1256 U.S. NATIONAL MUSEUM BULLETIN 237 part 3 



Museum of Comparative Zoology is very pale greenish white, heavily 

 marked with spots, blotches, and a few scrawls that practically obscure 

 the ground. Another set is dirty white with fine specklings over the 

 entire egg. In markings and coloring, they are very similar to those 

 of the white-crowned sparrow, but average slightly larger. The 

 measurements of 46 eggs average 22.2 by 16.7 millimeter; the eggs 

 showing the four extremes measure 24.7 by 16.4, 26.6 by 17.8, 20.3 

 by 16.1, and 21.5 by 15.0 millimeter. 



Of the 10 nests found in 1931 (Semple and Sutton, 1932), 6 contained 

 four eggs or young, 2 contained five, and 2 had three. Farley (corres.) 

 says: "I would say that four eggs is the usual number laid. Of 5 

 nests found in the last 3 years, 4 nests had 4 eggs and only 1 had 5." 

 Only one brood is reared in this subarctic setting, though nests de- 

 stroyed by untimely snow storms may be replaced as late as June 18. 



Young. — The length of the incubation period has only recently been 

 determined by Joseph R. Jehl, Jr., and D. J. T. Russell (1966) who 

 state: "Minimum incubation period for one nest 13% days, computed 

 from laying of fourth to hatching of third egg; the fourth egg did not 

 hatch." Little has been recorded of the development of young 

 Harris' sparrows beyond descriptions of the plumage. The only 

 observation on nest life that has been indicated is that both parents 

 are in attendance. Perhaps when the life histories of our commoner 

 and more easily-studied summer birds have all been put on record, 

 some intrepid young student will elect to fill in the many remaining 

 gaps in our knowledge of this bird of mystery. 



Plumages. — Edward A. Preble (1902) first described the juvenal 

 plumage of Harris* sparrow from those he collected at Fort Churchill 

 on July 24, 1900, as follows: "Upper parts dusky black, the feathers 

 edged with deep bufFy and brown, the black predominating on crown, 

 the brown on hind neck, and the black and brown about equally 

 divided on back; outer wing quills edged with deep buffy, inner with 

 brown; tail feathers edged and tipped with whitish; sides of head and 

 lower parts buffy; chest and side streaked with black, which is most 

 conspicious on sides of chest and forms a prominent malar stripe; 

 upper throat grayish white, with fine dusky markings." 



Margaret M. Nice (1929) notes: "Among Preble's and Seton's 

 specimens in the American Museum there are ten birds collected near 

 Great Slave Lake in September. One, taken September 4, is a full 

 grown bird in the nestling plumage. The others all have white 

 chins and throats. Their crowns differ a good deal, but all have a 

 more or less scaled appearance, for the feathers are black centrally, 

 margined with pale grayish buffy; in the least mature birds the effect 

 is predominantly buffy." 



