Context dependent foraging by seed-eating birds does not necessarily mean low ecological predictability

MARONE L; CAMÍN SR; CUETO VR

CANADIAN JOURNAL OF ZOOLOGY

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Lugar: Otawa; Año: 2015 vol. 93 p. 353 - 359

0008-4301

Flexibility of foraging behaviour affects our capacity to predict ecological outputs such as population responses to habitat change. Some birds forage following absolute valuation rules. Their realized diet is strongly correlated to option?s profitability and predictable. Consumers, however, do not always follow absolute rules. Opportunistic or text-dependent foragers adjust food consumption to options availability. Their diet is still predictable, although more elusive. Relativistic or context-dependent foragers change the ranks of food preferences depending on the presence of alternative options in the choice set. Predicting their contingent diet is particularly difficult. We tested if the context of seed availability affects foraging decisions of three seed-eating bird species by using choice experiments aiming at detecting if seed preferences for two types of target seeds changed according to context. Birds showed very similar rankings of preferences for target seeds, but preferences for attractive food options were not fixed but often increased in less valuable contexts. Although results imply some degree of context-dependent behaviour, predictability of bird diet was preserved since the ranking of preferences remained mostly unchanged between contexts (and among bird species), and the higher consumption of target grass seeds in a less attractive context was widely expected from seed intrinsic properties.