Date: 7/27/17 9:55 am From: David Pearson <dpearson...> Subject: [AZNMbirds] AZ, Pinal Co., Santa Cruz Flats_ Calidris shorebird
The shorebird Darrel Wilder and I initially identified as a Sanderling on 25 July has become a learning moment. Several have suggested that it is instead a leucistic Baird's Sandpiper or perhaps a hybrid of some type. The bill shape is unusual for a Sanderling but, according to a shorebird expert from Seattle, is within the range of variation of that species. Another expert from California hesitantly agreed with Sanderling mainly because of body attitude, smudgy shoulder color, and that the wing tips do not extend noticeably beyond the tail as would be expected for a Baird's Sandpiper. Although not apparent in the photos of the bird, during our observations, it appeared not to have a hind toe (hallux), another character of Sanderling. But we could not be absolutely sure of that obscure detail. Because of the ambiguities of identification among these experts, for now we will leave it as a member of the genus Calidris. See eBird (Evergreen Turf Sod Farm Hot Spot) for photo.
NOTE: These slop ponds in Santa Cruz Flats have been signed by the owner as a Biohazard area, and NO ONE is allowed into the pond area. Please observe from the road and use scopes to look for the shorebirds resting on the berms between the ponds.
David L Pearson
School of Life Sciences
Arizona State University
Tempe AZ 85287-4501