Diet and habitat selection in Cantabrian Capercaillie (Tetrao urogallus cantabricus): ecological differentiation of a rear-edge population

Current habitat management of the peripheral, regionally unique, and isolated Balkan capercaillie Tetrao urogallus rudolfi Dombrowski, 1912 meta-population in Bulgaria is based on obsolete knowledge of the spatial requirements of the species. Thus, we studied the habitat availability and the patterns of use by Capercaillie adult males, at the home range scale to inform and contribute to the conservation-oriented management of the threatened subspecies and its habitats. The field study was conducted during 2014–2015 in the northeastern part of Rila Mtn., Southwestern Bulgaria. Using GPS tags (“Bird 2A”, e-obs Digital Telemetry, Grünwald, Germany), a total of 38,640 GPS fixes from 3 displaying males, associated with one lek were gained. On this basis, we calculated annual and seasonal Minimum Convex Polygons (MCP), traditionally used as a measure of the maximum area of activity. Capercaillie habitat preference was computed using Manly’s habitat selection ratios (w), design III, combined with 90% Bonferroni simultaneous confidence intervals. To calculate habitat selection, we determined surface (Steepness and Exposure), forest stand succession and vegetation cover categorical variables. The habitat and surface layers was rasterized into 8 m square pixels. At the home range (MCP) scale, tagged roosters used vegetation cover non-randomly (annual: Khi2L=5738.89, df=14, p<0.001; winter: Khi2L=3773.28, df=13, p<0.001; summer: Khi2L=3646.32, df=14, p<0.001), and preferred forests dominated by Scots pine and Macedonian pine, such as the annual selection of Scots pine and summer selection of Macedonian pine are significantly different. In terms of forest stage succession, roosters used forest stages non-randomly (annual: Khi2L=3492.57, df=8, p<0.001; winter: Khi2L=2075.18, df=8, p<0.001; summer: Khi2L=1670.1, df=6, p<0.001), and demonstrated clear avoidance of forests stands in age classes: “0 to 40” and “41 to 80” years within the summer and annual ranges. The roosters demonstrated significant preference for southeastern exposure during the winter and annually, and significant overall avoidance of northern exposure, as well as avoidance of north-eastern aspect during the winter and south aspect during the summer (annual: Khi2L=4671.87, df=18, p<0.001; winter: Khi2L=3909.04, df=16, p<0.001; summer: hi2L=3095.84, df=18, p<0.001). The slope class “63.1 to 73o” was not used. In the summer, Capercaillie males significantly preferred slopes within the class “27.1 to 36o” and avoided the classes “0 to 9o”, “9.1 to 18o” and “54.1 to 63o”. The birds also demonstrated significant avoidance of flat terrains within the “0 to 9o” class annually (annual: Khi2L=608.24, df=17, p<0.001; winter: Khi2L=1148.37, df=16, p<0.001; summer: Khi2L=906.54, df=17, p<0.001).

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Estrés fisiológico en urogallos cantábricos (Tetrao urogallus cantabricus) silvestres y en cautividad: variaciones temporales e implicaciones metodológicas

Ecosistemas ◽

10.7818/ecos.2161 ◽

2021 ◽

Vol 30 (1) ◽

pp. 2161

Author(s):

Jesús Martínez Padilla ◽

Alba Estrada Acedo

Keyword(s):

Tetrao Urogallus ◽

Tetrao Urogallus Cantabricus

El estudio de los factores ambientales que pueden explicar los niveles de estrés fisiológico en poblaciones naturales es de vital importancia para especies vulnerables, ya que puede influir en la mortalidad de los individuos y, por tanto, en la viabilidad poblacional. En este trabajo se exploran los condicionantes ambientales que pueden explicar las variaciones de estrés fisiológico medido a través de niveles de corticosterona en plumas de urogallo cantábrico (Tetrao urogallus cantabricus). Se emplearon muestras recogidas de individuos en cautividad y de individuos silvestres. Las muestras recogidas de los individuos silvestres se recopilaron desde 1998 hasta 2017 y se consideraron 35 variables climáticas de temperatura y precipitación. Los análisis de repetibilidad sugirieron que los niveles de corticosterona en la combinación de plumas corporales y secundarias fueron repetibles dentro de individuos, mientras que en la combinación de plumas corporales y primarias no lo fueron, por lo que se consideraron sólo las medidas de las plumas corporales y secundarias. Los resultados indicaron que los individuos en cautividad tuvieron un menor estrés fisiológico y que, en individuos silvestres, hubo un incremento de los niveles de estrés hasta estabilizarse en los últimos años de estudio. Ninguna variable climática estuvo relacionada con los niveles de estrés fisiológico. Especulamos que la tendencia temporal en los niveles de estrés podría estar reflejando limitaciones alimenticias, quizá asociadas a cambios en la estructura o composición del hábitat o interacciones con otras especies silvestres o ganado doméstico, lo que podría explicar el menor estrés fisiológico de los individuos en cautividad. Desde el punto de vista metodológico, las plumas secundarias o corporales, independientemente del sexo, serían las preferibles para establecer un monitoreo del estrés fisiológico del urogallo en condiciones naturales o de cautividad.

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Trends in the abundance of Cantabrian Capercaillie Tetrao urogallus cantabricus at leks on the southern slope of the Cantabrian Mountains, north-west Spain

Bird Conservation International ◽

10.1017/s0959270905000626 ◽

2005 ◽

Vol 15 (4) ◽

pp. 397-409 ◽

Cited By ~ 8

Author(s):

CÉSAR J. POLLO ◽

LUIS ROBLES ◽

JUAN M. SEIJAS ◽

ÁNGEL GARCÍA-MIRANDA ◽

RAFAEL OTERO

Keyword(s):

Population Decline ◽

Small Population ◽

Limiting Factors ◽

Tetrao Urogallus ◽

Southern Slope ◽

Cantabrian Mountains ◽

North West ◽

Area Of Occupancy ◽

Tetrao Urogallus Cantabricus ◽

Number Of Males

We analysed the trend of the number of singing males of Cantabrian Capercaillie Tetrao urogallus cantabricus in 207 leks on the southern slope of the Cantabrian mountains, north-west Spain, in the period 1981 to 2003. The area of occupancy in 1981–1982 covered up to approximately 2,070 km2, but in 2000–2003 it was 693 km2, a 66% area reduction in 22 years. The 1981–1982 census estimated a minimum number of 274 singing male Capercaillie on the southern slope, but in 2000–2003 only an estimated 81 males were recorded, a reduction of 70%. A linear regression was used to detect and describe the changes in the size of the total population of the southern slope as well as individual subpopulations. The overall trend for the total subpopulations was a significant decrease in the number of males (y = 39.94−0.018x; R2 = 0.944, P < 0.001). The negative regression slopes indicated that the number of males had fallen in all the subpopulations considered. In the western core area the greatest annual mean rate of decline was detected in the Sierra de Picos de Ancares subpopulation (−6.22%) and in the eastern core in the Sierra de Riaño subpopulation (−3.43%). The principal local limiting factors (habitat fragmentation, human disturbance, small population size and competition) that have caused the population decline are discussed, together with the demographic, genetic and evolutionary consequences for the surviving subpopulations.

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Habitat selection and diet of Western Capercaillie Tetrao urogallus in an atypical biogeographical region

Ibis ◽

10.1111/j.1474-919x.2012.01217.x ◽

2012 ◽

Vol 154 (2) ◽

pp. 260-272 ◽

Cited By ~ 9

Author(s):

MANUEL A. GONZÁLEZ ◽

PEDRO P. OLEA ◽

PATRICIA MATEO-TOMÁS ◽

SERGIO GARCÍA-TEJERO ◽

ÁNGEL DE FRUTOS ◽

...

Keyword(s):

Habitat Selection ◽

Tetrao Urogallus ◽

Biogeographical Region

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Severe decline in Cantabrian Capercaillie Tetrao urogallus cantabricus habitat use after construction of a wind farm

Bird Conservation International ◽

10.1017/s0959270914000471 ◽

2015 ◽

Vol 26 (2) ◽

pp. 256-261 ◽

Cited By ~ 3

Author(s):

MANUEL A. GONZÁLEZ ◽

SERGIO GARCÍA-TEJERO ◽

ERIC WENGERT ◽

BENITO FUERTES

Keyword(s):

Habitat Use ◽

Wind Farm ◽

Tetrao Urogallus ◽

Mediterranean Forests ◽

Cantabrian Mountains ◽

Conservation Areas ◽

North West ◽

Negative Effect ◽

Tetrao Urogallus Cantabricus ◽

One Year

SummaryTetrao urogallus cantabricus is the most endangered capercaillie subspecies and unlike the others it inhabits deciduous forests in the Cantabrian Mountains (north-west Spain). Its southernmost distribution occurs in Mediterranean forests outside conservation areas where wind farm construction is increasing. We surveyed Cantabrian Capercaillie presence in a wintering site one year before and four years after wind farm construction. Sign abundance greatly decreased after wind farm construction indicating a likely negative effect on Cantabrian Capercaillie habitat use. According to the precautionary principle, in order to conserve Cantabrian Capercaillie, all its range should be legally protected to avoid further wind farm construction and human disturbance.

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