358 



NATURALIST'S GUIDE TO THE AMERICAS 



bank swallow, rouKh-winged swallow, 

 barn swallow, cliff swallow, phoebe. 



General 



The reptiles are represented by 36 

 species, only three of which are poison- 

 ous: The banded rattlesnake {Crotalus 

 horridus) of hilly or mountainous sec- 

 tions; the prairie rattlesnake (Sistrurus 

 catinatus) found in swampy ground and 

 prairies of western Ohio; and the cop- 

 per head (Agcistodon mokasen) along 

 streams, especially in the eastern half 

 of the state. 



Of amphibians, 25 species are recorded, 

 including toads, tree toads, frogs and 

 salamanders. 



Seventy species of fish are recorded 

 from the Scioto River and its tributaries 

 in Franklin County; 37 species from 

 Portage Lakes (30 of these also from the 

 Scioto River). Certain of the fishes 

 are confined to the Ohio drainage system, 

 others to the Lake Erie drainage system ; 

 6ome are common to both. There is also 

 a difference in the fish fauna of the lakes 

 of the two drainage systems. Some 

 species of glaciated and non-glaciated 

 sections of the state are different. H-ion 

 concentration in streams is also a factor 

 in fish distribution. 



The insect fauna of Ohio is rich in 

 species and in numbers of individuals. 

 The range of phytophagous species is in 

 general, though not always, coincident 

 with that of the food plant. While there 

 are no such sharp limits in distribution 

 as are found in some of the western 

 states, the different physiographic 

 regions of the state show general differ- 

 ences in the insect fauna. In some 

 instances there are insects characteristic 

 of and limited to a region. This is 

 especially true of the Lake shore, to 

 which some species are sharply limited, 

 and of the Allegheny Plateau, which has 

 in general a rich and characteristic insect 

 fauna. It is noteworthy, that in the 

 state, many plant-feeding species are 

 restricted to the Allegheny Plateau, 

 although the food plant has a much 

 broader range. Other insects are depend- 

 ent upon particular habitats found only 



in one region; thus the wet sandstone 

 moss and liverwort covered cliffs of the 

 Allegheny Plateau are the only known 

 locality for the rare moth, Epimartyria 

 auricrinella. Southwestern Ohio shows 

 a mingling of elements derived from the 

 east and from the west and southwest; 

 it lacks many of the species characteristic 

 of the Allegheny Plateau, but marks the 

 eastern and northern limit of other 

 species. 



INFLUENCE OF PHYSICAL FACTORS ON 

 DISTRIBUTION 



As Ohio lies at the southern edge of 

 glacial advance, much of its life, both 

 animal and plant, has been determined 

 through post-glacial migrations. Two 

 great recognized pathways of post- 

 glacial migration — the Appalachian 

 Plateau and the Mississippi-Ohio Valley 

 — enter its borders. The geographic 

 location, just north of the rather in- 

 definite boundary between warm tem- 

 perate and cool temperate (about 40° N. 

 latitude) ; and at the eastern edge of the 

 deciduous forest-prairie transition, 

 brings about a mingling of plants and 

 animals from the north and south, the 

 east and west. This mingling is evident 

 in the relationships of fauna and flora. 

 The migratory pathway of birds, both 

 water fowl and song birds, summering 

 farther north, crosses Ohio, so that the 

 number of species of birds in spring and 

 fall is enormously increased by these 

 transients. 



Barriers, such as Lake Erie, the Ohio 

 River, and the Erie-Ohio divide, have 

 interfered with migrations, not only in 

 proportion to the inability of migrants 

 to cross them, but in other less obvious 

 instances. The watersheds are barriers 

 only for some exclusively aquatic ani- 

 mals. They frequently form sharp 

 limits for distribution of species of cray- 

 fish — some of which are limited to 

 specific streams. The southern mocking 

 bird, while abundant in northern Ken- 

 tucky opposite Cincinnati, is rarely seen 

 north of the Ohio River at this place. 

 The absence of pronovmced barriers, 

 either physical or climatic, is partly 



