Prepared by David L. Suddjian
Santa Cruz Bird Club Bird Records Keeper
dsuddjian@aol.com
November 4, 1999
 

Clay-colored Sparrow (CCSP) and Chipping Sparrow (CHSP) are two similar
sparrows that offer an identification challenge. Both are small and fairly
nondescript, and are probably somewhat overlooked during fall migration in
Santa Cruz County. However, it is interesting to note that CHSP, a common and
widespread western breeder, is found less frequently in fall migration in the
county than CCSP, a species normally considered a "rare bird."

This summary includes records of these species from fall migration in Santa
Cruz County for the period 1987- November 3, 1999. I considered records from
August 1 - November 30. Some records from early winter may pertain to tardy
fall migrants, but were not included. Nearly all reports came from active,
skilled observers who would be equally likely to report either species. None
of the records came from bird-banding operations.

From 1987 to November 3, 1999, there were 42 fall records of CCSP compared to
only 14 fall records of CHSP. Both species are rare fall migrants in Santa
Cruz County, with annual averages of only 3.2 CCSP and 1.1 CHSP per fall. The
average ratio over the whole period was 2.9:1 in favor of CCSP, but for the
recent 5-year period (1995-1999) it was 5.4:1 in favor of CCSP. Unusually
many CCSP were found in 1998 (11 records) and 1999 (8 so far), compared to
only 1-3 records per year before 1998.

CCSP was reported from September 13 to November 19, with a broad peak from
late September to late October. CHSP was reported between September 15 and
November 9, with a slight peak in late October. Reports of both species came
mostly from the coast and the Pajaro Valley, and from similar habitats
(especially grassland edges, weedy areas, agricultural fields, margins of
scrub or riparian woodland, open garden areas and backyards with seed
feeders).

I doubt that CHSP was being seen but under-reported relative to CCSP. The
skilled observers who generated most of the observations understood that both
species were noteworthy. Bias may have arisen if CCSP was more readily
detected (doubtful), or if CHSP had a less coastward pattern of occurrence in
the county than CCSP (observer effort was biased toward the coast).