INVESTIGADORES
GRANDE Juan manuel
artículos
Título:
Stressful conditions experienced by endangered Egyptian vultures on African wintering areas
Autor/es:
CARRETE, M.; BORTOLOTTI, G.R.; SÁNCHEZ-ZAPATA, J.A.; DELGADO, A; CORTÉS-AVIZANDA, A; GRANDE, J.M
Revista:
ANIMAL CONSERVATION
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2012 vol. 16 p. 353 - 358
ISSN:
1367-9430
Resumen:
Among European breeding birds, those wintering in the Sahel region have undergonea sustained and severe decline. Long-term data show that variation inprimary production of the Sahelian staging area significantly affects survival ofmany species, a relationship probably mediated by trophic resource availability.However, the physiological, hormonal and behavioural responses underlying thisrelationship remain unexplored. We present a potential explanation for the importanceof prevailing conditions during winter to understand the population ecologyand current trends of migratory species. We measured corticosterone levels infeathers of Egyptian vultures Neophron percnopterus grown in Africa and Europe,showing how conditions faced by birds during wintering periods result in therelease of more corticosterone over time than when those individuals were on theirsummering grounds. This pattern was concordant with home-range size differences(c. 33 times larger in Africa than in Europe). We suggest that as winteringhabitat of Egyptian vultures in the Sahel region has degraded during recent times,food availability has also been reduced. An increase in corticosterone duringwinter with a consequent increase in locomotor activity, for example, food searchingbehaviour, may normally be adaptive. However, enlarging home ranges couldbe futile if conditions are not better in the dispersal area, and costs of the highercorticosterone level, including energy expenditure from enhanced activity, maypose a significant trade-off. These physiological responses may be characteristic ofother European trans-Saharan migrant birds that have undergone significantpopulation declines.