ECOLOGY OF ISLE ROY ALE. 105 



part of October hundreds were found dead each year. The Downy 

 and Hairy \Vood])eckers visited the clearings occasionally, as did the 

 Pileated Woodpecker. 



Several pairs of Kingfishers frequented the river banks, and one 

 pair nested in a sand bank, rearing 7 young. These birds gradually 

 disappeared, until on September 15 the last ones left. Families of 

 Eedbreasted Nuthatches occasionally visited the clearings, often ac- 

 companied by Chickadees. During August, Crows were commonly 

 seen, but by the latter part of September they had entirely disappeared, 

 whether to the south or not it was impossible to determine. Several 

 species of flycatchers and vireos were seen migrating, the Alder, Green- 

 crested, and Least Flycatchers being seen several times, while only one 

 Yellcw-bellied was found. Both young and adults of the Least Fly 

 catcher were seen, usually together. 



One pair of Chimney Swifts was observed circling over the river on 

 August 19. Whether these were migrating I do not know, but they 

 were the only ones noted here in 1905. One of the most conspicuous 

 species during August was the Thick-billed Redwing Blackbird which 

 came to the cleaning in flocks numbering from about 30 to 50. Flocks 

 composed of .young and adults arrived nearly every day. The propor- 

 tion between the two seemed to be about equal, or if anything, in favor 

 of the adults. None were in the black breeding dress, and only a few 

 males had the red on the shoulders out of the pin feather stage. The 

 majority left on August 26, a few were seen on August 29, 31, and Sep- 

 tember 2, and two young were found on the 8th, 9th and 10th. A single 

 specimen was taken September 16 and another, partially moulted, on 

 the 20th. 



There were many instances where only an individual or a single 

 flock of a certain species was seen. Among these might be mentioned 

 the Catbird observed on September 12, which was the only one the ex- 

 pedition noted either in the I'orcupine Mountains or Isle Royale during 

 both years, the Philadelphia Vireo, Blue-headed Yireo, Chimney Swift, 

 Vesper Sparrow, Humiming Bird, Migrant Shrike, Black-throated Blue 

 Warbler, Black-throated Green and Black and White Warblers, Yellow- 

 bellied Flycatcher, Red-eyed "\'ireo, and. Kingbird. Of these, only two 

 of the Philadelphia Vireo and Chimney Swift were seen, and but single 

 individuals of the Migrant Shi;ike, Black and White Warbler and Ruby- 

 throated Huimming Bird. 



IV. LARGE BIRD WAVES. 



During the period from August 18 to September 21, six large bird 

 waves passed over the island. Sometimes the waves were composed 

 principally of one species, and again several species occurred in vary- 

 ing numbers. These bird waves were mostly from the north, although 

 small ones, consisting of the birds which had accumulated on the island, 

 took place at various times. 



A bird wave may be recognized, first, by a sudden increase of indi- 

 viduals, second, an increase of species, or, third, by a sudden decrease 

 in the number of birds which were residents or had gradually accumu- 

 lated on the island. During the large wave of September 12, all of 

 14 



