()72 THE MAIMER ANCE OE A GROISE CROP 



l{i;ST()CKING DEFLETKl) HABITATS* 



Much of ihe iMolilcin nf ii'stuckiiig depleled habitats has heen thomughly discussed in the 

 chapter on artifiiial propagation." The hope that grouse niiglit be raised like pheasants or 

 quail for restocking purposes has been the compelling force behind most grouse propagation 

 attempts. The reasons for past failures are detailed there, as well as cautions for securing 

 stock for liberation. Those who have read this account will remember that )oung birds 

 seven to nine weeks of age are preferred to adults for restocking; that wild birds in good 

 condition, captured in habitats similar to the one in which they are to be released, probably 

 have a better chance of survival than do artificially raised birds, though the latter have been 

 successfully used. The value of re|)eated liberations, even in a good habitat, was also stressed. 

 Though most attempts to date have failed of their purpose, that does not necessarily mean that 

 satisfactory resuUs cannot be secured from liberated birds when the reasons for past failures 

 are thoroughlv understood and the proper corrective measures are applied. Certain addi- 

 tional considerations will, therefore, be discussed here. 



When to Restock 



Much misunderstanding has arisen concerning the purpose of restocking. Outstanding 

 among the influences popularly supposed to be responsible for grouse scarcity is the specter of 

 inbreeding. Yet the Investigation has not been able to unearth the slightest reason to justify 

 this theory. So far as can be determined, no wildlife species has ever suffered from this cause 

 and geneticists tell us that the possibility is extremely uidikely. 



The second reason commonly given for restocking is to increase the shootable surplus. 

 I'sually a fair crop of birds is known to exist but additional birds are added in the hope that 

 the increase will be manifold and the shootable surplus materially enlarged. Here, too, there 

 is some vague idea that a "change of blood" will revitalize the birds in the coverts thus stocked. 

 Again there seems no value to the assertion except that, if the coverts are not already fully 

 stocked, the birds may simply add numbers to the population. But, as the resident popula- 

 tion approaches the carrying capacity of the habitat, tlie probability that recently liberated 

 individuals will mo\c to less thickly settled coverts should not be overlooked. 



When, then, is restocking justified on the basis of profitable return'.' Brieflx the occasions 

 may be summed up as follows: 



1. When a habitat, originally suited to grouse, has lieen destroyed by fire or by man's 

 varied activities and has subsequently improved to a point where it again appears ade- 

 quate for grouse. 



2. When grouse have been eliminated from suitable habitats, presumably 1)\ preilators, dis- 

 ease or by overhunting and the cause is thought to be under control. 



3. When, over a fairly large area, grouse are almost nonexistent and re(o\er\ to a normal 

 population level is unusually slow and this lag is not ex|]l;iiiialile li\ liabilal inadequacy 

 or other circunislances. 



But, even uii<ler these conditions, isolation from a seed stock wliirii miglil olhcrwise spread 

 to it i> also a necessar) jirerequisite. 



When grouse are fairly abundant, the normal dispersion of the birds from well to poorK 

 stocked coverts is such thai few favor.d)le ones close by will remain seriously underpopulated 



* Hy Cardinei Bump 



A S» Chiplcr XI. p. SO-I. 



