MICHIGAN ACADEMY OF SCIENCE. 
15 
^ Possibly it is significant to note in this connection that the Chimney 
Swift is one of the few birds whose winter quarters are as complete a 
mystery now as they were 100 years ago. Yet we know with con¬ 
siderable accuracy the winter resorts of the great majority of our 
migratory birds, and each season gives us some additional facts as to 
the routes by which they go and return. 
Out of a total of about BOO species of birds known to occur in this 
state of Michigan, TeSs'than one-fourtli are found in winter, and of the 
100 or more species of common birds which may be found at any place 
in the state in June barely a score can be seen in January. 
Before attempting to probe any of the deeper mysteries of migration 
let us consider a few typical examples of our bird population: 
During winter the Crow is rarely seen in central Michigan, and except 
for a few individuals haunting the shores of the Great Lakes, none 
are seen north of the latitude of Lansing much before the end of Febru¬ 
ary or first of March. About that time, however, small bands of Crows 
appear everywhere, or single individuals Eire seen winging their way 
laboriously northward in spite of high winds or low temperature. Their 
numbers slowly increase; days there are when their hoarse notes fall 
from above us all day long, and sometimes toward night great com¬ 
panies, numbering many hundreds or even thousands, gather at some 
favorite rendezvous to rest and sleep before pushing further north on 
the morrow. 
This tide of sable voyagers rolls northward all through March and 
most of April, and the superficial observer may not notice that here 
and there Crows are flying back and forth in pairs, collecting nesting 
materials, even brooding their eggs, while thousands of their kindred 
are still pushing on toward the north. Through the late spring and 
early summer we see crows mainly in pairs or singly; later in little 
family parties of six or eight, or neighborhood groups of twenty or 
thirty, and by September flocks of several hundred gather at nightfall 
to roost in company, scattering during the day to forage in smaller 
bands or singly. These evening gatherings increase in size and enthu¬ 
siasm during September or early October, and sooner or later, with 
numbers augmented to perhaps a thousand, they start southward some 
fair October day, travelling in a more or less compact body, and at an 
elevation sufficient to protect them from ordinary firearms, yet near 
enough to the surface to see and be seen easily. 
Investigation warrants the statement that such companies may travel 
steadily southward for six or eight, or possibly ten, consecutive hours, 
when they stop to feed, rest and sleep, and a large part of them to move 
southward again on the morrow if the conditions are favorable. In this 
way, before the first of November, more than 95 per cent of all the 
crows which were reared north of the 42d parallel have removed entirely 
from that area and are congregated in a belt of country perhaps 150 
or 200 miles in width, its center being an approximately east and west 
line running through Baltimore, Cincinnati, St. Louis and Kansas City. 
Part, perhaps all, the crows, native to this east and west belt have 
meanwhile moved farther south, and have joined the great colonies win¬ 
tering in Florida, along the Gulf coast, and in Texas. 
The northward movement in spring appears to begin with the birds 
