42 The Wilson Bulletin. 



coes, Song Sparrows and Goldfinches are also a part of the 

 company. But in such a case the species of fewer individ- 

 uals should first be counted and recorded, and lastly the 

 whole company counted. Subtraction will then give the 

 number of Tree Sparrows. A large part of the work was 

 done in company with Rev. W. L. Dawson, during the first 

 four years, and with Mr. R. L. Baird, during the last two. 

 It is needless to say that counting large companies of birds 

 can be more accurately done by two working together than 

 by one alone. 



A glance at the weather for the months covered by this 

 study may add interest to the discussion, and perhaps offer 

 some explanation of the fluctuations from year to year. 



Temperature alone in winter probably has relatively little 

 to do with the winter movements of birds, unless the cold is 

 intense; but cold, attended with a blanket of snow or ice — 

 a frequent combination — is a condition to be reckoned with. 

 In the following summary of weather conditions during the 

 winters, I shall lay stress upon the conditions which would 

 cause southward movements, or later in the winter, cause the 

 winter birds on the ground to remain, leaving the reader to 

 infer that when nothing is said about the weather it was not 

 of such a character as to cause any marked movements of 

 the birds. 



The winter of 1895-6 opened during the first five days 

 of December with snow and nearly zero temperature. A 

 warm wave followed, removing the snow. The 11th brought 

 us nearly six inches of snow and temperature a little below 

 zero during the night of the 13th. This snow blanket be- 

 gan to grow thin on the 16th, and was gone after the rain 

 of the 1 8th. This winter weather had a marked influence 

 upon the birds, which was not offset by the summer weather 

 which continued to almost the end of the month. 



There was nothing in January which materially influenced 

 bird movements, although three mornings during the first 

 week the temperature was near the zero mark. A marked 

 cold- wave, with below zero temperatures in the middle of 



