Daniel R Ruthrauff, Ph.D. (Former Employee)

At what phenotypic level do closely related subspecies that live in different environments differ with respect to food detection, ingestion and processing? This question motivated an experimental study on rock sandpipers (Calidris ptilocnemis). The species' nonbreeding range spans 20 deg of latitude, the extremes of which are inhabited by two subspecies: C. p. ptilocnemis that winters...

Prevalence of avian influenza virus (AIV) antibodies in the western Atlantic subspecies of Red Knot (Calidris canutus rufa) is among the highest for any shorebird. To assess whether the frequency of detection of AIV antibodies is high for the species in general or restricted only to C. c. rufa, we sampled the northeastern Pacific Coast subspecies of Red Knot (Calidris canutus roselaari)...

Shorebirds are conspicuous and abundant at high northern latitudes during spring and summer, but as seasonal conditions deteriorate, few remain during winter. To the best of our knowledge, Cook Inlet, Alaska (60.6˚ N, 151.6˚ W), is the world’s coldest site that regularly supports wintering populations of shorebirds, and it is also the most northerly nonbreeding location for shorebirds in...

Shorebirds at northern latitudes during the nonbreeding season typically carry relatively large lipid stores and exhibit an up-regulation of lean tissues associated with digestion and thermogenesis. Intraspecific variation in these tissues across sites primarily reflects differences in environmental conditions. Rock (Calidris ptilocnemis (Coues, 1873)) and Purple (Calidris maritima...

The Dunlin (Calidris alpina) is a polytypic shorebird with complex patterns of distribution and migration throughout its holarctic range. We analyzed mark-re sighting data obtained between 1977 and 2010 from birds captured at two major staging areas in western Alaska to test the hypothesis that the migration patterns of Alaskan populations are a mixture of parallel and chain, similar to...

Closely related species or subspecies can exhibit metabolic differences that reflect site-specific environmental conditions. Whether such differences represent fixed traits or flexible adjustments to local conditions, however, is difficult to predict across taxa. The nominate race of Rock Sandpiper (Calidris ptilocnemis) exhibits the most northerly nonbreeding distribution of any...