66 Trans. Acad. Sci. of St. Louis 
ing thing to be noted is first, the surprisingly large number of 
opportunities for successful nesting there are in March and, 
secondly, the fact that nestings in northern Illinois have a 
greater chance than at Ithaca, New York. 
But the reason for March nests remains still incompletely 
explained. The habit was probably acquired very early and 
TABLE 1 
Hypothetical are ae — of the Prairie Horned Lark with the probable 
with regard to snow, in the Chicago, IIl., region, for 
the years 1910-1927 paces 1924). 
ultimat 
e success or fai 
Deep aximum Amount 
Year Sac aarag Nesting Snow on Ground of Snow on Result of, March 
eriods in March aes to Ground at 7 P.M. Nesting 
1910 2 to 6, 11 to 13, 
{ 18 to 31 } None. Successful 
1911 8 to 12, 19 to 22 
{ 24 to 27 } March 27 to April2.| 2in. April 2...... Successful? 
1912 | Snow on ground throjughout month. 
1913 12 to 14, 18 to 20, 
{ 23 to 24, 29 to 31 \ Ware 2h ee ees 2.2 in. March 21...} Successful? 
1914 | 14 to 16, 24to31 | None Successful 
1915 | 13 to14,23to25 | None Successful 
1916 12 to 18, 24 to 26, 
{ 29 to 31 \ PAMOR Pe ee ee: 2.6 in. March 22...| Successful? 
1917 | 10to11,20to31 | None Successful 
1918 (i to 5, 8 to 9, 11 to 
12: 171022, 29to31 None Successful 
1919 | 15 to 20,24to30 | None Successful 
1920 9 to 11, 14 to 16, 
{ 21 to 31 } April 4 to7........ 6.1 in. April 4..... Failure 
1921 ae 1 to 2, 5 to 21, 24 
o 27, 30 to 31 None Successful 
1922 5 to 6, 9 to 16, 
{ 27 to 28 } Marcel 3160020055, 1.1 in. March 31...| Successful 
1923 1 to 4, 21 to 22 March 18 to 19... 1.3 in. March 19... Baccemtel ae as 
ne a 
only) 
1925 | 6to10,16to31 | None.. Successful 
1926 19 to 25 March 26 to April 6.} 9.9 in. April 3..... Failure 
1927 | 8to19,25to31 | None Successful 
¥Niot leca +h + ‘ a Sth joovehn F. 
NOTE: All dates are nee: fetlosive: 
umber of years of ieilures due to snow: 2 
of years of problematical success: 4 
