60 Trans. Acad. Sci. of St. Louis 
and it would be rare for periods of mildness in February to be 
sufficiently extensive to allow nesting to proceed to the point of 
incubation. Still it is probable that February nestings are not 
numerous for the ovaries of two females, one of which was 
mated, collected March 11 at Ithaca, were still several days from 
a period of maturing eggs, though the testes of males, col- 
lected the same date, were exceptionally large. But if Feb- 
ruary nests are the exception March nests are the rule from 
Kansas to Manitoba, from Manitoba to the Atlantic. 
The following is an incomplete summary of March nestings 
by States: Kansas City, Missouri, March 12 (Harris, 1922) ; 
eastern Nebraska, late March (Bruner, Wolcott, Swenk, 1904) ; 
Marathon, Iowa, March 29 (Crone 1889) ; Manitoba, middle of 
March (Criddle, 1917) ; Quincy, Illinois, March 28, three nests 
(Poling, 1889) ; Champaign County, Illinois, March 15, March 
31 (Hess, 1910) ; Michigan, before middle of March (Barrows, 
1912) ; Ohio, last week of March (Jones, 1910) ; Ontario, March 
28 (Eifrig 1911); New York, young able to fly April 7, 1878 
(Langille, 1892) ; New York, late March (Bendire, 1895) ; New 
York, well started in incubation March 11 (Eaton, 1914); 
Pennsylvania, average March 25, earliest March 18 (Harlow 
1918). 
Before taking up the discussion of such a remarkable phe- 
nomenon as a Passerine nest in March, the few references be- 
fore me pertaining to the last nests of the season will be given: 
Nebraska, ‘‘well into July’’ (Bruner, Wolcott and Swenk, 
1904) ; Manitoba, July 14, eggs, ‘‘males still singing every- 
where’’ (Criddle, 1920) ; Illinois, July 6 (Hess, 1910) ; Mich- 
igan, June 19 (Barrows, 1912). At Evanston, Illinois, the 
earliest nests were started, apparently, about March 21 in 1926, 
the last nest was destroyed by an unknown external cause 
July 12. If it had been successful it would have persisted to 
about July 20. Nest building began at Ithaca about March 11 
: 1927, the last nesting would have persisted to June 28 had 
it not been disrupted by experimentation. 
Explanations of March nests.—To show why a bird nests 
when it does has been the endeavor of many an ornithologist 
theoretically inclined. Food, necessities of the nesting site, 
physiology cycle, distance of migration, have all been advan 
© explain the season of nesting of various species. No 
