Rufous-crowned Sparrow (Aimophila ruficeps)
A typical clutch for a Rufous-crowned Sparrow. This is the 6th clutch observed in 09 within a study area for Black-capped Vireo reproductive effort. We routinely examine other nesting species as we come across them for any incidental record of cowbird parasitism. While 4 of 31 Rufous-crowned Sparrow nest were parasitized 1988 &1990, in recent years (2001-2009) subsequent to cowbird control measures, no RCSP nests have been observed with cowbird eggs or young.