Foraging ecology of a reintroduced population of breeding Bald Eagles on the Channel Islands, California, USA, inferred from prey remains and stable isotope analysis

Tracking the origins and diet of an endemic island canid (Urocyon littoralis) across 7300 years of human cultural and environmental change

“…Rick et al (2009) noted that many of the Channel Islands fossil localities were thought to be ancient bald eagle nests (Guthrie, 1993) that likely would have contained remnant prey fox remains if they were available on the islands. While historic and modern bald eagle nests occasionally contain island fox remains (Erlandson et al 2007, Newsome et al 2010, Newsome et al, 2015, foxes have not been recovered from Pleistocene fossil contexts. The oldest date of ~7300 years also fits well with genetic estimates of island and gray fox divergence (Hofman et al, 2015b).…”

“…Data sets that track dietary changes over long-term timescales (centuries, millennia) are therefore valuable for identifying anthropogenic impacts. Stable isotope analysis provides a powerful tool for understanding food-web structure (Tieszen and Boutton, 1989) and, along with other data, can provide insights into past and present human-wildlife interactions (Beard and Johnson, 2000;Guiry, 2012;Newsome et al, 2015Newsome et al, , 2010Wiley et al, 2013).…”

Trophic ecology of the Endangered Darwin’s frog inferred by stable isotopes

“…Dietary information from locally imperiled species is a necessary component in designing management and conservation programmes (Solé & Rödder 2010). For instance, stable isotope studies have been a key aspect in assessing the success of reintroduction programmes in Przewalski's horses Equus ferus prze walskii (Kaczensky et al 2017) and bald eagles Haliaeetus leucocephalus (Newsome et al 2015). In amphibians, monitoring Australian green and golden bell frogs Litoria aurea subjected to conservation management has shown a reduction in reproduction in reintroduced frogs from created habitat compared to surrounding wild populations, probably associated with a reduced diversity of invertebrate prey in the created habitat.…”

Evaluating Bayesian stable isotope mixing models of wild animal diet and the effects of trophic discrimination factors and informative priors

“…If properly implemented, BSIMMs can produce accurate, probabilistic estimates of animal diets (Moore & Semmens, 2008;Parnell et al, 2013), yet concerns have been raised over misuse and sensitivity to input parameters (Boecklen, Yarnes, Cook, & James, 2011;Derbridge et al, 2015;Franco-Trecu et al, 2013;Martínez Del Rio, Wolf, Carleton, & Gannes, 2009). This has led to attempts to evaluate BSIMMs through experimental and observational studies (Derbridge et al, 2012(Derbridge et al, , 2015Franco-Trecu et al, 2013;Newsome, Collins, & Sharpe, 2015;Resano-Mayor et al, 2014;Weiser & Powell, 2011). Although studies of captive animals in controlled conditions provide a powerful approach to testing mixing model performance (Caut, Angulo, & Courchamp, 2008;Derbridge et al, 2015), they can lack the variation in diet and physiology typical of wild animals (Boecklen et al, 2011).…”