In an interesting 4 September comment under the Sandwich Tern bill color discussion, Joseph Kennedy presents a photo of a juvenile Royal Tern with partly yellow-orange legs. Compared to one of his photos of juvenile Sandwich with yellow legs, the Royal appears to have brighter leg color. Presumably that is variable, but it would be […]
Sandwich Tern – leg color Read More »
Size judgment is one of the constant quandaries of bird identification – critically important but fraught with error. In a recent online discussion about these photos of sandpipers in flight, I was intrigued by the question of how I, and others, “just knew” that these birds were too small to be Knot or Pectoral and
Judging size of birds Read More »
Several recent Massachusetts reports of Olive-sided Flycatchers seem to have used the presence of white patches on the sides of the back to age the birds as juveniles. This is incorrect and unfortunately the source of the error seems to be an ambiguous entry in the Sibley Guide – sorry. Both adults and juveniles can
Olive-sided Flycatcher – white patches and age in fall Read More »
— updated Sep 27, 2008 This photo by Greg Lavaty of Texas, generated a lot of discussion on the Texas Birds listserv recently, and brings up some interesting points and questions. First, this is definitely a juvenile Sandwich Tern, and the bill color is pretty typical of a recently fledged bird. Here are some photos of
Sandwich Tern – bill color of juveniles Read More »
Feb. 10, 2005 In late October 2004 I was privileged to visit the Nature Conservancy’s spectacular Santa Cruz Island preserve off the coast of Southern California. This island, along with the other California Channel Islands has been called the “Galapagos of the North” and has long been the focus of biological studies, but became more
Distinguishing Island and Western Scrub-Jays Read More »
December 11, 2004 I was intrigued by this problem in light of the discussion surrounding the recent (6 November 2004) bird from southern Texas (see photos here and here; and sincere thanks to Martin and Chris for making these photos available and thanks to all who have participated in the discussion and our collective education). We wouldn’t
Distinguishing South Polar Skua and Pomarine Jaeger Read More »
Illustration of the Red-footed Falcon perched. The smooth gray color is unlike any North American Falcon. Old juvenal wing and tail feathers are slightly brownish and barred, while adult feathers will be uniform blackish. Juvenal feathers are obvious on the outer tail, the primaries (molt reveals the boldly barred inner web of one outer primary),
Identification of the Martha’s Vineyard Red-footed Falcon Read More »
October 7, 2004 One of the most significant changes for birders in the 45th supplement of the AOU checklist (Banks et al., 2004) was the split of Canada Goose into two species. While widely anticipated – the highly variable Canada Goose has often been considered more than one species in the past – the split
Distinguishing Cackling and Canada Goose Read More »