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THE AUDUBON BULLETIN 



Photo by Orpheus M. Schantz 



Maple Hill Ravine 



and delighted to find numbers of birds feeding, and if you listen to their 

 cheerful conversation you will discover that they are apparently quite 

 comfortable, even in zero weather. 



In many forested areas the surface is too level for ravine formation, 

 but where the land is more broken or undulating, the ravines sink deeper 

 and deeper and often are of such depth that the tops of tall trees do not 

 reach the level of the rims. 



The ravines on the shore of Lake Michigan north of Chicago, have 

 long been famous for their treasures of plant life, and more recently, 

 since the coming of the cardinal grosbeak to our region, they have fur- 

 nished shelter for this hardy, year-round resident against the rigors of 

 the wind-swept North Shore. 



In the forest preserves at Chicago Heights is a deep ravine in which 

 is found the only colony of buckeye trees in Cook County. An old 

 ravine among the Palos Park hills has a wonderful growth of sugar 

 maples, butternut, ironwood, and other interesting trees which are only 

 found where the soil has reached a certain condition necessary to their 

 requirements. 



At the mouth of the Palos ravine is the famous swallow bank, where 

 regularly each season a colony of bank swallows makes its summer 

 home. This bank of loess is known to geologists and ornithologists. 



