This Chestnut-sided Warbler at Pt. Pinos had been present one full week when I photographed it. It obligingly hopped into the sun and preened, permitting me to snap a long series of photos that show details we can rarely see in the field. For example, a view of the underside of the tail (just above right, and enlarged directly right) show the abraded and pointed shape of the outer rectrices, which age this individual as a HY [hatch-year] bird. The lack of broad black centers to uppertail coverts tend to support this ageing, as do the primary coverts, which are the same color as the remiges (seen well in top and bottom photo on this page). The amount of white on the inner webs of the outer three rectrices, visible in several shots, suggests this is an HY male. Up to half of HY males may lack any chestnut wash to the flanks. All these in-hand details are from Pyle (1997).

Chestnut-sided Warbler is a regular fall vagrant to MTY, averaging 5-6 birds per autumn (Roberson 2002), but seems to be occurring with slightly higher frequency in recent years.

Photos: All photos © Don Roberson, all rights reserved.

Literature cited:

Pyle, P. 1997. Identification Guide to North American Birds. Part I. Slate Creek Press, Bolinas.

Roberson, D. 2002. Monterey Birds. 2d ed. Monterey Pen. Audubon Soc., Carmel CA.