100 



MICHIGAN SURVEY, 1908. 



bor, a daily record was kept of the direction of the wind, temperature, 

 and the general weather conditions. The barometric readings, taken 

 at INirt Arthur, thirty-five miles nearly due north from the Harbor, are 

 from the daily weather maps. A comparison of my observations ou 

 the weather with those from Port Arthur shows that the conditions 

 at the two places were much the same, so I feel safe in assuming the 

 barometric pressure at the island to be approximately that recorded just 

 to the north. An examination of the daily weather maps for this period 

 shows that the same isotherms and isobars include both localities. Un- 

 fortunately Port Arthur is the most northern station on the daily 

 Aveather map that could have any appreciable effect on the bird life 

 <if Isle Eoyale. A reference to the areas of high and low pressure in- 

 dicates that conditions similar to those on the island probably prevailed 

 over a large area to the north of it. 



The records for the entire thirty-five days are included in the foUowr 

 iiig table. The readings were made between 7:30 and 8 A. M. Other 

 readings were made during the day and where these are of importance 

 I will give them under the particular discussion upon which they bear. 

 All temperature readings were in Fahrenheit. The dates of the large 

 bird waves are starred. 



TABLE. 



* Large bird waves. 



2. The Bird 2Ii.grants. a. WarMers. Many warblers nest on the 

 island, and so the first indication of migration in this family was the 

 tendency to flock preparatory to the trip south. At first these flocks 



