Tachvcineta bicolor . 
! Concord, 
18S6. 
J Apr. 14. 
Apr .15. 
Mass. 
To Ball's Hill at 9 A.M. The warm wave of yesterday has 
had a most marked effect on the birds. I saw not less than 
300 White-bellied Swallows. In fact they covered the whole 
of the Great Meadows as well as the meadows below Ball's Hill 
flying close over the water in swarms wherever the wooded 
points gave shelter from the east wind and scattered aoout num- 
erously enough over the more exposed portions of the meadow. 
I had hoped to find the White-bellied Swallows on the 
meadows but during the passage to Ball's Hill I saw in all 
less than half-a-dozen and only a straggler or two during the 
remainder of the day. The immense numbers feeding on the 
meadows yesterday forenoon must have continued their migra- 
tion at about 4 P.M. when I saw upwards of fifty pass over 
Benson' s pasture heading due north but flying in their usual 
leisurely, desultory manner feeding by the way. At the time 
I suspected they were leavixig us and a little later when I 
paddled up to Concord I did not see a single individual. I 
wish I knew when this great flock arrived . Probably they came 
in early yesterday morning. 
