Migratory Shorebirds

[floraphile]

Hi, All.  I could not find a proper forum for my question, so I hope posting here is acceptable.  I am a little confused by the ranges/distributions of many of the peeps.  Most of these birds are stated/mapped in the various field guides to winter along the Gulf Coast, fly north to breed & are absent here in the Summer, but I felt we have small sandpipers at our beaches throughout the Summer?  Have I just not noticed their absence?  

[Tony Leukering]

Some individual shorebirds -- particularly one-year-olds -- do not complete northward migration in spring, and coastal areas see a smattering of arctic-breeding (and other) shorebird species that do not breed there through much of the summer, though usually in very small numbers. Certain species seem more prone to this than others, with Black-bellied Plover and Sanderling being the best examples.

[A brief aside: Note that Sanderling is NOT a peep. "Peep" is a term for only the smallest species of Calidris and covers only 10 species: Least, Baird's, White-rumped, Semipalmated, Western, and Spoon-billed sandpipers and all of the stints.]

However, many shorebird species are very early fall migrants, being on the move southward in June. The earliest fall-migrant shorebirds are typically those that breed on the prairies (American Avocet, Willet, Marbled Godwit, Long-billed Curlew), with apparent south-bound birds showing up south of breeding range in mid-June. Next are those breeding in the taiga (Greater and Lesser yellowlegs, Least Sandpiper, Solitary Sandpiper), with arrival at latitudes such as those of Ohio and Colorado in late June or early July.

Most shorebird species rely on long life, rather than high reproduction for species maintenance. This may be most true for arctic-breeding species, as appropriate breeding conditions at high latitudes are brief and sometimes non-existent. Thus, breeders of most species will initiate fall migration if nests fail.

In Colorado, the last apparently northbound Semipalmated Sandpipers are found in the first few days of June, while the first apparently southbound birds arrive in the last few days of June.

Finally, a few shorebird species conduct their prebasic molt on the breeding grounds after breeding (most do it on or near winter grounds), thus they are rare south of the breeding range before fall. The best examples of these species are Dunlin and Purple Sandpiper.

In mid-summer, noting the plumage of the bird(s) in question -- which plumage and how worn -- can assist in determining whether you're seeing a non-breeding one-year-old or a southbound adult whose breeding attempt failed early. Birds of the first sort will be scruffy, usually with little alternate plumage (aka breeding plumage), while the latter birds will be spanky adults in bright, relatively unworn plumage.

[floraphile]

Thank you, Tony for your excellent explanation. ?   As you surmised, I had been including Sanderlings as Peeps, and I feel it is the species I have most often seen on the Gulf Coast in the Shorebird "Off-season"