Frequency distribution plotting percent of total numbers testing positive as a function of Ct scores at 2 Ct intervals from <12 to 38 Ct. (A) All positive birds tested during 2010 and 2011. (B) Three corivd species: American Crow (AMCR, Corvus brachyrhynchos), Western Scrub-Jay (WESJ, Aphelocoma californica), and Yellow-Billed Magpie (YBMP, Pica nuttalli). (C) Three passerine species: American Robin (AMRO, Turdus migratorius), House Finch (HOFI, Carpodacus mexicanus), and House Sparrow (HOSP, Passer domesticus). Numbers in parentheses are the number of positive birds included within the frequency distribution.