all Drummond Island natural features
data, incorporating the results of 2001 surveys. An
explanation of the digitizing process within the context
of heritage data methodology is provided. Over the
four years of the island project a total of 430 occur-
rences have been digitized, representing nearly 4% of
the MNFI statewide natural features database.
Conservation Outreach: A conservation outreach
workshop, based on the previous format for Beaver
Island, was prepared and held for Drummond Island
residents and stakeholders in the fall of 2001. Prelimi-
nary planning for this workshop occurred in the fall of
2000 and the winter of 2001. Organization of the
workshop included collaboration with The Nature
Conservancy (TNC) Northern Lake Huron Bioreserve
Great Lakes Islands 2001 Page-ii
Office and key full-time island residents. A total of 22
residents attended the workshop, and relationships
were developed with key people of the Drummond
Island community. After this workshop, an evaluation
was prepared assessing and comparing the results of
the outreach workshops held for Beaver Island and
Drummond Island. The original goal of conservation
outreach workshops was to test what types and levels
of natural resource information are desired by island
communities. However, while collaborating with
partners and community leaders, conservation planners
learned to focus less on testing which information is
desired by communities while becoming more directed
to designing effective methods for conveying this
information. Further evaluation of conservation
outreach workshops will follow the final year of the
island project, which includes an outreach workshop
for Bois Blanc Island in the Straits region.
Identification of Significant Biodiversity Areas:
Several areas were briefly highlighted, including the
Maxton Plains, Huron Bay, Big Shoal Cove, and
Marblehead Peninsula.
Projected Work for 2002: Efforts for the fifth and
final year of the island project will include plant and
natural community surveys of Bois Blanc Island,
selected areas to complete inventories in the Les
Cheneaux Islands, a comprehensive massasauga
inventory of Bois Blanc Island, and Hines emerald
surveys on Bois Blanc Island and targeted areas in the
Les Cheneauxs.
Great Lakes Islands 2001 Page - iii
Table of Contents
Executive Summary ........................................................................................................................................................... i
Introduction ....................................................................................................................................................................... 1
Organization of Report ..................................................................................................................................................... 1
The Study Area .................................................................................................................................................................. 2
Methods for Animal Surveys ............................................................................................................................................ 2
Justification for Animal Target Selection ................................................................................................................... 2
Birds ........................................................................................................................................................................... 4
Insects ........................................................................................................................................................................ 6
Results of Animal Surveys ................................................................................................................................................ 6
Birds ........................................................................................................................................................................... 6
Insects ...................................................................................................................................................................... 13
Discussion of Animal Surveys ........................................................................................................................................ 13
Birds ......................................................................................................................................................................... 13
Insects ...................................................................................................................................................................... 17
Methods for Plant Surveys .............................................................................................................................................. 17
Results of Plant Surveys .................................................................................................................................................. 18
Discussion of Plant Surveys ............................................................................................................................................ 18
Methods for Natural Community Surveys ...................................................................................................................... 22
Results of Natural Community Surveys .......................................................................................................................... 22
Discussion of Natural Community Surveys .................................................................................................................... 24
Site Summaries ............................................................................................................................................................... 25
Digitization of Island Data .............................................................................................................................................. 26
Conservation Outreach for Drummond Island ................................................................................................................ 29
Background .............................................................................................................................................................. 29
Preparation .............................................................................................................................................................. 29
Presentation ............................................................................................................................................................. 30
Interactive Exercise ................................................................................................................................................. 30
Discussion and Conclusions .................................................................................................................................... 31
Identification of Significant Biodiversity Areas .............................................................................................................. 33
Projected Work for 2002 ................................................................................................................................................. 33
Acknowledgements ......................................................................................................................................................... 35
Literature Cited ............................................................................................................................................................... 36
List of Figures
Figure 1. The study area in northern Lake Huron. ........................................................................................................... 3
Figure 2. Bird and insect sampling sites on Drummond Island. ...................................................................................... 5
Figure 3. Distribution of birds on Drummond Island in 2001.. ..................................................................................... 11
Figure 4. Distribution of bird species on Drummond Island in 2001............................................................................. 11
Figure 5. Natural community survey sites...................................................................................................................... 23
Figure 6. Natural features as depicted in MNFI GIS database. ...................................................................................... 27
Figure 7. Changes in number of occurrences after digitizing. ....................................................................................... 28
Great Lakes Islands 2001 Page - iv
Great Lakes Islands 2001 Page - v
List of Tables
Table 1. Bird Species Recorded During Migration (M) and Breeding Seasons (B) in 2000 and 2001 on Drummond
Island. State listed and special concern species are in bold type. .............................................................................. 7
Table 2. Mean bird abundance, species richness and dominant species recorded during spring migration in Year 2001
and 2000 on Drummond Island. Calculations include a confidence interval of 95%. .............................................. 10
Table 3. Mean bird abundance, species richness and dominant species recorded during summer breeding season in
Year 2001 and 2000 on Drummond Island. Calculations include a confidence interval of 95%. ............................ 10
Table 4. Rare bird nesting occurrences documented during 2001 and 2000 surveys of Drummond Island. Occurrences
documented during 2000 are highlighted in blue. .................................................................................................... 12
Table 5. Number of species recorded during the migration and breeding season on four islands. Total number of
species recorded in both seasons is highlighted in blue. ........................................................................................... 14
Table 6. Rare plant and natural community sites inventoried during 2001 surveys of Drummond Island (Chippewa
County). .................................................................................................................................................................... 19
Table 7. Invasive plants occurring within alvar communities of the Maxton Plains, Drummond Island. ...................... 24
List of Appendices
Appendix I. Cumulative List of Natural Features Identified during 1998-2001 Island Inventories. ............................. A-3
Appendix II. Agenda for Natural Features Workshop Drummond Island. .................................................................... A-5
Appendix III. Example of Power Point Presentation given for Conservation Outreach Workshop
on Drummond Island. ............................................................................................................................ A-7
Appendix IV. Results of Interactive Exercise given at Drummond Island Community Workshop ............................... A-9
Appendix V. Species Abstracts.................................................................................................................................... A-11
Great Lakes Islands 2001 Page - vi
Great Lakes Islands 2001 Page-1
Introduction
This progress report presents the results of year
four of a five-year project to conduct systematic
inventories of selected Great Lakes islands and island
groups, followed by selected conservation planning
workshops. As noted previously (Penskar et al. 1999),
a considerable portion of the biological diversity
unique to the Great Lakes region is found on islands.
Soule (1993) stated that nowhere else does the
combination of vast, interconnected, mid-continental
bodies of freshwater and such a number of variety of
islands occur. Thus, the nearly 600 islands contained
within Michigans borders comprise a critically impor-
tant part of this freshwater landscape, owing to their
richness in variety of geography, geological origin,
indigenous and non-indigenous human history, and
biodiversity.
Over the past two decades Michigan Natural
Features Inventory (MNFI) has surveyed numerous
natural communities and rare species found on or allied
with Great Lakes islands. This extensive work was
described in part by Soule (1993) and was detailed in
previous years progress reports (Penskar et al. 1999,
2000, and 2001). Conducting comprehensive biologi-
cal inventories on Great Lakes islands is both timely
and crucial to the conservation of biodiversity, as
reflected in the findings and recommendations of The
State of the Great Lakes Island Report (Vigmostad
1999). This report comprises the proceedings of a
1996 U.S-Canada Great Lakes islands workshop
convened by the Great Lakes Island Project (Depart-
ment of Resource Development, Michigan State
University) to determine the state of Great Lakes
islands and elucidate potential conservation strategies.
Among the three fundamental findings of the workshop
was a recommendation for governments and other
entities to support island and archipelago conservation,
and to that end, to base conservation planning on sound
scientific information. Comprehensive inventories are
thus critical to building the strong base of scientific
knowledge upon which conservation strategies are
dependent.
In this compilation of our efforts for the fourth year
of the project, we provide the results of biological
inventories conducted by zoologists, botanists, and
ecologists on Drummond Island, which at the eastern
border of the Upper Peninsula comprises the second
largest island within the state of Michigan. As in the
three prior progress reports, important biodiversity
areas are briefly highlighted at the end. We also
provide a summary of digitizing work initiated to
convert all island natural feature occurrences into
spatial data for management within MNFIs Geo-
graphic Information System (GIS). Lastly, brief
descriptions of inventory targets for the 2002 field
season are given in addition to a brief overview of
planning for a conservation outreach workshop sched-
uled to be held on Bois Blanc Island during late
summer of 2002.
Organization of Report
This report has been organized according to the
various components of the project: biological invento-
ries and site summaries, data digitizing, conservation
outreach, identification of significant biodiversity
areas, and projected fifth-year work.
Biological inventories in year 2001 consisted of the
following types: 1) animal surveys, with an emphasis
on migratory birds, breeding birds, and selected rare
invertebrates, 2) plant surveys, focusing on Great Lakes
shoreline endemics, alvar and other limestone bedrock
sites, and the identification of intact coastal and interior
habitats, and 3) natural community surveys, emphasiz-
ing the delineation and assessment of high quality
natural communities, with an emphasis on Great Lakes
alvar communities, as well as interior communities
such as boreal forest, mesic northern forest, and conifer
swamps. Methods, results, and discussion are provided
separately for each of the aforementioned components.
Survey results are followed by site summaries for
significant areas covered in botanical and natural
community inventories. A discussion of the digitizing
process for island data is then provided, and then a
section with a detailed account of the conservation
outreach workshop prepared and given for Drummond
Island residents and other stakeholders. The report
concludes with an assessment of significant
biodiversity areas and a brief description of our pro-
jected work for 2002 surveys.
Great Lakes Islands 2001 Page-2
The Study Area
The study site for the third year of island inventory
was Drummond Island, Michigans second largest
island, which occurs on the eastern end of the Upper
Peninsula in northern Lake Huron (Figure 1).
Drummond Island is exceeded in size only by Isle
Royale within the State of Michigan, and comprises the
easternmost point of the Upper Peninsula along the
Canadian border. The island covers more than 83,000
acres and forms approximately 130 miles of Great
Lakes shoreline. A significant portion of Drummond
Island lies within Lake Superior State Forest.
Methods for Animal Surveys
Animal surveys on Drummond Island focused on
assessing the abundance and richness of migratory and
breeding birds, and in particular Neotropical migratory
songbirds. Targeted inventories for red-shouldered
hawk (Buteo lineatus) and wetland birds were also
conducted on both islands. Surveys were initiated on
Drummond Island for the federally endangered Hines
emerald dragonfly (Somatochlora hineana).
The MNFI Biological and Conservation Database
(BCD) was consulted for known occurrences of rare
animal species associated with these islands. Informa-
tion on various species was gathered by consulting
expert zoologists and wildlife biologists, pertinent
unpublished reports, and a variety of published sources.
Survey sites for each target species or group were
selected based upon historical occurrence records, air
photo interpretation, landcover maps, and by consulting
with individuals knowledgeable about the islands flora
and fauna. MNFI ecologists and botanists also assisted
in identifying potential survey sites via their site
inventories.
A field schedule was developed based on prior
Michigan observation and collection dates for each
animal group or species and the extent of suitable
habitat. Survey techniques varied according to species
groups and are described in the following sections.
Incidental observations of listed species, which have
been designated under the federal Endangered Species
Act and/or state endangered species legislation as
endangered or threatened were noted by all project
staff when they occurred. Special concern species
were also sought and recorded. Data from all sightings
of listed animal species were recorded on MNFI field
forms, including numbers of individuals observed and
the extent and quality of occupied habitat. These data
were then entered into the statewide BCD. All birds
species observed during spring and summer island
visits were noted and recorded.
Justification for Animal Target Selection
The importance of stopover sites to migratory
birds, which travel great distances between their
wintering and breeding grounds, has only recently been
addressed (Moore and Simons 1992, Moore et al.
1993). Migration is one of the most energy-demanding
processes in a birds life, resulting in a weight loss of
approximately one-percent per hour of flight (Alerstam
1990). The risks that migratory birds face in seeking to
replenish their energy reserves while avoiding predators
and adverse weather conditions in unfamiliar habitats
have been well documented (Lindstrom 1989, 1990,
Aborn 1993, Wiedenfield and Wiedenfield 1995). Since
birds spend as much as half of the year or more en
route between breeding grounds and wintering areas,
the habitats they depend on during this period are
critical links in their survival. Defining the characteris-
tics of suitable stopover habitat, and determining how
development and land-use affect their distribution and
quality is an important issue that must be addressed.
Degradation or elimination of suitable stopover habitats
has the potential to increase mortality, reduce reproduc-
tive potential, and contribute to overall population
declines of migratory birds.
The Great Lakes shorelines serve as important
migration corridors for large concentrations of migrant
land birds (Beebe 1933, Perkins 1964, Hussel et al.
1992). Great Lakes islands may act as focal points for
migratory birds which tend to accumulate near ecologi-
cal barriers (Moore and Simons 1992). Scharf (1996)
suggested three possible reasons that Great Lakes
islands are attractive to Neotropical birds as well as
short distance migrants including: 1) nocturnal mi-
grants that find themselves over open water at dawn
seek the nearest land, 2) islands often represent north-
ward extensions of the mainland and are included in
the flight-path north by internal orientation mecha-
nisms of birds and stochastic events of weather pat-
terns, 3) islands are the intended destination of migra-
tory species that regularly nest on the islands.
In their 1993 study, Ewert and Hamas (unpubl.
data) documented the importance of the immediate
shoreline along the northern shore of Lake Huron as
Great Lakes Islands 2001 Page-3
Figure 1. The study area in northern Lake Huron.
Great Lakes Islands 2001 Page-4
critical stopover habitat for Neotropical migratory
birds. They found that this shoreline habitat provides
an important food source, in the form of aquatic
midges (Chironomidae), to spring migrants that arrive
before terrestrial insects are abundant. It would thus
seem logical that Bois Blanc Island, located just
southwest of this study area, and Drummond Island
located to the east, with similar shoreline habitats,
might also provide important stopover sites for migra-
tory songbirds.
The state threatened red-shouldered hawk (Buteo
lineatus) has experienced declines in Michigan due to
loss of its preferred nesting habitat. It nests in flood-
plain forests or extensive mature deciduous or mixed
forest complexes. Typically these forest complexes
have wetland habitats nearby or wetlands interspersed
among these forested habitats (Cooper 1999). Red-
shouldered hawks have not been well documented on
Bois Blanc or Drummond Island although suitable
habitat exists on both of these islands.
Due to the abundance of wetland habitat on Bois
Blanc and Drummond Island, rare wetland birds were
targeted for surveys. These include the state endangered
yellow rail (Coturnicops noveboracensis), which is
only known from three locations in Michigan, includ-
ing one on Drummond Island, the state threatened least
bittern (Ixobrychus exilis), and the state special con-
cern American bittern (Botaurus lentiginosus).
The Hines emerald dragonfly is an extremely rare
dragonfly that was listed as federally endangered in
January 1995 (DOI 1995). This species is currently
known from northern Michigan, northeastern Illinois,
Door County in northeastern Wisconsin, and one site in
the Missouri Ozarks (D. Cuthrell pers. comm.).
Historically, the species was known to occur in three
areas of Ohio, and from one site in Indiana. In addi-
tion, one specimen has been collected in northern
Alabama. The Hines emerald dragonfly was first
documented in Michigan in 1997. Since this time, three
distinct populations have been found in Michigan in
the Upper Peninsula, northern Lake Huron (Bois Blanc
Island), and along the northern Lower Peninsula
shoreline. The Hines emerald dragonfly is thought to
be restricted to wetland habitats characterized by thin
soils over dolomite bedrock with marshes, seeps, and
sedge meadows (U.S. Fish and Wildlife Service 1999).
Birds
Bird counts using the point count method were
conducted using standard methodology as outlined by
Ralph et al. (1993, 1995). All birds heard or seen
within a 50-meter radius were tallied for 5 minutes
during spring migration (May) and for 10 minutes
during the breeding season (June). Birds heard or
observed outside the 50-meter radius circle were also
noted. Point counts were conducted at 41stations (or
sites) on Drummond Island (Figure 2). Each station
was visited once in May and once in June. Spring bird
counts were conducted between sunrise and 1200 hr on
16-20 May 2001. Breeding bird counts were conducted
between sunrise and 1100 hr on 14-18 June 2001. All
counts were conducted when there was no precipitation
and little or no wind. Surveys began immediately after
the observer arrived at the location. Point counts were
conducted at least 250m apart to ensure that each bird
was counted only once. Standard field forms for point
counts were used. Ten major habitat types were
sampled for migratory and breeding birds. They
included:
· Four forest habitats: mixed coniferous, white
cedar-dominated areas, northern hardwoods, and
aspen/birch sites;
· Four wetland habitats: sedge meadow adjacent to
lakes or rivers, northern fen adjacent to lakes,
Great Lakes Marsh, and scrub/shrub wetland;
· Two open habitats: alvar and old field;
· Shoreline survey sites were either classified as
bedrock, cobble and/or sandy shoreline.
Overall mean bird abundance was calculated by
dividing the total number of birds observed within 50m
at each of the point count stations by the total number
of stations censused (forty-one). Species richness was
calculated by dividing the total number of species
recorded at each of the point count stations by the total
number of stations censused. These means were
calculated with a 95% confidence level. Dominant
species were identified by calculating the total number
of observations for each species at each of the point
count stations by the total number of stations censused.
An informal assessment of habitat use by migra-
tory and breeding birds was conducted. Habitats were
categorized as shoreline, interior, or inland water sites.
Shoreline sites were those points located between the
shoreline and 0.4km (0.25mi) inland. Interior sites
were greater than 0.4km (0.25mi) from the shoreline.
Inland water sites were greater than 0.4km (0.25mi)
from the shoreline. Mean bird abundance and species
richness was calculated for shoreline, interior, and
inland water sites. Of the 41 point count stations on
Drummond Island, 15 were designated as shoreline, 16
were designated interior, and 10 were designated inland
water sites.
Surveys for wetland birds were conducted in
accessible and appropriate habitats. Taped American
Great Lakes Islands 2001 Page-5
Figure 2. Bird and insect sampling sites on Drummond Island.
Great Lakes Islands 2001 Page-6
bittern (Botaurus lentinginosus) calls were broadcast
with a predator caller at a number of wetlands on
Drummond Island. The state threatened common loon
(Gavia immer) is known to occur on Drummond
Island. Observations with binoculars or a spotting
scope were made at inland lakes on these islands to
determine if loons were feeding or nesting at these
locations.
Insects
Meander surveys were conducted for the Hines
emerald dragonfly by walking through suitable habitat
during the appropriate time of year on Drummond
Island on 17-19 July 2001around Marl Lake, Pigeon
Cove Wildlife Flooding, Pigeon Cove Creek, and
Isaacson Lake (Figure 2). Adult dragonflies in the
genus Somatochlora were caught with an aerial net,
identified, and then released. In addition, close-
focusing binoculars were used to observe dragonflies
that were perched higher up in the trees and those that
were flying over the open water.
Results of Animal Surveys
Birds
One hundred thirteen bird species were recorded
during both spring migration and the summer breeding
season in 2001 on Drummond Island (Table 1). Ninety-
four species were recorded separately during spring
migration and 97 species during the breeding season.
Forty-four species are classified as long distance
migrants (birds that winter south and breed north of the
Tropic of Cancer). Fifty species are classified as short
distance migrants (birds that winter in the southern
U.S. and northern Mexico and breed in the U.S. and
Canada). Nineteen species are considered residents
(birds that winter and breed in the same region).
Species data gathered in 2000 is provided as a between
year comparison.
Mean bird abundance during the 2001 spring
migration was calculated as 8.3 birds per station (Table
2). Species richness during spring migration was 6.4
species per station. The three most common bird
species encountered during migration point counts
were the black-throated green warbler (Dendroica
virens), Nashville warbler (Vermivora ruficapilla), and
ovenbird (Seirus aurocapillus).
Mean bird abundance during the summer breeding
season in 2001 was calculated as 9.9 birds per station
(Table 3). Species richness during the summer breeding
season was 7.3 species per station. The black-throated
green warbler, American redstart (Setophaga ruticilla),
and red-eyed vireo (Vireo olivaceus) were the most
common species encountered during breeding season
point counts.
A qualitative assessment of habitat use by migra-
tory and breeding birds on Drummond Island was
conducted. The 41 bird survey stations were divided
into one of three categories: shoreline site, inland site,
or inland water site. Of the 41 survey stations, 17 were
classified as inland sites, 9 were classified as inland
water sites, and 15 were classified as shoreline sites.
Shoreline sites are defined as being within 0.4 km
(0.25 mi) of the high water mark. Inland and inland
water sites are greater than 0.4 km (0.25 mi) from the
high water mark.
There was little difference between mean bird
abundance at inland (8.4 birds), shoreline (8.3 birds)
and inland water (8.1 birds) sites during migration
(Figure 3). During the breeding season, bird abundance
was highest at inland water (10.4 birds) and shoreline
sites (10.3 birds), followed by inland sites (9.3 birds).
Bird abundance during the breeding season had a
similar trend in 2000.
Species richness during migration was highest at
shoreline sites (6.8 species), followed close by inland
sites (6.4 species) and finally, inland water sites (5.7
species) (Figure 4). Species richness during the breed-
ing season was highest at shoreline sites (7.7 species),
followed by inland water (7.4 species) and finally
inland sites (6.9 sites). Most of these results differ from
last years findings (2000), when shoreline sites were
not registering as high as inland and inland water sites.
A pattern of use at shoreline, inland and inland water
sites is not evident, especially during migration. This
may be due to the short time period in which the bird
surveys took place. The surveys were designed to
provide a snapshot picture of bird use on the island,
which they did provide. A long term study of migrating
and breeding bird use on the island may elucidate a
more significant trend than what was undertaken here.
Bird survey results from the individual 41 point
count stations were compiled and an analysis over the
two-year study period was conducted. Individual
stations with nine or more birds (bird abundance)
recorded during migration and/or the breeding seasons
were identified. Individual stations with seven or more
Great Lakes Islands 2001 Page-7
Table 1. Bird Species Recorded During Migration (M) and Breeding Seasons (B) in 2000 and
2001 on Drummond Island. State listed and special concern species are in bold type.
Co
mm
o
n
N
am
e
Sc
i
e
ntifi
c
N
am
e
2
000
2
00
1
Lon
g
Distance Mi
g
rants:
Pied-billed Grebe
P
odil
y
mbus
p
odice
p
s M, B M, B
Blue-win
g
ed Teal Anas discors BM
American Wid
eon Anas americana B
Os
p
re
y
(
T
)
Pandion haliaetus
M, B M, B
Broad-win
g
ed Haw
k
B
uteo
p
lat
yp
terus M, B M, B
Merlin
(
T
)
Falco columbarius
BB
Solitar
y
Sand
p
i
p
e
r
Trin
g
a
s
olitaria M
S
p
otted Sand
p
i
p
e
r
Actitis macularia M, B M, B
Common Sni
p
e Gallina
g
o
g
allina
g
o M, B
Cas
p
ian Tern
(
T
)
Sterna cas
p
ia
BB
Common Tern
(
T
)
Sterna hirundo
B M, B
Black Tern
(
SC
)
Chlidonias ni
g
e
r
B M, B
Black-billed Cuckoo Cocc
y
zus er
y
thro
p
thalmus M
Chimne
y
Swift Chaetura
p
ela
g
ica B
Rub
y
-throated Hummin
g
bir
d
Archilochus colubris M M, B
Eastern Wood-
p
ewee Conto
p
us virens B M, B
Alder Fl
y
catche
r
E
m
p
idonax alnorum BB
Willow Fl
y
catche
r
E
m
p
idonax traillii B
Least Fl
y
catche
r
E
m
p
iodonax minimus M, B M, B
Great Crested Fl
y
catche
r
M
y
iarchus crinitus M.B M, B
Eastern Kin
g
bir
d
T
y
rannus t
y
rannus M, B M, B
Pur
p
le Martin
P
ro
g
ne
s
ubis M, B M, B
Bank Swallow
R
i
p
aria ri
p
aria B
Cliff Swallow
H
irundo
py
rrhonata M.B
Barn Swallow
H
irundo rustica B
Veer
y
Catharus
f
uscescens M, B M, B
Swainson s Thrush Catharus ustulatus M, B M, B
Wood Thrush
Hy
locichla mustelina B M, B
Gra
y
Catbir
d
D
umatella carolinensis B M, B
Blue-headed Vireo Vireo
s
olitarius M, B M, B
Warblin
g
Vireo Vireo
g
ilvus B
Red-e
y
ed Vireo Vireo olivaceus M, B M, B
Tennessee Warble
r
Vermivora
p
ere
g
rina M
Nashville Warble
r
Vermivora ru
f
ica
p
illa M, B M, B
Northern Parula
P
arula americana B M, B
Yellow Warble
r
D
endroica
p
etechia M, B M, B
Chestnut-sided Warble
r
D
endroica
p
ens
y
lvanica M M, B
Ma
g
nolia Warble
r
D
endroica ma
g
nolia M, B M, B
Black-throated Green Warble
r
D
endroica virens M, B M, B
Blackburnian Warble
r
D
endroica
f
usca MB
Palm Warble
r
D
endroica
p
almarum M
Black-and-white Warble
r
Mniotilta varia M, B M, B
American Redstart Seto
p
ha
g
a ruticilla M, B M, B
Ovenbir
d
Seiurus auroca
p
illus M, B M, B
Northern Waterthrush Seiurus noveboracensis M M, B
Mournin
g
Warble
r
O
p
orornis
p
hiladel
p
hia BB
Common Yellowthroat Geoth
y
l
p
is trichas M, B M, B
Canada Warble
r
Wilsonia canadensis B
Great Lakes Islands 2001 Page-8
Common Name Scientific Name 2000 2001
Scarlet Tana
g
e
r
P
iran
g
a olivacea MM
Rose-breasted Grosbea
k
P
heuticus ludovicianus M, B M, B
Indi
g
o Buntin
g
P
asserina c
y
anea BB
Chi
pp
in
g
S
p
arrow S
p
izella
p
asserina M, B M, B
Baltimore Oriole
I
cterus
g
albula M
Short distance mi
g
rants:
Common Loon
(
T
)
Gavia imme
r
M, B M, B
Double-crested Cormorant
P
halacrocorax auritus M, B M, B
American Bittern
(
SC
)
Botaurus lentin
g
inosus
M, B M, B
Great Blue Heron Ardea herodias M, B M, B
Canada Goose
B
ranta canadensis M, B M, B
Wood Duc
k
Aix
sp
onsa M, B B
Green-win
g
ed Teal Anas crecca M
American Black Duc
k
Anas rubri
p
es B
Northern Pintail Anas acuta B
Gadwall Anas
s
tre
p
era B
Hooded Mer
g
anse
r
L
o
p
hod
y
tes cucullatus M
Common Mer
g
anse
r
Mer
g
us mer
g
anse
r
M, B M, B
Red-breasted Mer
g
anse
r
Mer
g
us
s
errato
r
M M, B
Turke
y
Vulture Cathartes aura M, B M
Northern Harrier
(
SC
)
Circus c
y
aneus
BB
Shar
p
-shinned Haw
k
Acci
p
iter
s
triatus M
Red-shouldered Hawk
(
T
)
Buteo lineatus
B
Red-tailed Haw
k
B
uteo
j
amaicensis M
American Kestrel
F
alco
sp
arverius BM
Sandhill Crane Grus canadensis M, B M, B
Killdee
r
Charadrius voci
f
erus M, B M, B
American Woodcoc
k
Scolo
p
ax mino
r
M
Mournin
g
Dove
Z
enaida macroura M, B M, B
Belted Kin
g
fishe
r
Cer
y
le alc
y
on M, B M, B
Yellow-bellied Sa
p
sucke
r
S
p
h
y
ra
p
icus varius M, B M, B
Northern Flicke
r
Cola
p
tes auruatus M, B M, B
Eastern Phoebe Sa
y
ornis
p
hoebe M, B M
Tree Swallow Tach
y
cineta bicolo
r
M, B M, B
Brown Cree
p
e
r
Certhia americana B
House Wren Tro
g
lod
y
tes aedon M, B
Winter Wren Tro
g
lod
y
tes tro
g
lod
y
tes M, B M, B
Sed
g
e Wren Cistothorus
p
latensis B
Golden-crowned Kin
g
let
R
e
g
ulus
s
atra
p
a M, B M, B
Rub
y
-crowned Kin
g
let
R
e
g
ulus calendula MB
Eastern Bluebir
d
Sialia
s
ialis M, B M, B
Hermit Thrush Catharus
g
uttatus M, B M, B
American Robin Turdus mi
g
ratorius M, B M, B
Northern Mockin
g
bir
d
Mimus
p
ol
yg
lottos M
Brown Thrashe
r
Toxostoma ru
f
um M, B M, B
American Pi
p
it Anthus rubescens M
M
y
rtle Warble
r
D
endroica coronata M, B M, B
Pine Warble
r
D
endroica
p
inus M, B B
Eastern Towhee
P
i
p
ilo er
y
thro
p
hthalmus B
Field S
p
arrow S
p
izella
p
usilla B
Ves
p
er S
p
arrow
P
ooecetes
g
rammineus MB
Savannah S
p
arrow
P
asserculus
s
andwichensis M, B M, B
Great Lakes Islands 2001 Page-9
Common Name Scientific Name 2000 2001
Le Conte s S
p
arrow Ammodramus leconteii M
,
BM
Son
g
S
p
arrow Melos
p
iza melodia M, B M, B
Swam
p
S
p
arrow Melos
p
iza
g
eor
g
iana M, B M, B
White-throated S
p
arrow
Z
onotrichia albicollis M, B M, B
White-crowned S
p
arrow
Z
onotrichia leuco
p
hr
y
s MM
Red-win
g
ed Blackbir
d
Abelaius
p
hoeniceus M, B M, B
Eastern Meadowlar
k
Sturnella ma
g
na M, B B
Common Grackle
Q
uiscalus
q
uiscula M, B M, B
Brown-headed Cowbir
d
Moluthrus ate
r
M, B M, B
Pine Siskin Cardeulis
p
inus MM
American Goldfinch Carduelis tristis M, B M, B
Residents:
Mallar
d
Anas
p
lat
y
rh
y
nchos M, B M, B
Common Goldene
y
e
B
uce
p
ahla clan
g
ula BB
Bald Ea
g
le
(
T
)
Haliaeetus leucoce
p
halus
M, B M, B
Rin
g
-necked Pheasant
P
hasianus colchicus M, B M, B
Ruffed Grouse
B
onasa umbellus M, B M, B
Shar
p
-tailed Grouse T
y
m
p
anuchus
p
hasianellus M
Rin
g
-billed Gull
L
arus delawarensis M, B M, B
Herrin
g
Gull
L
arus ar
g
entatus M, B M, B
Rock Dove Columba livia B
Barred Owl Strix varia BB
Down
y
Wood
p
ecke
r
P
icoides
p
ubescens M M, B
Hair
y
Wood
p
ecke
r
P
icoides villosus M, B M, B
Pileated Wood
p
ecke
r
D
r
y
oco
p
us
p
ileatus M, B M, B
Blue Ja
y
C
y
anocitta cristata M, B M, B
American Crow Corvus brach
y
rh
y
nchos M, B M, B
Common Raven Corvus corax M, B M, B
Black-ca
pp
ed Chickadee
P
oecile atrica
pp
ilus M, B M, B
Red-breasted Nuthatch Sitta canadensis M M, B
Euro
p
ean Starlin
g
Sturnus vul
g
aris M, B M, B
Cedar Waxwin
g
B
omb
y
cilla cedrorum B M, B
Pur
p
le Finch Car
p
odacus
p
ur
p
ureus M, B M
Evenin
g
Grosbea
k
Coccothraustes ves
p
ertinus M
TOTAL
M=MIGRATION 90 94
B=BREEDING 99 97
Total # s
p
ecies recorde
d
118 113
(
T
)
= State Threatene
d
67
(
SC
)
= State S
p
ecial Concern 3 3
Great Lakes Islands 2001 Page-10
Table 2. Mean bird abundance, species richness and dominant species recorded during spring
migration in Year 2001 and 2000 on Drummond Island. Calculations include a confidence interval
of 95%.
Year 2001 Year 2000
Mean Bird Abundance
(Mean No. birds per point
count station)
8.3 ± 1.1 5.0 ± 0.9
Mean Species Richness
(Mean No. species per point
count station)
6.4 ± 0.9 4.0 ± 0.7
Dominant Species
(In order of abundance)
Black-throated Green Warbler
Nashville Warbler
Ovenbird
Myrtle Warbler
Black-capped Chickadee
Black-throated Green Warbler
American Redstart
Nashville Warbler
Black-and-white Warbler
Ovenbird
Table 3. Mean bird abundance, species richness and dominant species recorded during summer
breeding season in Year 2001 and 2000 on Drummond Island. Calculations include a confidence
interval of 95%.
Year 2001 Year 2000
Mean Bird Abundance
(Mean No. birds per point
count station)
9.9 ± 1.1 6.6 ± 1.1
Mean Species Richness
(Mean No. species per point
count station)
7.3 ± 0.7 4.5 ± 0.6
Dominant Species
(In order of abundance)
Black-throated Green Warbler
American Redstart
Red-eyed Vireo
White-throated Sparrow
American Robin
Cedar Waxwing
American Redstart
White-throated Sparrow
Black-throated Green Warbler
Song Sparrow
Great Lakes Islands 2001 Page-11
Figure 3. Distribution of birds on Drummond Island in 2001.
Mean Bird Abundance
8.4
8.1
8.3
10.4
10.3
9.3
0
2
4
6
8
10
12
Inland Inland Water Shoreline
Number of Birds
Migration
Breeding
Season
Species Richness
5.7
6.8
7.7
6.4
6.9
7.4
0
1
2
3
4
5
6
7
8
9
Inland Inland Water Shoreline
Number of Species
Migration
Breeding
Sesaon
Figure 4. Distribution of bird species on Drummond Island in 2001.
Great Lakes Islands 2001 Page-12
species (species richness) recorded during migration
and/or the breeding seasons were identified. Results
from 2000 and 2001 were overlayed. Sites on
Drummond Island that had high bird use over the two-
year study period are shown in Figure 2. The following
five sites are identified as having high bird numbers
and/or species numbers during migration (shown in red
bird icon):
Ø Warners Cove
Ø Big Shoal Cove
Ø Johnswood
Ø Marl Lake
Ø Potagannissing Bay Campground
The following six sites were identified as having high
bird numbers and/or species numbers during the
breeding season (shown with a heavy blue circle):
Ø Big Shoal Cove
Ø Johnswood
Ø Sheep Ranch Road Wetland
Ø Marl Lake
Ø Potagannissing Bay Campground
Ø Meadow
Three of the seven sites identified in the figure are
along the shoreline, two are inland sites and two are
inland water sites. The habitat varies at each site, with
white cedar being dominant at Big Shoal Cove, aspen/
birch at Johnswood, scrub/shrub wetland at Sheep
Ranch Road wetland, mixed coniferous forest at
Warners Cove, sedge meadow at Marl Lake, old field
and Great Lakes Marsh at Campground, and old field
at Meadow. Four of the seven sites were identified as
having high bird use during both the migration and
breeding season. Those four sites are: Big Shoal Cove,
Johnswood, Marl Lake and the Campground. The
variety of habitats, location (shoreline, inland, inland
water) use and identification of important bird sites
during both seasons supports the hypothesis that
Drummond Island as a whole provides critical stopover
and breeding habitat required by birds.
State threatened and special concern birds were
observed on Drummond Island in 2001 (Table 4).
Some noteworthy observations include:
v a new common tern (Sterna hirundo) nesting
colony on a small shoal near Rogg Island
v an update to a previously known common tern
nesting colony on Harbor Island Reef
v a new American bittern (Botaurus lentinginosus)
nesting occurrence at Pigeon Cove
v a new American bittern nesting occurrence at Marl
Lake
v a new northern harrier (Circus cyaneus) nesting
occurrence at Pigeon Cove
Other rare species that were observed but were not
confirmed nesting include common loons (Gavia
immer), red-shouldered hawk (Buteo lineatus), bald
eagles (Haliaeetus leucocephalus), osprey (Pandion
haliaetus), merlin (Falco columbarius), and black terns
(Chlidonias niger). The two years of bird surveys have
provided eight new element occurrences and three
updates to known occurrences.
Table 4. Rare bird nesting occurrences documented during 2001 and 2000 surveys of Drummond
Island. Occurrences documented during 2000 are highlighted in blue.
Site name Known occurrences-
relocated and updated
New occurrences documented
Shoal near Rogg Island Common Tern (T)
Harbor Island Reef Common Tern (T)
Pigeon Cove American Bittern (SC)
Marl Lake American Bittern (SC)
Pigeon Cove Northern Harrier (SC)
Scott Bay Black Tern (SC)
Snively Road Merlin (T)
Potagannissing River Wildlife
Flooding
American Bittern (SC)
Bruce Point Marsh American Bittern (SC)
Dickenson Lake American Bittern (SC)
Rabbit Bay Osprey (T)
Great Lakes Islands 2001 Page-13
Insects
Surveys conducted for the Hines emerald dragon-
fly on Drummond Island failed to locate any new
populations. However, another emerald species was
located at Pigeon Cove Creek. A total of four brush-
tipped emerald dragonflies (Somatochlora walshii)
were aerial net captured and released. Habitat appar-
ently exists for emeralds at this site. Other sites
surveyed this year may also reveal emerald occur-
rences. Further surveys are needed to determine the
presence of Hines emerald dragonflies on Drummond
Island.
Discussion of Animal Surveys
Birds
The diversity and abundance of birds documented
on Drummond Island is impressive and illustrates the
important role that islands play in providing critical
stopover and breeding habitat for birds. The previous
bird list for Drummond Island was compiled in 1993
from observations made from 1981 to 1993 which
focused on The Nature Conservancys Maxton Plains
Preserve (Stephenson 1993). Observations were made
during the spring, summer and early autumn months
and most observations were made incidental to alvar
grassland research activities occurring on the preserve.
Over the 13 year time span 101 species were consid-
ered breeding and 35 species were migratory and not
known as breeding populations. Surveys conducted in
2000 and 2001 on Drummond Island document a high
of 99 birds during the breeding season (2000) and 94
species during migration (2001).
Differences in bird numbers among islands. Bird
surveys have been conducted two years consecutively
on Beaver Island, Garden Island, Bois Blanc Island and
Drummond Island, from 1998 to 2001. With the
exception of Beaver and Garden Island having only a
migrating bird survey in 1998, the first year of our
survey efforts, all other islands had both migratory and
breeding bird surveys conducted. Drummond had the
highest total number of species recorded during both
migration and the breeding season, with 118 species in
2000 and 113 species in 2001. Beaver Island is next
with 108 species in 1999, followed by Bois Blanc with
98 species in 1999 and Garden Island with 83 species
in 1999 (Table 5). It is difficult to draw significant
conclusions based on these numbers with only two
years of data. Although, some factors to consider
include: size of island (Drummond is the largest of the
four), distance from mainland (Drummond is closest to
mainland), habitats surveyed (Drummond had the
widest variety), weather patterns during surveys (varied
between years) and timing surveys to migration (varies
year to year).
Mean species richness during migration was
basically equal among three of the islands. Drummond
Island had a mean average of 6.4 (± 0.9) species per
survey site in 2001; Beaver Island averaged 6.4 (± 0.9)
species in 1999; and Bois Blanc averaged 6.3 (± 0.9)
species in 1999. The near equality of species richness
on these three islands may indicate that they are equally
important to species as stop over sites during migra-
tion. A long term bird study on these islands may
support or reveal other important trends.
Bois Blanc Island had the highest mean number of
species during the breeding season in 1999, calculated
as 8.1 1.1) species per survey site. Following Bois
Blanc Island in this category are three lower, but
similar results for Drummond, Beaver and Garden
Islands. Drummond Island averaged 7.3 species per
survey site in 2001; Beaver Island had 7.2 species per
site in 1999 and Garden Island, 7.0 species per site in
1999. It is interesting to note that Bois Blanc is the
leader in species richness during the breeding season
even though Drummond Island had the highest number
of species recorded during the breeding season overall
(99 species on Drummond compared to the Bois Blanc
high of 74 species). As noted in the 2000 Island Report,
Bois Blancs high bird means may be explained by
several factors. The small size of Bois Blanc Island
compared to Drummond Island (approx. 24,000 acres
versus 83,000 acres) may concentrate species. Bois
Blanc is located just east of the Straits of Mackinac,
which is the narrowest waterway between the Lower
Peninsula and Upper Peninsula. The relatively large
size of Bois Blanc Island in the Straits area may
provide an advantageous stopping point as birds funnel
up the Lower Peninsula shoreline and cross the water
towards the Upper Peninsula. Finally, nearly half of
Bois Blanc Island lies within state ownership. The lack
of development on Bois Blanc may provide many
species with a place to breed, undisturbed. A large
portion of Drummond Island also lies within state
ownership and is therefore undeveloped. Much of this
area was not surveyed for birds due to its inaccessibil-
Great Lakes Islands 2001 Page-14
Table 5. Number of species recorded during the migration and breeding season on four islands. Total number of
species recorded in both seasons is highlighted in blue.
Year Drummond Island Bois Blanc Island Beaver Island Garden Island
1998 52 species (May) 33 species (May)
1999
78 species (May)
74 species (June)
98 species (May & June)
76 species (May)
89 species (June)
108 species (May & June)
63 species (May)
58 species (June)
83 species (May & June)
2000
90 species (May)
99 species (June)
118 species (May & June)
77 species (May)
68 species (June)
87 species (May & June)
2001
94 species (May)
97 species (June)
113 species (May & June)
Great Lakes Islands 2001 Page-15
ity. Future bird surveys should focus on this largely
undisturbed area.
Distribution of birds. Factors that likely contribute
to the distribution of migratory birds using islands as
stopover sites include: weather conditions, human use
patterns, abundance of food items, predation pressure,
and the composition, structure, and successional stage
of the vegetation. In their 1993 research (unpubl.)
Ewert and Hamas note that spring migrants often
arrive in Michigan before the leaves on trees have fully
emerged. Consequently, lepidopteran larvae, which are
a primary source of food for migrants in areas south of
Michigan, are not yet abundant. Migratory birds
instead take advantage of the swarms of emerging
aquatic insects, such as chironomid midges (Family:
Chironomidae), that are concentrated along Great
Lakes beaches, and along inland streams, lakes, and
wetlands. Spiders are also proving to be important food
for migrating birds (Smith, pers. comm.). Trees and
shrubs in close proximity to the shoreline and interior
riparian and wetland areas provide an excellent forag-
ing substrate, along with shelter, for migratory birds
feeding on these insects.
Based on two years of data on Drummond Island
there does not seem to be an association of migratory
birds with inland water or shoreline sites as Ewert and
Hamas (1993) found. This may be due to the lack of
long-term data on Drummond Island needed to make
such conclusions and/or possibly the difference in
shoreline substrate at study sites. The majority of the
Drummond Island shoreline is characterized as bedrock
substrate, with a few areas of cobble and sand. The
northern Lake Huron shoreline west of Drummond
Island is characterized by cobble shoreline, as is the
Bois Blanc Island shoreline, where associations
between migrating birds, midges, and cobble shoreline
have been documented. Midges may be less available
where substrate is sand or bedrock, making birds
search out other locations for protein sources.
Another explanation for the lack of association of
migratory birds to shoreline or inland water sites on
Drummond Island may be the habitats surveyed at
shoreline, inland and inland water locations. Habitats
were not controlled for in this study. Some habitats are
represented within each category while others are
unique to the category. For instance, shoreline habitats
include cedar dominated, mixed conifer forests, Great
Lakes Marsh, old field, northern fen, aspen/birch
forest. Inland water sites included: sedge meadow,
scrub/shrub wetland, aspen/birch forest, northern fen,
mixed conifer forest, and cedar dominated forest.
Inland sites included beech/maple forests, cedar
dominated forests, mixed conifer forests, alvar grass-
land, old field, and aspen/birch forest. Each of these
habitats has a particular suite of birds associated with
them and it is not clear whether the distribution of birds
is due to the habitat type or the proximity to shoreline.
Alvar habitat may be providing a food source that
has not yet been identified. At this time we are uncer-
tain of the role alvar habitat may play in providing
early food sources to migrating birds. Closer evaluation
of birds in alvar habitat may provide answers to what
this food source may be.
This informal analysis of the abundance and
distribution of migrating and breeding bird species on
Drummond Island is interesting and provides a good
foundation for future work. It is important to under-
stand that these data are not the result of a highly
controlled research study and conclusions should not be
casually inferred. Rather, these bird counts provide a
snapshot of bird use on Dummond Island and
suggest its relative importance in providing habitat to
migrating and breeding birds.
Important bird areas. The Great Lakes and
Michigan offices of The Nature Conservancy initiated
an ecoregion planning program for birds (Ewert 1999).
Information from field ornithologists, including
representatives of private and public organizations that
work in the Great Lakes region, contributed to the
identification of primary focus bird species, important
breeding sites for primary focus species and important
stopover and wintering sites in the Great Lakes
ecoregion. Avian species of primary focus have a
global Partners in Flight (PIF) score of 20 or more, or a
Nature Conservancy global rank of G1-G4. Species
with small ranges, low abundance, fluctuating popula-
tions, and long-term, relatively large population
declines are those of highest priority. Where identifi-
able, the working group also noted 10 sites with 25 or
more breeding pairs for each primary focus species,
and important stopover and wintering sites for
landbirds, raptors, shorebirds, and waterbirds in the
Great Lakes ecoregion. Scotts Marsh on the northwest
shore of Drummond Island has been identified as an
important stop over site for waterfowl, meeting the
criterion of 10,000 birds/site/migration season. Besides
being an important stop over site for waterfowl, Scotts
Marsh has been identified as one of 10 sites in the
Great Lakes ecoregion that provides breeding habitat
for two primary focus bird species. The American
bittern and LeContes sparrow (Ammodramus
leconteii) were identified as primary focus species
having greater than 25 breeding pairs consistently
using Scotts Marsh during the breeding season. Our
point count surveys on Drummond Island did reveal
LeContes sparrows using Scotts Marsh, but we did
not document American bittern occupying the site. It
should be noted that Scotts Marsh is very large, wet
Great Lakes Islands 2001 Page-16
and vast. We conducted our point count surveys from
the gravel road and did not venture off the road. We
could have easily missed the unusual and often muffled
call of the American bittern at this site. Further survey
work focusing specifically on wetland birds on
Drummond Island would likely reveal several new
occurrences for rare and declining species. Many of
the large wetland complexes on Drummond Island are
difficult to access. Adequate time, equipment and
resources would be required to complete an adequate
survey of these areas.
Declining bird species. There are two migratory
bird species that were recorded during bird surveys that
are worth noting, since there is evidence that they are
declining in all or part of their range. The wood thrush
(Hylocichla mustelina, see photo plate) was recorded
during migrating and breeding bird surveys on
Drummond Island in 2001 and during breeding surveys
in 2000. This species is one of 105 species currently on
the National Audubon Society, WatchList (Muehter
1998). The WatchList identifies North American bird
species that are faced with population declines, limited
geographic range, and/or threats such as habitat loss on
their breeding and wintering grounds. The WatchList is
compiled by Partners in Flight, a coalition of state,
federal, and private sector conservationists working
together to protect the birds of the western hemisphere.
The wood thrush has a Conservation Priority Score of
20 (Partners In Flight Bird Prioritization Technical
Committee 1998). Scores range between 18 (moderate
priority) and 30 (the highest priority). Criteria used to
score species include: relative abundance, breeding
distribution, winter distribution, threats to breeding
range, threats to non-breeding range, and population
trends. The wood thrush generally prefers dense mesic
woodlands with small streams and springs associated
with a thick understory. This species has undergone a
decline in the Midwest due to forest thinning and
fragmentation, loss of wetlands on the wintering
grounds and heavy cowbird parasitism in some areas
(Pinkowski 1991). Drummond Island appears to
provide suitable habitat for the wood thrush and its
forests should continue to support breeding pairs, as
long as they are managed to minimize fragmentation
and to enhance forest maturity.
The northern parula, observed during both migra-
tion and the breeding season on Drummond Island in
2001 and during the breeding season in 2000, is
another species worth noting. Although this species is
not on the WatchList, it is considered a habitat special-
ist on its breeding grounds. In Michigan, this warbler is
found primarily in northern coniferous forest, particu-
larly areas with hanging Usnea, a stringy epiphytic
lichen appropriately named old mans beard. This
lichen is a crucial component for supporting the
warblers pendant nest, and thus widespread loss of
Usnea is a suspected cause for substantial population
declines of parulas in portions of their breeding range.
Humid areas in mature eastern hemlock or balsam fir
forests are optimal habitats for Usnea and the northern
parula. Northern hardwood forest, northern white cedar
swamps, mesic mixed forests, and wet coniferous areas
with black spruce and tamarack are also used by the
northern parula (Evers 1991). Over the two year study
northern parulas were noted at the following locations:
Barbed Point Peninsula (cedar-dominated forest),
Cream City Point (mixed coniferous forest), Fossil
Formation (mixed coniferous forest) and Helen Lake
(mixed coniferous forest).
Observations of rare birds. A new colony of state
threatened nesting common terns (Sterna hirundo) was
observed on a small shoal near Rogg Island, just off
shore from Yacht Haven Marina in June, 2001. Boat
traffic in and out of the marina passes close to the
shoal. The terns seem to have habituated to some level
of disturbance at this site. Future success will likely
depend upon water levels and the level of disturbance.
An update to a previously known common tern nesting
colony on Harbor Island Reef was also documented.
The shoal was dominated by nesting ring-billed gulls
(Larus delawarensis), but the northern 1/3 of the shoal
was occupied by nesting common terns. Future success
at this site will depend upon ring-billed gull numbers
and water levels.
The discovery of two new American bittern (spe-
cies of special concern) records on Drummond Island
in 2001 brings the total of new occurrences for Ameri-
can bitterns to five, over the two year study period. The
five sites are as follows:
Ø Pigeon Cove Wildlife Flooding
Ø Marl Lake
Ø Dickenson Lake
Ø Potagannissing River Wildlife Flooding
Ø Bruce Point marsh
The American bittern inhabits marshes and the
edges of lakes and ponds where cattails, sedges and
bulrushes are plentiful. Habitat appears to be abundant
along many of the inland lake edges and shoreline
marshes that were surveyed. It is likely that this species
occurs at additional locations on the island. Preserving
the marshes and protecting them from human alteration
and disturbance will be important if this species is to
remain a part of the islands fauna.
One adult male northern harrier (species of special
concern) was observed hunting over the Pigeon Cove
Wildlife Flooding, capturing prey, and delivering prey
items on four instances to same spot in the flooding
complex. The male flew below the line of site (ground
Great Lakes Islands 2001 Page-17
level) and back up without the prey. Northern harriers
prefer open landscapes such as meadows, inland and
coastal marshes, cultivated and uncultivated fields, and
prairies. Pigeon Cove Wildlife Flooding could be
classified as an inland marsh. Nests are constructed on
the ground in association with shrubs. The female
northern harrier was assumed to be feeding young on
the nest, although visual confirmation of a nest was not
undertaken due to the risk of nest abandonment and
increasead predation.
Insects
Potential habitat for the federally endangered
Hines emerald dragonfly was surveyed at four loca-
tions on Drummond Island. The marly, northern fen
habitat along the southern and eastern margin of Marl
Lake appeared suitable habitat for the dragonfly based
on its presence in similar habitat in the Upper Penin-
sula of Michigan. Other areas of potential habitat
included the Pigeon Cove Wildlife Flooding, the
margins of Pigeon Cove Creek, and Isaacson Lake.
Brush-tipped emerald dragonflies were found at Pigeon
Cove Creek indicating at least suitable habitat for
emerald species on Drummond Island. The summer of
2001 was a very dry year on Drummond Island and
subsequently much of the habitat at these sites was less
than optimal. For example, Pigeon Cove Wildlife
Flooding and Isaacson Lake were almost dry during the
Hines emerald dragonfly survey period. Additional
surveys should be conducted in the future to determine
if the Hines emerald dragonfly occurs on the island.
Given the difficulty in surveying invertebrates, espe-
cially for such high-flying and deft aerialists as dragon-
flies, several days should be spent on the island at these
sites. However, no future surveys are targeted for 2002
in these areas; however, inventory of this group will
continue in likely habitats delineated on Bois Blanc
Island and in the Les Cheneaux Islands, all of which
are targeted for survey during the 2002 field season.
Methods for Plant Surveys
Prior to field surveys on Drummond Island, the
statewide Biological and Conservation Database
(BCD) was examined for previously known element
occurrences. MNFI staff ecologists were also con-
sulted regarding particular natural features and sites.
Information from recent surveys of the island was
compiled and studied to delineate the areas of highest
merit for inventory based on the relatively limited time
allocated for fieldwork. Unlike island surveys con-
ducted from 1998-2000 (Penskar et al. 1999, 2000,
2001), our inventories were largely directed to interior
sites, focusing on alvar (limestone pavement) and
several rare plant species known to be associated with
this globally rare natural community type. The princi-
pal species sought included prairie dropseed
(Sporobolus heterolepis), flattened spike-rush
(Eleocharis compressa), bulrush sedge (Carex
scirpoidea), Richardsons sedge (Carex richardsonii),
Hills thistle (Cirsium hillii), false pennyroyal
(Trichostema brachiatum), prairie smoke (Geum
triflorum), and Coopers milk-vetch (Astragalus
neglectus), all of which are well documented alvar
rarities.
As in previous island and Great Lakes shoreline
studies (Penskar et al. 2001, Penskar et al. 2000,
Penskar et al. 1999, Penskar et al. 1997, and Penskar et
al. 1993), our high priority targets were Great Lakes
endemic species such as dwarf lake iris (Iris lacustris),
Houghtons goldenrod (Solidago houghtonii), Pitchers
thistle (Cirsium pitcheri), and Michigan monkey-
flower (Mimulus glabratus var. michiganensis), all of
which are federal and state listed. Additional target
taxa included such well-known coastal rarities as
calypso orchid (Calypso bulbosa), English sundew
(Drosera anglica), butterwort (Pinguicula vulgaris),
Alaska orchid (Piperia unalascensis), rams head
orchid (Cypripedium arietinum), and several other
potential species known in this region of the state.
These taxa are strongly associated with shoreline areas,
where they occur in such natural communities as open
dunes, coastal rich conifer swamps, bedrock beaches,
alvar, cedar glades, northern fens, boreal forests, and
wooded dune and swale complexes.
As for all previous island inventories, emphasis
was also placed on delineating notable natural commu-
nity occurrences. This was done both to identify
significant potential rare plant habitats as well as to
conduct a preliminary assessment for high quality
community remnants for subsequent evaluation and
possible transcription by MNFI ecologists. All plant
inventories were conducted in collaboration with the
projects community ecologist, who provided the
primary evaluation of potential natural community
occurrences and also assisted in rare plant surveys.
The specific botanical survey methods, which
essentially consisted of meander searches, closely
follow those used during the previous three years of
island inventories. These have been presented in detail
Great Lakes Islands 2001 Page-18
by Penskar et al. (1999) and thus will not be presented
again here. Because most of the field inventories were
conducted jointly with a staff ecologist, aerial photo
interpretation and site selection were completed in
collaboration and thus not duplicated. Sites were thus
highlighted for field inventory based on their potential
for both natural community and rare plant occurrences.
Results of Plant Surveys
Botanists and ecologists jointly conducted rare
plant and natural community surveys, and therefore the
results of these surveys are combined in Table 6.
Natural community results are discussed more thor-
oughly in the community section below. Nine new rare
plant occurrences were collectively documented from
six sites during our surveys, consisting of four occur-
rences of state special concern Carex richardsonii
(Richardsons sedge), three occurrences of state special
concern Cirsium hillii (Hills thistle), one occurrence of
state special concern Piperia unalascensis (Alaska
orchid), and one occurrence of state special concern
Sporobolus heterolepis (prairie dropseed).
In addition to the discovery of new occurrences, we
identified 18 previously known rare plant occurrences
over a total of seven sites. Significant new status
information was obtained for these species, including
more detailed data on spatial extent, population and
site condition, artificial and natural disturbances, and
potential threats such as off-road-vehicle (ORV) use
and the presence of invasive exotic species.
Discussion of Plant Surveys
The extensive alvars of Drummond Island are well
known, especially those that comprise the Maxton
Plains in the north and along portions of the southern
shore. Although the nine new rare plant occurrences
were all state special concern species, comprising the
lowest category of rarity, their discovery is notable
given the number of previous surveys in these areas.
These occurrences were documented by combining
very intensive surveys with a wide coverage of sites,
and by focusing on specific microhabitats. Our surveys
were also facilitated by previous experience with
certain species and the ability to reliably recognize
them in sterile condition (e.g. vegetative colonies of
Carex richardsonii). Sites were systematically and
comprehensively meander-searched, targeting known
microhabitats, such as upland-wetland transition zones
where certain species are to be expected. Carex
richardsonii, for example, tends to occur along the
periphery of alvar areas in close proximity to Juniperus
communis (ground juniper) colonies, indicating
microsites of somewhat higher microtopographic relief
along the upland edges. These areas were carefully
traversed, resulting in a detailed mapping of the spatial
extent of new occurrences as well as previously docu-
mented rare species occurrences for these sites.
Many of the known occurrences that were updated
were identified during surveys of several discrete alvar
openings in the Maxton Plains and such well known
sites as Huron Bay and Big Shoal Cove on or in close
proximity to the southern coast. An opportunity was
also provided to explore the cliffs and bedrock expo-
sures of the Marblehead Peninsula, a remote portion of
the island difficult to access. The Marblehead cliffs
were examined very briefly during an exploration of
the eastern shoreline via boat in 1999 (Penskar et al.
2000). During the 1999 survey, it was discovered that
the cliff faces observed from Lake Huron were in fact
only a portion of a series of cliff exposures that ex-
tended inland. We thus returned in 2001 to access the
area from an inland route. The series of smaller inland
cliff faces and escarpments were examined more
carefully, and resulted in the discovery of a new
population of Piperia unalascensis (Alaska orchid).
Pterospora andromedea (pinedrops), which was
previously documented in this area, was observed in
flower in a small colony well inland from the shore,
and it is thus now known that it is not as local as
observed originally. Unfortunately, no GPS (geo-
graphic positioning system) equipment was available
for this survey, and thus our specific coverage of this
site is poorly known. The cliffs were inventoried as
well as possible, yet it remains evident that this com-
plex and remote site requires additional inventory and
characterization.
Great Lakes Islands 2001 Page-19
Table 6. Rare plant and natural community sites inventoried during 2001 surveys of Drummond
Island (Chippewa County).
Site name Known occurrences relocated
and updated
New occurrences documented
Marblehead Peninsula Dry non-acid cliff Piperia unalascensis
Asplenium ruta-muraria
Pellaea atropurpurea
Pterospora andromeda
Maxton Plains East (Site A) Alvar Carex richardsonii
Sporobolus heterolepis Cirsium hillii
Eleocharis compressa
Maxton Plains East (Site B) Alvar Carex richardsonii
Sporobolus heterolepis Cirsium hillii
Eleocharis compressa
Maxton Plains Middle (Site C) Alvar Cirsium hillii
Carex richardsonii
Carex scirpoidea
Eleocharis compressa
Sporobolus heterolepis
The Rock North Carex richardsonii
Sporobolus heterolepis
Huron Bay Road Alvar Carex richardsonii
Cirsium hillii
Big Shoal Cove Carex richardsonii Alvar
Cirsium hillii
Huron Bay Limestone Pavement Lakeshore
Carex richardsonii
Carex scirpoidea
Cirsium hillii
Pellaea atropurpurea
Great Lakes Islands 2001 Page-20
Plate 1. Alvar glade near Huron Bay,
southern shore of Drummond Island.
Photo by M. Kost
Plate 3. Wood thrush (Hylocichla
mustelina), a long distance
Neotropical migrant. Photo by
Mike Hopiak for the Cornell
Laboratory of Ornithology.
Plate 2. Purple cliff-brake (Pellaea
atropurpurea) in alvar glade, Huron
Bay. Photo by M. Kost
Great Lakes Islands 2001 Page-21
Plate 4. Outer cliffs of Marblehead
Peninsula, northeast Drummond
Island. Photo by M. Kost
Plate 5. State endangered wall-
rue (Asplenium ruta-muraria),
known only from Marblehead
in Michigan. Photo by M. Kost
Plate 6. Pinedrops (Pterospora
andromedea) at Marblehead,
j
ust prior to full bloom. Photo
by M. Kost
Great Lakes Islands 2001 Page-22
Methods for Natural Community Surveys
The natural community surveys on Drummond
Island were organized to provide additional informa-
tion on several sites that had been identified during
prior inventories (Albert et a. 1994). Natural commu-
nity surveys were conducted in coordination with rare
plant surveys from July 9 through July 14, 2001.
Preparation for the surveys involved conducting aerial
photo interpretation, prioritizing inventory sites, and
studying site records for potential and previously
identified element occurrences.
Site visits involved mapping the boundaries of
each delineated natural community occurrence on
topographic maps and collecting detailed biotic and
abiotic data. Data collection included compiling
comprehensive plant species lists with notations of
relative abundance, describing structural information
for the vegetation layers in each plant community, and
recording information on the landforms and soils that
characterized the sites. Site-specific information was
also gathered related to signs of past human distur-
bance and land-use activities. Insights into future
protection and/or management activities if apparent
during site visits were also recorded. High quality
natural communities were defined according to the
MNFI Natural Community Classification (MNFI
1989). Each natural community occurrence was given
a grade based on its relative quality, condition, and
landscape context compared to other known occur-
rences within the state and Great Lakes region. Finally,
information from field forms was transcribed and
submitted for mapping and incorporation into the
MNFI statewide database.
Results of Natural Community Surveys
Natural community inventories resulted in the
identification of one new high quality natural commu-
nity and significantly updated information on six
previously identified natural communities and (Table
6). A new occurrence of alvar was discovered north-
east of Big Shoal Cove (Figure 5). The community is a
relatively small alvar glade that contains two rare
species, Hills thistle and Richardsons sedge. The site
rises with distance from Lake Huron in a series of low,
exposed limestone ledges. Deep grykes (natural cracks
or fissures) within the exposed limestone/dolomite
bedrock were found to occur throughout the site. This
natural community occurrence was assigned a B rank
because it was found to be relatively pristine, undis-
turbed, and surrounded by natural habitat.
Updated communities includes one dry non-acid
cliff (Marblehead), one limestone pavement lakeshore
(Huron Bay), and three globally significant alvar
occurrences (Maxton Plains East, Maxton Plains
Middle, and Huron Bay Road) (Table 6, Figure 5), the
latter forming part of a large landscape complex
comprising much of the northern portion of
Drummond Island.
The survey of Marblehead resulted in several new
plant records (see above) and provided additional
insight into the complex topographical nature of the
site. A successively smaller set of new cliff faces were
discovered farther inland, indicating that extensive, still
unexplored habitat for rare plants exists in this specific
area of the island.
Huron Bay surveys resulted in updated information
for several rare plants (see above) and revealed the
need to increase protection efforts at this A-ranked
occurrence of limestone pavement. Several undevel-
oped lots along the Lake Huron shoreline in this
vicinity were being advertised for sale at the time of
our surveys
1
.
Overall, the Maxton Plains alvar sites we surveyed
are among the largest expanses of alvar grassland in
Michigan, and are comparable to those occurring in
New York and southern Ontario. Several new occur-
rences of rare plants were discovered during the
surveys (see above). In addition to obtaining informa-
tion on natural communities and rare plant species, we
compiled data on artificial disturbance and the pres-
ence of invasive plant species. Table 7 provides a list
of the principal exotic plants observed within the
Maxton Plains alvar complex during our community
and rare plant surveys.
1
Following our surveys The Nature Conservancy (TNC)
Northern Lake Huron office was notified of the advertised
properties.
Great Lakes Islands 2001 Page-23
Figure 5. Natural community survey sites.
Great Lakes Islands 2001 Page-24
Discussion of Natural Community Surveys
The statewide database contains 20 records for
alvar, including the alvar glade identified near Big
Shoal Cove during this study. Six of the 20 known
state alvar occurrences are ranked as A and AB, and
seven are B ranked. The Big Shoal Cove alvar glade
was classified as a B-ranked occurrence. The site is a
relatively small but is significant because of its close
proximity to a large occurrence of limestone pavement
lakeshore at Big Shoal Cove and it is in very good
condition, with only one invasive plant species, ox eye
daisy, noted during our survey. Long-term protection
of the site will require either land acquisition or a land
easement to prevent development of this desirable
lakeview property.
The Maxton Plains East site is ranked as a B
occurrence of alvar and Maxton Plains Middle is
ranked as an A occurrence (Figure 5). Both of these
represent some of the largest alvar grasslands in the
Great Lakes region. These communities are well
adapted to extreme weather events and natural distur-
bances such as drought, growing season frost, seasonal
flooding, high winds, grazing, and wildfire. However,
they are not likely to adapt well to the influence of
highly invasive plant species such as spotted knapweed
(Centaurea maculosa) and common St. Johns-wort
(Hypericum perforatum and H. punctatum). These
invasive species compete with native plants and can
negatively impact species diversity and community and
ecosystem function. At present, the invasive species
occur predominately along the roadsides in this area
but are likely to spread further unless actively man-
aged. Some control of invasive species should also be
implemented at the Huron Bay Road alvar glade and
elsewhere.
Huron Bay is an expansive, A-ranked occurrence
of limestone pavement lakeshore, and represents one of
only 13 occurrences for this rare community type in the
state. It is the largest area of dolomite beach on
Drummond Island and possibly within the entire state
(Albert et al. 1994). It also has more special plants (10
species) than any other site on the island (Albert et al.
1994). Nestled along the rocky northern Lake Huron
shoreline, the site is one of the most picturesque places
in Michigan. Invasive plants represent a minimal
problem here at present; however, development pres-
sure along the Lake Huron shoreline is seriously
threatens the site. We recommend that conservation
measures such as land acquisition and land easements
be pursued to protect this high priority site.
Marblehead is one of only 10 known occurrences
for dry non-acid cliff in Michigan. This A-ranked site is
extremely difficult to survey because of its remote
location and exceptionally uneven topography. While
we succeeded in identifying several new plant occur-
rences at the site, more survey work will be needed
before the site can be considered as adequately invento-
ried. Photo interpretation of the site reveals the exist-
ence of inland escarpments (some of which were
explored during this survey) and possibly alvar glade
(Albert et al. 1994). Marblehead is within the Lake
Superior State Forest. Because it is primarily forested
with aspen and northern hardwoods, periodic forest
management could impact potential areas of alvar
glade. Further survey work for alvar glade should be
conducted in the near future so that more accurate
information on the sites natural features can be utilized
for management planning.
Table 7. Invasive plants occurring within alvar communities of the Maxton Plains, Drummond
Island.
Scientific Name Common Name
Agropyron repens quack grass
Centaurea maculosa spotted knapweed
Chrysanthemum leucanthemum ox eye daisy
Daucus carota Queen Anne's lace
Hieracium aurantiacum orange hawkweed
Hypericum perforatum common St. John's-wort
Phleum pratense timothy
Poa compressa Canada bluegrass
Poa pratensis Kentucky bluegrass
Rumex crispus curly dock
Tragopogon dubius goat's-beard
Trifolium hybridum alsike clover
Trifolium pratense red clover
Great Lakes Islands 2001 Page-25
Site Summaries
As established in the format of several previous
MNFI reports concerning coastal zone inventories, we
provide here a description of our inventory areas. These
site summaries are presented for inventory sites covered
by MNFI botanists and community ecologists. Nearly
all of the sites surveyed on Drummond Island are well
known areas, including several nominated natural
areas, such as the extensive Maxton Plains alvar
complex. In addition, some areas have been summa-
rized in previous reports (e.g. Marblehead Peninsula),
thus the summaries provided below are relatively brief,
emphasizing the new information obtained for these
sites (Albert et al. 1994, Penskar et al. 1999).
Marblehead Peninsula. Marblehead is an A-
ranked, natural community occurrence for dry non-acid
cliff that was identified during surveys of Drummond
Island in 1999. The site consists of an extensive series
of tall (3m  5m) limestone cliffs located along the east
shore of the island. A rare fern, the state endangered
wall rue (Asplenium ruta-muraria), grows directly on
the cliff faces along with poison ivy (Toxicodendron
radicans) and several other fern species. Populations of
two other rare plants, the state threatened pinedrops
(Pterospora andromedea) and the state special concern
Alaskan orchid (Piperia unalascensis), were located
further inland, above the cliffs.
Maxton Plains East (Site A). Maxton Plains East
Site A is extensive open grassland that was previously
identified as an alvar element occurrence and assigned
a B rank. A gravel road bisects the site. The rare grass
species, state special concern prairie dropseed
(Sporobolus heterolepis), dominates large areas of the
site. Other rare plants identified at the site include the
state threatened flattened spike-rush (Eleocharis
compressa) and new occurrences of the state special
concern Hills thistle (Cirsium hillii) and the state
special concern Richardsons sedge (Carex
richardsonii). Common juniper (Juniperus communis)
and creeping juniper (Juniperus horizontalis) occur
sporadically growing on thin soil over bedrock along
the edges of the site, slightly elevated above the exten-
sive open grassland. The small rise between the juniper
and grassland areas provides evidence of the
grasslands history as an ancient lakebed. A small,
abandoned mine occurs within the site north of the
road. Numerous invasive species occur along the
roadside and should be removed to prevent their
spread. These pernicious species included spotted
knapweed (Centaurea maculosa), common St. Johns-
wort (Hypericum perforatum), quack grass (Agropyron
repens), ox-eye daisy (Chrysanthemum leucanthemum),
orange hawkweed (Hieracium aurantiacum), and
timothy (Phleum pratense).
Maxton Plains East (Site B). Maxton Plains East
Site B is extensive open grassland that occurs mostly
north of the road that runs through the site. The site
was previously identified, along with Site A (above), as
an alvar occurrence and assigned a B rank. Rare
species identified at the site included prairie dropseed,
flattened spike-rush and new occurrences of Hills
thistle and Richardsons sedge. Many of the same
invasive species mentioned above occur along the
roadside and should be removed to prevent their
spread.
Maxton Plains Middle (Site C). Maxton Plains
Middle is a well known site previously identified and
assigned an A rank. The site consists of several large
alvar grassland openings that are bordered by small
areas of alvar glade. Rare plants identified during
surveys of the site included the state threatened bulrush
sedge (Carex scirpoidea), prairie dropseed, flattened
spike-rush, Richardsons sedge and a new occurrence
of Hills thistle. Numerous rock cairns had been
assembled in the western portions of the alvar. These
cairns were built by removing pieces of exposed
bedrock, which is detrimental to the ants and other
invertebrates that live under the loose dolostone.
Invasive plants found growing mainly along the
roadside and which should be removed to prevent their
further spread include spotted knapweed, ox-eye daisy,
orange hawkweed, timothy, alsike clover (Trifolium
hybridum), and red clover (Trifolium pratense).
The Rock North. This site, which lacks a distinc-
tive landmark, is name for its relatively close proxim-
ity to a well-known Drummond Island lodge and golf
course facility. The site consists of a small roadside
opening in which prairie dropseed was observed. The
small localized colony is markedly south of the
Maxton Plains alvar complex, which lies more than
three miles to the north. This population thus presum-
ably occupies a small, disturbed alvar remnant. Inter-
estingly, as dominant as prairie dropseed is within the
Maxton Plains proper, it is nearly absent in the south-
ern portion of the island, as is prairie smoke.
Huron Bay Road. The Huron Bay Road site
consists of a small alvar glade located along Huron
Bay Road in the southwest portion of the Drummond
Island. The site was previously identified and assigned
a C rank. Areas of exposed dolostone with deep grykes
(cracks) occur throughout the site. Two rare species
were identified at the site, Hills thistle and
Richardsons sedge. During our surveys we discover
small populations of two invasive plants species,
spotted knapweed and ox-eye daisy. An effort should
be made to control these species before they become
widespread throughout the site.
Great Lakes Islands 2001 Page-26
Big Shoal Cove. Our surveys at Big Shoal Cove
identified a B-ranked alvar located north of a previ-
ously known limestone pavement lakeshore occur-
rence. The site consists of an alvar glade with many
low (1m  2m), limestone cliffs that support maiden-
hair spleenwort (Asplenium trichomanes), a common
fern that is an indicator of high quality outcrop habi-
tats. The site gradually rises in elevation with distance
from Lake Huron, and the low cliffs form a compli-
cated network of terraced steps. Flat areas of exposed
limestone with deep grykes are also common through-
out the site. Large, scattered white pine (Pinus strobus)
and red pine (P. resinosa), along with white spruce
(Picea glauca), northern white cedar (Thuja
occidentalis) and common juniper (Juniperus commu-
nis) give the site a savanna appearance. Two rare
plants, Hills thistle and Richardsons sedge were
discovered at the site.
Huron Bay. Huron Bay is a previously identified,
A ranked, natural community occurrence of limestone
pavement lakeshore located along the southeast shore
of Lake Huron. The site consists of large expanses of
exposed limestone with deep grykes, and scattered
northern white cedar, horizontal juniper, and common
juniper. Several rare plants occurrences that had
previously been found at the site were relocated,
including the state threatened purple cliff-brake
(Pellaea atropurpurea), bulrush sedge, Hills thistle,
and Richardsons sedge. Several parcels of land within
the alvar were being advertised for sale at the time of
our surveys.
Digitization of Island Data
An important component of island inventories has
included preparing field information for use within
MNFIs new, Geographic Information System (GIS)
based data platform. A GIS system allows the known
spatial extent of an occurrence to be represented. This
spatially represented data is far more useful for re-
source managers, land-use planners, scientists, and the
general public than a traditional natural heritage
database. Figure 6 shows a selected set of Drummond
Island natural features data depicting how these
occurrences are displayed and managed within our GIS
system.
Before the advent of GIS, occurrences were
recorded with an estimated lat/long point and a map-
ping precision. Three types of precision were used:
second (S), minute (M), and general (G). Second
precision means the location was known exactly.
Minute precision means the location was known to
within a mile. General means that the location is only
known to the township level.
Now, with GIS, the known spatial extent of an
occurrence can be digitally represented. Data best
represented by a point (i.e. single plants, small popula-
tions, etc.) are represented with a small, approximately
six-meter radius circle. Older, pre-GIS records are
represented spatially by applying a buffer to the esti-
mated lat/long point. The buffer size is based on the
mapping precision of the occurrence. Second precision
records are assigned a 100 meter diameter buffer,
minute precision records are assigned a 2,000 meter
buffer, and general records are assigned an 8,000 meter
buffer.
During the islands inventory project, new natural
features data were transcribed and entered with respect
to heritage data standards developed for the spatial
representation of element occurrences. Heritage data
standards and methodology are defined by the organi-
zation called NatureServe (www.natureserve.org).
Under heritage methodology, only the known extent of
an occurrence may be digitized. For example, if the
only information known about an occurrence is that it
occurs within a specific legal section, with no more
precise spatial information, the section boundary
becomes the extent of the occurrence.
In addition to digitizing data obtained during the
2001 island inventory, existing natural features infor-
mation was carefully reviewed, and where possible
circular buffers replaced with a digitized spatial extent.
This digitizing effort entailed closely examining source
information for previously documented records,
including field forms and any associated maps indicat-
ing the specific locations and the spatial extent of the
records. The result of the digitizing effort is a natural
features data set that supplies more precise and useful
information than either a stand-alone database or
circular spatial extents derived solely from a mapping
precision protocol. Figure 7 depicts the changes in the
number of occurrences per legal section as a result of
replacing the circular buffers with a digitized spatial
extent for the occurrences.
This process was used to systematically examine
all natural features information recorded for
Drummond Island, resulting in the digitizing of 220
natural feature occurrences. In addition to Drummond
Island, 161 natural feature occurrences have been
digitized for the entire Beaver island archipelago
(Beaver, Garden, High, Hog, Whiskey, Trout, Gull,
Squaw, and associated smaller islands), 43 for Bois
Great Lakes Islands 2001 Page-27
Figure 6. Natural features as depicted in MNFI GIS database.
Great Lakes Islands 2001 Page-28
Figure 7. Changes in number of occurrences after digitizing.
Great Lakes Islands 2001 Page-29
Blanc Island, and 6 for Burnt and Harbor islands in