TOPOGRAPHY. 13 



its course and unwittingly reach a higher latitude than else- 

 where. The river itself has, for the most part, little of the 

 character which entices swamp breeders to its shores. While 

 water birds follow its course they do not tarry to breed 

 there, but pass northward. 



On the north Lake Erie is a factor to be reckoned with. It 

 acts as a balance between the extremes of cold in winter and 

 heat in summer, thus maintaining- a more even temperature 

 at any time of year, preventing the sudden changes which 

 are so dangerous to both plant and animal life. Its chilling 

 spring influence holds vegetation back until time for it to 

 come forth, and by its warm breath in fall it wards off early 

 frosts. Recognizing this influence upon vegetation, we are 

 prepared for the appearance of some of the more southern 

 breeding birds along the shore of the lake, and for the pres- 

 ence all winter of some of the northern specie^ which ordi- 

 narily winter much fartner south. 



It has already been stated that marshes scattered sparing- 

 ly along the lake front, usually where streams enter the lake, 

 afford breeding places for many species. The archipelago 

 lying north of Sandusky also affords suitable summer homes 

 for many species not found breeding elsewhere in the state. 

 Wherever clay banks front the water Bank Swallows and 

 Belted Kingfishers nest in numbers. 



CLIMATE. 



For a detailed discussion of the climatic conditions of 

 Ohio the reader is referred to a paper on "Some Climatic 

 Conditions of Ohio," by Mr. Otto E. Jennings, in the Ohio 

 Naturalist for January, 1903. It is sufficient to say here 

 that the mean range of temperature, which is 49 F. in the 

 north and 55 F. in the south, and the much greater depth 

 of snowfall in the extreme north-eastern corner of the state, 

 are the principal factors which exert any marked influence 

 upon bird life. A number of species are not only more com- 

 mon in the warmer southern counties, but several never 

 reach even the middle of the state. Greater snowfall means 

 covered food in winter, and consequently fewer birds during 



