Part 4

The Pied-billed Grebe is such an excellent diver and can so artfully escape detection by swimming beneath the surface of the water, with only its bill exposed, that it is often a difficult bird to observe. On land it is virtually helpless. The shortness of the body of the swimming grebe makes it comparatively easy to identify, and the unmarked wings distinguish this species from the Horned Grebe. The Pied-billed Grebe will frequently be seen along smaller streams and in little ponds.

LOON Gavia immer immer (Brünnich)

Other Names.—Great Northern Diver; Loom.

Description.—Size large; bill long and sharp; tail very short, with legs sticking out behind. Adults in spring: Upperparts black, with bluish and greenish reflections; patches on throat and sides of neck streaked with white; back and wings marked regularly with rows of white squares; underparts silvery white; sides black, spotted finely with white; eyes red. Immature birds and adults in winter: Upperparts blackish, margined with gray and without white spots; throat and neck grayish; underparts white. Length: about 30 inches.

Range in Pennsylvania.—A fairly common migrant along the larger lakes and waterways from March 15 to May 10 and from October 1 to December 15; occasional in winter when the water is free of ice.

The Loon is at perfect ease in the water; on land it shuffles along, using its wings as feet, and it cannot rise in flight from the ground. It lives almost altogether on fish which it captures under water and swallows entire. As a rule, it is to be seen far out from shore, floating quietly. Easily it slips under the water, perhaps to reappear a hundred yards or more from the point at which it went down. The weird, laughing cry, which is famous in literature, is not often heard in Pennsylvania, since the birds do not nest here.

In the hand, the Loon is easily recognized by its striking coloration in spring; or in winter by its long, sharp bill and its large, webbed feet; at a distance, in the water, it may be confused with a cormorant, which has a hooked bill and a rather long tail, or with some of the larger ducks which have shorter, more stubby bills.

The smaller Red-throated Loon (Gavia stellata), usually a rare bird in Pennsylvania, is found during winter or early spring. In winter the back is gray, flecked with white; in spring there is a triangular patch of red-brown on the lower throat; it is always white below.

HERRING GULL Larus argentatus argentatus Pontoppidan

Other Names.—Sea Gull; Gray Gull.

Description.—Sexes similar. Adults in summer: White, with pearl-gray back and wings; tips of wings black with white spots; bill yellow with orange spot near tip of lower mandible; feet pale pink; eyes pale yellow. Adults in winter: Similar, with gray spots on head and neck. Immature birds: Dark gray-brown at a distance, with blackish bill and dark brown eyes; in the hand the upper-parts are found to be dark gray, considerably marked with buffy. The acquiring of fully adult plumage requires several moults. Birds which are not fully adult may have black-tipped, white tails. Young in their first flight plumage are darker than older individuals. Length: 24 inches.

Range in Pennsylvania.—A somewhat irregular migrant and winter resident throughout, save at Erie, where it is common during summer, though it does not, apparently, nest there. In the interior it appears in spring as soon as the ice breaks up and is usually noted along the larger waterways.

Large gulls seen in Pennsylvania are usually of this species. Their long wings and graceful flight mark them at great distance. The smaller Ring-billed Gull, which is not easy to distinguish from this species in the field, has greenish yellow feet and a black band across the bill. Herring Gulls are often abundant about the harbor at Erie.

RING-BILLED GULL Larus delawarensis Ord

Description.—Sexes similar. Adults in summer: Like the Herring Gull, but much smaller, with greenish yellow bill crossed near tip by black band, and with greenish yellow feet. In winter the head and neck are spotted with gray. Immature: Gray-brown; tail white, with black band near tip; end of bill black. Length: 18 inches.

Range in Pennsylvania.—An irregular migrant in February, March, and April, and in October and November, sometimes appearing in flocks; occasional in winter.

The Ring-billed Gull should be identified in the field with a glass. It is much like the Herring Gull in general appearance, and, unless it be compared directly with the larger bird, may pass undetected. Remember the yellowish feet and the black band across the bill.

BONAPARTE’S GULL Chroicocephalus philadelphia (Ord)

Description.—Size small; sexes similar. Adults in summer: White, with rosy flush on belly, head black with white spot at eye, pearl-gray mantle, and black-tipped wings. Adults in winter lack the rosy flush of the underparts and have white heads upon the back of which are two dusky spots. Immature birds are similar to adults in winter but have a black band near the tip of the tail. Length: 14 inches.

Range in Pennsylvania.—A fairly regular migrant along the waterways from about April 1 to May 10 (sometimes considerably later) and from September 1 to October 10. Not often seen in winter.

This, the smallest of our gulls, is often seen in flocks. At Conneaut Lake, Crawford County, where they are regular visitors, they circle about rapidly, like terns, resting on the water at intervals or standing on a floating timber. Their black heads distinguish them easily from all other species save the Laughing Gull (Chroicocephalus atricilla megalopterus) a larger species which nests along the Atlantic Coast, and which may occur occasionally along the waterways of the southeastern part of the Commonwealth.

COMMON TERN Sterna hirundo Linnæus

Other Names.—Sea Swallow; Striker; Wilson’s Tern.

Description.—Smaller than a gull, with long, deeply forked tail. Adults in summer: Top of head glossy black; rest of body pearl-gray, save throat, sides of head, and tail, which are white, the outer tail-feathers with outer webs pearl-gray; bill red, with black tip; feet orange-red. Adults in winter: Similar, but with forepart of head and underparts white, and bill blackish. Immature: Similar to adults in winter, but plumage considerably washed with brownish, lesser wing-coverts slaty, and tail short, though forked. Length: 15 inches.

Range in Pennsylvania.—A rather irregular migrant.

The more rapid flight, long forked tail, and habit of pointing the bill downward, rather than forward, while flying, distinguish the terns from the gulls. Common Terns are sometimes seen flying gracefully about a small pond, seeking small fish or aquatic insects, which they capture with great dexterity. During migration they are usually silent, and they do not often remain long in one locality.

The much larger Caspian Tern (Hydroprogne caspia imperator) is similar in color-pattern to the Common Tern but has a much heavier, red bill, and a short, though forked tail. This species, which is decidedly rare as a migrant in the interior, has established a small nesting colony near Erie. The Caspian Tern is 21 inches long.

BLACK TERN Chlidonias nigra surinamensis (Gmelin)