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.
Loon, Breeding Plumage
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.
Herring Gull, Breeding Plumage
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.