Population sampling
Oregon juncos were sampled across their breeding range using mist nets
and seed-baited walk-in traps during the breeding season, between the
months of April and June, and between the years 2004 and 2014. In
addition to samples collected at UCSD in San Diego, California, we
included in the study samples from all recognized Oregon junco
subspecies, including oreganus from British Columbia,montanus and shufeldti from Oregon, thurberi andpinosus from California, and pontilis and townsendifrom Baja California, Mexico (Fig. 1). At UCSD, birds were sampled both
during the breeding season and the non-breeding season, and genetic and
isotopic analyses were used to infer whether birds sampled in the
non-breeding season were local residents or wintering visitors breeding
elsewhere (see below).
Birds were marked with uniquely numbered aluminum bands to avoid
resampling, and then released after processing at the site of capture. A
blood sample was collected by venipuncture of the brachial vein and
stored in Queen’s lysis buffer (Seutin 1991) or absolute ethanol at
-80ºC in the laboratory. All sampling activities were conducted in
compliance with Animal Care and Use Program regulations at the
University of California Los Angeles, University of California San
Diego, North Dakota State University and Indiana University, and with
State and Federal scientific collecting and bird banding permits in the
USA, Canada and Mexico.