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 CBPPHI. 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 when migrating they 

 generally fly at a considerable elevation. The shrill and mournful notes of these 

 birds can be heaid 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 ruffs. 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 URJNATOR OUVIER. 

 Urinator imber 



Loon ; 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 



