On 30 January Mark Stevenson found an ABA Code-3 Black-capped Gnatcatcher (Polioptila nigriceps) in the Sonoita Creek State Natural Area near Patagonia Lake, adjacent to Patagonia Lake State Park, Arizona (permits for the Natural Area can be obtained at the gatehouse at Patagonia Lake State Park).
Black-capped Gnatcatcher is endemic to northwest Mexico. It has bred irregularly in Arizona, more frequently in recent years. It was first discovered in the U.S. after a family group of five birds, including three fledglings, were collected along Sonoita Creek, a few miles northeast of Nogales, Santa Cruz County, Arizona, on 22 June 1971. The discovery and description of the birds was described by Allan Phillips et al. in The Auk: 90 (2)(April 1973).
In Mexico, this species is found in gallery forest, tropical deciduous forest, and arid lowland scrub. The small range of Black-capped Gnatcatcher includes central Sonora, Sinaloya, Nyarit, Jalisco, to northernmost Colima. Although at times it has been considered conspecific with White-lored Gnatcatcher (P. albiloris) of Mexico's Pacific lowlands and interior valleys, Black-capped Gnatcatcher differs from White-lored in both morphology and vocalizations.