I. Hind toe minute. 



II. Tail forked to a depth of 1.25 inches. 



III. Tail square; hind toe developed. 



A. Head, in summer, blackish hooded; underparts flushed with 



rosy. 



1. Bill red in summer. 



2. Bill black in summer. 



B. Mantle gray; underparts white; head never hooded with black. 



1. Larger — length 22.00 or over; feet rosy or livid flesh-color. 



a. Primaries without black. 



(1). Primaries white throughout. 



(a). Larger — length over 26.00. 



(b). Smaller — length about 24.00. 



Note: The dimensions given in the text. p. 1365, are 

 erroneous. Read: wing 385 (15.20); tail 1.60 (6.30); bill 

 44 (1-73); tarsus 53-2 (2.09). 



(2). Primaries gray. 



b. Primaries tipped, broadly, with black. 

 (1). Mantle dark slaty blue. 



(2). Mantle much lighter, deep pearl-gray. 



2. Smaller — length usually under 22.00; feet and legs yellow 



or greenish gray. 



a. Bill relatively stout, marked at gonydeal angle with ver- 



milion and a touch of black; mantle deep pearl-gray; 

 feet and legs greenish gray; length 20.00-22.00. 



b. Bill crossed near tip by dark band; mantle pearl gray; 



feet and legs greenish yellow; length 20.00-22.00. 



c. Bill weaker, without black; mantle deep pearl gray; feet 



greenish yellow; length 16.00-18.00. 



C. Body-plumage dark, sooty to plumbeous slate; head and neck 



white; bill chiefly red. 



270. Pacific Kittiwake. 

 282. Sabine's Gull. 



279. Franklin's Gull. 



280. Bonaparte's Gull. 



271. Glaucous Gull. 



272. Iceland Gull. 



273. Glaucous-winged Gull. 



274. Western Gull. 



275. Herring Gull. 



276. California Gull. 



277. Ring-billed Gull. 



278. Short-billed Gull. 

 281. Heermann's Gull. 



Family 3. Sternid^e. Terns. 



Chiefly slenderly proportioned Lari, having extremely long, pointed 

 sharply pointed; curvature of culmen slight; gonydeal angle inconspicu 

 feet relatively small, webbing of toes usually incised. Found chiefly 

 About 60 species known, of which 8 Californian. 



I. Largest — length 20.00-23.00 inches; proportions stout; tail only 



slightly forked. 



II. "Crow-sized" — length about 19.00; proportions more slender; 

 tail deeply forked; feet and legs black. 

 Bill stouter, depth at base about .79 inches. 

 Bill slenderer, depth at base about .50. 



Length about 15.00; slenderest; tail deeply forked; plumage 



white and gray with black cap (breeding). 

 Bill red, broadly tipped with black in breeding season. 

 . Outer pair of feathers dark on inner webs. 

 . Outer pair of feathers dark on outer webs. 

 Bill pure red or only slightly tipped with black in breeding 

 season; also more slenderly proportioned. 

 Length 10.00 or less. 

 Normal coloration; bill and feet yellow tipped with black; tail 



deeply forked. 

 Plumage black (in breeding season); bill and feet black at all 

 seasons; tail only slightly forked. 



A 



B 



III. 



B. 



IV. 

 A. 



B. 



wings; tail usually deeply forked; bill slender, 

 ous; legs placed farther back than in Lariice; 

 upon inland waters save during migrations. 



283. Caspian Tern. 



284. Royal Tern. 



285. Elegant Tern. 



286. Forster's Tern. 



287. Common Tern. 



288. Arctic Tern. 



289. Brown's Least Tern. 



290. Black Tern. 



Order 12. ALCIFORMES. 

 Family 1. ^Ethiid^. Auklets. 



Small Alcids of chunky appearance, with beaks variously modified, and often with appendages or crests of feathers. 

 Tail of 14 feathers. 5 species, 2 Californian. 



I. Bill % as long as head, proportions ordinary; bird about 9 inches 



long. 291. Cassin's Auklet. 



II. Size of foregoing. Bill only % as long as head, stout and curious- 



ly upturned — pugged. 292. Paroquet Auklet. 



2088 



