No. 429.] RELATION OF WIND TO BIRD MIGRATION. 747 
the broad-winged hawks usually not until about eight o’clock, 
unless there has been a favorable wind the previous day, in 
which case the flight begins earlier. Many other species of 
birds, — woodpeckers, thrushes, blackbirds, etc., — apparently 
acting under the same influence that produces the migration 
of hawks, namely, the favorable winds, make their appearance 
before sunrise near the Connecticut shore and are abundant 
for a few hours only, because they soon fly back into the 
country to feed. The birds mentioned are known to migrate 
at night. Most species of hawks, on the contrary, appear to 
migrate during daylight only. This point is in agreement 
with observations made by others. 
THE MIGRATION OF THE BRoaAp-WiNGED Hawk. 
The behavior of the broad-winged hawks when they are 
migrating in flocks is peculiar. If, for example, these birds 
are soaring together in a flock of from twenty-five to fifty, 
one bird will be seen to separate from the flock, set its wings, 
and sail away in the migration direction (west in southern 
Connecticut). Presently another will follow at an interval of 
a few hundred feet ; then another, until finally the entire flock 
is observed to be sailing with set wings in single file. When 
the hawks have sailed from a half mile to two miles this way, 
they collect together and begin to soar again in an area of 
about one or two acres and continue circling until they have 
attained a considerable height. The peculiar manceuver is 
then repeated. 
The broad-winged hawk is the only one of the entire family 
that shows a decided tendency to collect in large flocks during 
the migration. Red-tailed hawks are sometimes observed in 
small flocks. 
HAWKS BLOWN OUT TO SEA. 
Strong northwest winds are undoubtedly the cause of 
many birds being blown out over the Atlantic Ocean and lost 
during the southward migration. Hawks form no exceptions, 
for instances like the following are not unfrequently reported : 
