FAMILY GAVIID^E. LOONS. 27 



FAMILY QAVIID^E. 



Loons. 



Toes, four; front toes, palmate (full webbed) ; bill, pointed; 

 tarsus, flattened ; hind toe, with flap or small lobe. 



* Group 1. Wing, 9.50 to 11 inches long. 



Back, with white spots ; throat, white or whitish (immature or winter). 



Gavin In mine. Red=throated Loon. 



See No. 7. 



Back, without distinct white spots; the feathers, edged with ashy; throat, white or 

 dusky (immature or winter). Gavia arcticus. BIack=throated Loon. 



See No. 6. 



Head, ashy gray ; throat, black (adult). G-avia arctic nx. Black ^throated Loon. 



See No. 6. 



Throat, gray; front of neck, chestnut brown (adult). 



Gavia lumme. Red=throated Loon. 



See No. 7. 



* Group 2. Wing, 11 to 15 inches long. 

 Section 1. Depth of bill at base, more than .85. 



Head, black (adult). Gavia imber. Loon. 



See No. 5. 



Top of head, grayish; throat, white (immature or winter plumage). 



Gavia imber. Loon. 

 See No. 5. 



Section 2. Depth of bill at base, less than .85. 



Head, ash gray ; throat, black (adult). Gavia arcticus. Black=throated Loon. 



See No. 6. 



Throat, gray; front of neck, chestnut brown (adult). 



Gavia lumme. Red=throated Loon. 



See No. 7. 



* For directions for measurement, see page !). 



