322 NYCTEA NIVEA. 



GENUS I. ^^YGTEA. THE WHITE OWLS. 



Gkn. On. The sternum is cunsiderahly arched, irith a moderately rounded keel ivhich does not enval in heiijht one half 

 the ividth of the sternvm. Outer maryinal indentations, more than twice the depth of the inner. Coracoids, short, not be- 

 in(j equal in lenijth to the top of the keel and are set on at a rather ivide anyle. Furcula, quite well developed. Tail and winc/s, 

 long. 



Memliers of this genus are piirtioularly noticeable on aceoiint of the prominent white markings to the plumage which 

 is strikingly long and downy. The eyes are large and yellow in color. The sterno-trachealis is quite st.iut, and there is 

 a slender bronchialis, but no other laryngeal muscles. The ojsophagus is nearly straight, being a little wider in the mid- 

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

 about ron in width. Thestomach is small, flat in form, with somewhat irregular outlines, and with very thin walls. The 

 coeca are quite long, small near the intestine, measuring -10 in diameter, with the blind ends dilated into long, oval sacs, 

 •25 in diameter by I'SO in length. The fold of the duodenum Ls long, inclosing a small, narrow pancrea-s. The spleen Ls an 

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

 cies within our limits. 



NYCTEA NIVEA. 



Snowy Owl. 



Nyctea nivca Stepu., Cont. of Shaw's Zool., XIII; 1826, 62. 



DESCRIPTION. 



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

 is r(mnded but not bifid. The bill and claws are very strong and well curved, long, but are nearly concealed by long, bristr 

 ly feathers. 



CoLoK. Adult male. Pure snowy-white, more or less mottled, spotted, and barred, especially above, withavery dark- 

 brown, but the white predominates. 



Adult female. 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 jjerfcctly 

 immaculate. 



Younij. Similar to the adult but mucli 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 but this is evidently the result of ageandses, other- 

 wise specimens are quite uniform in color. Very old birds become nearly, or wholly white. Distrilmted, a.s a constant res- 

 ident, thnmghout the more northern porticms 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; tai-sus, 

 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, 22-00; smallest extent of wing, 58-00; shortest wing, 16-00; tail, 8-27; bill, 1-25; tarsus, 1-90. 



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

 2-25. Longest specimen, 25-00; greatest extent of wing, 62-25; longest wing, 17-50; tail, 9-85; bill, 1-50; tarsus, 2-50. 

 Shortest specimen, 22-.50; smallest extent of wing, 58-83; shortest wing, 16-90; tail, 8-85; bill, 1-40; tarsus, 200. 



DESCRIPTION OF NESTS AND EGGS. 



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

 structures. 



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

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



HABITS. 

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

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



