Newfoundland Predator Project
CSI Newfoundland: molecular determination of caribou calf predators
Student: Matt Mumma
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The Newfoundland woodland caribou (Rangifer tarandus) population has decreased by greater than 66% since 1996. Habitat loss and overgrazing are likely implicated, but current recruitment is low due to high calf predation by black bears (Ursus americanus) and invasive coyotes (Canis latrans). Previously, kill site observations and necropsy results, when available, were used to assign the predator species to calf predation mortalities, but 26% of kills were unable to be assigned to a predator species. We used molecular techniques to identify the predator species at caribou calf kill sites in Newfoundland, Canada. In 2010, radio-telemetry collars were placed on 1 to 3 day-old caribou calves and calves were monitored from June through October. When a mortality signal was detected, the collar location was investigated to determine if predation had occurred. Calf mortality sites were searched for predator scat and hair. Calf carcasses were inspected for killing bite wounds as evidenced by hemorrhaging. An ethanol-soaked cotton swab was used to sample killing bite wounds for predator saliva cells. Other non-killing wounds were also sampled. In the absence of a carcass, bones, hide, and/or the collar were swabbed. Scat, hair, and swab samples were analyzed using several DNA species identification tests to distinguish among black bears, coyotes, lynx (Lynx canadensis) and red foxes (Vulpes vulpes). Molecular techniques identified a predator species at 92% of kill sites. None of these kill sites identified more than one predator species. 70% were attributed to coyotes and 30% were attributed to black bears. There was a 100% success rate in identifying the predator species from killing bite wound swabs. 75% were identified as coyotes and 25% were identified as black bears.
