Tracking data and retrospective analyses of diet reveal the consequences of loss of marine subsidies for an obligate scavenger

LAMBERTUCCI, SERGIO A.; NAVARRO, JOAN ; SANCHEZ-ZAPATA, JOSÉ A; HOBSON, KEITH A.; ALARCÓN, PABLO A. E.; WIEMEYER,GUILERMO; BLANCO, GUILLERMO; HIRALDO, FERNANDO; DONÁZAR, JOSÉ A.

PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON. SERIES B: BIOLOGICAL SCIENCES.

ROYAL SOC

Lugar: Londres; Año: 2018

0962-8452

Over the last century, marine mammals, especially whales have been dramatically reduced in the world?s oceans. We studied how this change caused dietary and foraging patterns shifts of the Andean condor (Vultur gryphus). We hypothesized that, after the decrease in marine mammals and the increase in human use of coastlines in this region, condor diet should have changed to a more terrestrial makeup which, in turn, might have influenced their movement patterns. By means of stable isotope analysis (δ13C, δ15N and δ34S) of current (last decade) and historical (1841-1933) feathers, we evaluated possible changes in the contribution of marine resources to the diet. We further evaluated the movement patterns of 23 modern condors using satellite tracking of individuals. Andean condors reduced their use of marine-derived prey in recent compared to historical times from 33±13% to less than 8±3% respectively, but still breed close to the coast. Some birds must currently travel farther, crossing over the mountain range to find food, which entails extra costs. The worldwide reduction in the availability of marine mammals carcasses, especially whales, can have major consequences on the pattern of movement and foraging ecology of scavengers as well as on the flux of marine inputs within terrestrial ecosystems