Coyote (Canis latrans) use of marine resources in coastal California: A new behavior relative to their recent ancestors

Abstract

Coyotes (Canis latrans) are known to consume marine foods, but the importance and persistence of marine subsidies to coyotes is unknown. Recent access to a marine subsidy, especially if gained following apex predator loss, may facilitate coyote expansion along coastal routes and amplify the effects of mesopredator release. Our goal was to quantify and contextualize past and present marine resource use by coyotes on the central coast of California via stable isotope analysis. We measured δ 13 C and δ 15 N values in coyotes, their competitors, and their food resources at two modern sites, seven archaeological sites spanning in age from ~3000 to 750 BP, and from historical (AD 1893-1992) coyote and grizzly bear hair and bone sourced from coastal counties. We found evidence for marine resource use by modern coastal California coyotes at one site, Año Nuevo, which hosts a mainland northern elephant seal (Mirounga angustirostris) breeding colony. Seals and sea lions account for ~20% of Año Nuevo coyote diet throughout the year and this marine subsidy likely positively impacts coyote population size. Isotopic data suggest that neither historic nor prehistoric coyotes consumed marinederived foods, even at sites near ancient mainland seal rookeries. Marine resource use by some contemporary California coyotes is a novel behavior relative to their recent ancestors. We hypothesize that human alteration of the environment through extirpation of the California grizzly bear and the more recent protection of marine mammals likely enabled this behavioral shift.

A ~1000-year 13C Suess correction model for the study of past ecosystems

“…Stable isotope analysis has helped clarify baseline information regarding the niche (sensu Newsome et al, 2007b) of past organisms and how niches change or remain constant through time. Historical shifts in animal diet, habitat preference, migration, and reproduction have been tracked using stable isotopes (Braje et al, 2017;Chamberlain et al, 2005;Fox-Dobbs et al, 2007;Hofman et al, 2016;Koch et al, 2017;Newsome et al, 2007aNewsome et al, , 2007bNewsome et al, , 2010Reid et al, 2018). However, employing this technique comes with some methodological hurdles.…”

“…However, if the more recent sample of interest spans anywhere between 1760 and the present day, then the correction value that should be applied becomes ambiguous. However, this ambiguity has been handled in different ways (see for instance Chamberlain et al, 2005;Long et al, 2005;Reid et al, 2018;Schelske and Hodel, 1995).…”

Host and geographic differences in prevalence and diversity of gastrointestinal helminths of foxes (Vulpes vulpes), coyotes (Canis latrans) and wolves (Canis lupus) in Québec, Canada

“…The higher prevalence of adults and eggs of diphyllobothriids in coyotes ( Tables 2a-3 ) suggests a diet that includes more piscine intermediate and paratenic hosts containing plerocercoids ( Ching, 1984 ; Jenkins et al, 2013 ; Reid et al, 2018 ). Given the known geographic distribution of diphyllobothriids, and the distance of collected specimens from marine environments, the most likely identification for these cestodes in our data set are the freshwater species Dibothriocephalus latus (previously Diphyllobothrium latum ) or D. dendriticus (previously Diphyllobothrium dendriticum ) ( Jenkins et al, 2013 ).…”

Revisiting the Foraging Ecology and Extinction History of Two Endemic Vertebrates from Tenerife, Canary Islands

“…This "canopy effect" is caused by higher relative humidity, lower light availability, and incorporation of microbe-respired CO 2 by understory plants. Lastly, individuals living near the ocean, or consuming marine foods, can have elevated δ 13 C and δ 15 N values, e.g., [58][59][60][61]. It is critical to account for the influence of habitat when interpreting isotope data, particularly when comparing individuals from different localities.…”