ArticlePDF Available

Distribution, habitat use, and implications for the conservation of the globally threatened Azure-rumped Tanager Tangara cabanisi in Guatemala

Authors:
  • Eisermann & Avendaño Bird Studies Guatemala
  • University of Greifswald - Partner in the Greifswald Mire Centre

Abstract and Figures

The Azure-rumped Tanager Tangara cabanisi is a globally threatened species restricted to the Pacific slope mountains of western Guatemala and Chiapas, Mexico. We studied the habitat use of this tanager on the southern slope of Atitlán volcano, department Suchitepéquez, Guatemala, applying distance sampling along transects in humid broadleaf forest and coffee plantations. The tanager was recorded in both habitat types, but encounter rates were significantly greater in broadleaf forest. The estimated density of tanagers in forest at 1,400–1,900 m was 33–93 birds km−2. Tanagers were recorded mainly in the upper vegetation strata of forest and shade coffee plantations. In coffee plantations tanagers used mainly tall solitary trees or the canopy of shade trees, which were dominated by Inga spp. The number of observations of feeding tanagers in Ficus aurea (Moraceae) indicated a high importance of this food source. The density of F. aurea trees and the encounter rate of tanagers were positively correlated. From 1987 to 2009 tanagers have been recorded at nine topographic units and a total of 16 sites in Guatemala, in the departments of San Marcos, Quetzaltenango, Sololá, Suchitepéquez, and Chimaltenango. We analysed the available habitat for tanagers in the potential area of distribution (1,170 km2), ranging from 900 to 1,900 m altitude and from the Mexican border in the West to the municipality of Pochuta in the East. Broadleaf forest covers 250 km2 or 21% of the potential area of distribution, and coffee plantations cover 800 km2 or 68%. Assuming that population density in prime habitat throughout the potential distribution range is similar to our study area at Atitlán volcano, total tanager population in Guatemala is estimated to be 8,250–23,250 birds. Our findings support the maintenance of the IUCN Red List status of Endangered EN B1a+b(ii,iii,v). To enhance the available habitat for Azure-rumped Tanager, we propose alterations in the shade management of coffee plantations, supported by incentives and certification programmes.
Content may be subject to copyright.
Bird Conservation International (2011)21:423437. © BirdLife International, 2011
doi:10.1017/S0959270910000638
Distribution, habitat use, and implications for
the conservation of the globally threatened
Azure-rumped Tanager Tangara cabanisi in
Guatemala
KNUT EISERMANN, SUSANNE ARBEITER, GERARDO LÓPEZ, CLAUDIA
AVENDAÑO and JOSUÉ DE LEÓN LUX
Summary
The Azure-rumped Tanager Tangara cabanisi is a globally threatened species restricted to the
Pacic slope mountains of western Guatemala and Chiapas, Mexico. We studied the habitat use of
this tanager on the southern slope of Atitlán volcano, department Suchitepéquez, Guatemala,
applying distance sampling along transects in humid broadleaf forest and coffee plantations. The
tanager was recorded in both habitat types, but encounter rates were signicantly greater in
broadleaf forest. The estimated density of tanagers in forest at 1,4001,900 m was 3393 birds
km
2
. Tanagers were recorded mainly in the upper vegetation strata of forest and shade coffee
plantations. In coffee plantations tanagers used mainly tall solitary trees or the canopy of shade
trees, which were dominated by Inga spp. The number of observations of feeding tanagers in
Ficus aurea (Moraceae) indicated a high importance of this food source. The density of F. aurea
trees and the encounter rate of tanagers were positively correlated. From 1987 to 2009 tanagers
have been recorded at nine topographic units and a total of 16 sites in Guatemala, in the
departments of San Marcos, Quetzaltenango, Sololá, Suchitepéquez, and Chimaltenango. We
analysed the available habitat for tanagers in the potential area of distribution (1,170 km
2
),
ranging from 900 to 1,900 m altitude and from the Mexican border in the West to the
municipality of Pochuta in the East. Broadleaf forest covers 250 km
2
or 21% of the potential area
of distribution, and coffee plantations cover 800 km
2
or 68%. Assuming that population density
in prime habitat throughout the potential distribution range is similar to our study area at Atitlán
volcano, total tanager population in Guatemala is estimated to be 8,25023,250 birds. Our
ndings support the maintenance of the IUCN Red List status of Endangered EN B1a+b(ii,iii,v).
To enhance the available habitat for Azure-rumped Tanager, we propose alterations in the shade
management of coffee plantations, supported by incentives and certication programmes.
Resumen
La Tángara de Cabanis Tangara cabanisi es una especie globalmente amenazada que está
restringida a las montañas de la vertiente Pacíca en el oeste de Guatemala y a Chiapas, México.
Estudiamos el uso de hábitat de esta tángara en la vertiente sur del volcán Atitlán, departamento
de Suchitepéquez, Guatemala, aplicando el método de distance samplinga lo largo de transectos
en bosque latifoliado húmedo y en plantaciones de café. Las Tángaras de Cabanis fueron
registradas en ambos tipos de hábitat, pero el índice de detección fue signicativamente mayor en
bosque latifoliado. La densidad estimada de la poblacón de la Tángara de Cabanis en bosque de
1,4001,900 m fue de 3393 individuos km
2
. Las tángaras fueron registradas principalmente en
el estrato superior de vegetación. En plantaciones de café las tángaras usaron principalmente
árboles altos solitarios o el dosel de árboles de sombra, que fue dominado por Inga spp. El número
de observaciones de tángaras alimentándose en Ficus aurea (Moraceae) indicó una alta
importancia de este recurso alimenticio. La densidad de árboles de F. aurea y el índice de
detección de Tángara de Cabanis estuvieron positivamente correlacionadas. De 1987 a2009 la
Tángara de Cabanis ha sido registrada en nueve unidades topográcas y un total de 16 lugares en
Guatemala, en los departamentos de San Marcos, Quetzaltenango, Sololá, Suchitepéquez y
Chimaltenango. Analizamos el hábitat disponible para las Tángaras de Cabanis en su área
potencial de distribución (1,170 km
2
), cubriendo desde 900 hasta 1,900 m de altitud, y desde la
frontera con México al oeste hasta el municipio de Pochuta en el este. Los bosques latifoliados
cubren 250 km
2
ó21% de esta área y las plantaciones de café cubren 800 km
2
ó68%. Asumiendo
una densidad de Tángaras de Cabanis similar al área de estudio en volcán Atitlán en todos los
bosques latifoliados, la población total en Guatemala se estima en 8,25023,250 individuos. La
información de uso de hábitat y extensión de hábitat apropiado justica mantener el estado de
Amenazada EN B1a+b(ii,iii,v) en la Lista Roja de UICN. Para aumentar el hábitat disponible para
la Tángara de Cabanis proponemos alteraciones en el manejo de sombra de plantaciones de café,
apoyado por programas de incentivos y certicaciones.
Introduction
The Azure-rumped Tanager Tangara cabanisi is a species of restricted range occurring in the
Pacic slope mountains of Guatemala and Chiapas, Mexico, where it has been reported from
a narrow altitudinal belt between 1,000 and 1,700 m (Parker et al. 1976, Hilty and Simon 1977,
Vannini 1989, Heath and Long 1991, Cooper 2003, Tenez 2005, Valdez et al. 1999, Eisermann
and Avendaño 2006,2007a). South of Lake Atitlán it was rst reported in the Pachuj Reserve in
1999, later also in the Los Andes Reserve in 2000 (Eisermann and Avendaño 2006), and in the Los
Tarrales Reserve in 2004 (Jones 2004).
Information on the ecology of the Azure-rumped Tanager originates mainly from observations
in the Sierra Madre de Chiapas. Brodkorb (1939) collected the rst specimen there in cloud forest,
and Heath and Long (1991) provided information on habitat preferences, where by this time it had
only been recorded in the interior and on the edge of broadleaf forests. They reported Ficus cookii
as the dominant tree species in Azure-rumped Tanager habitat in the El Triunfo Biosphere
Reserve. Ficus cookii belongs to the F. aurea species complex (Berg 2007). Heath and Long (1991)
estimated suitable tanager habitat as 1,125 km
2
in Chiapas. The species is considered Endangered
at a global level because of its small area of distribution and loss of habitat, primarily through the
replacement of broadleaf forests by coffee plantations (Collar et al. 1992, BirdLife International
2008).
The Guatemalan Pacic slope highlands are one of the countrys main areas for coffee
cultivation. Recently, the Azure-rumped Tanager has been observed in both habitat types, humid
broadleaf forest and coffee plantations (Dietsch 2000, BirdLife International 2008). For
Guatemala, the extent of suitable habitat has not yet been quantied. Here we quantify the
use by the species of forest and coffee plantations, and then analyse the extent of suitable habitat
throughout Guatemala. Because we observed feeding tanagers mainly in Ficus aurea trees, we
furthermore determine the correlation of the population density of this tree with the abundance
of Azure-rumped Tanager. We provide implications for conservation of this species.
Methods
Study area
The Azure-rumped Tanagers known area of distribution in the western Pacic slope mountains
of Guatemala is characterised by a chain of several major volcanoes. The altitudinal belt between
K. Eisermann et al. 424
1,000 and 1,900 m is shaped by very pronounced slopes of .30%. The mean annual rainfall
amounts to 2,0004,600 mm, but can locally reach a maximum of 6,000 mm annually. The wet
season extends from April to November with a mean monthly precipitation of 150800 mm, and
the dry season from December to March with mean monthly precipitation of 5150 mm (MAGA
2002).
Annual mean minimum temperature is 15º C; annual mean maximum is 25º C (MAGA 2002).
The natural climax vegetation in this area is humid evergreen broadleaf forest, with broadleaf-
conifer forest in higher and less humid areas. Much of the forest ,1,600 m altitude has been
replaced by coffee plantations and other agricultural crops in the 19th century.
To determine habitat use by Azure-rumped Tanagers, we conducted counts along trails in the
neighbouring private nature reserves Los Tarrales, Los Andes, and San Jerónimo Miramar,
department Suchitepéquez, where the species had been recorded previously (Eisermann and
Avendaño 2007a). The rectangle encompassing all trails had a size of 1,950 ha (geographic
coordinates of the centre point of the rectangle: 14º32N91º10W; Figure 1)
Landcover
For land cover analyses in the potential area of distribution of Azure-rumped Tanager in
Guatemala we used the most recent national landcover mapping at a scale of 1:50,000, based on
Landsat images and ground truthing with local experts (MAGA 2006). Land cover in the study
area on Atitlán volcano was mapped based on orthoimages with a ground resolution of 0.4m,
based on aerial photographs from December 2005 (MAGA 2010) and ground-truthed eld
observation in 2008. We mapped Ficus aurea trees within a total strip width of 120 m along all
transects from orthoimages with some ground-truthing. Software ESRI ArcView GIS 3.2was
used for all spatial analyses.
Figure 1. Study area at Atitlán volcano. The inset map shows the location of the study area in
Guatemala.
Azure-rumped Tanager in Guatemala 425
Vegetation structure
We produced foliage-height proles modied after Blondel and Cuvillier (1977) by determining
vegetation density in 20 strata. We used a 9m long telescopic pole, which was marked from 0.5to
9m, and a laser rangender (Nikon ProStaff Laser 440). Along 15 of 21 transects, four evenly
spaced sites were dened using a handheld GPS device. At each site, foliage coverage was measured
at six points at the perpendicular distance of 10,20, and 30 m on both sites of the transect. At each
point the telescopic pole was positioned vertically, noting whether plants touched the pole on
marks at 0.5,1,1.5,2,2.5,3,4,5,6,7,8, and 9m. Above this height, we used the laser rangender
to determine whether plants touched at the imaginary elongation of the pole at 10,12,15,20,25,
30,35, and 40 m. All measurements were taken by the same observer (KE). The percentage of
presence of plant parts was used as vegetation density index.
Bird surveys
Counts of Azure-rumped Tanagers were conducted along 21 line transects in forest and in coffee
plantations (Table 1, Figure S1, in online supplementary material) applying the distance sampling
method (Buckland et al. 2001). Because habitat distribution was patchy, none of the transects in
coffee plantations was farther than 150 m away from the nearest forest edge. After familiarisation
with the different vocalisations of the tanagers (Eisermann et al. 2011), two observers (SA, GL)
walked along the transect at an average speed of 1km h
1
between 06h15 and 10h00 (sometimes
until 15h30) under favourable weather conditions (i.e. without rain and no or low wind [wind
speed not more than 3on the Beaufort scale]). All tanagers heard and seen were recorded,
together with the following data: number of individuals per ock, perpendicular distance from the
Table 1. Number of Azure-rumped Tanagers recorded at each transect line with an effective strip width
of 60 m.
Transect and
habitat*
Transect
length Ć(m)
Number of Ć
visits
Total
length Ć(m)
Number of Ć
individuals
Number of
individuals Ć/100 m
10 (fh) 1,040 12 12,480 55 0.44
20 (fh) 2,570 7 19,190 90 0.47
22 (fh) 350 7 2,450 5 0.20
23 (fh) 610 21 12,810 8 0.06
24 (fh) 310 5 1,550 5 0.32
26 (fh) 1,340 2 2,680 11 0.41
27 (fh) 300 2 600 11 1.83
2()340 1 340 0 0.00
5()450 1 450 0 0.00
8()1,120 7 7,680 1 0.01
16 ()1,470 7 10,290 7 0.07
17 ()890 6 5,340 0 0.00
11 (ci) 1,480 8 11,840 0 0.00
15 (ci) 520 7 3,640 0 0.00
21 (ci) 730 7 5,110 0 0.00
29 (ci) 1,220 2 2,440 0 0.00
13 (cn) 1,220 9 10,980 8 0.07
14 (cn) 870 16 10,140 0 0.00
25 (cn) 500 5 2,500 0 0.00
30 (cn) 330 10 3,300 2 0.06
31 (cn) 240 6 1,440 0 0.00
*ci: intensive coffee plantation; cn: non-intensive coffee plantation; fh: forest at 1,4001,900 m; : forest at
9001,300 m
K. Eisermann et al. 426
transect (measured with a laser rangender), estimated height of birds above ground and height
of vegetation at the same point. Geographic coordinates of all records were recorded on the trails
using a handheld GPS device (Garmin 60CSx). When tanagers were observed feeding, food
source was noted. Voucher specimens of food plants were deposited in the herbarium BIGU of the
School of Biology of San Carlos University, or in the herbarium AGUAT of the Faculty of
Agronomy of the San Carlos University, both located in Guatemala City (Table S1). Coincidental
observations of Azure-rumped Tanager were recorded together with the geographic coordinates
determined with a GPS device.
Available foot trails were used for line transect counts, which were repeated between one and 21
times from 19 June to 8August 2008. Because data from repeated transect lines are not
independent, we pooled data from all repetitions and calculated with the total transect length of all
repetitions, as recommended by Buckland et al. (2001). Density was estimated using software
Distance 5.0Release 2(Thomas et al. 2006).
To compare mean encounter rates between forest and coffee plantations, we truncated data at
30 m. Each transect line was considered a replication unit and differences in mean values where
compared with a randomisation test with a50.05 using SsS software (Engel 1998). Means are
given together with standard deviation if not otherwise indicated. Geometric Mean Regression
(Ricker 1984, Krebs 1999) was applied to analyse the correlation between the distribution of Ficus
aurea trees and encounter rate of Azure-rumped Tanagers using SsS software (Engel 1998) with
a50.05.
Distribution and population size of Azure-rumped Tanager in Guatemala
As a basis for derivation of total population size of Azure-rumped Tanagers in Guatemala, we
compiled data on the presence of the species in other areas from published references, from our own
occasional observations, from data in eBird Guatemala (http://ebird.org/content/guatemala/), and
from Christmas Bird Counts on Atitlán volcano (http://www.audubon.org/bird/cbc/hr/index.html).
We calculated the total population size for Guatemala assuming that the population density
throughout the remaining prime habitat is similar to the density determined at Atitlán volcano.
Results
Vegetation cover and structure at Atitlán volcano
The Atitlán volcano is one of the major forest patches in the Guatemalan Pacic slope mountains,
although much of the forest below 1,600 m has been replaced by coffee plantations. All coffee
plantations within the study area were shaded monocultures according to a classication by
Perfecto et al. (2005), with a shade cover of 1030% and 15species of shade trees. Within the
study area we discriminated between intensive and non-intensive coffee plantations, classied by
differences in shade coverage and density of coffee shrubs. Vegetation cover within the study area
was as follows: broadleaf forest covered 1,411 ha (72% of the study area), intensive coffee
plantations 337 ha (17%), non-intensive coffee plantations 105 ha (5%), other intensive
plantations (ponytail Beaucarnea recurvata, tea Camellia sinensis and others; complete
nomenclature of all plant names is indicated in Table S1)59 ha (3%), scrub 12 ha (1%), and
orchard-like settlements 14 ha (1%) (Figure S1).
Foliage-height proles show that broadleaf forest along transects was up to 40 m high, with
a dense understorey of herbs and shrubs (including palms) and a dense canopy (Figure 2a,b). Vines
were included in the class of shrubs, which were more abundant in forest at 9001,300 m than in
high-elevation forest at 1,4001,900 m. Coverage of Ficus aurea trees in the canopy was higher in
high-elevation forest.
Coffee plantations had a shrubby understorey with an open canopy of shade trees (Figure 2c,d).
Non-intensive coffee plantations had a low density of coffee shrubs in the understorey, where
Azure-rumped Tanager in Guatemala 427
Figure 2. Foliage height proles of a) broadleaf forest at 1,4001,900 m, b) broadleaf forest at 900
1,300 m, c) non-intensive coffee plantation, and d) intensive coffee plantation. n
1
indicates the
number of transects and n
2
the number of points where vegetation cover was measured. Percent
cover represents the mean percentage of plant touches on a pole in the indicated height classes.
K. Eisermann et al. 428
they compete with native shrubs and herbs. Herbs were absent in intensive coffee plantation
because of intensive use of herbicides. The canopy of shade trees in non-intensive plantations was
dominated by Inga spp. trees (mainly Inga micheliana, but also I. spuria, I. rodrigueziana, and
I. laurina) with a dense cover. Inga trees in intensive plantation were heavily pruned and these
plantations also had non-native species of shade trees (Acrocarpus fraxinifolius,Eucalyptus sp.).
Habitat use, density, and abundance of Azure-rumped Tanagers at Atitlán volcano
Azure-rumped Tanagers were recorded on the south-eastern slope of Atitlán volcano from 860 to
1,900 m in primary humid broadleaf forest, in coffee plantation, and in edge habitat. A total of
134 observations of Azure-rumped Tanager involving 282 birds were recorded during transect
counts between 19 June and 8August 2008. In the forest interior (.30 m from habitat edge)
92 observations (202 birds) were recorded; in forest edge habitat (,30 m to forest edge) 21
observations (38 birds); in the interior of non-intensive coffee plantations three observations (six
birds); in non-intensive coffee plantation edge habitat 11 observations (21 birds); and in intensive
coffee plantation edge habitat 7observation (15 birds). No tanagers were recorded in the interior
of intensive coffee plantations. Because the sample size of tanagers in the interior of coffee
plantations is too small to calculate a detection probability in this habitat, we compare encounter
rates between habitats. For that we used only data of tanagers observed in the interior (.30 m
from the edge) of the sampled habitat, and truncated data at 30 m in order to lower the effect of
higher detection probabilities in coffee plantations than in forests. Mean number of individuals
recorded per 100 m of transect with a strip width of 60 m (Table 1) was signicantly higher in
forest (both types of forest pooled) than in coffee plantations (both types of coffee plantations
pooled) (randomisation test, differences in means 0.303,P,0.05, based on 1,000 permutations).
Mean number of tanagers was also signicantly higher in high-elevation forest (tanagers prime
habitat) versus non-intensive coffee plantation (randomisation test, differences in means 0.507,
P,0.05, based on 792 permutations).
Although tanagers were recorded as low as 860 m above sea level, mean encounter rate in
forests 1,4001,900 m(0.53 60.59 birds/100 m) was signicantly higher than in forests at 900
1,300 m(0.02 60.03 birds/100 m) (permutation test, differences in means 0.517,P,0.05,n5
972 permutations), indicating that high-elevation forest is the tanagers main habitat. Sample size
in forests at 1,4001,900 m was sufcient to model detection probability. Along seven transect
lines in forest at 1,4001,900 m with a total sampling effort of 49.2km, 89 detections of Azure-
rumped Tanager were recorded. Data from distance sampling procedure tted best a hazard-rate
distribution, using Akaikes Information Criterion (AIC) for model selection and best goodness-
of-t tested with chi-square test for each interval. A good model t was achieved with data
truncation at 65 m and classication in ve distance intervals (Figure 3). Mean ock size was 2.17
individuals (SE 0.07;95% condence interval: 2.022.33). Estimated density of Azure-rumped
Tanagers in forest at 1,4001,900 m was 26 ocks km
2
(95% condence interval: 1543 ocks
km
2
)or56 birds km
2
(95% condence interval: 3393 birds km
2
) from June to August 2009.
Thus, population size of Azure-rumped Tanager in the approximately 5km
2
of forest between
1,400 and 1,900 m within the study area at Atitlán volcano is estimated to be 165465 individuals.
The largest ock seen during transect counts consisted of ve birds. During occasional
observations of Azure-rumped Tanager, birds were seen usually in pairs or small groups of 34
individuals during the breeding season. After edging, larger groups were seen. A ock of seven
birds was seen on 3September 2009 (GL pers. obs.), among them were two young birds. At least
14 tanagers were observed on 13 August 2008 (GL pers. obs.) moving in the canopy of a Ficus
aurea tree in primary forest, among them were at least ve young birds. We never observed
Azure-rumped Tanagers in true mixed foraging ocks. On occasions when we recorded them
together with other species, for instance with White-winged Tanager Piranga leucoptera on 11
July 2008 (SA and GL pers. obs.) in Los Tarrales, and with Common Bush-tanager Chlorospingus
ophthalmicus on 15 August 2009 in the forest reserve of San Rafael Pie de la Cuesta (KE and CA,
Azure-rumped Tanager in Guatemala 429
pers. obs.), they were apparently together in the same fruit tree by coincidence, and did not move
on together.
The height of observed Azure-rumped Tanagers in vegetation was recorded during transect
counts for 90 detections in forest and edge, and for 16 detections in coffee plantation and edge. The
height above ground ranged in forest from 836 m(24.366.1,n590) and in coffee plantation
from 830 m(18.967.2,n516). Tanagers stayed mainly in the upper vegetation strata, mean
relative height in vegetation was 83%617 (n590) in forests and 83%620 (n516) in coffee
plantations. In coffee plantations tanagers were recorded mainly in solitary large trees (Ficus
aurea and F. costaricana) or in the canopy of shade trees (Inga spp.). Occasionally tanagers were
also seen very low in the understorey, foraging on fruiting shrubs in the forest or collecting nest
material from coffee shrubs as low as 1m above ground.
During transect counts a total of 41 observations of feeding tanagers were recorded, of which 35
were feeding on fruit of the strangler gFicus aurea (Moraceae), one on Ficus costaricana, two on
Rhamnus discolor (Rhamnaceae), one on Trema micrantha var. strigillosa (Ulmaceae), one in
mistletoe Phoradendron heydeanum (Verbanaceae), and one in Perrottetia longistylis (Celas-
traceae). During occasional observations throughout the tanagers range in Guatemala, the species
was seen feeding also on fruit of Miconia sp. (Melastomataceae) (KE and CA pers. obs.), on
Cecropia obtusifolia (Cecropiaceae) (KE, JLL, EB pers. obs.), on Chomelia brachypoda (Rubia-
ceae), on Cestrum sp. (Solanaceae) (KE and CA pers. obs.), and on Urera sp. (Urticaceae) (J. L.
Yuxón pers. comm.) (see Table S1for complete nomenclature of all plant names). Tanagers were
also seen foraging among inorescences of Meriana macrophylla (Melastomataceae), probably on
invertebrates (KE and CA pers. obs.).
The number of observations of feeding tanagers in Ficus aurea suggests a high importance of
that food source. F. aurea is semi-deciduous and the trees are leaess for some weeks in the dry
season and identiable on orthoimages. The density of F. aurea trees within a strip width of 120
m ranged from 02trees ha
1
along all forest transects (Table S2). The slope (0.626 60.149 SE)
of the Geometric Mean Regression line comparing density of F. aurea trees from Table S2versus
number of Azure-rumped Tanagers per 100 m of transect from Table 1is signicantly different
from 0(Students t-test, t54.21,df510,P,0.005), indicating a positive correlation between
the abundance of Azure-rumped Tanager and density of F. aurea trees (Figure 4).
Distribution in Guatemala
The Azure-rumped Tanager has been reported in Guatemala from nine topographic units and
a total of 16 sites from 1987 to 2009, located in the departments of San Marcos, Quetzaltenango,
Figure 3. Histogram of the distance data for Azure-rumped Tanagers detected in forest between
1,400 and1,900 m, and detection functionobtained by tting thehazard-rate model(software Distance
5.0Release 2) to the data which were truncated at 65 m, and grouped into ve distance classes.
K. Eisermann et al. 430
Sololá, Suchitepéquez, and Chimaltenango (Table S3, Figure 5a). The easternmost record is from
Unión Victoria (14º34N91º03W), former Finca El Salvador, municipality Pochuta, 5km
northeast of Pochuta. The potential area of distribution of Azure-rumped Tanager in Guatemala
can be limited by the upper and lower altitudinal limits of all records, as well as the easternmost
record and the Mexican border. This area has a size of 1,170 km
2
.
From information on habitat use in our study area at Atitlán volcano we derived the coverage of
adequate habitat within the potential area of distribution. Based on a nationwide land cover
mapping on the scale 1:50,000 (MAGA 2006), broadleaf forest covers approximately 250 km
2
or
21% of the entire potential area of distribution of Azure-rumped Tanager in Guatemala (Figure
5b). Most of the potential area of distribution is covered by coffee plantations (approximately 800
km
2
or 68%). Largest forest patches are located south of San Marcos (northern part of the
municipalities Tumbador, Nuevo Progreso, and La Reforma), on the southern slope of Lacandón
volcano, on the south-eastern slope of Chicabal volcano, on the southern slopes of Santa María,
Santo Tomás, and Atitlán volcanoes, and on the southern part of the municipality Santiago
Atitlán, and in the valley of the Río Madre Vieja southeast of San Lucas Tolimán (Figure 5b).
Assuming that the density of Azure-rumped Tanagers in all broadleaf forests is similar to the
value determined in the study area at Atitlán volcano, total population of Azure-rumped
Tanagers in Guatemala is estimated to be 8,25023,250 birds.
Discussion
Distribution and conservation status
The type specimen of Azure-rumped Tanager was collected in Costa Cuca (Cabanis 1866, Sclater
1868; type specimen ZMB 18921 reviewed). In the 19th century, Costa Cuca was not a town or
village, but a region of about 1,300 km
2
, which is today the southern part of the department of
Quetzaltenango (Gallini 2009). The type locality has been erroneously attributed to the village
Flores Costa Cuca (elevation 500 m) in several publications (Heath and Long 1991, Collar et al.
1992). All recent records are from the altitudinal range of 8601,900 m, which is a narrow belt
about 10 km wide. Therefore the type specimen had most likely been collected in the upper part of
the former Costa Cuca area. After the type specimen of Azure-rumped Tanager was collected in
the 19th century, only recently have additional localities been reported in the modern department
of Quetzaltenango (Heath and Long 1991, Cooper 2003, Eisermann and Avendaño 2006,2007a).
This study documents an expansion of the altitudinal (8601,900 m) and longitudinal range (east
Figure 4. Encounter rate of Azure-rumped Tanagers in relation to the density of Ficus aurea
trees. The slope of the geometric mean regression line is signicantly different from 0(Students
t-test, t54.21,df510,P,0.005).
Azure-rumped Tanager in Guatemala 431
of the valley of the Nicán river). This species may be expected even further east in Guatemala,
such as on the southern slope of Fuego and Agua volcanoes in the department of Sacatepéquez,
which is supported by an anecdotal record at Pacaya volcano on 12 April 2010 (Dan Poalillo pers.
comm.).
Figure 5. Distribution and habitat availability of Azure-rumped Tanager in Guatemala. a)
Locations of all records in Guatemala, altitudinal zones, and department limits. b) Landcover in
the potential area of distribution, limited by the Mexican border in the West and the easternmost
record, and by contour lines of 900 m and 1,900 m, representing approximate altitudes of the
lowest and highest records.
K. Eisermann et al. 432
The Azure-rumped Tanager has been reported previously from humid broadleaf forest and also
from coffee plantations (Dietsch 2000, BirdLife International 2008). Our comparison of encounter
rates in forest and coffee plantation shows that the species is more abundant in humid broadleaved
forest. In addition, most of our records from coffee plantations were within a distance of 30 m from
forest edge. Thus, the Azure-rumped Tanager is primarily a forest bird, which also uses forest
edge and adjacent open habitat as do many other tanagers (Isler and Isler 1987).
Most of the prime habitat of Azure-rumped Tanager in Guatemala has been converted to coffee
plantations and only 250 km
2
of potential habitat remain (Figure 5b). The tanager is fairly
common and occurs with a density of 3393 birds km
-2
on the southern slope of Atitlán volcano.
It is also common at other sites such as in the departments of San Marcos (Cooper 2003) and
Quetzaltenango (Table S3). However, the species is vulnerable to population declines, because
most of the suitable habitat is located in a zone especially favourable for agriculture, except for the
steepest canyons and mountain slopes. According to recent information on protected areas
(CONAP 2009), within the potential area of distribution, only 370 km
2
(32%) occur within
protected areas, and 138 km
2
(55%) of the remaining broadleaf forest in this area are legally
protected (Table S4), but none of the reserves is a strictly protected area in IUCN categories I or II
(IUCN 1994). Efcient conservation of habitat cannot be guaranteed in the short term in any of
the reserves. Although many of the privately protected areas currently are among the best
protected preserves in Guatemala, driven by a strong personal interest of owners, national law of
protected areas (Decreto 489, Congreso de la República de Guatemala) and its rules (Acuerdo
Gubernativo 75990) do not require a long-term commitment of owners for conservation, nor do
they require continued conservation from future land owners. Guatemalas state reserves lack
adequate management and law enforcement, which makes them vulnerable to illegal invasions
followed by an advancing agricultural border, illegal extraction of forest resources and hunting
(ParksWatch 2002,2005, Godoy 2008). The remaining suitable habitat of Azure-rumped Tanager
in Chiapas was estimated to be 1,120 km
2
in the 1980s (Heath and Long 1991), but rapid human
population growth in Chiapas (1.6% annual growth rate from 2000 to 2005; INEGI 2008)
combined with an ongoing human pressure on the Sierra Madre de Chiapas (Richter 2000)
suggest recent considerable loss of habitat there. The total extent of occurrence in both countries
(minimum convex polygon encompassing all sites of occurrence) is less than 2,500 km
2
.We
expect a further decline of the extent of suitable habitat because of continued growth of human
population, which in Guatemala is expected to double between 2010 and 2050 to a total of 27.9
million (CEPAL 2007). The maintenance of the IUCN Red List status of Endangeredis justied
according to the IUCN (2001) Red List criteria EN B1a+b(ii,iii,v).
Conservation implications and population monitoring
The survival of the Azure-rumped Tanager depends on conservation of natural habitat and habitat
restoration in and outside of protected areas. The necessity of conservation efforts in human-used
landscape in Guatemala has been recognised during the identication of Important Bird Areas
(Eisermann and Avendaño 2007b, 2009a,b), and it has also been recognised on a regional level in
Mesoamerica (Harvey et al. 2008, Chazdon et al. 2009, Gardner et al. 2009). Because most of the
tanagers range in Guatemala is covered with coffee plantations, these areas need to be considered
in a conservation strategy. Coffee is being cultivated under a variety of management systems,
ranging from intensive unshaded monoculture with an intensive use of agrochemicals, to rustic
coffee plantations, which are cultivated under the shade of the natural forest. Between these
extremes exist a variety of plantation types differentiated by species richness of shade trees and
shade cover (Perfecto et al. 2005, López-Gómez et al. 2007, Hernández-Martínez et al. 2009). The
conservation value of coffee plantations has been discussed since the 1990s (Komar 2006), and
plantations with a diverse shade have been identied as the most valuable for biodiversity
(Perfecto et al. 1996, Perfecto et al. 2003, Philpott et al. 2008).
Azure-rumped Tanager in Guatemala 433
Most coffee plantations in the potential range of Azure-rumped Tanager in Guatemala are
shaded monocultures. The use of forest edge and single trees within coffee plantations by
foraging tanagers suggests that the area of suitable habitat could be augmented considerably by
some shade alterations among plantations. The dense network of maintenance roads in coffee
plantations could be used to establish lines of native trees, especially Ficus aurea,whichwould
provide both food and nesting sites. In many plantations we saw Eucalyptus spp. trees planted
along roads, so there would be little loss of cultivated area by replacing Eucalyptus or other
non-native trees with Ficus aurea and other fruit trees. The creation of tree rows could even
benet the coffee plantations. Pollination experiments in Costa Rica showed that pollination of
coffee blossoms is higher within a distance of 100 m from forest fragments and that forest-
based pollinators increased coffee yield by 20%(Ricketts2004,Rickettset al. 2004). Increased
shade and plant species richness in coffee plantations increases bird abundance (Philpott et al.
2008). Bird exclosure experiments in Chiapas showed that avian predation on Lepidoptera
larvae was signicantly higher in plantations with high oristic diversity (Perfecto et al. 2004).
A similar test in Jamaican coffee plantations concluded that birds reduced signicantly the
infestation by coffee berry borers Hypothenemus hampei, Coleoptera: Scolytidae (Kellermann
et al. 2008), which is also a common pest in Guatemalan coffee plantations. Johnson et al.
(2009) pointed out that greater shade cover in a Jamaican coffee plantation increased predation
on arthropods by birds, but it also increased fungal leaf damage on the coffee shrubs. Local
environmental conditions vary widely, and the task is to nd for each farm the balance between
high coffee yield and satisfying support for biodiversity conservation. Incentives and
certication programmes could play an important role in promoting these efforts. Habitat
restoration measures should be accompanied by population monitoring of Azure-rumped
Tanager. To continue monitor the distribution of the tanager we would appreciate receiving
reports of observation sent by e-mail or submitted to eBird Guatemala at ,http://www.ebird.
org/content/guatemala/..
Supplementary Material
The online supplementary materials for this article can be found at journals.cambridge.org/bci
Acknowledgements
We appreciate the logistical support by the people of Los Tarrales Reserve. SA and KE are thankful
to Andy Burge and Mónica Barrios for providing a temporary home at El Vesubio/Los Tarrales.
We thank Olga Hazard and Jaime Freire (Los Andes), as well as Mark Brissani and Arnoldo
Villagrán (Reserva San Jerónimo Miramar) for permitting us to work in their private reserves.
We appreciate the eld assistance and hospitality provided by Jamie Staples, Carlos Mazariegos,
Marcelino Orozco and Saúl Sandoval (San Rafael Pie de la Cuesta), Mario Castillo and Fernando
García (Las Nubes Reserve), the late Federico J. Fahsen (Pachuj Reserve), Olga Hazard, Jaime
Freire, Jesús Lucas Yuxón, Juan Calvo Cortéz (Los Andes Reserve), people of Loma Linda, Mario
Aguilar (Patrocinio Reserve). We thank Juan José Castillo Mont, Mario Veliz, and David
Mendieta for the identication of plant specimens. We thank Kenset Rosales and Rafael Ávila of
Consejo Nacional de Areas Protegidas (CONAP) for providing updated information on
Guatemalas protected areas. We thank Sylke Frahnert and Pascal Eckhoff of the Museum für
Naturkunde in Berlin, Germany, for their assistance during reviewing specimens in the ZMB. We
appreciate the review of the manuscript by Joseph M. Wunderle and Phil Atkinson, and the
revision of English usage by Peter Lowther through the Association of Field Ornithologists
programme of editorial assistance. Optics for the Tropics donated binoculars. This study was
nancially supported by Cayaya Birding, Los Tarrales Reserve, and PROEVAL RAXMU Bird
Monitoring Program.
K. Eisermann et al. 434
References
Berg, C. C. (2007) Proposals for treating four
species complexes in Ficus subgenus uros-
tigma section americanae. Blumea 52:295
312.
BirdLife International (2008) Species fact
sheet: Tangara cabanisi.,http://www.
birdlife.org/datazone/species/index.html.;
(downloaded 17 June 2008).
Blondel, J. and Cuvillier, R. (1977)Uneméth-
ode simple et rapide pour décrire les habitats
doiseaux: le stratiscope. Oikos 29:326331.
Brodkorb, P. (1939) Rediscovery of Heleo-
dytes chiapensis and Tangara cabanisi.Auk
56:447450.
Buckland, S. T., Anderson, D. R., Burnham,
K. P., Laake, J. L., Borchers, D. L. and
Thomas, L. (2001)Introduction to distance
sampling: estimating abundance of biolog-
ical populations. New York: Oxford Uni-
versity Press.
Cabanis, J. (1866) Über neue oder weniger
bekannte exotische Vögel. J.für Ornitholo-
gie 14:159165.
CEPAL (2007)2006 Anuario estadístico de
América Latina y el Caribe / Statistical
yearbook for Latin America and the Carib-
bean. Santiago, Chile: UN.
Chazdon, R. L., Harvey, C. A., Komar, O.,
Grifth, D. M., Ferguson, B. G., Martínez-
Ramos, M., Morales, H., Nigh, R., Soto-
Pinto, L., van Breugel, M. and Philpott, S.
M. (2009) Beyond reserves: A research
agenda for conserving biodiversity in
human-modied tropical landscapes. Bio-
tropica 41:142153.
Collar, N. J., Gonzaga, L. P., Krabbe, N.,
Madroño Nieto, A., Naranjo, L. G., Parker,
III, T. A. and Wege, D. C. (1992)Threatened
birds of the Americas: the ICBP/IUCN Red
Data Book. Washington and London: Smith-
sonian Institution Press, and Cambridge, UK:
International Council for Bird Preservation.
CONAP (2009) Lista de áreas protegidas
inscritas en el SIGAP. Guatemala: Consejo
Nacional de Áreas Protegidas (CONAP).
[Institutional database, data provided in
November 2009.]
Cooper, D. S. (2003) New distributional and
ecological information on birds in south-
western Guatemala. Cotinga 19:6163.
Dietsch, T. V. (2000) Assessing the conserva-
tion value of shade-grown coffee: a biolog-
ical perspective using Neotropical birds.
Endangered Species Update 17:122124.
Eisermann, K. and Avendaño, C. (2006) Di-
versidad de aves en Guatemala, con una
lista bibliográca. Pp. 525623 in E. Cano,
ed. Biodiversidad de Guatemala, Vol. 1
Guatemala Ciudad, Guatemala: Universidad
del Valle de Guatemala.
Eisermann, K. and Avendaño, C. (2007a) Lista
comentada de las aves de Guatemala -
Annotated checklist of the birds of Guate-
mala. Barcelona, Spain: Lynx Edicions.
Eisermann, K. and Avendaño, C. (2007b)
Áreas propuestas para la designación como
IBA (Área importante para la conservación
de aves) en Guatemala, con una priorización
para la conservación adentro de las IBAs y
una evaluación de las IBAs para aves mi-
gratorias Neárticas-Neotropicales.Informe
nal a BirdLife International, Quito, Ecuador.
Sociedad Guatemalteca de Ornitología, Gua-
temala. ,http://www.avesdeguatemala.org/
iba.htm.; (downloaded 25 November 2009).
Eisermann, K. and Avendaño, C. (2009a) Con-
servation priority-setting in Guatemala
through the identication of Important Bird
Areas. Proc. Fourth International Partners in
Flight Conference, Tundra to Tropics:315
327.
Eisermann, K. and C. Avendaño (2009b)
Guatemala. Pp. 235242 in C. Devenish, D.
F. Diaz Fernández, R. P. Clay, I. Davidson
and I. Yépez Zabala, eds. Important Bird
Areas Americas, priority sites for biodiversity
conservation.Quito,Ecuador:BirdlifeInter-
national. (BirdLife Conservation Series 16).
Eisermann, K., López, G., Berry, J., de León
Lux, J. and Burge, A. (2011 in press) Vocal-
isations and juvenile plumage of Azure-
rumped Tanager Tangara cabanisi.Cotinga
33.
Engel, J. (1998)SsS. Eichenau, Germany:
Rubisoft Software.
Gallini, S. (2009)Una historia ambiental del
café en Guatemala: la Costa Cuca entre
1830 y1902. Guatemala: AVANCSO.
Gardner, T. A., Barlow, J., Chazdon, R.,
Ewers, R. M., Harvey, C. A., Peres, C. A.
Azure-rumped Tanager in Guatemala 435
and Sodhi, N. S. (2009) Prospects for
tropical forest biodiversity in a human-
modied world. Ecol. Lett. 12:561582.
Godoy, J. C. (2008) Central America: Belize,
Costa Rica, El Salvador, Guatemala, Hon-
duras, Nicaragua, Panama. Pp. 199207 in
S. Chape, M. Spalding and M. Jenkins, eds.
The worlds protected areas: status, values,
and prospects in the 21st century Berkley
and Los Angeles, CA: University of Cal-
ifornia Press and UNEP World Conserva-
tion Monitoring Centre.
Harvey, C. A., Komar, O., Chazdon, R.,
Ferguson, B. G., Finegan, B., Grifth, D.
M., Martínez-Ramos, M., Morales, H.,
Nigh, R., Soto-Pinto, L., van Breugel, M.
and Wishnie, M. (2008) Integrating agri-
cultural landscapes with biodiversity con-
servation in the Mesoamerican hotspot.
Conserv. Biol. 22:815.
Heath, M. and Long, A. (1991) Habitat,
distribution and status of the Azure-
rumped Tanager Tangara cabanisi in Mex-
ico. Bird Conserv. Int. 1:223254.
Hernández-Martínez, G., Manson, R. H. and
Contreras Hernández, A. (2009) Quantita-
tive classication of coffee agroecosystems
spanning a range of production intensities
in central Veracruz, Mexico. Ag. Ecosyst.
Environ. 134:8998.
Hilty, S. L. and Simon, D. (1977) The Azure-
rumped Tanager in Mexico with compara-
tive remarks on the Gray-and-gold Tana-
ger. Auk 94:605606.
INEGI (2008)II conteo de población y viv-
ienda 2005. México y sus municipios. Méx-
ico: Instituto Nacional de Estadística,
Geografía e Información.
Isler, M. L. and Isler, P. R. (1987)The
tanagers: natural history, distribution and
identication. Washington, DC: Smithso-
nian Institution Press.
IUCN (1994)Guidelines for protected area
management categories. Gland, Switzer-
land and Cambridge, UK: IUCN.
IUCN (2001)IUCN Red list categories and
criteria: version 3.1. Gland, Switzerland
and Cambridge, UK: IUCN Species Survival
Commission.
Johnson, M. D., Levy, N. J., Kellermann, J. L.
and Robinson, D. E. (2009) Effect of shade
and bird exclusion on arthropods and leaf
damage on coffee farms in Jamaicas Blue
Mountains. Agroforest. Syst. 76:139148.
Jones, H. L. (2004) Spring migration, March
though May 2004: Central America. N.
Am. Birds 58:446448.
Kellermann, J. L., Johnson, M. D., Stercho, A.
M. and Hackett, S. C. (2008) Ecological and
economic services provided by birds on
Jamaican Blue Mountain coffee farms. Con-
serv. Biol. 22:11771185.
Komar, O. (2006) Ecology and conservation of
birds in coffee plantations: a critical review.
Bird Conserv. Int. 16:123.
Krebs, C. J. 1999.Ecological methodology.
2nd edition. Menlo Park, CA: Benjamin /
Cummings.
López-Gómez, A. M., Williams-Linera, G.
and Manson, R. H. (2007) Tree species
diversity and vegetation structure in shade
coffee farms in Veracruz, Mexico. Ag.
Ecosyst. Environ. 124:160172.
MAGA (2002)Atlas de Guatemala. CD-Rom.
Guatemala: Ministerio de Agricultura, Ga-
nadería y Alimentación (MAGA).
MAGA (2006)Mapa de cobertura vegetal y
uso de la tierra a escala 1:50,000 de la
República de Guatemala, Año 2003 (In-
cluye 5cultivos perennes actualizados al
año 2005). Memoria técnica y descripción
de resultados. Guatemala Ciudad, Guate-
mala: Ministerio de Agricultura Ganadería
y Alimentación MAGA/ Unidad de
Planicación Geográca y Gestión de
Riesgo UPGGR.
MAGA (2010, in press) Obtención de image-
nes digtales de la República de Guatemala
del año 2006. Ministerio de Agricultura
Ganadería y Alimentación (MAGA),
Guatemala.
Parker, T. A. III, Hilty, S. and Robbins, M.
(1976) Birds of the El Triunfo cloud forest,
Mexico, with notes on the Horned Guan
and other species. American Birds 30:779
782.
ParksWatch (2002)Park proleGuatemala:
Sierra de las Minas Biosphere Reserve.
Guatemala: ParksWatch. ,http://www.
parkswatch.org.; (downloaded 21 Novem-
ber 2009).
ParksWatch (2005)Park proleGuatemala:
Laguna del Tigre National Park and
Laguna del TigreRío Escondido Protected
K. Eisermann et al. 436
Biotope. Guatemala: ParksWatch. ,http://
www.parkswatch.org.; (downloaded 21
November 2009).
Perfecto, I., Rice, R., Greenberg, R., Van der
Voorts, M. (1996) Shade coffee: a disappear-
ing refuge for diversity. BioScience 46:
598608.
Perfecto, I., Mas, A., Dietsch, T. and Vander-
meer, J. (2003) Conservation of biodiversity
in coffee agroecosystems: a tri-taxa com-
parison in southern Mexico. Biodivers.
Conserv. 12:12391252.
Perfecto, I., Vandermeer, J. H., López Bautista,
G., Ibarra-Núñez, G., Greenberg, R., Bichier,
P. and Langridge, S. (2004) Greater predation
in shaded coffee farms: the role of resident
Neotropical birds. Ecology 85:26772681.
Perfecto, I., Vandermeer, J., Mas, A. and Soto
Pinto, L. (2005) Biodiversity, yield, and shade
coffee production. Ecol. Econ. 54:435446.
Philpott, S. M., Arendt, W. J., Armbrecht, I.,
Bichier, P., Dietsch, T. V., Gordon, C.,
Greenberg, R., Perfecto, I., Reynoso-San-
tos, R., Soto-Pinto, L., Tejeda-Cruz, C.,
Williams-Linera, G., Valenzuela, J. and
Zolotoff, J. M. (2008) Biodiversity loss in
Latin American coffee landscapes: review of
the evidence on ants, birds, and trees.
Conserv. Biol. 22:10931105.
Richter, M. (2000) The ecological crisis in
Chiapas: a case study from Central Amer-
ica. Mountain Res. Dev. 20:332339.
Ricker, W. E. (1984) Computation and uses of
central trend lines. Can. J. Zool. 62:1897
1905.
Ricketts, T. H. (2004) Tropical forest frag-
ments enhance pollinator activity in nearby
coffee crops. Conserv. Biol. 18:12621271.
Ricketts, T. H., Daily, G. C., Ehrlich, P. R. and
Michener, C. D. (2004) Economic value of
tropical forest to coffee production. PNAS
101:1257912582.
Sclater, P. L. (1868) On a recently discovered
tanager of the genus Calliste. Ibis 4(series
2): 7172.
Tenez, D. (2005)Avifauna del volcán Lacandón,
Quetzaltenango. Guatemala: Consejo Nacio-
nal de Áreas Protegidas. Unpublished report.
Thomas, L., Laake, J. L., Strindberg, S.,
Marques, F. F. C., Buckland, S. T., Borchers,
D. L., Anderson, D. R., Burnham, K. P.,
Hedley, S. L., Pollard, J. H., Bishop, J. R. B.
and Marques, T. A. (2006)Distance 5.0.
Release 2. University of St. Andrews, UK:
Research Unit for Wildlife Population
Assessment.
Valdez,O.I.,Marroquín,D.E.,Orellana,R.E.,
Pérez, S. G., Sandoval, K. J., Villar, L.,
Godínez, C. V., Acevedo, M. E., Morales, J.
E. and Reyes, L. E. (1999)Fauna en peligro
de extinción de Guatemala: inventarios ráp-
idos para la conservación. Informe nal
(noviembre).Guatemala:CentrodeEstudios
Conservacionistas, Univ. San Carlos. Unpub-
lished report.
Vannini, J. P. (1989) Preliminary checklist to
the birds of Finca el Faro, Quetzaltenango,
Guatemala. Publicación Ocasional No. 2.
Guatemala: Fundación Interamericana de
Investigación Tropical.
KNUT EISERMANN,
*
SUSANNE ARBEITER, CLAUDIA AVENDAÑO
PROEVAL RAXMU Bird Monitoring Program, Cobán, Alta Verapaz, Guatemala. c/o P.O. Box
98 Periférico, Guatemala City, Guatemala.
SUSANNE ARBEITER
University of Applied Sciences Eberswalde, Friedrich-Ebert-Str. 28,16225 Eberswalde, Germany.
GERARDO LÓPEZ AND JOSUÉ DE LEÓN LUX
Los Tarrales Reserve, Km 164.2Ruta Nacional 11, Patulul, Suchitepéquez, Guatemala.
*Author for correspondence; e-mail: knut.eisermann@proeval-raxmu.org
Received 31 May 2010; revision accepted 26 October 2010;
Published online 11 February 2011
Azure-rumped Tanager in Guatemala 437
Supplementary Material
Distribution, habitat use, and implications for the
conservation of the globally threatened Azure-rumped
Tanager Tangara cabanisi in Guatemala
K. EISERMANN, S. ARBEITER, G. LÓPEZ, C. AVENDAÑO and J. DE LEÓN LUX
Contents
Figure S1. Landcover, contour lines, and location of transects (numbered lines) in the study
area at Atitlán Volcano.
Table S1. Nomenclature of all plant names mentioned in the text and voucher specimens of
species used as food source by Azure-rumped Tanager.
Table S2. Abundance of Ficus aurea trees along forest transects with a strip width of 120
m.
Table S3. Site of recent records (1976-2009) of Azure-rumped Tanager in Guatemala.
Table S4. Legal protection within the potential area of distribution of Azure-rumped
Tanager in Guatemala, according to recent information on Guatemala's protected areas
(CONAP 2009).
Figure S1. Landcover, contour lines, and location of transects (numbered lines) in the study
area at Atitlán Volcano.
Table S1. Nomenclature of all plant names mentioned in the text and voucher specimens of
species used as food or nesting substrate by Azure-rumped Tanager.
Species Family Note*
Acrocarpus fraxinifolius Wight & Arn. Fabaceae
Beaucarnea recurvata Lem. Agavaceae
Camellia sinensis (L.) Kuntze Theaceae
Cecropia obtusifolia Bertol. Cecropiaceae voucher: Eisermann, K., 36, AGUAT
Cestrum sp. Solanaceae
Chomelia brachypoda Donn. Sm. Rubiaceae food source (voucher: Eisermann, K., 34,
AGUAT)
Eucalyptus sp. Myrtaceae voucher: Eisermann, K., 15, BIGU
Ficus aurea Nutt. Moraceae food source, (voucher: Eisermann, K., 46,
AGUAT)
Ficus costaricana (Liebm.) Miq. Moraceae food source (voucher Eisermann, K., 48,
AGUAT)
Inga laurina (Sw.) Willd. Mimosaceae
Inga micheliana Harms Mimosaceae voucher: Eisermann, K., 44, AGUAT
Inga rodrigueziana Pittier Mimosaceae voucher: Eisermann, K., 39, AGUAT
Inga spuria Humb. & Bonpl. ex Willd. Mimosaceae voucher: Eisermann, K., 38, AGUAT
Meriana macrophylla (Benth.) Triana Melastomataceae voucher: Eisermann, K., 33, AGUAT
Miconia sp. Melastomataceae food source (voucher: Eisermann, K., 32,
AGUAT)
Perrottetia longistylis Rose Celastraceae food source (voucher: Eisermann, K., 19,
AGUAT)
Phoradendron heydeanum Trel. Viscaceae food source (voucher: Eisermann, K., 17,
BIGU)
Rhamnus discolor (Donn. Sm.) Rose Rhamnaceae food source (voucher: Eisermann, K., 16,
BIGU)
Trema micrantha var. strigillosa
(Lundell) Standl. & Steyerm.
Ulmacae food source (voucher: Eisermann, K., 13,
BIGU)
*Voucher specimens deposited at: AGUAT (Herbarium of of the Faculty of Agronomy of the San
Carlos University, Guatemala City), BIGU (Herbarium of the School of Biology of San Carlos
University, Guatemala City).
Table S2. Abundance of Ficus aurea trees along forest transects with a strip width of 120
m.
Transect Area (ha) Number of Ficus aurea Number of Ficus aurea/ha
2 4.1 0 0.00
5 5.5 0 0.00
17 10.7 0 0.00
16 17.6 1 0.06
8 12.2 1 0.08
10 12.5 4 0.32
23 7.0 6 0.86
22 4.1 5 1.22
26 14.5 21 1.45
24 3.7 6 1.64
27 3.6 7 1.95
20 30.2 61 2.02
Table S3. Site of recent records (1976-2009) of Azure-rumped Tanager in Guatemala.
Topographic
unit
Site Elevation (m) and
Habitat
Note and Reference
Tajumulco
volcano
El Porvenir
(village), 14º58'N
91º55'W, dpto. San
Marcos
1,200 broadleaf
forest and edge
seen several times in September 1999
(Valdez et al. 1999)
Sierra Madre
south of San
Marcos
San Rafael Pie de la
Cuesta, reserva
municipal, 14º56'N
91º52'W , dpto. San
Marcos
1,800–1,900
broadleaf forest
2 flocks of 3 birds each along a trail of 2 km
length on 15 August 2009; at least 2 birds
(including a young) on 27 October 2009 (K.
Eisermann, photo, and C. Avendaño, pers.
obs.)
Sierra Madre
south of San
Marcos
Finca Dos Marias,
14º49'N 91º48'W ,
dpto. San Marcos
1,500–1,700
broadleaf forest
up to 25 birds per day in January 1997 and
January 2002 (Cooper 2003)
Lacandón
volcano
Vista Alegre, Río
Negro (village),
14º49' N 91º45'W,
dpto.
Quetzaltenango
1,500 forest edge 2 birds seen on 12 June 2005 (Tenez 2005)
Chicabal
volcano
Loma Linda
(village), 14º44'N
91º38'W, dpto.
Quetzaltenango
1,280–1,420
broadleaf forest,
shade coffee
plantation
at least 2 birds on 19 August 2009; at least 2
flocks of 3 and 6 birds (including juveniles)
on 29 October 2009, and 2 flocks of 2 and 3
birds on 30 October 2009 (K. Eisermann,
photo, and C. Avendaño, pers. obs.)
Santa María
volcano
Finca Montebello,
14º43'N 91º37'W ,
dpto.
Quetzaltenango
1,140 broadleaf
forest
at least 3 individuals recorded on 31
October 2009 (K. Eisermann and C.
Avendaño, pers. obs.)
Santa María
volcano
Fincas El Faro y El
Patzulín and
surroundings,
14º43'N 91º34'W ,
dpto.
Quetzaltenango
1,280–1,500
broadleaf forest
sightings in 1976 and 1990 in El Patzulín,
small flock in El Faro in 1987 (Vannini
1989, Heath and Long 1991, Collar et al.
1992)
Santa María
volcano
Finca Los Pirineos,
14º41'N 91º33'W,
dpto.
Quetzaltenango
1,100 secondary
broadleaf forest
and coffee
plantation
nesting in May–June 2001 (J.Berry/eBird
Guatemala*)
Santo Tomás
volcano
Santa María de
Jesús, 14º43'N
91º32'W
d
to.
1,600 humid
broadleaf forest
common in February, June, July, October,
and December 2000, and in March, May,
June
,
Jul
y,
Au
g
ust
,
and Se
p
tember 2001
Quetzaltenango Eisermann and Avendaño (2007), J.
Berry/eBird Guatemala*)
Santo Tomás
volcano
Las Nubes Reserve,
14º40'N 91º29'W,
dpto. Suchitepéquez
1,550 broadleaf
forest edge and
interior of forest
fragment along
stream
at least 4 birds on 16 August 2009 (K.
Eisermann and C. Avendaño, pers. obs.)
Atitlán volcano Los Andes Reserve,
14º33'N 91º11'W,
dpto. Suchitepéquez
1,200–1,700
humid broadleaf
forest and edge
first recorded in 2000 (Eisermann and
Avendaño 2006), lowest record at 1,200 m
(J. L. Yuxón, pers. comm.), during
Christmas Bird Counts (GMAV* 2007-
2009), frequent during current study incl.
nesting record in 2008
Atitlán volcano Los Tarrales
Reserve (including
El Vesubio
Reserves and La
Chusita Reserve),
14º33'N 91º10'W,
dptos.
Suchitepéquez and
Sololá
860–1,900 humid
broadleaf forest
and edge, coffee
plantation
first recorded in 2004, frequently recorded
each day in forest and edge between 1,400–
1,800 m and coffee plantation at 1,400–
1,600 m, yearly nesting records 2006-2009
(Eisermann and Avendaño 2007; Christmas
Bird Count GMAV 2007–2009*; current
study)
Atitlán volcano San Jerónimo
Miramar Reserve,
14º34'N 91º10'W ,
dptos.
Suchitepéquez and
Sololá
1,300–1,800
humid broadleaf
forest, coffee
plantation
recorded frequently each day in forest at
1,500-1,800 m, nesting recorded in 2008
(current study)
Atitlán volcano Santa Teresa
Reserve, 14ºN 34'N
91º08'W, dpto.
Sololá
1,200 humid
broadleaf forest
flock of 8 birds seen on 16 December 2009
(Christmas Bird Count GMAV 2009*)
Valley of Madre
Vieja river
Pachuj Reserve,
14º37'N 91º07'W,
dpto. Sololá
1,300–1,450
broadleaf forest
and edge
1 bird recorded on 7 February 1999
(Eisermann and Avendaño 2006), 10 birds
on 14 December 2008 (Christmas Bird
Count GMAV 2008*)
Valley of Nicán
river
Unión Victoria,
14º34'N 91º03'W,
dpto.
Chimaltenango
1,260 broadleaf
forest and edge
active nest in 2007 (D. Ruby, pers. comm.),
2 birds on 5 November 2009 (KE and CA,
pers. obs.)
*Data from Christmas Bird Counts at Atitlán Volcano (GMAV) online at
http://www.audubon.org/bird/cbc/hr/index.html, data in eBird Guatemala online at
http://ebird.org/content/guatemala/
Table S4. Legal protection within the potential area of distribution of Azure-rumped
Tanager in Guatemala, according to recent information on Guatemala's protected areas
(CONAP 2009).
CONAP (2009)
Category
Area (km2) and % of
1,170 km2 of the
potential area of
distribution
Area (km2) of broadleaf
forest within the protected
areas and % of the total area
(250 km2) of broadleaf
forest in the potential area
of distribution
IUCN (1994)
category of
protected area
Parque Regional
Municipal (regional
park)
3.0 (0.3%) 0.8 (0.3%) V
Area de Uso Múltiple
(multiple use area )
207.6 (17.7%) 91.8 (36.7%) VI
Reserva Natural
Privada
(private protected
area)
58.2 (5.0%) 21.0 (8.4%)
Zona de
Amortiguamiento
(buffer zone)
62.3 (5.3%) 7.4 (3.0%)
Zona de Veda
Definitiva
(no hunting zone)
39.4 (3.4%) 16.8 (6.7%)
TOTAL 370.5 (31.7%) 137.9 (55.2%)
7
... Amaurospiza concolor (C, D; R) Poorly known but often found with mast-flowering bamboo (Stiles & Skutch 1989, Howell & Webb 1995. Recorded several times at Volcán Atitlán (Jones & Komar 2009b,c, 2011a). An adult male feeding a juvenile in humid broadleaf forest at 850 m in Reserva Natural Privada Los Tarrales, dpto. ...
... Endangered (IUCN 2017) and endemic to Pacific slope highlands of Guatemala and Chiapas, Mexico. Since the summary of Guatemalan distribution by Eisermann et al. (2011a) it has been reported at three new sites. A bird photographed in humid forest on the south slope of Volcán Agua, dpto. ...
... Escuintla, in April 2013 (Jones & Komar 2014a; A. Duarte pers. comm.) was the first documented record within the potential range east of the known area of distribution (Eisermann et al. 2011a). A bird seen in cloud forest at 1,700 m, 5 km south of Santiago Atitlán (south of Mirador Rey Tepepul), dpto. ...
Article
Full-text available
We present an update on the status and distribution of birds in Guatemala relative to a previous summary (Eisermann & Avendaño 2007) and based upon a review of new published and unpublished records. During the period 2006 to 2017, 50 species were first documented in Guatemala. Another 11 species were reported for the first time but without verifiable documentation. Breeding was newly confirmed for 58 species. Noteworthy observations, including range extensions, are summarised for 131 species. The Guatemalan avifauna now comprises 758 species of which 23 lack documentation. Of the 758 species, 509 breed in Guatemala, 240 are non-breeding visitors, transients or vagrants, and the status of nine is uncertain.
... However, in the 1860s, Costa Cuca was not a village, but a region of c.1,300 km 2 (Fig. 2), which nowadays forms the southern part of the department of Quetzaltenango 12 . Because all modern records are from >800 m elevation, the type locality was probably in the upper part of the Costa Cuca region 9 . More details concerning the type locality might be contained in Bernoulli's notebooks, which remain missing. ...
... Subsequently, available habitat in Chiapas was quantified to be 1,125 km 2,14 . Post-1976, infrequent sightings of this tanager were made in Guatemala 9 , enabling some knowledge of its distribution in the country, where it is now known from nine major topographic units and 16 localities, from the Mexican border in the west to the municipality of Pochuta in the east 9 . ...
... Azure-rumped Tanager is considered locally common 5,9 , and the first assessment of its population density came from Volcán Atitlán, where an estimated 33-93 Azure-rumped Tanagers / km 2 inhabit the humid broadleaf forest at 1,400-1,900 m altitude 9 . Whilst in Chiapas the species has been recorded only at 1,000-1,700 m 14 , Guatemalan records range from 860 to 1,900 m, including nesting records 9,10 . ...
... The Azure-rumped Tanager (Tangara cabanisi) is restricted to the Pacific slope mountains of Guatemala and Chiapas, Mexico, where it has been reported in a narrow altitudinal belt at 860-1900 m (Parker III et al. 1976, Hilty & Simon 1977, Heath & Long 1991, Eisermann et al. 2011. The tanager is considered Endangered at the global level because of its small range size and loss of habitat, primarily through the replacement of broadleaf forests by coffee plantations (Collar et al. 1992, BirdLife International 2008, Eisermann et al. 2011. ...
... The Azure-rumped Tanager (Tangara cabanisi) is restricted to the Pacific slope mountains of Guatemala and Chiapas, Mexico, where it has been reported in a narrow altitudinal belt at 860-1900 m (Parker III et al. 1976, Hilty & Simon 1977, Heath & Long 1991, Eisermann et al. 2011. The tanager is considered Endangered at the global level because of its small range size and loss of habitat, primarily through the replacement of broadleaf forests by coffee plantations (Collar et al. 1992, BirdLife International 2008, Eisermann et al. 2011. Due to the limited distribution and few observations, to date little has been published on the ecology and behavior of the Azurerumped Tanager. ...
... Available information on habitat use originates from observations in the Sierra Madre de Chiapas (Brodkorb 1939, Heath & Long 1991 and from recent studies in Guatemala (Cooper 2003, Eisermann et al. 2011). Existing information on nesting is limited to a few nests which were observed in humid broadleaf forest in Chiapas in the early wet season (April-June; Isler & Isler 1987, Long & Heath 1994. ...
Article
Full-text available
The Azure-rumped Tanager (Tangara cabanisi) is a little studied and endangered species restricted to the Pacific slope mountains of Guatemala and Chiapas, Mexico. We studied the nesting ecology of this species on the south-eastern slope of Atitlán volcano, dpto. Suchitepéquez, Guatemala, and compiled information of other nesting sites. Thirty-two nests were recorded in Guatemala from 2001–2009, of which 30 were observed at Atitlán volcano. The altitude of nesting sites ranged from 860 to 1850 m. Fifteen nests were located in broadleaf forest with a distance to the nearest forest edge ranging from 0–700 m. Another 17 nests were in coffee plantations and orchard-likehabitat with a distance from the nearest forest ranging from 5–130 m. We recorded tanagers nesting successfully in primary broadleaf forest, but also in plantations with a greatly reduced or absent upper canopy of native broadleaf trees. The 32 nests were placed in 20 differenttree species. Nesting was observed in all months from April through September and was synchronized with the wet season. One nest provided data from the first day of nest-building to the fledging of juveniles. Nest-building took six days, incubation 14 days, and brooding 17 days, which is longer than the nestling period observed previously for the Azure-rumped Tanager in Chiapas and for congeners throughout the Neotropics. Using the Mayfield method for calculating nest survival from onset of incubation to the fledging of the first young, nest success was 16% (95% confidence interval: 5–45%). Our findings provide a base for practical conservation measures in the coffee-dominated landscape of the Guatemalan and Chiapan Pacific slope highlands.
... Tanagers (Passeriformes: Thraupidae) stand as denizens of the Neotropics, spanning from Central to South America, and occur in diverse habitats, including lowland rainforests, grasslands, and high-altitude fields (Rosenberg et al. 1999;Rodríguez-Ruíz et al. 2011;Eisermann et al. 2011a;Rodrigues et al. 2019;Winkler et al. 2020;Aguiar de Souza Penha et al. 2022. Tanagers are believed to be socially monogamous, with both sexes participating in parental care, with clutch size typically ranging from 1-4 eggs and an incubation period lasting 12 to 14 days, but with a high species variation (Aguiar de Souza Penha et al. 2022. ...
Article
Body condition in individuals is intricately linked to behaviour, physiology, and immunity. This study investigated how seasonal factors, such as reproduction and moulting, influence the body condition of 21 tanager species in the Atlantic Forest. Utilising publicly available data, I employed phylogenetic generalised linear mixed models to dissect these influences. Notably, females with brood patches exhibited concurrent body and feather moult, suggesting simultaneous energy-costly constraints. Furthermore, females with brood patches displayed higher body condition, indicating proactive preparation or increased resource availability during breeding. Lastly, individuals moulting body feathers exhibited enhanced body condition, suggesting heightened foraging activity. These data suggest complex connections between sex, moulting, and reproductive status in tanagers in the Atlantic Forest.
... Aunque se han registrado 758 especies de aves en Guatemala (Eisermann & Avendaño, 2018) nunca se ha estudiado la riqueza de especies presentes en la Finca Universitaria San Julián. Se estima que la diversidad de aves en este sitio puede ser importante pues se encuentra cerca -a unos siete kilómetros en distancia euclidiana-de la Reserva Privada Los Tarrales, uno de los hotspots para la observación de aves en Guatemala (Eisermann, 2007) y donde se han realizado varios estudios para la conservación de especies de aves muy valoradas para el aviturismo (Eisermann et al., 2011a;Eisermann et al., 2011b;Jiménez & Omelas, 2016). ...
Article
Full-text available
Guatemala is a megadiverse country that hosts an importantbiodiversity.It is necessary to propose actions for the conservation and sustainable use of these natural resources. Birds, as a taxonomic group, offer an exceptional opportunity for sustainable developmentthrough avitourism.San Julián University Farm (FUSJ), heritage of UniversidaddeSan Carlos de Guatemala, is situated in a strip of great biodiversity. Aiming to determine the observed and expected richness of bird species inFUSJ, observations were done in a4.3 km transect locatedinthe west side of FUSJ. In addition, historic sighting records generated in the same transect were consulted. A documentary investigation was also carried out to determine the expected richness of bird species in the FUSJ. For this purpose, the Fagan & Komar bird guide (2016) and the Merlin Bird ID ® application for Android were consulted. We registered 103 species of birds out of 245 expected species. The generated information can be used to value the resource and to promote the conservation and sustainable use of the bird community and the ecosystem that supports it, through birdwatching and within the framework of the sustainable development goals. Keywords: Sustainable use; birdwatching, avitourism, biodiversity.
... The soil types of the region are volcanic and sandy loam, and the elevation varies between 760 and 2500 masl. The average annual rainfall is between 1450 and 3000 mm (Bressani et al., 2004) and the vegetation found in this area is humid evergreen broadleaf forest, with broadleaf-conifer forest in higher and less humid areas (Eisermann et al., 2011). The farms are: Pampojila Pena Flor (PPF), San Jeronimo Miramar (SJM), and SantoTomas Pachuj (STP), and are located within the Multipurpose Reserve of Lake Atitlan Basin (RUMCLA) (Fig. 1), an area located in the southwestern part of Guatemala (Consejo Nacional de Áreas Protegidas, 2007). ...
Article
Full-text available
Agricultural practices can have detrimental impacts on biodiversity, but some studies have shown the benefits of agroforestry practices like shade-grown coffee to bird communities and, to a lesser extent, to mammal communities. To better understand whether shade-grown coffee plantations can contribute to the conservation of mammal communities, we deployed camera traps in private reserves with a matrix of shade-grown coffee plantations and forest in the highlands of Guatemala. At each reserve we estimated species richness of terrestrial medium- and large-sized mammals. We also estimated mammal relative abundance and occupancy probabilities as proxies for mammalian habitat associations and evaluated how these were affected by key landscape features (e.g., land-use type, asphalt roads, and distance to protected areas). We used hierarchical multi-species Bayesian abundance models that account for imperfect detection to estimate our parameters of interest and model the influence of landscape features on site-level species richness and species relative abundance. We detected 14 species across all reserves and found a strong influence of land use and presence of asphalt roads on mammalian relative abundances and species richness. More species used areas around the camera traps in forest than in shade-grown coffee plantations and far from asphalt roads. Our study shows that reserves with shade-grown coffee plantations can harbor terrestrial mammalian communities of conservation interest. Our results also suggest that to maintain mammalian diversity and abundances in our study area, shade-grown coffee crops should be mixed in with natural forests and the presence of asphalt roads within these should be avoided or minimized.
... This focal area is a 30 km wide belt stretching along the Pacific versant. Much of the humid broadleaf forests in that area have been converted to coffee plantations (Eisermann et al. 2011). Protected areas cover 26% of the focal area, including several regional parks and private protected areas (Figure 10). ...
... Deforestation and forest degradation caused by agricultural intensification in the studied shade coffee farms mean that the recorded threatened species are particularly at risk and that future species losses of these threatened species and other sensitive species may be expected (see also Peres et al. 2010, Moura et al. 2013. Improving shade management in the coffee farms in function of the habitat requirements for such species may enhance habitat quality and help to avoid further species losses (see also Eisermann et al. 2011 ). But even so, certified agroforestry systems like shade coffee cannot be seen as substitutes for natural forest. ...
... Deforestation and forest degradation caused by agricultural intensification in the studied shade coffee farms mean that the recorded threatened species are particularly at risk and that future species losses of these threatened species and other sensitive species may be expected (see also Peres et al. 2010, Moura et al. 2013. Improving shade management in the coffee farms in function of the habitat requirements for such species may enhance habitat quality and help to avoid further species losses (see also Eisermann et al. 2011). But even so, certified agroforestry systems like shade coffee cannot be seen as substitutes for natural forest. ...
Article
Summary Agricultural intensification in shade coffee farms has strong impacts on the structure and diversity of the agroforest, with negative consequences for forest specialist birds, understorey insectivores and their associated ecosystem services. Utilising variable distance transect counts, we sampled the bird community in a multiple-certified yet changing shade coffee landscape in the Peruvian East Andean foothills, to evaluate bird functional diversity and to assess potential impacts of coffee production on avian ecosystem services. To account for incomplete detection, we also calculated expected species richness per functional group, and to evaluate the effect of future species losses, we derived reduced bird communities by subsampling our data using a Monte Carlo procedure. We compared the relative abundances of functional groups based on preferred diets in the observed, expected and reduced bird communities to global functional signatures of tropical bird assemblages of forest, agroforests and agriculture. The birds in the shade coffee landscape were predominantly birds of secondary and disturbed forest habitats, indicating, as expected, strong human impact on the forest structure. Yet, the diet signatures of the observed, expected and simulated bird communities were not significantly different from global diet signatures of forest and agroforest bird communities of mixed tropical landscapes. Our results suggest that avian ecological function can be conserved at bird community level despite intensive human ecosystem use and associated losses of forest specialist and other less resilient bird species. These results underscore that forest management strategies or certification audits focused solely at ecosystem services may be insufficient to support conservation of rare or threatened bird species and that shade coffee systems can in no way replace the role of protected natural forests.
Chapter
Habitat loss and degradation are currently the main anthropogenic causes of species extinctions. The root cause is human overpopulation. This unique volume provides, for the very first time, a comprehensive overview of all threatened and recently extinct mammals, birds, reptiles, amphibians, and fishes within the context of their locations and habitats. The approach takes a systematic examination of each biogeographic realm and region of the world, both terrestrial and marine, but with a particular emphasis on geographic features such as mountains, islands, and coral reefs. It reveals patterns useful in biodiversity conservation, helps to put it all into perspective, and ultimately serves as both a baseline from which to compare subsequent developments as well as a standardization of the way threatened species are studied.
Article
Full-text available
La Tángara de Cabanis Tangara cabanisi es endémica de la vertiente Pacífica de Guatemala y de Chiapas, México. La especie está en Peligro de Extinción y su biología es poco conocida. Para facilitar futuros esfuerzos de monitoreo de las poblaciones, sedescriben por primera vez el plumaje y las vocalizaciones de polluelos y de juveniles. En general los juveniles parecían grisáceos, pero su apariencia fue similar a la de los adultos por varias marcas conspicuas oscuras (antifaz, auriculares inferiores, puntos en el pecho) y bordes azules en las plumas remeras. Los juveniles obtienen el plumaje de adulto rápidamente. Se documentan con grabaciones y espectrogramas los llamados de polluelos en los últimos días antes de salir del nido, y dos diferentes vocalizaciones de juveniles perchados en el dosel del bosque. Además se documentan por primera vez con espectrogramas tres diferentes vocalizaciones sibilantes de adultos, así como llamados de gorjeo. Se describe por primera vez una vocalización de agresión entre adultos y también hacia invasores al territorio del nido.
Article
Taking Chiapas as an example, most of its landscapes were recently subject to a change in land use which manifests itself in various environmental problems, driving a "highland-lowland interactive system". In the coastal plain of Soconusco cash crops with long dry fallow phases caused a decline of precipitation, whereas in the lower escarpment of the Sierra Madre coffee plantations with unshaded cultivation in rows and herbicidal input enforced major hydrological fluctuations. While these innovations have been reduced during the last decade, in the upper part of the Sierra Madre and in the Altos de Chiapas demographically determined continuous need for land causes an advancement of the frontier down into steeper parts of the Sierra as well as towards Lacandonia. The resulting erosion and leaching promote not only a further degradation, but have together with elevated runoff-rates a very strong impact on the forelands - as shown in September 1998 by disastrous inondations and devastations in the Soconusco.
Article
The "stratiscope" described permits a rapid quantification of avian habitats. The stratiscope is an optical device which divides the biological space into horizontal planes (layers of vegetation) and vertical planes for each layer by the appropriate position of a diaphragm. Several structural parameters can be measured, i.e. number of layers, per cent cover, and horizontal and vertical structural diversity. The use of the stratiscope is exemplified along a gradient of increasing vegetational complexity, where it allows drawing of foliage profiles. Simultaneously, the structure of the breeding bird communities were determined by census in each habitat, in order to measure the richness S of the communities, their overall density D and the information-theoretical diversity H'. It is shown that these basic parameters of bird communities are significantly correlated with those of habitat structure: 5 out of 15 coefficients of correlation are significant at the 1% level, and 8 at the 5% level. The main importance of this technique is that it is standardized and leads to a general classification of habitats regardless of, e.g., species composition. /// Описанный "стратископ" позволяет быстро дать количественную характеристику местообитаний птиц. Стратископ - оптическое устройство, разделяющее биологическое пространство на горизонтальные планы (ярусы растительности) и вертикальные планы для каждого яруса соответствующим положением диафрагмы. Могут быть измерены при этом некоторые структурные параметры, тоесть количество ярусов, процент покрытия, горизонтальное и вертикальное структурное разнообразие. Применение стратископа продемонстрировано на градиенте увеличиваю щейся сложности растительного покрова, где он позволяет описывать профили крон. Одновременно была определена структура комплексов птиц регистрацией в каждом местообитании для оценки богатства Ѕ комплексов, их общей плотности D и информационно-теоретического разнообразия Н. Показано, что эти основные параметры комплексов птиц коррелируют с параметрами структуры местоовитаний: 5 из 15 коэффициентов корреляции достоверны на уровне 1% и 8 - на уровне 5%. Основное значение данного метода - стандартизация. позволяющая провести общую классификацию местообитания, независимо от видового состава.
Book
The most authoritative, detailed, and updated checklist of the 725 bird species recorded in Guatemala. Also includes information about status, habitats and endemic species, along with detailed distribution maps, information on species to watch for and species of special concern.
Article
A bivariate array of naturally variable observations can take many different forms, depending on the relative lengths of the measurement units used. Each of these has a different central trend or major axis. In a standard presentation the major axis has a slope of + or -1 obtained when 1 standard deviation (s) of each variate, Y and X, occupies the same distance on its co-ordinate axis. With any other presentation the position of the standard trend is indicated by a line whose slope is the ratio of the standard deviations; it is called the standard (or reduced) major axis, or geometric mean regression line (GMR). The GMR is symmetrical, invariant with change of scale, and 'robust'. Besides indicating the central trend, it is a suitable line for estimating Y from X, or X from Y, in 2 common situations where ordinary regressions fail: 1) when the sampling procedure was not random with respect to the entire population (but was random with respect to its standard trend); 2) when the population sampled departs seriously from a bivariate normal configuration. In the latter case an alternative 'Schnute' line is appropriate if components of the populations may have different sy/sx ratios.-Author