ECOLOGY OP ISLE ROYALE. 99 



Sharp-shinned and Sparrow Hawks rarely remained here, except dur- 

 ing the night, or in very stormy weather. The warblers were scarcely 

 ever fonnd in the heavy timber, but along the more open part of the 

 river and in the alder thickets they were abundant. By far the most 

 common warbler along the river was Grinnell's Water Thrush. This 

 bird was coniined alm,ost entirely to the forest, and especially to that 

 poi-tion. bordering Ihe stream Avhere fallen logs and rubbish furnished 

 their favorite haunt. They seemed to be migrating in pairs, but no 

 immature birds were seen with them. During the stormy period last- 

 ing from September 2 to 5, the Water Thrush came out into the road 

 and clearings. The Wilson and Olive-backed Thrushes bred in the 

 forest, but during migration they preferred the open and were only 

 occasionally found in the heavy timber. The path skirting the river 

 was also a favorite route for them. The maple brush which 

 bordered the forest in many places was the favorite habitat 

 of the Hermit Thrush. This and the diminutive Winter Wren were 

 sometimes met with among the very densest conifers. Among the 

 other birds occurring here were the Brown Creeper, Golden-crowned 

 Kinglet, and Bed-breasted Nuthatch. Chickadees were nearly always 

 present. This habitat was chosen by nearly all of these birds during 

 migration, probably because it furnished the right kind of food and 

 excellent protection. ;Many other species were occasionally met with, 

 but they were only wanderers and no particular significance can be 

 attributed to tJieir occurrence here. 



3. Food. The clearing afforded abundant food for nearly all species; 

 The grassy meadows and dry hillsides were infested with great swarms 

 of grasslio])pers which rose up befoi-e one as a buzzing cloud. Nearly 

 all the birds taken, among which might be mentioned the Sharp-shinned 

 and Sparrow Hawks, Thick-billed Redwing, Busty Grackle, Flicker and 

 Nighthawk, fed to a, greater or less extent on these pests, as was shown 

 by an examination of their stomachs. Many other species of insects 

 were abundant, blackflies, deer flies, and "no-see-ums" being; at times 

 almost unbearable. The Deer Mouse was very plentiful; and also the 

 Xorthern Hare, as many as twenty or thirty of the latter being seen 

 at one time feeding in the road between the first and second clearings. 

 These animals together with the large number of Red Squirrels found 

 along the edge of the road furnished abundant food for the owls and 

 migrating hawks. Seeds were plentiful and constituted the principal 

 food of the Savannah and other sparrows. Wild red raspberry bushes 

 were common and these berries together with several other kinds were 

 greedily eaten by many of the birds, especially the Cedar Waxwings. 

 A few wild flowers grew in the clearing and these were occasionally 

 visited by the Ruby-throated Humming Bird. Insect life characteris- 

 tic of coniferous forests was probably abundant because the Brown 

 Creeper, Chickadee, and Golden-crowned Kinglet fed here almost ex- 

 clusively; otherwise this habitat did not appear to furnish much food 

 for the migrants. 



III. THE WEATHER CONDITION'S AND MIGRANTS. 



1. Weather Conditions. Throughout the period of thirty-flve days 

 during which obsei-vations were made on migration at Washington Har- 



