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- Title
Scavenging by brown bears, Ursus arctos, and glaucous-winged gulls, Larus glaucescens, on adult sockeye salmon, Oncorhynchus nerka
- Authors
Quinn, T. P.; Buck, G. B.
- Abstract
Adult Pacific salmon that have returned to spawn in streams are vulnerable to predation and are also susceptible to scavenging after death by animals such as bears and gulls. The distinction between predation and scavenging is important in furthering our understanding of thebehavior of bears and gulls as well as the population dynamics of salmon. To understand better the role of these animals, we tagged freshly dead Sockeye Salmon, both spent and ripe, and recorded instances of scavenging on a small stream in southwestern Alaska. Both Brown Bears and Glaucous-winged Gulls scavenged about 20 - 30% of the salmon <1 day of tagging (1-2 days after death). With respect to gender, bears exhibited a preference for male salmon, gulls for females. With respect to spawning status, both showed a preference for ripe female salmon, a pattern that gulls also showed for male salmon. The proportionof salmon carcasses scavenged by bears increased to about 70% within7 days of tagging, and many carcasses were partly scavenged on more than one occasion. Because of the high rate of bear scavenging and the tendency for this to mask scavenging by gulls, it was difficult to quantify gull scavenging accurately beyond 2-3 days. Bears tended to eat the cranial region of males and the bellies of females. 'the proportion of carcasses scavenged by bears varied greatly over the courseof the spawning run, but was generally high early and late in the run when there were fewer live and dead salmon available.
- Subjects
ALASKA; UNITED States; SOCKEYE salmon; PREDATION; ANIMALS; BROWN bear; GLAUCOUS-winged gull
- Publication
Canadian Field-Naturalist, 2000, Vol 114, Issue 2, p217
- ISSN
0008-3550
- Publication type
Article