10 Wood, The Spring Migration, 1907, at Ann Arbor, Mich. [f^^^ 



NOTES ON THE SPRING MIGRATION (1907) AT 

 ANN ARBOR, MICHIGAN.^ 



by norman a. wood. 



Introduction. 



From the last week in April to June 6, 1907, the writer made 

 almost daily observations on the bird life in the vicinity of Ann 

 Arbor, ]\Iichigan. Beginning at 4 a. m., from four to six hours per 

 day were spent in the field, listing all of the species seen and col- 

 lecting the rarer and doubtful specimens. Unusually low tempera- 

 tures in May attended by continued snow and ice to the north, 

 apparently prevented large numbers of the migrant warblers from 

 leaving this vicinity until the last of May and the first of June, 

 giving us the latest records on our migration lists, and furnishing 

 rare opportunities for observation and study of these and other 

 species. 



General Conditions. 



January, 1907. This was not a cold month for this region, as 

 the average temperature was only 20.6° F. But few winter visit- 

 ants were seen; a few Pine and Evening Grosbeaks, one small 

 flock of White-winged Crossbills, a few Pine Siskins, and several 

 flocks of Redpolls, make up the list of recorded species. Several 

 small colonies of Red-headed Woodpeckers wintered in heavy 

 oak woods, and numbers of Song Sparrows along the streams. 

 The former is a rare winter resident in this vicinity although the 

 latter is common. 



Fehruary. As a whole this was also a relatively mild month, the 

 average temperature being 18.1°, and the Robin, Bluebird and 

 Meadow Lark came (before Feb. 26) earlier than the average 

 arrival, which is the first week of March. 



March. The first part of March was colder and for the first 

 ten days the temperature was below the normal (29.1°). No 

 migrants were seen until the 10th. From the 10th to the 21st, 



1 From the University Museum, University of Michigan. 



