Arctic WarblerPhylloscopus borealis This species breeds in subarctic forest zone, especially in coniferous tracts but also in birch and other deciduous trees, often near water. It's a larger, chunkier and heavier version of the Greenish Warbler (Phylloscopus trochiloides), but they can be very difficult to separate in the field. General pattern and overall plumage tone are similar, the chief differences being as follows: longer, heavier bill, broader at base; supercilium slightly longer behind eye and beginning above bill base (not, as on Greenish, at side of forehead); dark eye-stripe continuous on lores and reaching base of bill; legs pale orange-brown to yellowish, but not grey-brown. First-winter birds are brighter green above, and less white below than adults, with second wingbar on median coverts. Call remains a most certain way to tell Arctic and Greenish apart. Arctic produces a hard -tzik- with a Dipper-like quality, quite unlike Greenish Warbler's. Cruel, cruel bird !
Short-billed DowitcherLimnodromus griseus The two North American Dowitchers, generally regarded as a single species until 1950, are easily separated from other waders by their rufous , brown or grey plumages and long "snipe-like" bills. Unlike snipes, however, they do not have prominently-striped heads and upperparts patterns, and there are seasonal changes in coloration. Godwits (Limosa sp.) and Asiatic Dowitcher (Limnodromus semipalmatus) also have long bills but are darker-legged and considerably larger.
The principal characters by which Short-billed Dowitcher can be separated from Long-billed D. are: in breeding plumage, (1) the light bars on tail, usually wider than black bars, (2) the belly partly or entirely withe or whitish, with foreneck, center of breast, belly and vent lightly to moderately spotted, (3) a red coloration usually paler, orange or brown. In non-breeding plumage, (4) its throat and upper breast are light grey, finely speckled and with the lower edge of breast often spotted, while in Long-billed, the throat and entire breast are grey, unspeckled, ending abruptly at white belly. Juveniles are easily separable by plumage characters, at least until december-january: (5) scapular and inner wing-coverts are broadly edged with bright (not dark) reddish-buff, with conspicuous internal markings; (6) tertials are broadly edged, stripped and/or barred with reddish-buff. Bill lenght is of little value in field conditions …and on this picture…