RED-THROATED LOON 77 



teristic of the first winter plumage and never disappear entirely dur- 

 ing the winter; they are never seen in any subsequent winter plumage 

 and may consequently be regarded as sure signs of immaturity. 



At the first prenuptial molt, which is only partial, the head and 

 neck acquire a plumage resembling that of the adult, but dull and 

 incomplete; the red throat patch is dull yellowish red and much 

 restricted ; the white markings of the back have largely disappeared 

 by wear. At the next complete molt, the first postnuptial, when 

 a little over a year old, the young bird assumes the adult winter 

 plumage. This is similar to the first winter plumage except that 

 the throat is immaculate white, or nearly so, and is sharply sepa- 

 rated from the crown which is mottled with dusky gray and white; 

 the back is mottled with round white spots. 



The adult has two annual molts; a partial prenuptial molt, involv- 

 ing at least all of the feathers on the forepart of the body, produces 

 the handsome head and neck of the nuptial plumage and quite an 

 extensive growth of dark, new, glossy feathers on the back and 

 scapulars. I have seen the beginning of this molt as early as Decem- 

 ber 28, but usually it is accomplished during March and April; and a 

 complete postnuptial molt, during' the latter part of the summer, 

 produces the adult winter plumage, described above. The adult 

 winter plumage is often not complete until late in the season. I have 

 seen birds in very much worn plumage and only partially molted in 

 December; this plumage is worn for a comparatively short time and 

 the molt into it is often incomplete and sometimes not accomplished 

 at all. I have seen a bird in full spring plumage in October and 

 another, in the same month, in regular winter plumage with the 

 full, rich, red throat of the nuptial plumage. Fall adults are scarce 

 in collections and, if we had them in large series, we might be sur- 

 prised to know to what extent old birds retain part or all of their 

 spring plumage during the fall. 



Food. The food of the red-throated loon consists principally of 

 small fishes which it obtains by diving and chasing them under 

 water. On the coast of Labrador the little capelin is its principal 

 prey, which it flies to salt water to seek. Mr. W. L. Dawson writes 

 to me that 



it was a pretty sight to see a straightaway race between this bird and a 

 herring. The fish rose to the surface with the bird in hot pursuit, and it took 

 20 feet, after the bird came near enough to the surface to be seen, to catch the 

 sprat. Once at the surface and overtaken, the fish tried twisting and turning, 

 but the bird was better at it and soon had the fish down. I took pains to 

 notice that the diver did not spear, but seized the fish. 



In addition to fish it eats a variety of animal food, when available ; 

 frogs, fish spawn, crustaceans, mollusks, shrimps, leeches, and 

 aquatic insects have been reported by various writers; it has even 

 been suggested that it occasionally eats portions of aquatic plants. 



