432 U.S. NATIONAL MUSEUM BULLETIN 237 paet i 



Most of the nests discovered were similar in composition, but the 

 lining was mixed, not distinct as in these two. 



According to Weaver and West (1943), at Hanover, N.H.: 



Three days were required to complete the outer layers and bottom of the 

 nest. On the fourth day, lining materials were added. Several attempts to 

 break off small twigs from the nest branch were observed. After the fifth day, 

 materials were added to the nest sporadically until the eggs were laid. On the 

 seventh day the female began making trips to the nest without materials and 

 sitting on it for short periods. This procedure continued with the trips to the 

 nest becoming more frequent and the time spent on the nest increasing to as 

 much as fifty minutes before the tenth day, April 18, when the first of the two eggs 

 was laid. The second egg was laid on the following day. 



Eggs. — The data summarized from Mierow (1946) plus other 

 available published and unpublished information through 1954, 

 indicate that three-egg clutches predominate, about two-thirds as 

 many have four eggs, a third as many have two, that clutches of 

 five are rare but occur more often than those presumed complete with 

 a single egg. C. W. Bowles (1903), for example, mentions sets of 

 one (complete?), three, and four in Washington, and stated that 

 three seemed most common. Carriger and Pemberton (1907), 

 wi'iting of San Mateo and San Francisco Counties, Calif., states 

 that the "average set seems to be three eggs, but four is also a common 

 number. Several sets of two eggs were taken in advanced stages 

 of incubation, and also two sets of five, but these are rare." There 

 seems to be no geographic variation in clutch size, but it is difficult 

 to assess the data since most sets observed were from Pacific 

 coastal states. 



Carriger and Pemberton (1907) write: "The eggs are a pale greenish 

 blue several shades lighter than the eggs of Astragalinus [goldfinches] , 

 and are marked with chocolate spots and irregular blotches, with a 

 number of pale lavender blotches which appear to be beneath the sur- 

 face of the shell. Eggs vary from very nearly unmarked, to well 

 marked about the larger end and sparingly over the whole surface. 

 The average size of all eggs at hand is .63 X .48 inches." 



In a manuscript note, Robert R. Talmadge of Eureka, Calif., 

 states: "Several sets which I have found had one or two unmarked 

 eggs. The markings vary from small blackish spots to semi-elabo- 

 rate scrolling of dark sepia and lavender." 



All egg data at hand indicate that complete sets of fresh eggs 

 usually are to be found in the United States and Canada from early 

 April to early May. Eggs in March, or indications of their probable 

 occurrence then, are as follows: young nearly ready to leave the 

 nest March 19 at Woodstock, Vt. (E. H. Forbush, 1929); nest nearly 

 completed March 15 (had thi-ee eggs on the 31st) and another started 

 March 18, at Lincoln, Nebr. (M. H. Swenk, 1929) ; Siskin gathering 



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