Impacts of salmon on estuarine birds

Salmon (Oncorhynchus spp.) that spawn around the Pacific Rim subsidize coastal ecosystems with marine-derived nutrients. I examined effects of (1) salmon biomass availability for scavenging birds in the fall, and (2) the stored salmon nutrients on bird assemblages in the summer, while accounting for the influences of other environmental variables. Over two years, I studied 17 estuaries in fall and 21 estuaries in summer, which varied across a range of spawning salmon biomasses. I discovered that many aspects of scavenging and breeding bird abundance and diversity were strongly related to salmon biomass and landscape features. Overall, findings suggest that nutrients from salmon are important to avian consumers through both indirect and direct pathways and point to the possibility of using birds as indicators of salmon nutrient input to watersheds.