ECOLOGY OF ISLE ROYALE. 97 



THE FALL MIGRATION OF BIRDS AT WASHINGTON HARBOR, 



ISLE ROYALE, IN 1905. 



BY MAX MINOR PEET. 

 I. INTEODUCTIOX. 



Our observaitions of the fall migrations of birdf? at Washington Har- 

 bor extended over the period from August 18 to September 22. A 

 hasty examination was made of the bird life here before migration had 

 really set in (August 5 to 8), and the observations gathered at this time, 

 together with the records obtained the previous year, gave us an insight 

 into the conditions existing thei*e. This was important, as migration 

 had commenced while we were still at Siskowit Bay. 



Isle Royale is situated about fifteen miles from the north shore of 

 Lake Superior, and lies nearly northeast by southwest. Situated as 

 it is several miles from the north shore and with an unbroken stretch 

 of water 100 miles across lying south of it, the island makes an ex- 

 cellent point for the migrants to stop before crossing the lake. The 

 birds seemed to center at Washington Harbor as if focussed there from 

 the north shore, and in all probability the birds observed there repre- 

 sented the avian life of many square miles on the mainland. Records 

 were kept of the species seen each day and are given in tabulated form 

 at the end of this paper. 



II. THE ENVIEONIXENT. 



1. The Clearing. Under the head of clearings, we include the three 

 artificial clearings and the narrow roads connecting them. The first of 

 these was situated on the shore of Washington Harbor, near its head 

 and close to the mouth of Washington River. The trees had been en- 

 tirely cleared away over an area of several acres, making a rectangular 

 clearing which had been seeded to timothy and short grasses. The waves 

 had cut away the soil along the shore leaving a nearly vertical bank 

 two or three feet high, in some places overhanging the water. The 

 land gradually rises from the water's edge, more rapidly at the south- 

 ern end where a low bluff is formed. On this bluff the Club-house 

 stands, and beloAA', nearer the lake, is a little group of four small 

 houses, the largest of which we used as a camp. Other buildings were 

 also located in this clearing. Part of the clearing was overgrown with 

 brush and small trees. These had been burned and the debris left 

 where it fell. Many small bushes, weeds, and vines sprang up among 

 the fallen logs and branches, forming on ideal retreat for the smaller 

 birds such as warblers and sparrows. The rank growth of the vegeta- 

 tion made it almlost impossible to penetrate any distance into it. Here 

 the Lincoln Sparrows were most abundant during their migration. 

 As the soil was very shallow, the timothy gi-ew short and scattering, 

 and probably furnished little protection for the birds, as it was cut 

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