y2 THE ^I'ECIES^ITS TAXU.\ 0,1/1 . RA.\GE. BIOLOGY. & ECO.\ OMIC IMPORTANCE 



Over the next month, the birds regain some % oz. 1 9 to 27 prams) of the weight they have 

 lost. Possibly the melting snows by then have uncovered foods of greater nutriti\e value or, 

 perhaps with spring's warmer weather, the energy outgo is less than that provided by the food 

 taken in. At all events, the increase is short-lived for, through the active days of May and 

 June, more weight is lost. The low point of the year, for females, is about June 15. for 

 males about August 15. when they average about 1 lb. 2 oz. I 500 grams) and 1 lb. 6 oz. I 604 

 grams) respectively. The demanding responsibilities of courtship, of starting a family, and 

 of moulting about over, their weight rises, slowly at first, then more rapidly throughout the 

 early fall to its November peak. 



oz 



24 



CMS 



, eao 



Moles- Adult 



-— - Males- Young 



^^ Ferrlales - Adul+ 

 — — Femal es - Young 



SEP OCT. NOV DEC JAN FEB MAR APR MAY JUN. JUL AUG SEP 

 15 15 15 15 15 15 15 15 15 15 15 15 15 



MONTHS 



FIGURE 10. AVERAGE SEASONAL WEI(;HTS OF 394 ADULT AND lOii YOUNG WILD GROUSE FROM 



NEW YORK 



Differences Between the Sexes 



Many a biologist, in attempting to identify the sex of grouse in the field, has been puzzled 

 by the over-lapping of indicative characteristics*. Among the best of these is liic length 

 of the tail, for in males it will a\crage nearb three-quarters of an inch longer. By study- 

 ing the weight graph, one also finds that thi> rule-of-thumb judgment of many hunters by 

 which the heavier grouse are considered to be males, iiolds good in gener;il. During the 

 hunting season, the male adult will usualK average aliout 2-3 oz. (77 grams I lii'a\ icr tliaii 

 its mate. Even a male of the year, while a\eraging about 2 oz. (57 grams) lighter than one 

 of the preceding year, is, nevertheless, apt to be some % oz. (20 grams) heavier than an adult 

 female. 



Weight must, of course, be accepted merelv as a general indication of sex. for many birds 

 of each group are killed which are above or below the levels here given. Usually, however, 

 a heavy, long-bodied bird is a male; a plum]), fairly light bird, a female. On the average. 

 an adult female is still 2/3 oz. (17 grams) liglilcr. i-vcn at her December peak, than is the 



* Sep di»cu»Bion iindrr Hnw to Krroiinilc Sex, p, 39. 



