Vol. XXIX1 



1912 



J Nichols, Recognition Marks in. Birds. 47 



are very inconspicuous from above, even when mo\'ing actively 

 about on mud flats. The color of a Yellow-leg I recently observed 

 sitting quietly at the edge of a bit of marsh rendered it very incon- 

 spicuous, and I have seen a White-rump when startled, crouch 

 down concealing the bulk of the dead white underparts and practi- 

 cally disappear against the brightly lighted mudflat on which 

 it had been feeding. The Sanderling, which frequents the bright 

 lights of the ocean line, is lighter colored than usual. 



Yet most of the species when on the wing are conspicuous, and 

 then, or particularly when starting to fly, show colors as clearly 

 of recognition value as the diagnostic whistles of many species. 



The writer finds the sharply contrasted black and white colors 

 of the Sanderling's wing the best field mark to determine that 

 species in any plumage. The White-rumped Sandpiper, a non- 

 commital enough looking bird on the ground, is easily recognized 

 by its white rump as it takes wing. Its tail is darker than usual 

 in the group and emphasizes the white rump. The narrow white 

 line in the wing of the Spotted Sandpiper has a different look from 

 that of any other species, and the blackish under wing surfaces of 

 the Solitary Sandpiper are at once an infallible and conspicuous 

 criterion of that species. The black patch under the wing of the 

 Black-breasted Plover, which distinguishes young and fall l)irds 

 from the Golden Plover, is much more conspicuous than one would 

 think. Only recently the writer was observing one on a distant 

 tussock which he could not be sure was even a plover. As it took 

 flight this mark could be seen and its pe-a-ive note also proclaimed 

 it. 



There seems to be no good long-distance mark for telling Semi- 

 palmated from Least Sandpipers; with us they perhaps occur 

 in mixed flocks, and neefl none. The white under-surfaces of a 

 compact, swiftly moving flock of these birds showing conspicuously 

 at intervals perhaps has some recognition and directive significance. 



Few birds are as consistently concealingly colored as the Wood- 

 cock. Perhaps the whistling of its wings as it rises takes the place 

 of recognition marks of other species. 



At any rate advertisement is so common in animals that it is 

 hard to believe it has no particular value to them. In the Cana- 

 dian Rockies three species of mammals sometimes occur living in 



