Pete een We BrOrNG BE Usb Gb Beret N 7 
controlling influence; a warm spell may accelerate the movement, and 
a cold snap slow it up. 
In checking new arrivals it is difficult to identify many of the smaller 
birds without a good bird book, as members of the sparrow family, the 
flycatchers, vireo, thrush and warbler families, while having distinctive 
differences, at a distance are not so easily identified. Close acquaintance 
with bird songs is also a great help. Most of the better bird books print 
migration charts, giving average dates of arrival so that it is possible to 
know within a few days when the different birds are due to appear. The 
late Wells Cooke, during his lifetime, by personal observations and the aid 
of many correspondents, made over 1,000,000 card index records of bird 
migrations. Since the scientific use of bird banding has been developed the 
movement of birds has been better understood. 
The peak of spring’ migration in the Chicago region is usually reached 
in mid-May. If the weather happens to be favorable, birds that are headed 
for the far north make only short stops as they have far to go. Wood- 
lands and gardens then become welcome “filling stations,” the birds paying 
for their lunches by destroying insects and their eggs and larvae. If, how- 
ever, they are overtaken by inclement weather the smaller insectivorous 
birds that migrate only on clear nights are frequently delayed, sometimes 
for several weeks. During the delayed time they “pile up” so that they 
may be found everywhere, in gardens, parks, woodlands and on the open 
prairies. At times they are held back by cloudy and rainy weather until 
after the first of June. Then suddenly the weather may clear up and, after 
the first suitable night, those whose passage to the far north was arranged 
for, disappear as if by magic. 
During the autumn migration, as the birds born during the spring and 
summer have not acquired full adult plumage, they are much more difficult 
to identify. 
The writer’s cycle of years goes back to the time when passenger 
pigeons congregated in such numbers that the flocks extended from horizon 
to horizon and frequently darkened the sun like clouds. When roosting they 
broke branches of great trees by their weight. The time was the late 
seventies of the last century, the place, central Ontario in the forested 
region south of Georgian Bay and north of Lake Erie. In addition to the 
passenger pigeon, other birds have become scarce or have entirely dis- 
appeared. 
Later, between 1881 and 1888, in Iowa, along the Cedar River the 
spring migration of waterfowl made a _ never-to-be-forgotten impression. 
Wild geese, ducks of many kinds, white pelicans, great blue herons, gulls 
and terns, silhouetted against the deep blue sky, made a marvelous “mov- 
ing picture.” 
While the Mississippi Valley route is the most popular and most used 
migration highway, there are others in the west and along the Pacific Coast 
where species of birds not known east of the Mississippi may be identified. 
Many western birds have the same characteristics as their eastern kin, but 
through long separation have acquired different plumage. Thrashers, jays, 
bluebirds, robins, the Arkansas kingbird, warblers, many sparrows, etc. at 
first glance seem the same but close observation shows the differences. 
