6 
BIRDS OF PENNSYLVANIA. 
ing of muck as above described; but as we ascertained by repeated 
visits at night and in the early morning they are uncovered at dusk by 
the bird who incubates them until the morning sun relieves her of her 
task.” 
Suborder CEPPHI. Loons and Auks. 
Family URINATORID-ffi. Loons. 
THE LOONS. 
Loons live almost habitually in the water ; they dive with wonderful rapidity and 
skill, and are also remarkable for their ability of swimming long distances under 
the water, especially if endeavoring to elude their enemies. As divers they are the 
most expert of all birds. They retire during the summer season to high boreal re- 
gions to rear their young, and as cold weather advances migrate southward. During 
migrations Loons are most numerous about our seacoasts and on the large lakes in 
the interior. Like the Grebes they move over the ground in a slow, floundering 
and awkward manner, their flight, however, is rapid, and \#ien migrating they 
generally fly at a considerable elevation. The shrill and mournful notes of these 
birds can be heard at a great distance ; it is asserted by some that Loons, like the 
Cuckoos, are more frequently heard before a storm than at other times. The flesh 
of these birds is tough, dark-colored and fishy.” The white plumage of the under 
parts and the spotted feathers of the back are sometimes used by milliners and 
furriers. 
The nest is described as a rudely-built structure of reeds, grasses, etc., on the 
ground near the water ; the dark-colored and spotted eggs are said to be usually two 
in number. Bill long, hard, straight, tapering and sharp-pointed, being quite spear- 
like in appearance, and well adapted to catching their prey, consisting principally 
of fishes. Lores completely feathered. Head without crests or ruff's. Tall well 
developed, but very short and rounded. Legs situated far behind. Tibia mostly 
concealed in belly. Feet with four toes, the three in front long and wholly webbed. 
Genus URINATOR Cuvier. 
Urinator imber (Gunn.). 
Lioon ; Great Northern Diver. 
Description {Plate 51). 
Adult. — Bill and legs (dried specimen) bluish-black ; iris, red; head and neck 
dark bluish-green ; sides of head quite purplish ; lower part of neck glossy-green ; 
throat with transverse streak of six or eight distinct patches of white feathers ; tri- 
angular patches of white streaks on sides of neck, almost uniting behind and nar- 
rowing as they extend to front of neck, where they are about one inch apart ; upper 
parts and sides glossy-black, conspicuously spotted with white ; spots on lower 
part of back, rump and sides are small ; spots on back arranged in transverse rows, 
and increase in size from lower part of neck backward ; sides of breast black with 
white streaks, lining of wings, breast, abdomen and crissum white ; tail brownish- 
black, somewhat glossy above and unspotted. 
Young. — Top of head, back and rest of upper parts brownish-black ; chin, throat 
and lower parts white, sides of breast and sides brownish-black ; back unspotted 
(specimens are sometimes found in which the scapular and tertial feathers are quite 
well marked with the square white spots so conspicuous in the full plumaged adult) ; 
iris, brown ; bill (dried specimen) bluish-white, dusky on ridge and yellowish at 
