Michigan Ornithological Club 21 



k'irilaiidi is in the coniferous region of llie n(jrtb, and yet, if this point is 

 view is correct, it slavishly follows the old ancestral paths in its spring mi- 

 grations. It should be remembered that in early post-glacial times the 

 conifers extended much farther south than at the present time, so that in all 

 probability there was not as great a break between the northern and southern 

 conifer belts as there is to-day. 



At least, it seems worth while, as a working hypothesis, to consider the 

 present point of view, and see to what degree the migration routes of the 

 northern migratory birds have been iniluenced by glacial drainage lines and 

 laKe shores. One would not expect uniformity in this respect any more than 

 we may expect uniform results upon diverse material even to-day, and yet 

 certain types of routes may find their explanation in early post-glacial con- 

 ditions as- suggested by Kirtlandi. 



REFERE.XCES. 



1898. Butler, A. IV. The Birds of Indiana. Ind. Dept. Geol. and Nat. Re- 



sources. 22nd Ann. Rep. pp. ."il.'i-llS?. 



]89S. Chat^man, F. M. Kirtland's Warbler {Dcudroica Kirtlandi). Auk. 

 Vol. XV. pp. 289-293. 



]S9:5. Cook, J. J. Birds of Michigan. Bull. No. 94, Mich. Agr. Exp. Sta- 

 tion pp. 1-148. 



1897. Dixon. Chas. The Migration of Birds. London. Amended Edition. 



190:;. Jours, Lyuds. The Birds of Ohio. Ohio Acad. Science. Special Pa- 

 pers No. 0. 



190:;. Knmlicn. L. and Ilollistcr, X. The Birds of Wisconsin. Bull. Wis. 

 Nat. His. Soc. (N. S.) Vol. HI, pp. 1-14:]. 



1897. Leveret t, F. Wafer Resources of Indiana and Ohio. Eighteenth Ann. 

 Rep. U. S. G. S. Pt. IV, pp. 419-559. 



:I899. . The Illinois Glacial Lobe, ^lonog. XXXVllI, U. S. 



Geol. Survey. 



1902. . Glacial Formations and Drainage Features of the 



Erie and Ohio Basins. Monog. XLT, U. S. Geol. Survey. 



189.'). Louchs, JJ\ E. The Life History and Distribution of the Prothono- 

 tary Warbler in Illinois. Bull. 111. St. Lab. Nat. His. Vol. TV, pp. 

 10-38, also Osprey, Vol. II, 1S9S. 



1902. Ridgway, R. Birds of North and Middle America. Bull. 50, U. S. 

 Nat. Museum. Part II, pp. 60:;-G05. 



1899. Roberts, T. S. The Prothonotary or Golden Swamp Warbler (Pro- 

 tonotaria citrea) a Common Summer Resident in Southeastern ^Minnesota. 



Auk. Vol. XVI, pp. 236-246. 

 1899. .Stejneger. L. The Birds of Indiana. Amer. Nat. Vol. XXXIII. pp. 

 65-69. 

 University Museum, University of Michigan, Ann Arbor. 



