(u(y HIE MAI^TEI^ANCE OF \ GROUSE CROP 



This method is useful where a consideralilc unifnirnitv of cover exists and populations are 

 lelalivcly high, hut otherwise the prohahle error is too great. It is nut suitahle to the well 

 mixed coverts characteristic of the princi])al grouse territory in New York. Its weakness lies 

 in the fact that in this kind of cover such a system of strips seldom intersects enough well 

 ]iopu!ate(l habitats to provide a number of flushes sufficient to avoid large errors in compu- 

 tation. -And to include a larger proportion would require an undue amount of labor since 

 each strip must be worked at least three times to secure a reasonably accurate estimate of 

 the birds occupying it. 



Relative abundance from year to year but not total numbers can often be estimated after 

 the hunting season by requiring that kill records be kept. An example of these covering 

 17 years for New York is found in Chapter IX. p. 372. Though many hunters do not report 

 their take accuratelv. the proportion of error remains rclativelv constant thus providing rea- 

 sonably accurate trends. The largest defects here are that such information is not available 

 in time to be useful during the season in question, and that a good kill one year is no guar- 

 antee of the presence of many birds in the coverts the following fall. The length of open 

 seasons, as well as the number of man davs in the field, must also be taken into considera- 

 tion. 



Other indices of production such as brood and nest counts are occasionally useful where 

 considerable trained labor is available and birds are to be found in sufficient mnnbers. In 

 using the results as indices, however, a correction for the loss occurring between the census 

 and the harvest period is necessary, a difficult job since this figure may vary widely between 

 years. 



Enough has been said to make it apparent thai no one census method applicable to all con- 

 ditions is to be found. 



Where a research problem requires an accurate determination of breeding and of early 

 fall po|)nlati(ins and the necessarv expenditure is justified, the complete census based on 

 three closely spaced coverages of an area has proven satisfactory. 



Probably the most practical method of judging the general ])ros|)ects for the hunting sea- 

 son in local co\erts is through a late August brood count. Enough time nujst be s])ent to 

 cover the area thoroughly, parlicularlv young growth and "edges". Belter results will be 

 olitairic<l if two or more individuals work together. The nund>er of broods found, together 

 with tile a\i'rage lunnber of birds in each, will indicate the general population level. One nmst 

 remember, however, that most broods «ill ha\c broken-up ami ihc binls become scattered by 

 the time the hunting season opens. Furthermore, thev will seldom be found in the same 

 jjlaces. \e\erllu'l('ss. if such a practice is contiinied over a period of years in the same area, 

 information secured in this manner should pro\ ide a valuable ind<'x. 



Over more extensive areas one must be content with estimated abundance. Eor this a 

 combination of a large number of random obser\'ations. backed u|) b\ a brood count in late 

 sunnner or earlv fall on an adequate number of re|)resentati\(' sanq)les of ordinarilv weil- 

 l)o]julated habitats will u>u;dl\ la\ llii' basis for arrixing al an ind<'\ suffiriently good to 

 judge the harvestable crop. 



The Projiorlion nj llir C.ioj) Iriiihihlf ior fliirrrst hy lluntinf^ 



If all grouse habilals were fullv stocked, the entire increment each year, save onl\ that 

 recpiired to replace nornud losses, could be removed by hunting. Rut fully stocked coverts 



