Aerial (top) view of Barn Swallow's bill"Hirundo horreorum. Barn Swallow. Bill of moderate size for this family, of the usual shape, with straight commissure; nostrils lateral overarched by a membranous scale." Elliot Coues, 1884

Barn Swallow Bill

Aerial (top) view of Barn Swallow's bill "Hirundo horreorum. Barn Swallow. Bill of moderate size for…

"Botaurus. Bittern. Bill moderately longer than head, shorter than tarsus, which is shorter than middle toe and claw." Elliot Coues, 1884

The Bill of a Bittern

"Botaurus. Bittern. Bill moderately longer than head, shorter than tarsus, which is shorter than middle…

"Bill averaging somewhat longer, about 1.90; culmen, commissure, and gonys nearly straight; upper mandible somewhat dilated toward the base along the cutting edges, and less feathered; gonydeal angle prominent. Bill consequently approaches that of the next species, in width and depth, but exaggerates the length and straightness of that of the last species." Elliot Coues, 1884

Californian Guillemot Bill

"Bill averaging somewhat longer, about 1.90; culmen, commissure, and gonys nearly straight; upper mandible…

"Bill black; bill along culmen 1.75; gape 2.50; gonys 1.15; depth at base .55; width .30." Elliot Coues, 1884

Common Guillemot Bill

"Bill black; bill along culmen 1.75; gape 2.50; gonys 1.15; depth at base .55; width .30." Elliot Coues,…

"Uria columba. Pigeon Guillemot. Bill stouter than that of grylle, and more obtuse." Elliot Coues, 1884

Pigeon Guillemot Bill

"Uria columba. Pigeon Guillemot. Bill stouter than that of grylle, and more obtuse." Elliot Coues, 1884

"Bill larger than Pigeon Guillemot, 1.5-1.70 along culmen, along gape 2.20, from feathers on side of lower mandible 1.50; depth at base .50; width .38."

Sooty Guillemot Bill

"Bill larger than Pigeon Guillemot, 1.5-1.70 along culmen, along gape 2.20, from feathers on side of…

"Lomvia arra. Thick-billed Guillemot. Arrie. Bill short, stout, wide, deep; culmen curved throughout; commissure decurved at end; gonys if anything concave in outline, the angle very protuberant; cutting edges of the upper mandible dilated and denuded toward the base, this bare turgid space flesh-colored in life, drying pale yellowish." Elliot Coues, 1884

Thick-billed Guillemot Bill

"Lomvia arra. Thick-billed Guillemot. Arrie. Bill short, stout, wide, deep; culmen curved throughout;…

"Chroicocephalus atricilla. Laughing Gull. Black-headed Gull. Bill longer than middle toe and claw, shorter than tarsus or head, moderately compressed, rather stout for this genus. Culmen and commissure both decurved and the end, the latter somewhat sinuate at the base. Gonys considerably concave in front of the angle, somewhat so between the angle and tip; although the angle id well defined, the tip of the bill is so decurved that a chord from tip to base does not touch it." Elliot Coues, 1884

Laughing Gull Bill

"Chroicocephalus atricilla. Laughing Gull. Black-headed Gull. Bill longer than middle toe and claw,…

"Synthliborhamphus umizusume. Japanese Murrelet. Temminck's Auk. Bill more elongate and acute than in the type of the genus, less compressed, not so deep for its length. Bill yellow, with black ridge; feet livid-bluish, with dusky webs. A large crest, of a dozen (more or fewer) feathers springing from extreme forehead, not recurved, but drooping backward over the occiput." Elliot Coues, 1884

Japanese Murrelet Bill

"Synthliborhamphus umizusume. Japanese Murrelet. Temminck's Auk. Bill more elongate and acute than in…

'Rhynchops. Skimmer. Bill hypognathous Among the singular bills of birds that frequently excite our wonder, that of the skimmers as one of the most anomalous. The under mandible is much longer than the upper, compressed like a knife-blade; its end is obtuse; its sides come abruptly together and are completely soldered; the upper edge is as sharp as the under, and fits a groove in the upper mandible; the jawbone, viewed apart, looks like a short-handled pitchfork. The upper mandible in also compressed, but less so, nor is it so obtuse at the end; its substance is nearly hallow, with light cancellated structure, much as in a toucan; it is freely movable by means of an elastic hinge at the forehead." Elliot Coues, 1884

The Bill of a Skimmer

'Rhynchops. Skimmer. Bill hypognathous Among the singular bills of birds that frequently excite our…