^'^1908^^] Adams, Ecological Succession of Birds. 139 



ground cover of herbaceous plants; and although Ground Hemlock 

 is abundant locally, yet in places the forest floor is quite open and 

 free from louver shrub growth. The remarkable preservation of 

 trails or roads through such tracts shows clearly how slowly changes 

 take place. Such a habitat must be relatively equable in its 

 temperature and moisture relations. 



Geographically speaking, the primary characteristic of the climax 

 is its relative stability, due to a dominance or relative equilibrium 

 produced by the severe environmental and biotic selection and 

 adjustment throughout the process of succession. 



At this point attention should be called to the fact that dominance 

 is a resultant of an equilibrium produced by neutralizing or over- 

 coming other forces and influences. We may think of the process 

 of succession as a stream of forces whose development may be com- 

 pared with the transformation of a drainage line, — such as, for 

 example, that of a riAailet into a creek, and then into a river. The 

 stream and the character of the ground mutually influence each 

 other and the course followed is a resultant of the mutual adjust- 

 ments. The stream is deflected by one condition and then another, 

 just as succession varies with local conditions; yet the water con- 

 tinues to run down grade and seeks an equilibrium, and similarly, 

 biotic succession continues on its course deflected here and there by 

 local influences, yet forever tending toward a state of biotic equi- 

 librium. The dominance of the climax society or formation, con- 

 sidered as a process rather than a product, has much in it that is 

 analogous to the dominance produced by the process of baseleveling. 



The characteristic birds of the climax forest are: — the Chickadee, 

 Golden-crowned Kinglet, Red-breasted Nuthatch, Canada Jay, 

 Downy, Hairy, Arctic Three-toed and Pileated Woodpeckers, and 

 the White-winged Crossbill. Here again the association becomes 

 small in variety of species and comparable with the small society 

 which must have been associated with the complete dominance of 

 the Lake waters. Thus there has been a development of diversity 

 from simplicity, with later a return to simplicity. To these birds 

 of the forest should also be added those species of general distribu- 

 tion, as the Eagle, Swift, Swallows, etc., a class of birds whose 

 predaceous, insect-feeding and wide ranging habits make them 

 particularly difficult to properly associate. A careful study of 



