54 The Wilson Bulletin. 



within the species, during the winter, but the different spe- 

 cies are seldom found together. The birds of prey and 

 Northern Shrike are essentially solitary in habits. Blue- 

 birds and Robins are found as solitary individuals simply be- 

 cause they are so rare as winter birds. 



It is clear, then, that to be successful in the winter study 

 of birds one must know something of their favorite feed- 

 ing places before they can be found at all. In extreme 

 weather they seek protected places, just as you would 

 if compelled to pass all of your time out of doors — indeed, 

 just as you do when you step out of the storm into your 

 home and the comforts of the fireside. I sometimes think 

 that we make too hard work of our bird studies. By in- 

 quiring what we should do if we were forced to live the life 

 of the bird, we shall not go far wrong in our interpretation 

 of bird life. Of course we should not reason out what it 

 might be ultimately best to do, but what the first impulse 

 dictates. Birds are the most impulsive creatures living. 



Undoubtedly one of the great determining influences upon 

 the local and general distribution of birds, since they are 

 able to travel so easily and so far, is the food supply. Birds 

 are great eaters, because they live so fast. A fever heat 

 temperature requires a large amount of fuel. That is why 

 the birds are feeding all day long in winter. Of course they 

 will go where the food is the most abundant, or where it is 

 obtainable with the least effort. Usually that will be in 

 some sheltered place for the woods birds, but may be an ex- 

 posed place for the field birds. But since field birds feed 

 upon the ground very largely, they will not be greatly ex- 

 posed to cold winds there. When such a bird must feed in 

 a' strong wind it will invariably turn facing the wind. The 

 other way its plumage would be blown away from its body 

 and so expose it to the full force of the cold. Heading into 

 the wind becomes pretty nearly a necessity in winter. 



In the most severe weather, or when the country has be- 

 come snow-bound for a considerable time, the Crows, Mourn- 

 ing Doves, Meadowlarks and the two forms of Horned Larks, 



