182 THE PASSING OF THE BIRDS. 
they mounted into the sky in a great spiral 
till they passed out of sight; and for that 
year there were no more swallows. This, 
he insisted, took place in the. afternoon, 
“from three to four o’clock.” He was un- 
questionably telling a straightforward story 
of what he himself had seen, but his memory 
may have been at fault; for I find it to be 
the settled opinion of those who ought to 
know, that swallows migrate by day and not 
by night, while the setting out of a great 
flock late in the afternoon at such a height 
would seem to indicate a nocturnal journey. 
Morning or evening, I would give something 
to witness so imposing a start. 
The recollection of this seaside gathering 
raises anew in my mind the question why, if 
swallows and swifts migrate exclusively in 
the daytime, we so rarely see anything of 
them on the passage. Our Ipswich birds 
were all tree swallows, — white-breasted 
martins, —and might fairly be supposed to 
have come together from a comparatively 
limited extent of country. But beside tree 
swallows there are purple martins, barn 
swallows, sand martins, cliff swallows, and 
chimney swifts, all of which breed to the 
