Farallon Institute scientists have been analyzing diet data from three puffin species in Alaska. Puffin diet data were collected since the 1970s by the USGS Alaska Science Center, Alaska Maritime National Wildlife Refuge Seabird Monitoring Program, and the Institute for Seabird Research and Conservation. Researchers from these agencies collected data from approximately 40 sites around the Gulf of Alaska and across the Aleutian Islands.
In order to study puffin diet, field biologists collect samples of the fish and invertebrates (such as squid) that adult puffins bring back to nest burrows to feed to chicks. These diet samples are brought to the lab where they are identified to species, weighed, and measured. For diet analysis, Farallon Institute organized the sample data in a database that contains over 100,000 records of the fish and invertebrate samples collected at the nest burrows, and their sizes. Research and data collection are ongoing, but we have three major analyses of these data.
Temporal variability -- We recently published a paper describing temporal variation in puffin diet from 1978-2012. Variation in puffin diet over time can be indicative of changes in the local fish community, which may be driven by large-scale environmental factors.
Geographic variability -- By studying puffin diet at so many sites, we can also explore how fish communities might be different from place to place. In the Gulf of Alaska and Aleutian Islands, the ocean habitat around puffin colonies varies. Colonies in the east are more continental shelf-oriented than the sites in the west, which are in a more oceanic system (see map below, and the proximity of colonies to the 2000-m isobath). As such, puffin diet varies in accordance with the habitat characteristics of these sites. A manuscript on this geographical variation is in progress.
Fish condition -- Condition of fish can be determined from their size and weight. We are currently analyzing these size measurements to create a condition index that can be related to environmental conditions in the ecosystem.