Assessment of Tufted Puffin <i>Fratercula cirrhata</i> Diet using DNA Metabarcoding

Investigating trophic relationships can be critical for understanding relationships between marine predators and their prey. DNA analysis of feces is used increasingly as a non-invasive method to uncover seabird dietary patterns across space and time. Tufted Puffins Fratercula cirrhata are listed as Endangered in the state of Washington (WA), USA, and reduced prey availability is thought to be a key factor in the species’ decline. Recent information on Tufted Puffin diet is lacking, and present opportunities for direct diet observation are limited. We conducted a pilot study to characterize Tufted Puffin diet on Destruction Island, WA, in 2019 using DNA metabarcoding of feces from burrow entrances and from soil in nesting chambers. Smelt (Osmeridae) and rockfish (Scorpaenidae) were detected in all fecal samples, along with a variety of other fish taxa, squid, crab, and shrimp. Smelt was detected in most soil samples, as were a variety of other fish, crustaceans, and terrestrial insects. While DNA metabarcoding detected several taxa also identified in Tufted Puffin bill-loads in 2019, fecal and soil samples detected multiple taxa not identified in bill-loads. It appears that Tufted Puffin diet can be characterized using DNA metabarcoding, provided that fecal samples are of sufficient quality and that contamination is minimized. Amplifying prey DNA from soil samples opens opportunities for sampling burrows after breeding, which would minimize disruptions to study colonies. Future strategies to characterize Tufted Puffin diet could combine direct observation and DNA metabarcoding methods where possible and could focus on the latter methods where observation is difficult. These non-destructive and non-disruptive methods hold promise for characterizing the diet of other burrow-nesting species of conservation concern