488 
Bulletin No. 162.—1915. 
former, and therefore the total number of females in the broods in 
which the sex of both squabs was determined exceeds the total number 
of males by 8 (rows 15 and 16). This difference, of course, cannot be 
taken as having any significance. 
Time of Laying of Eggs A and B. 
That a day intervenes between the laying of the two eggs is a 
fact known by all breeders of pigeons, but no accurate study of the 
time of laying appears to have been made. The statement by 
Wright is more definite in this respect than most. He says (Wright, 
1879, p. 33): “Soon after matching—generally ranging from one to 
three weeks, according to age and time of year—the cock will begin 
to drive the hen towards her nest, and seem uneasy whenever she is 
away from it. That is a sign laying is near, and in fact the eggs 
generally appear in from two to five days after. Two are laid; the 
first usually about five or six o ’clock in the afternoon, the hen standing 
more or less over it all the next day and night, and laying the second 
egg about two o ’clock on the third day. ” 
During the first eighteen months of our work an attempt was 
made to obtain as accurate records as possible of the time of laying 
and of hatching of the eggs. A routine was established of making 
hourly observations from 7 A. M. to 8 P. M., and this was adhered 
to as far as conditions permitted. As a result we have records of 
101 sets of eggs, the time of laying of each of which is known within 
the limits of one hour; 12 of these records are scattered through 1907, 
while the remaining 89 were made during the months of January to 
July, inclusive, in 1908. In many cases the time of laying is known 
more closely than the limit here ascribed, but for statistical treatment 
the records have been grouped into one-hour classes, the mid-value 
of the class being the half hour. Such records as fall exactly on the 
even hour have been uniformly placed in the class preceding that 
hour; for example, an egg recorded as laid at 4 P. M. has been classed 
as 3—4 P. M. We have many other records in which the time of 
laying is known within a somewhat longer period than one hour, but 
such records have not been included in the present discussion. 
