THE BLACK-THROATED LOON. 637 



attempt made to conceal the nest. On the contrary, a position on some 

 promontory or plain stretch of shore is chosen so that the bird may command 

 a wide sweep of territory. The eggs are sometimes placed on the bare sand, 

 but oftener upon a loose heap of trash or upon a grassy bog. If at some dis- 

 tance from the water, a path or runway marks the connection. 



Soon after the chicks are brought off the parents separate v for the rest of 

 the season, the male retiring either to some unfrequented lake or to the sea- 

 coast to undergo the summer moult. At this season both birds cast their 

 feathers so thoroughly as to be for a time quite incapacitated for flight. 



The Loon is famous, especially in its northern breeding ground, for its 

 far-sounding and unearthly cry. Of this performance, Rev. J. H. Langille 

 says : "The notes of this bird being most frequent before a storm are re- 

 markable. Beginning on the fifth note of the scale, the voice slides through 

 the eighth to the third of the scale above in loud, clear sonorous tones, which 

 on a dismal evening before a thunder storm, the lightning already playing 

 along the inky sky, are anything but musical." The bird has also a softer. and 

 less awful cry of weird laughter, which resounds from shore to shore in some 

 mountain solitude with strange ventriloquistic effect. 



No. 318. 



BLACK-THROATED LOON. 



A. O. U. No. 9. Gavia arctica (Linn.). 



Synonym. BLACK-THROATED DIVER. 



Description. Adult in summer: Somewhat similar to preceding species but 

 smaller ; top of head and nape bluish gray ; a short transverse bar of white streaks 

 on throat, and the sides of the neck between the black and the gray similarly 

 streaked in longitudinal series ; sides of breast more widely black and white 

 striped than in G. imber (in which only the sides of the cervix so striped) nearly 

 meeting in front ; a blackish bar across base of lower tail-coverts ; under parts 

 pure white ; above and on sides of back, marked and spotted with white. Adult 

 in winter and immature : Corresponding closely with the similar stages in G. 

 imber and distinguishable with certainty only by smaller size. Length 27.00 (685) ; 

 wing ii.oo (279.4) ; bill 2.00 (50.8) ; 'tarsus 2.60 (66.) (Chapman). 



Recognition Marks. Brant size; like G. imber but smaller; top of head and 

 nape, in summer plumage, bluish gray. 



Nesting. Does not breed in Ohio. Nest and Eggs as in preceding species. 

 Av. of eggs 3.15 x 2.05 (80. x 52.1). 



General Range. Northern part of the northern hemisphere. In North 

 America of casual occurrence in autumn and winter in the northern United States 

 east of the Rocky Mountains. 



