Management of the RuflFed Grouse 367 



portant considerations. The use of the census in practical wild-life 

 management is quite a different matter. It must be simple, quick, 

 and inexpensive. Its basic purpose is the same— to determine the 

 size and distribution of a population— but the accuracy required 

 is not so great and no supplementary data are needed. The use of 

 a management census is to determine the harvestable crop. This 

 may be the crop on a single area of cover, such as a private holding 

 or a public hunting ground, or the crop over a whole state. In the 

 latter case, the estimate would be based on sample censuses from 

 representative areas and would furnish the basis for seasons and bag 

 limits. 



Accurate determination of a grouse population in most of the 

 northeastern range requires detailed coverage of the entire census 

 area by trained observers. In most circumstances this expenditure 

 is not warranted. The most expedient method is one of using indexes 

 and samples. 



The period of census-taking for the estimation of shooting season 

 populations is from mid-August to mid-October. The middle of this 

 period falls in the height of the moult when the birds are difiBcult 

 to flush. It is generally best to avoid the month of September and 

 confine the counts to late August and early October. 



One of the best indexes of grouse populations is the productivity 

 of the year. A comit of brood size in late August is a quickly available 

 method for gauging the productivity. If the brood size, female in- 

 cluded, averages four, the probability is for a population the same 

 size as the year before ( if other factors are equal ) . If the brood size 

 averages five or more, the probability is for an increasing popula- 

 tion; if three or less, the likelihood is for a decline. 



The second figure needed in addition to brood size is brood den- 

 sity. To obtain a fair index of this figure the census should be made 

 in good weather: moderate in temperature for the season, at least 

 partly sunny, and with little or only moderate wind. The best hours 

 are from an hour after daylight to an horn* before sunset. The cov- 

 erage should be confined primarily to summer cover: brushy cover, 

 and hardwood edges. Covering fifty acres per man-day of eight 

 hours, an average of two broods per man-day would constitute an 

 average good year record. This, with an average unit size of five, 

 would give a full brood count of ten birds per man-day on fifty 

 acres. If the brood density is one per man-day on a fifty acres per 



