1893
Aug 5
(No 2)
Concord, Mass.

  The chirping of Warblers passing overhead a few
nights since (July 30th & Aug 2nd) has set me to thinking
about migration. On talking with F'axon about the
matter I find that he fully agrees with me in
regard to the following points:
[margin]Thoughts on
Migration[/margin]

1. That the first southward nocturnal flights of small land birds
- especially of Warblers - start in the most southern
localities where the species based. Good evidence of
this is the fact that many migrants occur on the
Florida Keys at the dates earlier than they are ever or
often seen in Mass. (G. Atkins & Scott's papers & my collection)
The reason is obvious: - southern breeding birds nest
earlier than those which breed further north.

2. That the first movements in any given locality
are composed chiefly if not wholly of local birds,
individuals as well as species. In E. Mass. there
can be little doubt that the first small birds which
we hear flying at night are Yellow Warblers, Black & White
Creepers, Redstarts, Oven-birds, Nashville Warblers (?) etc.
-Species which rear but are brood and moult early.
Evidence: - at about the time Warblers begin to be
heard in the sky at night the species just named
- with a few others - begin to diminish in numbers
and this diminution continues until the country
is well-nigh drained of them. Some of them reappear (as species)
later, more or less numerously, but in comparing with,
or on the same dates as, allied species which breed
only further northward. If the more northern breeding
individuals of our "summer residents" [delete]breeders[/delete] started first many