0000000000481615
AUTHOR
Juan Antonio Gil
Adult coloration of the Bearded Vulture (Gypaetus barbatus) in the Pyrenees: relation to sex, mating system and productivity.
Cosmetic coloration is not a common phenomenon among bird species. Adult Bearded Vultures Gypaetus barbatus typically show orange coloration in head, chest, belly and tarsus feathers that is the result of mud baths in ferruginous substrates. Several non-mutually exclusive visual signalling hypotheses can be proposed to explain this phenomenon. Coloration could be used to signal: (1) dominance towards conspecifics, with darker birds being dominant (status signalling hypothesis); (2) sex (gender signalling hypothesis) because females are usually more intensely coloured; (3) individual quality for mate choice (quality signalling hypothesis); or (4) different reproductive strategies between ind…
Post-fledging dependence period and onset of natal dispersal in Bearded Vultures (Gypaetus barbatus): new insights from GPS satellite telemetry.
Utilizamos telemetría satelital para estudiar el periodo de dependencia post emplumamiento de tres individuos silvestres y seis individuos cautivos de Gypaetus barbatus. El primer vuelo tuvo lugar cuando los pollos tenían 126 ± 7 días de edad (rango = 111–134 días) y el inicio de la dispersión ocurrió a los 193 ± 40 días desde el primer vuelo (rango = 143–231 días). Los jóvenes permanecieron en sus áreas natales (o de liberación, en el caso de aves criadas en cautiverio) durante los primeros dos meses desde la fecha de emplumamiento. Luego, comenzaron a incrementar progresivamente la distancia a sus áreas natales; durante este tiempo, la mayoría de los desplazamientos de larga distancia…
First cases of polygyny for the Bearded Vulture Gypaetus barbatus in the central Pyrenees
ABSTRACTWe report the first cases of polygyny for the Bearded Vulture Gypaetus barbatus in the central Pyrenees, Spain. Although polyandry is frequent in the study area (31.8% of all reproductive units in 2016), we only observed the occurrence of three cases of polygyny over the period 1994–2017. Polygyny in Bearded Vultures is possibly a consequence of habitat saturation.
The flight feather moult pattern of the bearded vulture (Gypaetus barbatus)
Moult is an extremely time-consuming and energy-demanding task for large birds. In addition, there is a trade-off between the time devoted to moulting and that invested in other activities such as breeding and/or territory exploration. Moreover, it takes a long time to grow a long feather in large birds, and large birds that need to fly while moulting cannot tolerate large gaps in the wing, but only one or two simultaneously growing feathers. As a consequence, large birds take several years to complete a full moult cycle, and they resume the moult process during suboptimal conditions. A clear example of this pattern is the Bearded Vulture (Gypaetus barbatus), which needs 2-3 years for chang…
Population Decline of the Capercaillie Tetrao urogallus aquitanicus in the Central Pyrenees
El seguimiento a largo plazo de las aves amenazadas es esencial para estimar las tendencias poblacionales e identificar las posibles causas de declive, siendo particularmente importante en el caso de las aves alpinas que habitan en areas montanosas en los limites de su area de distribucion. Analizamos la tendencia poblacional del urogallo en los Pirineos centrales espanoles a partir de investigaciones realizadas entre 2000 y 2017. Encontramos un declive significativo de la poblacion (alrededor del 58%) en el numero de aves contadas en las areas de exhibicion (lek). la mayoria de los urogallos habitan bosques de coniferas de pino negro con una cobertura elevada de arandano y rododendro en el…