BurNs—On BrROAD-wWINGED HAwk. 200 
Tt will be seen that we have here another instance of a sub- 
stantial increase in the number of eggs in a set from the south 
northward. The number of eggs in a set is therefore 2 or 3, 
oecasionally 1 or 4. When the first complement of eggs has 
been destroyed, the second clutch usually contain one less egg 
and the individual ege may suffer only a slight diminuation in 
size, or diminish in length and increase in short diameter (Rich- 
ards, Spaulding, Hoag and Currie ms.). A third set seldom 
consists of more than one egg of inferior dimensions. 
NUMBER OF SETS IN A SEASON.—This hawk, undisturbed, 
produces but one set in a season; and when the nest is dis- 
turbed, not all have the vitality to attempt a second set in the 
midst of the moulting period. Riley states that he believes but 
one brood is reared, unless the first is destroyed, when another 
set may be laid. Flanagan never found a second set after the 
first was taken, but on the other hand, Richards gives two in- 
stances, one pair producing the third set. Spaulding recalls 
two second sets of two eggs each which had previously sets 
of three eggs, laid in the very same nests. Hamlin collected 
a set of three eggs on May 14, °89, and a few days later on 
ascending to the nest he found a new lining had been added 
and three more eggs deposited. These were allowed to hatch 
but later the young were taken by a friend and reared in cap- 
tivity. The bird then built in a tall chestnut some 10 rods dis- 
tant and brought forth their young in safety. Currie writes 
me that he used to collect a few sets each year and in every 
case the birds would lay a second clutch of one less egg and 
always hatch them in peace. Bendire is without question cor- 
rect in his statement that a single brood is reared in a season. 
MerASUREMEN’T oF Eccs.—In selecting the eggs figuring in 
the averages | have used only well authenticated sets carefully 
measured by competent persons. Eggs abnormal or infertile, 
and those known to be the second or third laying of the sea- 
son. have not been used in this connection. The value of any 
set of eggs would be greatly enchanced, were each egg marked 
according to the incubation or the succession in which they 
were deposited. The few sets | have been able to thus sep- 
