Luck and tactics in foraging success: the case of the imperial shag

• Autores: Wilson, Rory P; Holton, Mark; Neate, Andrew; del Caño, María Monserrat; Quintana, Flavio Roberto; Yoda, Ken; Gómez Laich, Agustina Marta
• Año de publicación: 2022
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: LEUCOCARBO ATRICEPS; CORMORANT; FORAGING ECOLOGY; GAMBLING; PROBABILITY OF FOOD ENCOUNTER; TACTICS
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

It has been proposed that predators searching for prey acquire food according to a probabilistic framework, where success is based on 'luck' and the odds of success vary with prey abundance. If true, this has major ramifications for variation in the rates of energy acquisition within animal populations, which is particularly pertinent in offspring provisioning and breeding success, be - cause smaller animals (the young) cannot starve for as long as the adults. However, despite much general speculation about rates of food acquisition, no study has measured whether food encounter is probabilistic in wild animals. We used animalmounted cameras to document all prey captures by wild imperial shags Leucocarbo atriceps as they hunted underwater and show that, although they mostly do not have inter-prey acquisition time distributions that accord with a 'luck-based' framework assuming a constant probability of finding prey over time, there is no difference in the predicted amount of food captured between models that use the empirical data or theoretical Poissonbased fits of the data. We also noted considerable inter-individual differences in foraging success that far exceeded any differences between empirical and theoretical inter-prey acquisition time distributions. The data were used in a probabilistic for aging model that made explicit the mechanistic link between random prey encounters and fooddependent breeding success, indicating that 'less lucky' individuals could not provision their broods at rates commensurate with normal growth while the 'lucky' birds could do so easily. Given the nature of food encounter in these birds, coupled with substantial inter-individual variation in foraging success, we suggest that more successful individuals are particularly choosey about when, how and where to forage, which results in them operating with higher odds of success.
Fil: Wilson, Rory P. Swansea University. College of Sciences; Reino Unido. Swansea University; Reino Unido
Fil: Holton, Mark. Swansea University. College of Sciences; Reino Unido
Fil: Neate, Andrew. Swansea University. College of Sciences; Reino Unido
Fil: del Caño, María Monserrat. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina
Fil: Quintana, Flavio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina
Fil: Yoda, Ken. Nagoya University; Japón
Fil: Gómez Laich, Agustina Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina