338 LIFE HISTORIES OF NORTH AMERICAN BIRDS. 



pose. A suitable site once taken possession of is tenaciously held from year 

 to year, no matter how persistently the birds may be nibbed of their eggs 

 IT young. Only when such a site is not to be obtained in the vicinity of 

 their chosen home is an old Hawk's or Crow's nest made use of. If this is 

 not sufficiently bulky it is deepened by throwing out the inner and finer 

 material, as well as the lining, should there be any. They rarely add any- 

 thing to a nest, unless such feathers as fall from the body of the incubating 

 bird can be called additions. The Barred Owl rarely builds a nest of its own; 

 a cavity being selected the eggs are simply deposited on the rubbish, chips 

 of decayed wood, and dried leaves which may have accumulated therein. 



In the more southern parts of its range it usually commences laying in 

 February, while in the Middle States it generally begins from about the second 

 week in March to the first week in April. It is sometimes influenced by the 

 condition of the weather. Even in the southern New England States, near 

 Norwich, Connecticut, Mr. C. L. Rawson has occasionally found them nesting 

 in February, and has taken their eggs lying on a solid cake of ice, both 

 from holes and open nests in trees when the ground was covered with a 

 foot of snow. 



But a single brood is raised in a season. Should the first set of eggs 

 be taken, a second, and even a third, is occasionally laid, the last generally 

 smaller in number than the first. The female seems to attend mostly to the 

 duties of incubation, which lasts from three to four weeks. When so engaged 

 she is loth to leave her treasures, and occasionally has to be dislodged by 

 force, uttering her protests either by an angry snapping of her mandibles or 

 by a hissing noise from a limb close by. 



The number of eggs laid varies from two to four; sets of three seem to 

 predominate slightly over the smaller number, while four are rare. The 

 U. S. National Museum collection contains a so-called set of five eggs col- 

 lected in Iowa in April, 1869. In three of these specimens the holes are 

 much larger than in the remaining two, and if really all taken at one time 

 the first eggs were probably laid at a considerable interval from the last. 

 Ordinarily they are deposited every third day. Like all Owls' eggs they 

 are pure white in color, the shell is more or less granulated, slightly rough 

 to the touch, and not very glossy. In shape they are oval or rounded oval. 



The average measurement of eighty-two of these eggs is 49.5 by 42.5 

 millimetres; the largest specimen measures 55.5 by 44, the smallest 41 by 

 37.5 millimetres. The latter from a set of two (the other being of the nor- 

 mal size, 49 by 43 millimetres), was collected by Mr. C. L. Rawson in New 

 London County, Connecticut, on March 29, 1890, and is really a runt egg, 

 but contained a well formed yolk. 



The type specimen, No. 20633 (Bendire collection), from a set of three, 

 was taken by Mr. G. Peck in Black Hawk County, Iowa, March 2, 1878. 

 It is figured on PI. 12, Fig. 4. 



