NYCTEA N1VEA. 267 



GENUS I. NYCTEA. THE WHITE OWLS. 



(li \. Cii. The sternum is insi<l>-rnlili/ arrheil, irith a modcrnle/y rounded keel which does not e>[ual in hei</ht one half 

 tfn width of the Ittnmm. Outer mari/inal intlmlations, mure than twice the depth of the inner. Coracoids, short, not be- 

 in</ rifuiil in Icnyth to the top of the keel and are set on at a rather wide anyle. Furcula, ijuile well developed. Tail and. winys, 



Member* nf this jrenus are particularly noticeable on account of the prominent white markings to the plumage which 

 i< -trikin^ly \<>KZ and downy. Tlie eye-; arc large and yellow in color. The sterno-traehealis is quite stout, and there is 

 slender bruncliialis, hut no other laryngeal muscles. The oesophagus is nearly straight, being a little wider in the mid- 

 dle, and opens into a small proventrirulu-i with simple, oval glands arranged in a narrow, zonular band which measures 

 nbout I'OO in width. Thestomaeh is small, flat in form, with somewhat irregular outlines, and with very thin walls! The 

 ernes arc ijuite loci;, small near the intestine, measuring '10 in diameter, with the blind ends dilated into long, oval sacs, 

 d": in ili;imctiT by 1-50 in length. The fold of the duodenum is long, inclosing a small, narrow pancreas. The spleen is an 

 elliptical body lying directly on the proventriculus. Both lobes of the liver are nearly equal in size. There is butone spe- 

 cies within our limits. 



NYCTEA NIVEA. 



Snowy Owl. 

 Nyctea nivea STBPH., Cont. of Shaw's Zool., XIIT; 1820, 62. 



DESCRIPTION. 



Sr. Cn. Form, robust. Size, very large. Sternum, stout. Tongue, rather thick and fleshy, horny at the tip which 

 is rounded but not bifid. The bill and claws are very strong and well curved, long, but are nearly concealed by long, brist- 

 ly feathers. 



('num. Adult male. Pure snowy-white, more or less mottled, spotted, and barred, especially above, with a very dark- 

 brown, but the white predominates, 



Adult fi-male. White, as in the male, but with the dark markings much more prominent, frequently extending over 

 both surfaces including wings and tail. The face, chin, throat, under wing coverts, tibia, and tarsus are always perfectly 

 immaculate. 



Young. Similar to the adult but much more widely barred with dark-brown, and also show a tinging of yellowish- 

 rufous on the back. Iris, yellow, cere, greenish, bill and claws, greenish-brown, in all stages. 



OBSERVATIONS. 



There is considerable variation in amount of dark-brown markings hut this is evidently the result of age and sex, other- 

 wise specimen* are quite uniform in color. Very old birds become nearly, or wholly white. Distributed, as a constant res- 

 ident, throughout the more northern portions of both Continents, migrating southward in winter, in North America, reg- 

 ularly, at least, to New Jersey and rarely as far as South Carolina. 



DIMENSIONS. 



Average measurements of male specimens. Length, 22-50; stretch, 59-00; wing, 16-75; tail, 8-55; bill, 1'30; tarsus, 

 1-95. Longest specimen, 23-00; greatest extent of wing, 60-00; longest wing, 17-35: tail, 8-85; bill, 1-35; tarsus, 2-00. 

 Shortest specimen, 2-J'OO; smallest extent of wing, 58'00; shortest wing, IB'OO; tail, 8'27; bill, 1-25; tarsus, 1'90. 



Average mea-urements of female specimens. Length, 23'70; stretch, 60-54; wing, 17'25; tail, 9'35; bill,' 1*45; tarsus, 

 S'25. Longest specimen, 25'00; greatest extent of wing, 6-2"25; longest wing, 17-50; tail, 9'85; bill, T50; tarsus, 2'50. 

 Shortest specimen, 22-50; smallest extent of wing, 58-83; shortest wing, 16-90; tail, 8-85; bill, 1'40; tarsus, 2'00. 



DESCRIPTION OP NESTS AND EGGS. 



Nests, placed on the ground, composed of sticks, twigs, grass, etc., lined with grass and weeds. They are bulky 

 structures. 



Eyys, three or four in number, oblong-oval in form, white in color, with the surface very smooth. Dimensions from 

 I'85x2-50 to 1-90x2-55. 



HABITS. 



Fortunate for admirers of the Snowy Owls, these beautiful birds are migratory, for if 

 they did not choose to come to us we should seldom be gratified by a sight of their mag- 



