120 COl EH CHARACTERISTICS A.\U SHELTER REQLIREME\TS 



were set up as needed for special project study. On the |)rimar) areas, surveys were in process 

 for from six to twelve months over a 13-year period. Over lO.UUU man days were spent gath- 

 ering data on the conditions surrounding the 19,619 grouse flushes, 1,515 grouse broods and 

 1.270 nests, which are here analyzed. The nesting studies were extended to cover those lo- 

 cated by cooperators in most of the counties of the State where the grouse are common. 



Not being certain as to just what details might be of value, the policy of recording every 

 item, uhirh might conceivably be of interest, was adopted. In furtherance of this, each time 

 a grouse was flushed it was found desirable to record data covering 36 sej)arate items on a 

 specially devised form sheet*. Similar notes were made for nests, broods and dead birds en- 

 countered. By 1937, the mass of data thus gathered had become sufficient (over 700,000 

 records) to warrant its tabulation'^ as a basis for analyzing the shelter and other requirements 

 of the grouse in New \ ork State. 



At the beginning, the authors little realized the complications involved in securing records 

 representative of true conditions and sufficiently numerous to remove, in large measure, the 

 probabilitv of error. Though the best statistical advice possible was earh secured, the ap- 

 |)li(alion of biometrics to such an ecological problem was still in its infancy. Full advantage 

 has been taken, however, of the tremendous advance in the past decade in setting up and 

 evaluating the tabular material from which most of the conclusions later described, have been 

 drawn. 



The problem of securing records representative of the actual situation was attacked by at- 

 tempting to secure a sampling of actual conditions sufficiently large to reduce the probability 

 or error to a minimum. Technically, representativeness can only be accomplished, as Dr. 

 Mottley^ aptlv put it, by "giving each and every grouse nest, brood and adult, in every type 

 of grouse habitat, in each year and under each condition, an equal and independent chance 

 of being observed." Obviously, this is not practical in a species like the grouse although it 

 was ap])roached in studying the cover relationships of grouse broods and adults by following 

 the birds on most of the study areas, throughout all four seasons year after year, with about 

 the same degree of ititensity. In arriving at the conclusions here presented, wherever practi- 

 cal, the corrections necessarv to account for such items as variations in the amount of each 

 cover type available to the grouse, have been made. This is necessary before one can secure 

 a true picture of grouse cover use. 



In studying grouse nest locations, it is assumed, on the basis of experience, tiiat cacii bird 

 will choose the cover type and nest site most nearly fulfilling its requirements. Many instances 

 have been observed where females have travehxl considerable distances, presmnably to .secure 

 conditions favorable to the location of the nest. Except for this special situation, it is believed 

 that grouse I broods and adults) to a considerable extent must make the best of conditions 

 within their territories as they find them. Thus the results here presented cannot be consid- 

 ered to be absolutely representative of what a grouse WDuld select if given an unlimited choice 

 or if all habitats represented optimum conditions. 



The lar^c rminl)cr of records analyzed, however, is believed suHiciciit to present a picture 

 of "average choice" undi'r New York conditions. 



Nesting Cover 

 Though grouse are not particularK adept at hiding their rii'sl. their concealing coloration. 



* Sop riniirrn 73 In 76 in Aiiprnilix. 



A Mptlliiilit liarit arc (lescrilird in tile Apprnilix. p. 701. 



t Mottlfy, C. Mi-C. pcrsunul Ivlirr to the author*. 



