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COSEWIC Assessment and status report on the Harris’s Sparrow (Zonotrichia querula) in Canada

Authors:
COSEWIC
Assessment and Status Report
on the
Harris’s Sparrow
Zonotrichia querula
in Canada
SPECIAL CONCERN
2017
COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of
being at risk. This report may be cited as follows:
COSEWIC. 2017. COSEWIC assessment and status report on the Harris’s Sparrow Zonotrichia querula in
Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. x + 36 pp.
(http://www.registrelep-sararegistry.gc.ca/default.asp?lang=en&n=24F7211B-1).
Production note:
COSEWIC would like to acknowledge Natural Resource Solutions Inc. (Kenneth Burrell) for writing the status
report on Harris’s Sparrow, Zonotrichia querula, in Canada, prepared under contract with Environment and
Climate Change Canada. This report was overseen and edited by Marcel Gahbauer, Co-chair of the
COSEWIC Birds Specialist Subcommittee
For additional copies contact:
COSEWIC Secretariat
c/o Canadian Wildlife Service
Environment and Climate Change Canada
Ottawa, ON
K1A 0H3
Tel.: 819-938-4125
Fax: 819-938-3984
E-mail: ec.cosepac-cosewic.ec@canada.ca
http://www.cosewic.gc.ca
Également disponible en français sous le titre Ếvaluation et Rapport de situation du COSEPAC sur le Bruant à face noire (Zonotrichia
querula) au Canada.
Cover illustration/photo:
Harris’s Sparrowphoto by Ron Ridout (with permission).
Her Majesty the Queen in Right of Canada, 2017.
Catalogue No. CW69-14/751-2017E-PDF
ISBN 978-0-660-08708-5
iii
COSEWIC
Assessment Summary
Assessment Summary April 2017
Common name
Harris’s Sparrow
Scientific name
Zonotrichia querula
Status
Special Concern
Reason for designation
This northern ground-
nesting bird is the only songbird that breeds exclusively in Canada. Data from Christmas Bird
Counts in the US Midwest wintering grounds show a significant long-term decline of 59% over the past 35 years, including
16% over the past decade. The species may be affected by climate change on the breeding grounds, while threats on the
wintering grounds include habitat loss, pesticide use, road mortality, and predation by feral cats.
Occurrence
Northwest Territories, Nunavut, Alberta, Saskatchewan, Manitoba, Ontario
Status history
Designated Special Concern in April 2017.
iv
COSEWIC
Executive Summary
Harris’s Sparrow
Zonotrichia querula
Wildlife Species Description and Significance
Harris’s Sparrow is a large sparrow with a distinctive black hood and bib. Both sexes
have similar plumage. Non-breeding and first-year birds are similar to each other in
plumage, lacking much of the black bib and facial patterning found in breeding individuals.
Harris’s Sparrow is the only passerine that breeds exclusively in Canada.
Distribution
Harris’s Sparrow is a long-distance temperate migrant that is found exclusively in
North America. The species breeds along the tree-line in northern Canada (Northwest
Territories, Nunavut, Saskatchewan, Manitoba, and irregularly Ontario), and winters in the
central Midwest region of the United States (regularly in Nebraska, Kansas, Oklahoma,
Texas, and irregularly in Arkansas, Missouri, Iowa, and South Dakota). Because of limited
accessibility of the breeding range, relatively little is known about the species in Canada.
Habitat
Harris’s Sparrow favours a mosaic of upland and tundra, with scattered lakes.
Breeding territories typically include coniferous trees; densities are highest where forest
stands are dominated by spruce or tamarack, interspersed with shrubs typically <1 m tall. In
winter and during migration, the species frequents a variety of habitats, with riparian
thickets, grasslands, woodland edges, hedgerows, and willow thickets commonly used.
Biology
Harris’s Sparrow is a socially monogamous breeder that consumes fruits, seeds, and
insects. Throughout the breeding season, the species is initially heavily dependent on fruits,
before switching its diet as the breeding season progresses to include more insects and
seeds as snow cover disappears. Nests are constructed and incubated by the female and
are placed on the ground in densely concealed ground vegetation. Average clutch size is
4.07 eggs, with a range of 3 5 eggs. Incubation lasts 12 13.5 days and young fledge
after 8.5 10 days. Research on the Thelon River in Northwest Territories documented a
hatching rate of 76%, fledging rate of 62.5%, and overall nest success rate of 47.5%, with
2.07 fledged young per pair.
v
Population Sizes and Trends
The global population, which breeds exclusively in Canada, is estimated at 500,000
5,000,000 individuals, with the most recent estimates indicating ~2,000,000 individuals.
Christmas Bird Count (CBC) data indicate a significant long-term rate of annual
decline of -2.58% between 1980 and 2014, amounting to a total population loss of 59%
over the last 35 years. Over the most recent 10-year period (2004 to 2014), CBC data show
a decline of -1.77% per year amounting to a cumulative loss of 16%.
Threats and Limiting Factors
Throughout the wintering grounds in the Midwestern United States, the conversion of
grassland and fringe lands for agricultural purposes is thought to be a factor in the decline
of Harris’s Sparrow. Pesticide use throughout the wintering grounds has been linked to
declines in Harris’s Sparrow; while the relative influence of this factor is unknown, it is
anticipated to be negative and potentially considerable in severity.
Within the breeding range, concerns include habitat loss linked to deforestation near
the northern edge of the species’ range associated with forest fires, quarries and mine
development, and climate change, which may reduce suitable breeding habitat while
allowing ectoparasites and mammalian predators, such as Red Fox, to spread north.
More studies are needed to assess the species throughout its annual life cycle and
assess the relative importance of different threats on its breeding and wintering grounds.
Protection, Status and Ranks
Harris’s Sparrow and its nest and eggs are protected in Canada under the Migratory
Birds Convention Act. The Act prohibits the sale or possession of migratory birds and their
nests, and any activities that are harmful to migratory birds, their eggs, or their nests,
except as permitted under the Migratory Birds Regulations. It is protected in the United
States under the Migratory Birds Treaty Act.
Harris’s Sparrow is ranked as globally secure by NatureServe. Within Canada the
species is ranked as secure nationally, secure in Alberta and Saskatchewan and vulnerable
in Manitoba and the Northwest Territories. COSEWIC assessed this species as Special
Concern in April 2017.
vi
TECHNICAL SUMMARY
Zonotrichia querula
Harris’s Sparrow
Bruant à face noire
Range of occurrence in Canada: Northwest Territories, Nunavut, Alberta, Saskatchewan, Manitoba,
Ontario
Demographic Information
Generation time
2 to 3 yrs
Is there an [observed, inferred, or projected] continuing
decline in number of mature individuals?
Yes, observed
Estimated percent of continuing decline in total
number of mature individuals within [5 years or 2
generations]
Unknown
[Observed, estimated, inferred, or suspected] percent
[reduction or increase] in total number of mature
individuals over the last [10 years, or 3 generations].
16% reduction observed over the most recent 10-
year period of data from the Christmas Bird Count
[Projected or suspected] percent [reduction or
increase] in total number of mature individuals over the
next [10 years, or 3 generations].
Unknown, but long-term decline expected to
continue unless threats are identified and
addressed.
[Observed, estimated, inferred, or suspected] percent
[reduction or increase] in total number of mature
individuals over any [10 years, or 3 generations]
period, over a time period including both the past and
the future.
Unknown, but long-term decline expected to
continue unless threats are identified and
addressed.
Are the causes of the decline a. clearly reversible and
b. understood and c. ceased?
a. Unknown
b. No
c. No
Are there extreme fluctuations in number of mature
individuals
No
Extent and Occupancy Information
Estimated extent of occurrence
Based on a minimum convex polygon provided in
Figure 1
1,368,784 km² (breeding range)
1,377,973 km² (wintering range)
Index of area of occupancy (IAO)
(Always report 2x2 grid value).
>2,000 km²
vii
Is the population “severely fragmented” ie. is >50% of
its total area of occupancy in habitat patches that are
(a) smaller than would be required to support a viable
population, and (b) separated from other habitat
patches by a distance larger than the species can be
expected to disperse?
a. No
b. No
Number of “locations” (use plausible range to reflect
uncertainty if appropriate)
Unknown, but >10
Is there an [observed, inferred, or projected] decline in
extent of occurrence?
Unknown
Is there an [observed, inferred, or projected] decline in
index of area of occupancy?
Unknown
Is there an [observed, inferred, or projected] decline in
number of subpopulations?
N/A
Is there an [observed, inferred, or projected] decline in
number of “locations”*?
Unknown
Is there an [observed, inferred, or projected] decline in
[area, extent and/or quality] of habitat?
Unknown
Are there extreme fluctuations in number of
subpopulations?
N/A
Are there extreme fluctuations in number of
“locations”?
No
Are there extreme fluctuations in extent of occurrence?
No
Are there extreme fluctuations in index of area of
occupancy?
No
Number of Mature Individuals (in each subpopulation)
Population
N Mature Individuals
Crude estimate ranging between 500,000
5,000,000 (Blancher et al.
2007); more recent
estimate of 2,000,000 based on Rosenberg et al.
(2016).
Total
2,000,000
Quantitative Analysis
Probability of extinction in the wild.
Quantitative analysis not undertaken
See Definitions and Abbreviations on COSEWIC website and IUCN (Feb 2014) for more information on this term
viii
Threats (actual or imminent, to populations or habitats, from highest impact to least)
Was a threats calculator completed for this species and if so, by whom?
Yes, on September 26, 2016 by Kenneth Burrell, Dave Fraser, Marcel Gahbauer, Suzanne Carrière, Richard
Elliot, Pam Sinclair, Myles Lamont, Chris Norment, Rudolf Koes, Jim Rising, Samuel Hache, Amy Ganton,
Joanna James.
Overall threat of high-medium, based on:
i. Direct and indirect effects of agricultural and forestry pesticides (high-low)
ii. Habitat conversion in relation to housing and urban areas on the wintering grounds (low)
iii. Collision risk from roads and railroads (low)
iv. Invasive non-native/alien species, in particular cat predation on the wintering grounds (low)
Habitat conversion for agriculture, renewable energy, fire and fire suppression, and climate change are
among the other potential threats that may affect Harris’s Sparrow, but not enough is known to evaluate their
effects at this time.
Rescue Effect (immigration from outside Canada)
Status of outside population(s) most likely to provide
immigrants to Canada.
N/A. Speciesbreeding range is found exclusively in
Canada.
Is immigration known or possible?
N/A
Would immigrants be adapted to survive in Canada?
N/A
Is there sufficient habitat for immigrants in Canada?
N/A
Are conditions deteriorating in Canada?+
N/A
Are conditions for the source population
deteriorating?
+
N/A
Is the Canadian population considered to be a sink?+
N/A
Is rescue from outside populations likely?
N/A
Data Sensitive Species
Is this a data sensitive species? No; the species is widely distributed and still relatively common throughout
the breeding range in Canada.
Status History:
COSEWIC: Designated Special Concern in April 2017.
Status and Reasons for Designation:
Status:
Special Concern
Alpha-numeric codes:
Not applicable
Reasons for designation:
This northern ground-nesting bird is the only songbird that breeds exclusively in Canada. Data from
Christmas Bird Counts in the US Midwest wintering grounds show a significant long-term decline of 59% over
the past 35 years, including 16% over the past decade. The species may be affected by climate change on
the breeding grounds, while threats on the wintering grounds include habitat loss, pesticide use, road
mortality, and predation by feral cats.
+ See Table 3 (Guidelines for modifying status assessment based on rescue effect)
ix
Applicability of Criteria
Criterion A (Decline in Total Number of Mature Individuals):
Not applicable, as the decline over the past 10 years is ~16%.
Criterion B (Small Distribution Range and Decline or Fluctuation):
Not applicable, given extensive distribution.
Criterion C (Small and Declining Number of Mature Individuals):
Not applicable, given population estimate of ~2 million.
Criterion D (Very Small or Restricted Population):
Not applicable, given population estimate of ~2 million.
Criterion E (Quantitative Analysis):
Not assessed.
x
COSEWIC HISTORY
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of
a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official,
scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced
its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On
June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body
ensuring that species will continue to be assessed under a rigorous and independent scientific process.
COSEWIC MANDATE
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species,
subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on
native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs,
vascular plants, mosses, and lichens.
COSEWIC MEMBERSHIP
COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal
entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal
Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science
members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge
subcommittee. The Committee meets to consider status reports on candidate species.
DEFINITIONS
(2017)
Wildlife Species
A species, subspecies, variety, or geographically or genetically distinct population of animal,
plant or other organism, other than a bacterium or virus, that is wild by nature and is either
native to Canada or has
extended its range into Canada without human intervention and has
been present in Canada for at least 50 years.
Extinct (X)
A wildlife species that no longer exists.
Extirpated (XT)
A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.
Endangered (E)
A wildlife species facing imminent extirpation or extinction.
Threatened (T)
A wildlife species likely to become endangered if limiting factors are not reversed.
Special Concern (SC)*
A wildlife species that may become a threatened or an endangered species because of a
combination of biological characteristics and identified threats.
Not at Risk (NAR)**
A wildlife species that has been evaluated and found to be not at risk of extinction given the
current circumstances.
Data Deficient (DD)***
A category that applies when the available information is insufficient (a) to resolve a species’
eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.
*
Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.
**
Formerly described as “Not In Any Category”, or “No Designation Required.”
***
Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to
base a designation) prior to 1994. Definition of the (DD) category revised in 2006.
The Canadian Wildlife Service, Environment and Climate Change Canada, provides full administrative and financial
support to the COSEWIC Secretariat.
COSEWIC Status Report
on the
Harris’s Sparrow
Zonotrichia querula
in Canada
2017
TABLE OF CONTENTS
WILDLIFE SPECIES DESCRIPTION AND SIGNIFICANCE ........................................... 4
Name and Classification .............................................................................................. 4
Morphological Description ........................................................................................... 4
Population Spatial Structure and Variability ................................................................. 5
Designatable Units ...................................................................................................... 5
Special Significance .................................................................................................... 5
DISTRIBUTION ............................................................................................................... 5
Global Range ............................................................................................................... 5
Canadian Range .......................................................................................................... 7
Extent of Occurrence and Area of Occupancy ........................................................... 10
Search Effort .............................................................................................................. 10
HABITAT ........................................................................................................................ 10
Habitat Requirements ................................................................................................ 10
Habitat Trends ............................................................................................................11
BIOLOGY ...................................................................................................................... 12
Life Cycle and Reproduction ...................................................................................... 12
Food .......................................................................................................................... 13
Physiology and Adaptability ....................................................................................... 13
Dispersal and Migration ............................................................................................. 14
Interspecific Interactions ............................................................................................ 14
POPULATION SIZES AND TRENDS ............................................................................ 14
Sampling Effort and Methods .................................................................................... 14
Abundance ................................................................................................................ 16
Fluctuations and Trends ............................................................................................ 17
Rescue Effect ............................................................................................................ 22
THREATS AND LIMITING FACTORS ........................................................................... 22
PROTECTION, STATUS AND RANKS ......................................................................... 24
Legal Protection and Status ....................................................................................... 24
Non-Legal Status and Ranks ..................................................................................... 24
Habitat Protection and Ownership ............................................................................. 25
ACKNOWLEDGEMENTS AND AUTHORITIES CONTACTED ..................................... 25
INFORMATION SOURCES ........................................................................................... 25
BIOGRAPHICAL SUMMARY OF REPORT WRITER(S) ............................................... 31
COLLECTIONS EXAMINED ......................................................................................... 31
List of Figures
Figure 1. Global distribution of Harris’s Sparrow during breeding (light gray; adapted from
James et al. 1976; Cadman 2007) and wintering (dark gray; adapted from
National Audubon Society 2015; eBird 2016; Norment et al. 2016) seasons,
including irregular occurrences within dashed lines. ....................................... 6
Figure 2. Harris’s Sparrow breeding evidence during the Manitoba Breeding Bird Atlas,
2010-2014 (MBBA 2015). Numbers spaced throughout the map (1-14) represent
atlas coverage zones. ..................................................................................... 8
Figure 3. Harris’s Sparrow breeding evidence during the 2nd (2001-2005) Ontario Breeding
Bird Atlas, 2010-2014 (Cadman et al. 1987 and 2007). The gray lines delineate
the boundaries of the Carolinian, Lake Simcoe-Rideau, Southern Shield,
Northern Shield, and Hudson Bay Lowland ecological regions (from south to
north). .............................................................................................................. 9
Figure 4. Annual trends of Harris’s Sparrow observations (1980 2014) from the
Christmas Bird Count (National Audubon Society 2015), in the USA, Kansas,
Nebraska, Oklahoma, and Texas. ................................................................. 18
Figure 5. eBird records (eBird 2016) of Harris’s Sparrow (2004 2014), December
February in the core non-breeding states within the USA. ............................ 19
Figure 6. Last Mountain Lake Bird Observatory trends of Harris’s Sparrow (1994 2014)
in spring; * denotes a significant trend. ......................................................... 20
Figure 7. Last Mountain Lake Bird Observatory trends of Harris’s Sparrow (1993 2014)
in fall; * denotes a significant trend. ............................................................... 21
Figure 8. Delta Marsh Bird Observatory trends of Harris’s Sparrow (2006 2010),
spring. ........................................................................................................... 21
Figure 9. Delta Marsh Bird Observatory trends of Harris’s Sparrow (1993 2010), fall.22
List of Tables
Table 1. Summary of Harris’s Sparrow population trends over the past 10 and 35 years,
according to the Christmas Bird Count (National Audubon Society 2015). * denotes
P<0.05, ** denotes P<0.001, and ns denotes not significant. .......................... 17
Table 2. Summary of Harris’s Sparrow population trends over the past ten years, according
to eBird (2016) data adjusted to the frequency of observation during the December
1 February 28 period of 2004 2014. * denotes P<0.05, ** denotes P<0.001,
and ns denotes not significant. ........................................................................ 20
List of Appendices
Appendix 1. Threats Assessment Worksheet for Harris’s Sparrow. ............................... 32
4
WILDLIFE SPECIES DESCRIPTION AND SIGNIFICANCE
Name and Classification
Scientific Name: Zonotrichia querula (Nuttall, 1840)
English Name: Harris’s Sparrow
French Name: Bruant à face noire
Class: Aves
Order: Passeriformes
Family: Emberizidae
Genus: Zonotrichia
Species: Zonotrichia querula
Classification follows the American Ornithologists’ Union (AOU 1998; Chesser et al.
2015). No geographic variation or subspecies are recognized (AOU 1998; Norment et al.
2016). Currently there are five species within the genus Zonotrichia (AOU 1998).
Morphological Description
Harris’s Sparrow is a large sparrow (body length: 17-20 cm, body mass: 30-45 g) with
a distinctive facial and breast pattern. Both sexes have similar plumage. Breeding adults
have a well-defined black hood and bib, which includes black throughout the front of the
face and the top of the head extending to the nape and upper throat. Black streaking
occurs throughout the breast and flanks. The bill and legs are a fleshy pink. The wings are
dominated by two white wing bars, while the remainder of the wings and back are mottled
brown and gray. Non-breeding and first-year birds are similar to each other in plumage,
lacking much of the black bib and facial patterning found on breeding individuals. Variation
in the amount of black in the face and bib occurs, with older birds and males typically
showing more black, while the face is primarily brown and gray. Vocalizations for the
species are similar to other species in the genus, specifically the first part of the White-
throated Sparrow (Zonotrichia albicollis) song. The song is described as a plaintive whistle
by Semple and Sutton (1932) and a one-toned whistled “seeeeeee seeee seeee” by Sibley
(2000). Aging of individuals, particularly first-year birds, is possible by examining retained
juvenile flight feathers (Pyle 1997; Norment et al. 2016).
5
Population Spatial Structure and Variability
No evidence exists for population structuring within the species’ population. The
species’ population is contiguous throughout the breeding range; no significant barriers to
dispersal and movement have been identified. There is a clinal increase in clutch size as
latitude increases (Norment 1992a,b).
Designatable Units
No subspecies have been recognized for Harris’s Sparrow (AOU 1998; Norment et al.
2016); all Harris’s Sparrows breeding in Canada are within a single population and
therefore only one designable unit is considered in this report.
Special Significance
Harris’s Sparrow is the only endemic breeding passerine in Canada (Norment et al.
2016). The species is one of the last North American songbird species to have its nests and
eggs discovered, in 1931, with relatively little known about its basic breeding ecology until
recently (Norment et al. 2016).
No Aboriginal Traditional Knowledge is currently available for this species.
DISTRIBUTION
Global Range
Harris’s Sparrow is a medium-distance temperate migrant that is found exclusively in
North America. The species breeds along the treeline in northern Canada (Northwest
Territories, Nunavut, Saskatchewan, Manitoba, and irregularly Ontario), and winters in the
central Midwest region of the United States (South Dakota, Nebraska, Kansas, Oklahoma,
Texas, Arkansas, Missouri, and Iowa). The core of the winter range includes north-central
Texas, Kansas, Oklahoma, and Nebraska (Figure 1). Migratory routes are not well
understood, but are expected to follow a narrow band between the breeding and wintering
grounds. Additionally, the species winters, as a vagrant, in scattered peripheral locations
throughout the lower 48 contiguous US states and less so in southern Canada and extreme
northern Mexico (National Audubon Society 2015; eBird 2016).
6
Figure 1. Global distribution of Harris’s Sparrow during breeding (light gray; adapted from James et al. 1976; Cadman
2007) and wintering (dark gray; adapted from National Audubon Society 2015; eBird 2016; Norment et al.
2016) seasons, including irregular occurrences within dashed lines.
7
Canadian Range
Harris’s Sparrow breeds principally near the treeline, in parts of the Southern Arctic,
Taiga Plains, Taiga Shield, and Hudson Plains EcoZones, west of Hudson Bay
(Government of Canada 2013).
In Manitoba, the species breeds in the Far North, where it is regularly observed along
and west of the Nelson River, extending to the far northwestern corner of the province and
northeastern Saskatchewan (eBird 2016; Norment et al. 2016; Figure 2). In Nunavut, the
species breeds in the Kivalliq and Kitikmeot regions. Within the Kivalliq Region, it is found
primarily in the southern two-thirds of the Region, as far north as Rankin Inlet, at which
point the breeding range extends northwest from the coastline to an area east of
Umingmaktok, in the Kitikmeot Region (eBird 2016; Norment et al. 2016). In Kitikmeot,
Harris’s Sparrow is found along the Arctic Ocean coastline, west to Kugluktuk and Clifton
Point (eBird 2016; Norment et al. 2016). In the Northwest Territories the species’ range
extends west to the Mackenzie River delta, and possibly into extreme northeastern Yukon
(Eckert pers. comm. 2015). The southwestern edge of the range extends from the
northwestern Northwest Territories across the south of Great Bear Lake, to northeastern
Saskatchewan (eBird 2016; Norment et al. 2016).
Data from the Ontario Breeding Bird Atlases (1981-1985 and 2001-2005; Cadman et
al. 1987, 2007) and James et al. (1976) indicate that irregular breeding occurs at scattered
locations near the Hudson Bay coast (Figure 3).
8
Figure 2. Harris’s Sparrow breeding evidence during the Manitoba Breeding Bird Atlas, 2010-2014 (MBBA 2015).
Numbers spaced throughout the map (1-14) represent atlas coverage zones.
9
Figure 3. Harris’s Sparrow breeding evidence during the 2nd (2001-2005) Ontario Breeding Bird Atlas, 2010-2014
(Cadman et al. 1987 and 2007). The gray lines delineate the boundaries of the Carolinian, Lake Simcoe-
Rideau, Southern Shield, Northern Shield, and Hudson Bay Lowland ecological regions (from south to north).
10
Extent of Occurrence and Area of Occupancy
Extent of occurrence is estimated to be 1,368,784 km2 in the breeding range, and
1,377,973 km2 in the wintering range (Figure 1). Distribution within the breeding range is
not sufficiently documented to calculate area of occupancy, but it is certainly >2,000 km2.
Search Effort
Distributional data for Harris’s Sparrow in Canada predominantly come from the
Manitoba Breeding Bird Atlas (2015), conducted in 2010-2014, the Saskatchewan
Conservation Data Centre, and observations from individual observers contacted for the
preparation of this status report (see Acknowledgements).
The distribution maps from NatureServe Explorer (2015) and Birds of North America
(Norment et al. 2016) are considered the most reliable for the species, and have been
corroborated with data from the Northwest Territories/Nunavut Bird Checklist Survey
(ECCC 2016) and eBird (2016) for the past 10 years in June and July.
HABITAT
Habitat Requirements
Breeding Habitat
Throughout their breeding range, Harris’s Sparrows favour the forest/upland tundra
transition zone. Breeding territories typically include coniferous trees; densities are highest
where forest stands are dominated by spruce (Picea sp.) and to a lesser extent Tamarack
(Larix laricina), with shrubby understorey vegetation (Harper 1953; Gillespie and Kendeigh
1982; Norment 1992a; Norment et al. 2016). Densities have been observed to decline with
decreasing tree and understorey vegetation abundance (Norment et al. 2016). The species
infrequently nests in areas where trees are absent; in these cases shrub cover is
particularly important for nest placement and concealment (Clarke 1944; Sealy 1967;
Norment et al. 2016). Favoured breeding habitat typically has small, isolated forest stands
(ranging from a small clump of trees to 12 ha) interspersed throughout the breeding territory
(Norment 1992a; Norment et al. 2016).
Highest densities occur where vegetation composition is varied and shrubs are
generally taller (i.e., >1m) (Obst pers. comm. 2015), with highest abundances occurring
where forests are characterized as 10% Black Spruce (P. mariana) and White Spruce (P.
glauca) forest, 27% Dwarf Birch (Betula glandulosa) Willow (Salix sp.) shrublands, and
63% tundra (Norment 1992b; Norment et al. 2016). Breeding populations have been
estimated to range from a low of 0.025 territorial males per ha in lowest density habitats
(Harris et al. 1974) to 0.125 0.82 breeding pairs per ha in highest density habitats
(Gillespie and Kendeigh 1982; Norment 1992b).
11
Subtle clinal variation occurs throughout the species’ breeding range with respect to
vegetation found in their breeding territories (Norment et al. 2016). In the Northwest
Territories the species generally nests in shrubby vegetation dominated by Dwarf Birch,
alder (Alnus spp.), and willow (Semple and Sutton 1932; Harper 1953; Norment 1992b),
while in Churchill, Manitoba the species is most common at the edge of spruce and
tamarack forests (Gillespie and Kendeigh 1982), in clearings, and at the edges of burned
areas (Semple and Sutton 1932; Norment et al. 2016).
Wintering and Migration Habitat
The species frequents a variety of habitats throughout the winter and migration
periods, with riparian thickets, woodland edges, hedgerows, and willow thickets commonly
used (NatureServe 2015). Studies conducted in Kansas (Graul 1967) and Oklahoma (Nice
1929; Bridgwater 1966) indicate the species favours disturbed areas, such as hedgerows,
brush piles, and agricultural fields, as well as natural habitats such as secondary
succession and riparian corridors (Norment et al. 2016).
Habitat Trends
Breeding Habitat
Human activities such as mining and road construction occur within the breeding
range; the extent to which they affect breeding habitat remains unclear, but overall rate of
change to breeding habitat is likely to be low.
Quantitative effects of climate change are not known; however, anecdotal evidence
suggests that shifting of the treeline north may affect the species (Obst pers. comm. 2015),
potentially both positively (e.g., increased abundance of shrub species beneficial to Harris’s
Sparrows for foraging and nesting) and negatively (e.g., reduced suitable habitat at the
southern edge of the species’ range; i.e., northern Manitoba). The amount and quality of
breeding habitat for this species is not being monitored (trends are not available).
Wintering Habitat
The winter range includes the central and southern Great Plains region of the USA,
extending from South Dakota to Texas (Norment et al. 2016) where Harris’s Sparrows use
open habitats, including riparian thickets, woodland edges, hedgerows, and willow thickets.
The conversion of these types of habitat to agriculture and to a lesser extent urban sprawl
is identified as a threat to the species, though it is unknown to what extent (NatureServe
2015).
12
BIOLOGY
Few recent studies have been conducted on Harris’s Sparrow in Canada. Past studies
conducted by C. Norment in the Thelon River area, Northwest Territories, provide much of
what is documented on the species’ breeding biology (e.g., Norment 1992a,b, 1993, 1994,
1995a, b). As a result, much of the information presented below draws on information
summarized in the revised Birds of North America species account (Norment et al. 2016).
Life Cycle and Reproduction
Harris’s Sparrow is a socially monogamous breeder (Norment et al. 2016). Paired
birds forage together, with the male following the female, most closely just prior to
incubation (Norment et al. 2016). The species forms loose flocks in the late summer, just
prior to fall migration (Norment et al. 2016).
Harris’s Sparrows generally arrive on their breeding territories in late May to early
June (Norment et al. 2016). Nests are typically initiated in the second and third week in
June (i.e., ~14 days after average arrival), or when snow-cover is ≤60% (NatureServe
Explorer 2015; Norment et al. 2016). Nests have two layers: an inner layer composed
primarily of dry grasses, mosses, and sedges, and an outer layer composed of lichens,
mosses, and small twigs (Rees 1973). Females build the nests, incubate, and brood the
young (Norment et al. 2016). Both sexes feed the young; however, males tend to do so less
frequently, particularly early in the hatching stage (Norment et al. 2016). The species only
initiates second broods if the first brood has failed before the eggs have hatched (Norment
1992b; Norment et al. 2016).
Norment (1992b) documented the incubation period as lasting 12 13.5 days and the
nestling period 8.5 10 days. Average clutch size (n = 155) was 4.07 eggs, with a range
from 3 5 eggs; timing of hatching was noted to be synchronous among nests (Norment
1992b). The hatching rate in Northwest Territories was 76%, fledging rate was 62.5%, and
overall nest success (minimum one offspring fledged successfully) was 47.5%, with 2.07
young fledged per pair on average (Norment 1992b; NatureServe Explorer 2015; Norment
et al. 2016). Fledgling mortality was noted to be primarily due to predation, with Arctic
Ground Squirrels (Spermophilus parryii) and, to a lesser extent, Short-tailed Weasels
(Mustela erminea) as the principal predators of young (NatureServe Explorer 2015).
Nests are always located on the ground and usually within dense ground vegetation
for cover (Norment 1993). The probability of nest success increased with nest concealment
(Norment 1993). Nests are often positioned under shrubs <1 m (NatureServe Explorer
2015; Norment et al. 2016). Plant species used for cover vary by latitude, but most are
woody (Norment 1993). In Nunavut, Dwarf Birch (Betula pumila) is most commonly
selected (68%; n = 65), while in Manitoba, it is Dwarf Labrador Tea
(Rhododendron tomentosum) (32%; n = 26) (Norment 1993). In Northwest Territories,
mean nest entrance orientation is at 140.5°, which is 170° away from the direction of
prevailing storms (Norment 1993).
13
The age for birds to first breed is not known; however, it is believed to be one year, as
for other Zonotrichia species (Norment 1992a; Chilton et al. 1995). The species has a sex
ratio of 1:1 throughout established breeding territories (Norment et al. 2016).
The longevity record is 11 years, 8 months (Norment et al. 2016). Average survival of
chicks from eggs to hatching ranged from 63.8% - 90.5% (Norment 1992b). Annual survival
data indicate that adult survivorship averaged 38% over a 2-year study in Nunavut
(Norment 1992b); the low estimate is likely a reflection of individuals shifting breeding sites.
While generation time has not specifically been calculated, it is assumed to be 2-3 years,
as for most other small passerines. One recorded hybrid with White-crowned Sparrow
(Zonotrichia leucophrys) was collected at Long Point, Ontario (Payne 1979).
Food
Harris’s Sparrows consume fruits, seeds, and insects; employing similar feeding
habits to other Zonotrichia species, feeding on the ground, where they scratch and kick
ground refuse (Norment 1992a). They forage in shrubs and trees less frequently than on
the ground (Nice 1929; Semple and Sutton 1932; Norment et al. 2016).
Harris’s Sparrows consume a wide variety of plant species, including sedges (Carex
spp. and Cyperus spp.), bulrushes (Scirpus spp.), birch (Betula spp.), pigweed
(Amaranthus spp.), lamb’s-quarters (Chenopodium spp.), blueberry (Vaccinium spp.),
crowberry (Empetrum nigrum), and bearberry (Arctostaphylos uva-ursi) (Semple and Sutton
1932). Berries are particularly important to Harris’s Sparrow when the birds first reach the
breeding grounds and insects have not yet emerged (Norment and Fuller 1997). Norment
and Fuller (1997) found that fruits such as Blueberry (Vaccinium sp.), Crowberry
(Empetrum nigrum), and Bearberry (Arctostaphylus sp.) comprised 82% of stomach
contents before birds nested. In the same study, Norment and Fuller (1997) found that
arthropods comprised 72.5% of adult Harris’s Sparrows diet during the nestling period and
81.5% of nestling diets.
Physiology and Adaptability
Relatively little information on the species’ physiology exists; Norment (1995a)
determined optimum temperature for Harris’s Sparrows during incubation was between
+10°C and +20°C, allowing females to leave the nest for longer periods to forage and to
return less frequently to tend to eggs. The same study (Norment 1995a) found that
temperatures above +20°C resulted in adults attending the nest more frequently in an effort
to provide shade and to help regulate fledgling body temperature (Norment et al. 2016).
Harris’s Sparrows were also found to be poorly adapted to extreme temperatures during
nesting, specifically when temperature reached above +30°C and below -10°C (Norment et
al. 2016).
During periods of inclement weather, birds abandon newly acquired breeding
territories, returning to resume nesting after the inclement weather has passed (Norment et
al. 2016). This strategy is beneficial when birds have not initiated egg-laying; however, it is
detrimental and can be fatal to young birds or eggs recently laid.
14
Dispersal and Migration
After fledging, juveniles disperse up to 500 m from natal sites; young and some adults
may disperse over longer distances within the breeding range but this has not been
documented (e.g., there are no banding encounters involving longer distance movements
of birds captured or banded within Canada; Brewer et al. 2006; Norment et al. 2016).
Norment (1994) documented a 38% return rate for banded birds in NWT, with no
substantial difference by sex. Adults which were unsuccessful nesters returned in
subsequent years at much lower rates than successful birds (Norment 1994).
Based on banding and observation data (Brewer et al. 2006; eBird 2016) most birds
are expected to migrate north and south through a narrow band between the breeding and
wintering grounds. However, single individuals are observed frequently outside the
expected wintering grounds and migration corridor.
Interspecific Interactions
Throughout the breeding grounds the species is socially monogamous and forms
loose flocks prior to departing for fall migration (Norment et al. 2016). During spring and fall
migration and winter the species joins mixed-species flocks which may include White-
crowned Sparrow, American Tree Sparrow (Spizelloides arborea), and Northern Cardinal
(Cardinalis cardinalis) (Shuman et al. 1992; Thompson 1994; Robel et al. 1997).
POPULATION SIZES AND TRENDS
Sampling Effort and Methods
Harris’s Sparrow is one of the least studied passerines in North America, with only a
few programs adequately designed to estimate population size or trends. Due to its remote
northern breeding range, the species is not effectively surveyed by the Breeding Bird
Survey, which typically provides population trend data for songbirds. Surveys providing
relevant data are presented below.
The Christmas Bird Count (CBC)
The Christmas Bird Count originated in 1900 and tracks winter bird populations
through annual surveys within fixed 24 km diameter count circles (National Audubon
Society 2015). This program provides population and abundance estimates on most
wintering landbirds in Canada and the USA, including Harris’s Sparrow. Within each count
circle, CBC volunteers record all bird species and individuals on a single day between 14
December and 5 January of a given year. With the breeding grounds of Harris’s Sparrow
almost completely unmonitored, the CBC provides the most reliable source of data for
analyzing population trends.
15
CBC coverage in the Harris’s Sparrow’s core non-breeding range (Texas, Oklahoma,
Kansas, and Nebraska) was relatively limited until 1980. Trend analyses were conducted
using data from 1980 2014, and were analyzed in relation to an adjusted observation
value for effort (birds per party hour). The analysis also looked at the entire winter range for
the same timeframe, to capture the overall trend and to account for potentially substantial
numbers of birds falling outside the core non-breeding range. State-specific analyses were
also conducted for five states peripheral to the core non-breeding range; however, sample
sizes were sufficient for generating trends only in Missouri and Iowa. Other states (e.g.,
Colorado, South Dakota, Arkansas) where Harris’s Sparrow occurs with some regularity
during winter were reviewed, but sample sizes were too small to provide meaningful results
or generate trends, and are therefore not discussed further. Analyses were not conducted
for Canada or Mexico, given the small sample size for these regions.
The CBC trend analysis consisted of fitting simple linear regressions through effort-
adjusted annual indices (birds per party hour), with trends expressed as geometric mean
rates of change between the first year value of the line and the final year value (Smith et al.
2014). Annual indices consisted of single data points for each region-year, calculated as
averages of all the CBC count circles per year, as available for download using the
historical results by species filter from National Audubon Society (2015). Statistical
significance was determined by P-values (P<0.05) describing the slope of the regression
line. Data were analyzed using R v.3.2.3 (R Core Team 2015).
Manitoba Breeding Bird Atlas
The Manitoba Breeding Bird Atlas (MBBA), provides the first systematic mapping of
the province’s breeding birds. Field data were collected over 2010 2014 (Manitoba
Breeding Bird Atlas 2015). Coverage varied, especially in the Far North within the breeding
range of Harris’s Sparrow; overall 30% of atlas squares (10 km x 10 km) received at least
some coverage, and effort of ≥10 hrs was considered adequate to detect the majority of
species occurring in a square (Artuso pers. comm. 2016).
As this is the first breeding bird atlas for the province, data collected were only used to
determine occurrence and abundance, but not trends.
eBird
eBird is a real-time, interactive, online checklist program, to which observers submit
their observations (eBird 2016). The data can be compiled to summarize distribution and
abundance patterns, and can then be used for conservation and educational purposes
(eBird 2016). This program is relatively young (created in 2002) and usership has steadily
increased since inception (eBird 2016). Although eBird data contain substantial bias in the
form of false-positives, it was determined that these data should be presented, given the
paucity of other data for Harris’s Sparrow and to compare with CBC data trends.
16
For the purpose of this status report, data were analyzed from the species’ core non-
breeding range in the United States (Texas, Oklahoma, Kansas, and Nebraska) as well as
these states individually, and two peripheral states (Iowa and Missouri) with sufficient
quantities of data. Data were compiled for the months of December through February, and
were used to generate the mean frequency of observations per checklist, to determine a
trend analysis from 2004 2014.
Statistical modelling was conducted in the same manner as the CBC data analysis
described above, using frequency of checklist observation as the method to calculate year-
adjusted trends.
Canadian Migration Monitoring Network (CMMN)
The Canadian Migration Monitoring Network is a joint program, run by individual
observatories in collaboration with Bird Studies Canada and the Canadian Wildlife Service,
aimed at monitoring landbird populations throughout Canada (Bird Studies Canada 2016).
The CMMN includes over 25 monitoring stations throughout Canada that track landbird
populations through standardized monitoring programs, such as mist-netting and daily
censuses (Bird Studies Canada 2016).
Data were analyzed from the only CMMN sites within the narrow migration corridor of
Harris’s Sparrow, Delta Marsh in Manitoba and Last Mountain Lake Bird Observatory in
Saskatchewan. Data from Delta Marsh Bird Observatory were analyzed from 2006 2010
in spring and 1993 2010 in fall. Data from Last Mountain Lake Bird Observatory were
analyzed from 1994 2014 in spring and 1993 2014 in fall.
Trend analyses were generated by NatureCounts (2016), using the ‘Population
Trends’ tool. Statistical modelling was conducted using census and banding totals to
calculate year-adjusted trends.
Abundance
Based principally on data extrapolated from the Christmas Bird Count, an estimate by
Blancher et al. (2007) suggested that the population was 500,000 5,000,000; however, it
should be noted that data for this species were limited. Based on more current data, the
revised population estimate by Rosenberg et al. (2016) is a population of approximately
2,000,000 individuals. Given that the entire breeding population occurs within Canada, this
estimate equates to the Canadian population.
Preliminary results from the Manitoba Breeding Bird Atlas suggest that 200 atlas
squares (10 x 10 km) recorded breeding evidence for Harris’s Sparrow. Breeding evidence
for the species was most commonly recorded as possible (118 squares), with probable (62)
and confirmed (20) squares less common (MBBA 2015). In atlas squares where Harris’s
Sparrows were observed, the species was observed on 44.4% of all point counts (n =
1,096), with a mean abundance of 0.71 birds per count (n = 2,469). Additional data shared
by the Manitoba Breeding Bird Atlas indicate that the probability of detection is high (i.e.,
17
>70%) within extreme northwestern Manitoba, even along the Hudson Bay coast east of
the Nelson River to the Ontario border, despite the scarcity of previous observations there
(Artuso pers. comm. 2016, unpubl.).
Studies conducted by Gillespie and Kendleigh (1982) and Norment (1992b) in
Manitoba and Northwest Territories suggest that densities range from 0.125 0.82 pairs
per ha in suitable habitat. However, average density throughout the species range remains
unknown.
Fluctuations and Trends
Christmas Bird Counts
Data from the Christmas Bird Count (CBC; Table 1; Figure 4) indicate that over 35
years (1980 2014), Harris’s Sparrow has experienced a statistically significant long-term
decline of -2.58% per year (P <0.001), representing a reduction in the total population
through this timeframe of 59%. This rate of decline appears to have lessened in the past 10
years (-1.77% per year, P=0.211), equating to a statistically not significant estimated
reduction in the total population of 15% from 2004 to 2014.
CBC data from three of the four core non-breeding states (Texas, Oklahoma, and
Nebraska) indicate significant long-term annual rates of decline (-3.18%, -0.94%, -7.03%,
respectively), while in the remaining state (Kansas), there has been a statistically significant
short-term (10 year) decline (-9.48% per year).
Trends from the peripheral states examined (Missouri and Iowa) were predominantly
positive, but not significant. These states account for a small proportion of wintering Harris’s
Sparrows and do not reflect the overall trend of the species.
Table 1. Summary of Harris’s Sparrow population trends over the past 10 and 35 years,
according to the Christmas Bird Count (National Audubon Society 2015). * denotes P<0.05, **
denotes P<0.001, and ns denotes not significant.
Region
Period
Annual rate of change (%/year)
P value
USA
1980 2014
-2.58
**
USA
2004 2014
-1.77
ns
Texas
1980 2014
-3.18
**
Texas
2004 2014
+14.17
ns
Oklahoma
1980 2014
-0.94
*
Oklahoma
2004 2014
-1.55
ns
Nebraska
1980 2014
-7.03
**
Nebraska
2004 2014
+2.96
ns
Kansas
1980 2014
-0.78
ns
Kansas
2004 2014
-9.48
*
Missouri
1980 2014
+0.33
ns
Missouri
2004 2014
+11.34
ns
Iowa
1980 2014
-1.01
ns
Iowa
2004 2014
+10.66
ns
18
Figure 4. Annual trends of Harris’s Sparrow observations (1980 2014) from the Christmas Bird Count (National
Audubon Society 2015), in the USA, Kansas, Nebraska, Oklahoma, and Texas.
19
The only significant trend over the short-term period was in Kansas (-9.48%; P <0.05).
In Texas, a dramatic increase of 14.2% per year has been observed; however, it is not
statistically significant at ɑ=0.05 (P = 0.099). Potential explanations for this include
concentration of the species in suitable habitat, as a result of habitat losses (due to
agricultural conversion) in the northern extent of its wintering range, or harsher winters
forcing the species farther south in recent winters. While there appears to be some
plasticity in winter distribution from year to year, no consistent change in area of winter
occurrence is evident.
eBird
For the purpose of this status report, data from eBird have been compared with data
from the CBC. Based on trend analyses for the 2004 2014 time period, significant trends
were noted for the core non-breeding states overall (-13.47%, P=0.031; Figure 5) as well as
Missouri (+11.09%, P=0.035) (Table 2). While the downward trend for the core wintering
states as a group is larger than that indicated by the CBC, both programs point to
significant overall declines over the short or long term. Non-significant declining trends were
noted for Texas, Oklahoma, Kansas, and Iowa, while observations in Nebraska increased.
Figure 5. eBird records (eBird 2016) of Harris’s Sparrow (2004 2014), December February in the core non-breeding
states within the USA.
20
Table 2. Summary of Harris’s Sparrow population trends over the past ten years, according
to eBird (2016) data adjusted to the frequency of observation during the December 1
February 28 period of 2004 2014. * denotes P<0.05, ** denotes P<0.001, and ns denotes not
significant.
Region
Period
Annual rate of change (%/year)
P value
Core non-breeding states
2004 2014
-13.47
*
Texas
2004 2014
-1.91
ns
Oklahoma
2004 2014
-2.39
ns
Nebraska
2004 2014
+8.16
ns
Kansas
2004 2014
-1.54
ns
Missouri
2004 2014
+11.09
*
Iowa
2004 2014
-4.38
ns
Canadian Migration Monitoring Network (CMMN)
Data from the CMMN indicate that significant trends were detected for Last Mountain
Lake Bird Observatory, Saskatchewan, but not from Delta Marsh Bird Observatory,
Manitoba. At Last Mountain Lake, Harris’s Sparrow has undergone a significant decline
throughout the fall long-term dataset (1993 2014); however, both spring (Figure 6) and fall
(Figure 7) datasets indicate a short-term (2004 2014) increase (24.23% and 1.41%
respectively), with the spring trend being significant.
Figure 6. Last Mountain Lake Bird Observatory trends of Harris’s Sparrow (1994 2014) in spring; * denotes a
significant trend.
21
Figure 7. Last Mountain Lake Bird Observatory trends of Harris’s Sparrow (1993 2014) in fall; * denotes a significant
trend.
Data from Delta Marsh Bird Observatory indicate non-significant trends for both spring
(short-term; Figure 8) and fall (long-term; Figure 9) datasets. Spring data (20042010)
indicate an increase of 12.56% per year, while fall data (1993 2010) indicate a decrease
of -0.02% per year.
Figure 8. Delta Marsh Bird Observatory trends of Harris’s Sparrow (2006 2010), spring.
22
Figure 9. Delta Marsh Bird Observatory trends of Harris’s Sparrow (1993 2010), fall.
Rescue Effect
Not applicable. Harris’s Sparrow is an endemic breeding species in Canada; as such
there is no potential for rescue from outside populations.
THREATS AND LIMITING FACTORS
Threats are described below and summarized in Appendix 1 based on a modified
version of the IUCN-CMP (World Conservation Union-Conservation Measures Partnership)
unified threats classification system (COSEWIC 2014), which resulted in an overall score
for Harris’s Sparrow of high to medium.
Category 9.3: Agricultural and forestry effluents (low to high threat)
Pesticide use throughout the wintering grounds has been linked to declines in
grassland birds (Norment pers. comm. 2016). Neonicotinoids in particular have been
implicated in widespread declines of a variety of taxa in the last decade (Hallmann et al.
2014; Gibbons et al. 2015). The degree to which pesticides have historically or are currently
affecting Harris’s Sparrow is unclear (Norment et al. 2016), but severity is likely slight at
minimum, and could be moderate to serious.
Category 1.1: Housing and urban areas (low threat)
Residential and, to a lesser extent, commercial developments may be removing
suitable wintering habitat for Harris’s Sparrow (Norment et al. 2016); however, development
is largely confined to the fringes of existing urban areas. Window kills may represent the
greatest concern with respect to this threat (Bracey et al. 2016); however, no studies have
specifically documented the frequency of window kills of Harris’s Sparrow.
23
Category 4: Transportation and service corridors (low threat)
Most Harris’s Sparrows are exposed to roads on their wintering grounds, and as
terrestrially foraging birds, they may be at risk of vehicle collisions (Molhoff 1979), though
only a small percentage of individuals are likely to be affected, and the overall effect is likely
low. Transmission and distribution lines are unlikely to pose more than a negligible collision
risk and may actually be neutral or beneficial to Harris’s Sparrow on the wintering grounds
by providing suitable habitat (Norment et al. 2016).
Category 8.1: Invasive non-native/alien species (low threat)
Cat predation is a possible threat on wintering grounds, given the overall extent of this
issue and the particular vulnerability of birds that forage terrestrially (Blancher 2013; Loss
et al. 2013); while no reports have specifically addressed cat predation on Harris’s Sparrow
to date, it is nonetheless likely a credible concern.
Negligible and unknown threats:
Increases in the population of various raptors (e.g., Sharp-shinned Hawk (Accipiter
striatus), Cooper’s Hawk (A. cooperii), and Peregrine Falcon (Falco peregrinus)) may be
resulting in greater predation risk on Harris’s Sparrow through its annual cycle (Sauer et al.
2014), although it is unclear to what extent, and this threat is currently assessed as
unknown.
The conversion of grassland and fringe lands for agricultural purposes in the
Midwestern United States could be one of the most important factors in the Harris’s
Sparrows decline (Norment pers. comm. 2016; Norment et al. 2016). Within the species’
northern wintering range limit (i.e., Nebraska, South Dakota, Iowa, Missouri, and Kansas),
approximately 530,000 ha of grass-dominated land cover was converted to cropland
between 2006 and 2011 (Wright and Wimberly 2013); similar changes have been
documented in the core wintering range in Texas, Nebraska, Kansas, and Oklahoma and
are negatively affecting a suite of grassland species in this region (Coppedge et al. 2001;
Evans and Potts 2015). Clearing of hedgerows and other shelterbelts in association with
agricultural intensification and the reduction of fringe lands may be particularly detrimental
towards the species (Norment et al. 2016). However, because Harris’s Sparrow uses open
habitat and may feed on waste grain, the net effect of agriculture (Threat Category 2) is
unknown at this time.
Oil and gas and renewable energy developments (Threat Category 3) may represent
potential threats to a wide group of species, including Harris’s Sparrow, given the large
areas required for infrastructure placements (Preston and Kim 2016) and potential causes
of mortality, especially at wind energy facilities (Zimmerling et al. 2013; Bird Studies
Canada et al. 2016). However, these potential impacts have not been studied with respect
to Harris’s Sparrow in particular and it has been noted that right-of-way areas may actually
be beneficial for the species (Norment pers. comm. 2016); therefore these effects are
24
currently considered negligible to unknown. Effects of mining are considered negligible,
since up to 2.8% of the Harris’s Sparrow’s breeding range is within 10 km of mines or
exploratory quarries (Fournier and Carrière pers. comm. 2016), but the primary effect of
vegetation clearing for mines would be over a smaller area and associated impacts, such
as increased vehicle traffic, would be increased.
Within the breeding range, fire has potential to negatively affect nesting success in a
given year (Black and Bliss 1980; Arsenault and Payette 1992; Flannigan et al. 2001), but
also to positively affect the species through creating habitat openings suitable for nesting.
As such, the net effects of fire and fire suppression (Threat Category 7.1) are considered
unknown.
Climate change (Threat Category 11) may reduce the forest-tundra zone located along
the southern edge of the species’ breeding range and potentially result in a geographic shift
northwards (Rizzo 1988; Zoltai 1988; Payette et al. 2001). The species’ response to treeline
shifts northward is supported through the change in observations of the species in the
Churchill, MB region dating back to the 1930s, when the species was more common,
compared to the present day (Jehl and Smith 1970; Jehl 2004; Di Labio pers. comm. 2015).
Additionally, climate change may result in more severe weather events which could have
negative impacts on survival rates of nestlings (Norment et al. 2016). Range expansions of
mammalian predators, such as Red Fox (Vulpes vulpes) (Naughton 2012), and flying
ectoparasites (e.g., biting midges (Diptera: Ceratopogonidae) and mosquitoes (Diptera:
Culicidae) (Tomás et al. 2008) may result from climate change, and negatively impact
nestling Harris’s Sparrows.
PROTECTION, STATUS AND RANKS
Legal Protection and Status
In Canada, Harris’s Sparrow and its nest and eggs are protected under the Migratory
Birds Convention Act (MBCA 1994). The MBCA prohibits the sale or possession of
migratory birds and their nests, and any activities that are harmful to migratory birds, their
eggs, or their nests, except as permitted under the Migratory Bird Regulations. It is similarly
protected in the United States under the Migratory Birds Treaty Act (1918).
Non-Legal Status and Ranks
Harris’s Sparrow is ranked as Least Concern on the IUCN Red List by BirdLife
International (2015) and Globally Secure (G5; reviewed 1996) by NatureServe Explorer
(2015). In Canada the species is ranked as Secure, Breeding and Nonbreeding (N5B and
N5N); within Nunavut the species is not ranked (SNR), in Saskatchewan it is ranked Secure
(S5), while in Manitoba and the Northwest Territories the species is listed as Vulnerable
(S3; NatureServe Explorer 2015). Within Texas, the species is ranked as Apparently Secure
(S4; NatureServe Explorer 2015). The species has not been ranked elsewhere.
25
Habitat Protection and Ownership
Harris’s Sparrow is reported to breed in Wapusk National Park in Manitoba and likely
also does in Tuktut Nogait National Park in Northwest Territories. Individuals may pass
through other protected areas during migration or on the wintering grounds, but overall
there is limited legal protection of habitat throughout the Harris’s Sparrow’s annual range.
ACKNOWLEDGEMENTS AND AUTHORITIES CONTACTED
Many people responded to a general request for information on Harris’s Sparrow in
Canada and the USA, including the following people: Ken Abraham, Christian Artuso, Bruce
Bennett, David Britton, Dick Cannings, Syd Cannings, Suzanne Carrière, Vanessa
Charlwood, Mike Chutter, Bruce Di Labio, Kiel Drake, Cameron Eckert, Bonnie Fournier,
Marcel Gahbauer, Samuel Hache, Audrey Heagy, Reid Hildebrandt, Rudolf Koes, Tom
Jung, Bruce MacDonald, Scott MacDougall-Shackleton, Stuart Mackenzie, Jon McCracken,
Patrick Nantel, Chris Norment, Joachim Obst, Rhiannon Pankratz, Lisa Pirie-Dominix,
Jennie Rausch, James Rising, Rich Russell, Pamela Sinclair, Sonia Schnobb, Don
Sutherland, Doug Tate, Phil Taylor, Doug Tozer, and Ken Tuininga. In addition to those who
all provided information, the report writer would like to thank the appropriate Conservation
Data Centres, Natural Heritage Information Centres, and the Parks Canada Agency for
input on the species.
This report was greatly aided by comments received from the following people: Mike
Burrell, Richard Elliot, Marcel Gahbauer, Elaine Gosnell, Lillian Knopf, Nathan Miller, and
David Stephenson.
Doug Tozer kindly helped with the statistical analysis of the Christmas Bird Count
data, which was integral to this status report. Lillian Knopf created Figures 4 and 5. Gerry
Schaus created Figure 1 and completed the EOO calculation, per guidance from Jenny Wu.
INFORMATION SOURCES
American Ornithologists’ Union (AOU). 1998. Check-list of North American birds: the
species of birds of North America from the Arctic through Panama, including the
West Indies and Hawaiian Islands. Seventh edition, American Ornithologists’ Union,
Washington, D.C.
Arsenault, D., and S. Payette. 1992. A post-fire shift from lichen-spruce to lichen-tundra
vegetation at tree line. Ecology 73:1007-1018.
Artuso, C., pers. comm. 2016. Email correspondence to K.G.D. Burrell. January 2016.
Manitoba Projects Manager, Bird Studies Canada, Winnipeg, Manitoba.
BirdLife International. 2015. Species factsheet: Zonotrichia querula. Web site:
http://www.birdlife.org [accessed December 2015].
26
Bird Studies Canada. 2016. About the Canadian Migration Monitoring Network. Web
site: http://www.birdscanada.org/volunteer/cmmn/index.jsp?targetpg=about
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BIOGRAPHICAL SUMMARY OF REPORT WRITER(S)
Kenneth Burrell is a biologist with Natural Resource Solutions Inc. (NRSI), an
environmental consulting firm, located in Waterloo, Ontario. At NRSI, Kenneth serves as
the lead ornithological consultant and specializes in natural resource inventories and
evaluations, research and impact studies. Kenneth is actively involved in the Ontario
birding community, including eBird and the Ontario Field Ornitholgoists, serving on the
Board of Directors since 2014 and the Ontario Bird Records Committee since 2011. Since
completion of his MSc in 2013, Kenneth has published papers covering a range of topics in
field ornithology, including spring reorientation flights in the Pelee region, hybrid warblers,
eBird and its applications, and most recently on the assignment of stable isotopes in
determining species origins.
COLLECTIONS EXAMINED
No collections were examined.
32
Appendix 1. Threats Assessment Worksheet for Harris’s Sparrow.
Species or Ecosystem Scientific Name
Harris's Sparrow
Element ID
Elcode
ABPBXA405
Date (Ctrl + ";" for today's date):
26/09/2016
Assessor(s):
Kenneth Burrell, Dave Fraser, Marcel Gahbauer, Suzanne Carrière, Richard Elliot, Pam
Sinclair, Myles Lamont, Chris Norment, Rudolf Koes, Jim Rising, Samuel Hache, Amy
Ganton, Joanna James
References:
Overall Threat Impact Calculation Help:
Level 1 Threat Impact Counts
Threat Impact
high range
low range
A
Very High
0
0
B
High
1
0
C
Medium
0
0
D
Low
3
4
Calculated Overall Threat Impact:
High
Medium
Assigned Overall Threat Impact:
BC = High - Medium
Impact Adjustment Reasons:
Overall Threat Comments
Several categories are unknown, and
trend data are more limited than for
some other birds. However, the range
of medium-high is likely appropriate
given the best available information.
Threat
Impact
(calculated)
Scope (next 10
Yrs)
Severity (10
Yrs or 3 Gen.)
Timing
Comments
1
Residential &
commercial
development
D
Low
Large (31-70%)
Slight (1-10%)
High
(Continuing)
Overall low human population
within the breeding grounds,
not
expected to affect the species.
Within wintering range,
development may be displacing
suitable habitat, but largely limited
to fringes of existing urban areas.
Window kills may be the greatest
concern with respect to this threat,
but magnitude has not
been
documented for this species in
particular.
1.1
Housing & urban areas
D
Low
Large (31-70%)
Slight (1-10%)
High
(Continuing)
The focus for this threat is an
increase in housing in the
wintering range, with a specific
focus on window kills and the
effects of housing in urban areas.
However, urban expansion within
the wintering range is generally not
rapid. While the species frequents
backyard feeders and may
therefore have some tolerance to
suburban expansion, this also
increases risk of window collisions.
This may also be a risk along parts
of the migratory route, although
specific evidence is lacking.
1.2
Commercial &
industrial areas
Negligible
Negligible (<1%)
Unknown
High
(Continuing)
33
Threat
Impact
(calculated)
Scope (next 10
Yrs)
Severity (10
Yrs or 3 Gen.)
Timing
Comments
1.3
Tourism & recreation
areas
Negligible
Negligible (<1%)
Slight (1-10%)
Moderate
(Possibly in the
short term, < 10
yrs)
May be some slight impact through
the breeding grounds associated
with lodges; unknown to what
extent, however. Score applies to
entire range (life cycle) of the
species.
2
Agriculture &
aquaculture
Unknown
Unknown
Unknown
Unknown
2.1
Annual & perennial
non
-timber crops
Unknown
Unknown
Unknown
Unknown
Threat applies primarily to winter
range, and to a lesser extent
migratory routes, but not breeding
range. The species
prefers open
habitat with adjacent shelter (e.g.,
hedgerows), and as such, loss or
conversion of such habitat could
be a threat, but more data are
required to understand potential
scope and severity.
2.2
Wood & pulp
plantations
Negligible
Negligible (<1%)
Unknown
High
(Continuing)
This threat could be present in the
wintering range to a minimal
extent.
2.3
Livestock farming &
ranching
Pasture land may provide good
habitat, with a mix of grassy and
shrubby areas
2.4
Marine & freshwater
aquaculture
3
Energy production &
mining
Negligible
Negligible (<1%)
Extreme -
Serious (31
-
100%)
High
(Continuing)
3.1
Oil & gas drilling
Unknown
Small (1-10%)
Unknown
Moderate
(Possibly in the
short term, < 10
yrs)
Minimal scope within breeding
range; somewhat more within
wintering range, but severity is
unclear because pipeline right
-of-
way habitat can be attractive for
this species and disturbance would
be limited to development periods.
Fracking is occu
rring in parts of
the wintering grounds, but effects
on Harris's Sparrow have not been
documented.
3.2
Mining & quarrying
Negligible
Negligible (<1%)
Extreme -
Serious (31
-
100%)
High
(Continuing)
Some mining and exploratory
quarries expected to be developed
within the
breeding range in the
near future. With a conservative 10
km buffer around each proposed
mine, this could account for 2.8%
of the breeding range, but the
primary effect of direct habitat loss
would be limited to a fraction of
this area, although some less
intense effects of noise and dust
may extend farther. This threat
does not apply to the wintering
grounds.
3.3
Renewable energy
Negligible
Negligible (<1%)
Unknown
High
(Continuing)
Some solar and wind energy
developments exist within the
wintering
range, and more are
likely to be built, but effects on this
species are unclear
34
Threat
Impact
(calculated)
Scope (next 10
Yrs)
Severity (10
Yrs or 3 Gen.)
Timing
Comments
4
Transportation &
service corridors
D
Low
Pervasive (71-
100%)
Slight (1-10%)
High
(Continuing)
4.1
Roads & railroads
D
Low
Pervasive (71-
100%)
Slight (1-10%)
High
(Continuing)
Most individuals are likely exposed
to roads and railroads on wintering
grounds; few exist on breeding
grounds, though increasing
somewhat. As there is no evidence
that this species is particularly
susceptible to vehicle collisions,
severity is considered slight.
4.2
Utility & service lines
Unknown
Pervasive - Large
(31-100%)
Unknown
High
(Continuing)
Many to most individuals are likely
exposed to utility and service lines
on migration and on wintering
grounds, but collision risk is
expected to be minimal, and in
some situations, rights
-of-
way may
have a positive effect through
providing suitable habitat for the
species; overall the severity is
unknown.
4.3
Shipping lanes
4.4
Flight paths
5
Biological resource use
5.1
Hunting & collecting
terrestrial animals
5.2
Gathering terrestrial
plants
5.3
Logging & wood
harvesting
5.4
Fishing & harvesting
aquatic resources
6
Human intrusions &
disturbance
Negligible
Negligible (<1%)
Unknown
High
(Continuing)
6.1
Recreational activities
Negligible
Restricted (11-
30%)
Negligible (<1%)
High
(Continuing)
Very low human population
throughout the breeding range,
and even on wintering range,
effects of recreational activities
expected to be negligible.
6.2
War, civil unrest &
military exercises
Negligible
Negligible (<1%)
Unknown
High
(Continuing)
6.3
Work & other activities
7
Natural system
modifications
Unknown
Restricted (11-
30%)
Unknown
High
(Continuing)
7.1
Fire & fire suppression
Unknown
Restricted (11-
30%)
Unknown
High
(Continuing)
Forest fires are known to occur at
the southern extent of its range.
While they have potential to
affect
the species negatively (e.g., loss
of nests), they can also have a
positive influence (e.g., creation of
new habitat); as such, severity at
present is considered unknown.
7.2
Dams & water
management/use
7.3
Other ecosystem
modifications
35
Threat
Impact
(calculated)
Scope (next 10
Yrs)
Severity (10
Yrs or 3 Gen.)
Timing
Comments
8
Invasive & other
problematic species &
genes
D
Low
Large (31-70%)
Slight (1-10%)
High
(Continuing)
8.1
Invasive non-
native/alien species
D
Low
Large (31-70%)
Slight (1-10%)
High
(Continuing)
Cat predation is a concern for
most terrestrial birds, and likely to
cause some mortality on wintering
grounds and along parts of
migratory routes.
8.2
Problematic native
species
Unknown
Unknown
Unknown
High
(Continuing)
Increases in populations of various
raptors
(e.g., Sharp-
shinned Hawk,
Cooper's Hawk, Peregrine Falcon)
may be increasing predation
pressure throughout the annual
cycle, but data specific to Harris's
Sparrow are lacking. On the
breeding grounds, northward
range expansion and increasing
abundance of
Red Foxes and
blood
-sucking insects potentially
may also pose a risk to Harris's
Sparrow, but more research is
required to determine potential
effects.
8.3
Introduced genetic
material
9
Pollution
BD
High - Low
Pervasive - Large
(31-100%)
Serious - Slight
(1-70%)
High
(Continuing)
9.1
Household sewage &
urban waste water
9.2
Industrial & military
effluents
9.3
Agricultural & forestry
effluents
BD
High - Low
Pervasive - Large
(31-100%)
Serious - Slight
(1
-70%)
High
(Continuing)
Harris's Sparrow could encounter
pesticides (such as neonicotinoids)
in its wintering range and during
migration, especially because it
consumes seeds. While the
severity of the effect is unclear, it
is almost certainly negative and
coul
d potentially be considerable,
through direct effects (from eating
seeds) or indirect effects
(reduction in insect prey).
9.4
Garbage & solid waste
9.5
Air-borne pollutants
9.6
Excess energy
10
Geological events
10.1
Volcanoes
10.2
Earthquakes/tsunamis
10.3
Avalanches/landslides
11
Climate change &
severe weather
Not
Calculated
(outside
assessment
timeframe)
Pervasive (71-
100%)
Unknown
Low (Possibly
in the long
term, >10 yrs)
36
Threat
Impact
(calculated)
Scope (next 10
Yrs)
Severity (10
Yrs or 3 Gen.)
Timing
Comments
11.1
Habitat shifting &
alteration
Unknown
Small (1-10%)
Unknown
High
(Continuing)
There is some evidence of shifting
range in relation to climate
change, including greater shrub
cover in some parts of the
breeding range, compared to a
decline in occurrence around
Churchill, Manitoba, which may be
related to drying out of land
because of
isostatic rebound.
Overall, a northward shift in range
is expected as temperatures
increase, but whether there will be
a net effect on the population is
unknown.
11.2
Droughts
11.3
Temperature extremes
Not
Calculated
(outside
assessment
timeframe)
Pervasive (71-
100%)
Unknown
Low (Possibly
in the long
term, >10 yrs)
The species is vulnerable to
extreme temperature fluct
uations
during nesting, when chicks are
unable to cope with body heat
regulation. It is possible that
climate change may
bring greater
temperature fluct
uations, but likely
only in the longer term, and
severity is difficult to predict at this
point.
11.4
Storms & flooding
Classification of Threats adopted from IUCN-CMP, Salafsky et al. (2008).
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