510 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 64 



of intensity, the year around or only part of a breeding season. It 

 may represent either higUy sterotyped or highly adaptive behavior. 



A territory, as for a nesting pair of peregrine falcons, may be several 

 miles across; or, as in some colony-nesting birds, approximately the 

 distance that a bird can reach with its beak while sitting on its nest. 

 For one species of East African bishopbird, a territory may have 

 boundaries that are exceedingly resistant to change, yet, for a closely 

 related species of bishopbird, a territory may be almost indefinitely 

 compressible. There are examples of communal territories defended 

 by whole colonies. There are examples of the defended territories of 

 some waterfowl actually lying outside of the nesting grounds. 



Wliile usually directed against members of the same species, terri- 

 torial exclusiveness may also take the form of antagonisms toward 

 members of different species. Wrens and coots include species of birds 

 that can be among the more savagely aggressive toward other species 

 about territorial boundaries. 



Savagely aggressive social intolerance is not necessarily restricted to 

 defense of territories, as is illustrated by the mobbing of hawks and 

 owls by crows and the mobbing of the crows, in their turn, by smaller 

 birds. Social tolerances and intolerances may also be influenced by 

 the traditions that either individuals or populations may build up. 

 Much may depend upon what animals become accustomed to. 



Concerning territorial and other intolerances, one may again easily 

 regard Nature's way as being any way that works. 



A wolf pack may lay claim to a whole watershed, and the wolves 

 may jealously keep that area for themselves. Or, they may admit 

 to their social order or their holdings neighboring groups of wolves 

 or unattached individuals — depending upon interplays of wolfish 

 (really doggish) formalities, necessities, and the tolerance or dis- 

 crimination allowed by individual dispositions. The chief prey ani- 

 mals of these wolves in the northern Lake States and adjacent Canada 

 are the white-tailed deer, which have social intolerances too weak to be 

 much of a self -limiting factor ; and the deer may increase up to such 

 numbers that they starve and seriously damage their environment 

 while so doing. At least under some conditions, an adequate popula- 

 tion of wolves may hold the deer down to levels that are in better 

 biological balance than populations not subject to effective predation. 



Social intolerances of minks may not fit too well into the category 

 of actually defended areas, but the intolerances do work to keep mink 

 populations spread out. As essentially solitary animals, their winter 

 densities on the marshes that are the most food-rich for them — the 

 most generally attractive for them of which I know — seem to level off 

 at between 12 and 20 minks per square mile. I have never observed 

 that any superabundance of readily available food ever resulted in 

 concentrations of free-living minks to the extent that individuals 



