Moose (Alces alces) hunters subsidize the scavenger community in Alaska

Abstract

In many temperate ecosystems animal carcasses resultant from wildlife harvest can provide a high-quality food source for myriad facultative scavengers. We investigated scavenger use of human-provisioned ungulate carrion from a fall moose (Alces alces) hunt during 2010 and 2011 on the Gustavus Forelands, Alaska, USA. Using data from remote cameras, we (1) identified the scavenger species that used these resources and (2) evaluated their spatial and temporal responses to this seasonal resource event by indexing their activity patterns and relative order of arrival at carrion sites. We also quantified the length of time carrion persisted and estimated the amount of moose biomass provisioned to vertebrate scavengers by human hunters. Our results indicated that 11 vertebrate species (five birds and six mammals) scavenged moose carrion. We found that the common raven was the only species documented at all carrion sites and the most abundant species at moose carrion sites. As a species group, corvids [black-billed magpie (Pica hudsonia), common raven (Corvus corax); 0.1 ± 2.3 days] were the first to arrive at human-provisioned moose carrion sites, whereas ursids [brown bear (Ursus arctos), black bear (U. americanus); 1.3 ± 1.0 days] arrived after corvids but sooner than expected and canids [gray wolf (Canis lupus), coyote (C. latrans); 3.9 ± 3.0] arrived later than expected compared to our null model. On average, carrion persisted >20 days and hunters provided scavengers with a minimum of 2720 kg (82.7 kg/km2) and 1815 kg (64.8 kg/km2) of moose carrion during 2010 and 2011, respectively. Understanding how scavengers, particularly large carnivores, interact with human-provisioned moose carrion at the rural–wildland interface is essential for mitigating potential human–wildlife conflicts associated with humans subsidizing predators with a high-quality food resource.