Abundance and nest characteristics of Dusky and Hammond’s flycatchers across a 1750 meter elevational gradient

This data publication contains tabular data on abundance, nesting success, and nest site selection for dusky (Empidonax oberholseri) and Hammond’s flycatchers (Empidonax hammondii) breeding in the southern Sierra Nevada, California. As part of a larger study examining the abundance and productivity of forest birds, dusky and Hammond’s flycatchers were studied in four forest types along a 1750 meter elevational gradient in the High Sierra Ranger District of the Sierra National Forest on the western slope of the southern Sierra Nevada. From 1995 through 2002, field technicians censused birds on eight (1995) or 16 (1996 – 2002) study sites using a time transect method. Observers walked at a rate of 50 meters per 3 minutes, recording all birds detected within 50 meters of the transect line and those detected at unlimited distance. Each site was visited six times per season by three or four observers each year of the study. For nests whose contents could be examined, the number of eggs and nestlings as well as the appearance of the nestlings (size, whether the eyes were closed, slits, or open, presence of down and pin feathers, and the extent of emergence of the remiges and rectrices) were recorded. After the nest fledged or failed, elevation, nest substrate type (shrub, tree or snag), nest height, substrate height, and substrate species and substrate height were recorded.
These data were collected as part of a study to examine abundance and reproductive ecology of bird species over an elevational gradient in the southern Sierra Nevada, California.
For more information about this study and these data, see Purcell (in review). For more information about the larger study, see Purcell (2006, 2007, 2012), Purcell and Dryan (2008), Purcell et al. (2012), Purcell and McGregor (2021).