28 Tur Witson Butietin, No. 74. 
OBSERVATIONS ON THE SPRING MIGRATION 
(1910) AT ANN ARBOR, MICHIGAN: 
BY A. D. TINKER. 
The following series of notes is a compilation of the records 
secured by Messrs. N. A. Wood, F. O. Novy, and the writer 
during the past spring. One or another of the party, and 
sometimes all, were in the field daily from the first of March 
to the last of May. making observations on the progress of 
the migration and taking specimens of the rarer species. 
Nearly all of the field work was done in the immediate vi- 
cinity of Ann Arbor. Mr. Wood made an occasional trip to 
Portage Lake, Washtenaw County, securing records of water- 
birds that otherwise would not have been noted. 
A great many of the weather conditions prevalent during 
the spring of 1910 were quite similar to those of the cor- 
responding season of 1907. However, the cold waves this 
year did not have the same effect upon the migration as in 
1907. It will be well remembered that during that spring 
bird-life in general, and warblers in particular, were very 
abundant here and prolonged their stay to an unusual extent. 
This was especially true of the later migrants (Wood—Auk, 
vol. xxv, page 10). But this year there was no such abund- 
ance of individuals of the various species, although about the 
usual number of species were recorded. In fact, the migrants 
last to arrive, that is the great majority of the warblers, and 
some of the sparrows and thrushes, were rather scarce, while 
others were not noted at all. Whether this discrepancy was due 
to the destructive force of the heavy storms that took place 
along the Gulf States when the migration was at its height in 
that region or not must remain an open question. It is also 
quite possible that other forces combined to influence the mi- 
grating hosts to such an extent as to cause them to pass on 
without stopping here, as is their custom. Whatever the 
causes may have been, field-work throughout the entire sea- 
son gave abundant evidence of the fact that there was a great 
falling off in the number of individuals of some of the species. 
