Vol. XXV-j Wood, The Spring Migration, 1907, at Ann Arbor, Mich. 



11 



•the temperature was above the normal most of the time, and from 

 the latter date to March 31, the departure from the normal was 

 considerable, the increase over the usual temperature ranging from 

 ten to twenty degrees per day. The maximum (71°) was on March 

 27. The temperature for the month was 34.6°. The continued 

 warm weather of the last week may have caused the large number 

 of migrants; 27 species being recorded after the 21st. 



April. This was an unusually cold month, the average tempera- 

 ture being 35.1°, nearly the same as that of ]March, making this 

 the coldest April in Michigan since 1874. Only three species of 

 migrants were seen before April 18, when the first warbler (Myrtle) 

 was seen. This was only three days later than our earliest record 

 for this species. From April 18 to 30, 31 species of birds were 

 noted and, notwithstanding the cold weather, several of the early 

 warblers arrived; the Yellow and the Pine Warblers on April 26. 

 May. This month was also very cold with some snow and ice, 

 with many hard frosts as late as the 28th. The average tempera- 

 ture was 44.5°, or 7.6° below the normal. These conditions did 

 not seem to affect the bird migration, as the species continued to 

 come with very little variation from the usual dates of arrival. 

 This was especially true of the earlier warblers, and the most of 

 them arrived at about the average date for the species in spite of 

 the fact that all vegetation was at least two weeks later than common. 

 But notwithstanding the fact that most of the species arrived here 

 at the usual date, they continued to linger long after that time. 

 Nor was it the spring migrants alone that lingered, but several 

 of the winter visitants also, as the Pine Siskin was seen on May 17, 

 the White-throated Sparrow on May 21 and the Junco on May 22. 

 Associated with these species I found the Cape May, Palm, Black- 

 poll, Bay-breasted, Chestnut-sided, Tennessee, Myrtle, Magnolia, 

 Black-throated Blue, and Black-throated Green Warblers. On 

 the morning of May 21 I found ice one eighth of an inch thick 

 that had formed in a boat on the beach at Portage Lake, Wash- 

 tenaw County, Mich., but all the birds just mentioned were seen 

 along the bluff near this lake, and again on June 2, with the excep- 

 tion of the Junco, White-throated Sparrow, Palm, and Cape May 

 Warblers, which were not seen after May 22. The morning of 

 May 28 was cold with a hard white frost and a temperature of 34°, 



