Thoughts 
on 
Migration 
Massachusetts there can be little doubt that the 
first small birds which we hear flying at night 
are Yellow Warblers, Black and White Creepers, 
Redstarts, Oven-birds, Nashville Warblers(?), etc.— 
species which rear but one 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 company with, or on the same 
dates as, allied species which breed only further 
northward. If the more northern breeding indi¬ 
viduals of our "summer residents" started first, 
many would tarry with us between stages and the 
numbers of our local birds be augmented for a 
time, which is never the case. 
3. That in spring the individuals which breed with 
us are the first to arrive, the more northern 
breeders arriving later and those going furthest 
north closing the spring flight of each species. 
Evidence . Faxon and I have both watched certain 
individuals which were among the first of their 
kind to arrive and which from some peculiarity 
of note or coloring or from marked attachment to 
a certain locality were easily recognizable and 
in repeated instances we have found that these 
early arrivals remained to breed at or near the 
pla.ce where they were first seen. 
4. That in most if not all genera of land birds, the 
species which breed furthest south are the first, 
and those which go furthest north the last, to 
arrive in spring. This rule is subject to but 
few exceptions. It is especially satisfactory 
in respect to the Thrushes, Warblers and Sparrows. 
(e.g. Turdus fusescens vs. Turdus alicia e 
trt*. JUiU- ; Siurus motacilia vs. « 
Seiurus noveboracensis r ; v)<JXC - - 
■ anamany others). 
5. Tha^,in most if not all of these genera, the 
species which breed only well to the northward 
of Massachusetts do not return in autumn until 
their nearest allies among our local breeding 
birds have departed. 
r< 
