MICHIGAN ACADEMY OF SCIENCE. 77 



riparian ornis. The chimney swift, to all appearances, was also favored by 

 the hollow trees, though this case was difficult to determine definitely. 

 The bluebird also fell into this group. 



Another noteworthy division of this class was made up of those species 

 which do not nest in holes or hollows of trees, but are characteristic of the 

 open. To them the fire provided a long, new area of open land, much of 

 which has since been covered to a greater or less degree with weeds and 

 grasses. This permitted the birds to enter a region previously excluded 

 from their range. The vesper sparrow must early have taken advantage of 

 this condition, as it was a common species in 1909. The goldfinch, too, 

 fed commonly on patches of Canada thistles that had succeeded the fire 

 while the cowbird 'more rarely lingered to feed among the long grasses. 

 The ruby-throated hummingbird, too, haunted the acres of flowering fire- 

 weed. 



In the second class — the migrants — the sandpipers were the favored spe- 

 cies. As it left undeniably insufficient food for large flocks, the burn must 

 have been unfavorable for many species during migration, A'et it did actually 

 favor others. Thus the sparrow hawks found grasshoppers — a favorite 

 food — in abundance in local areas as they passed. More interesting are 

 the waders. As stated, the mud flats of the river were of minor habitat 

 significance owing to their small size, a fact which would tend to be un- 

 favorable to waders. The conditions on the flats, however, were extended 

 by the burned spruce, cedar and tamarack swamps. Many of these furnished 

 wide shallow ponds, with muddy shores and bottoms in which was abundant 

 food. These conditions made possible the occurrence in greater numbers 

 of such species as the least sandpiper, the solitary sandpiper and, more 

 particularly, the lesser yellowlegs, and there can be but little doubt that 

 other species and more flocks visited the region than are recorded. The 

 swamps provided with these conditions were remote from camp, widely 

 distributed, and quite impossible of thorough study by a single observer in 

 the limited time available. 



Another phase of the effect of the burn was a concentration of the birds 

 along the streams in the willow and alder thickets. In the main, this concen- 

 tration of life in the stream thickets effected both the residents and the migrants 

 and for the same reasons. First, it was here that the food was to be found; 

 for many species, as some of the warblers, the only considerable food supply 

 was in these living thickets. Water was abundant, which also increased the 

 number of insects over that of the dark forests bordering the burn. Second, 

 the breeding species find favorable nesting sites and concealment which 

 they cannot find in the burn. These thickets along the streams afforded an 

 abundant bird life, both as regards species and individuals. Usually, too, 

 the species were here relatively fearless, reluctant to leave the cover and 

 eager to return to it. In general, then, the burn has concentrated the l)ird 

 life quite as the forest species are restricted to the wooded margins of streams 

 in the plains areas. 



ACKNOWLEDGMENTS. 



The writer here wishes to acknowledge the indebtedness of the survey 

 to Mr. R. C. Flannigan and his family, who placed their camp and care- 

 taker at our disposal and in other ways did much to further the work of 

 the expedition and to contribute to the personal comfort of the men while 

 in the field. 



