FAMILY PODICIPID.K. Oh'EHES. 



25 



WATER BIRDS. 



KEY TO THE SPECIES. 



FAMILY PODICIPID/E. 



Grebes. 



Toes, four ; three in front, one behind, with lobate webs. 



* Group 1. Wing, less than 6.50 inches long. 



Depth of bill at base of culmen, over .40. In summer: Bill, with black band; throat, 

 black. 



In winter: Bill, without black band; throat, white. 



Podilymbus poiliceps. Pied -billed Grebe. Hell Diver. 



See No. 4. 



Depth of bill at base of culmen, less than .40. In summer: Two small tufts of 

 brownish gray or buff-colored feathers behind the eye; crowu, nape, and throat, black. 



In winter: Plain colored, without black or buff on head; upper plumage, grayish black; 

 uuderparts, silvery white, often tinged with ash gray on throat and sides. 



Colymbus auritus Horned Grebe. 

 See No. 2. 



* Group 2. Wing, over 6.50 inches long. 



In summer: Crown, black; upper throat, gray; lower throat and breast, chestnut rufous; 

 rest of underparts, silvery grayish white. 



In winter : No rufous brown on throat or breast. Oolymbus holbodli. Holboell's Grebe. 



See No. 1. 



* For directions for measurement, see page 9. 



