FAMILY SCOLOPACIDAE 421 



April 11 at Jaque, Darien. It is probable that some remain to near 

 the end of the month. 



These birds are found in little flocks, or alone, both on sand 

 beaches and on rock flats and headlands. Also they come inland on 

 the tidal reaches of the rivers, and along the larger channels in the 

 lowlands, where open, muddy shores or gravel bars afford feeding 

 grounds. 



EROLIA FUSCICOLLIS (Vieillot): White-rumped Sandpiper; Playerito de 



Rabadilla Blanca 



Trtnga fuscicollis Vieillot, Nouv. Diet. Hist. Nat., nouv. ed., vol. 34, Dec., 1819, 

 p. 461. (Parag^uay.) 



Similar to Baird's sandpiper, but with middle upper tail coverts 

 white. 



Description. — Length, 160 to 175 mm. Bill heavier, tip somewhat 

 broadened, with the surface distinctly pitted. Breeding dress, above 

 brownish gray, with the feathers black centrally, those of crown and 

 back edged with buff to cinnamon, and those of hindneck bordered by 

 buff ; wing coverts brownish gray, with shaft lines of dusky ; greater 

 coverts tipped narrowly with white ; outer primaries dusky ; sec- 

 ondaries and inner primaries paler edged with white; rump dusky 

 brown, with feathers margined with dull buff; central pair of upper 

 tail coverts dusky black, tipped with white ; lateral upper tail coverts 

 white with concealed darker markings ; rectrices with central pair 

 black, others dusky brown or gray edged with white; under surface 

 white, with foreneck heavily streaked and spotted, and sides barred, 

 with dusky. 



Winter plumage, crown, hindneck, scapulars, and upper back 

 brownish gray, with concealed mottling of black and buff; markings 

 on under surface less in extent and grayer brown. 



It is common to find specimens in which details of the markings on 

 the upper tail coverts are not sufficient for identification. The form 

 of the bill described above and under the account of Baird's sand- 

 piper, will serve invariably to separate these two species. 



Iris brown ; maxilla, except area below nostril, and tip of mandible 

 dull black ; maxilla below nostril, and base of mandible brown. 



Measurements (from Ridgway, I.e., p. 285). — Males, wing 117- 

 122.5 (119.7), tail 50-53 (51.4), exposed culmen 21-24 (22.7), tarsus 

 22-24 (23.1) mm. 



Females, wing 116.5-124 (120.6), tail 50-54 (51), exposed culmen 

 21-26 (23.1), tarsus 22-24 (22.8) mm. 



