566 FLUCTUATIONS IN GROUSE ABUNDANCE 



flict somewhat necessitating interpretation as to the average status of grouse abundance. 

 Ontario, on the other hand, has been divided into three parts according to Clarke' ivhose data 

 have been used for the years through 1934. Admittedly a closer alinement with ecological 

 boundaries would be desirable but the data have not been adequate for such treatment. 



MINNESOTA O • O • 0« 09 C3» 



WISCONSIN 0« O* O* O* O* 



MICHIGAN O* O* O* O* O* 



NORTHWESTERN ONTARIO O • O • O • O • :;« 



CENTRAL ONTARIO O • 0« O • O • CO 



EASTERN a o • O • O • O • •..» 

 SOUTHERN ONTARIO 



NEW YORK O* O • O • C'O 



PENNSYLVANIA 0» O • O • O* O • 



MASSACHUSETTS 8 Q* O • O • 0« 

 CONNECTICUT 



VERMONT a 0» O • O • 0» 

 NEW HAMPSHIRE 



MAINE O* 0«0* • • 



QUEBEC O • • O • O • 



NEW BRUNSWICK O* ;:« :/» 



NOVA SCOTIA O • O • 



1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 

 YEAR 



LAST YEAR OF GENERALLY HIGH ABUNDANCE FIRST YEAR OF GENERALLY LOW ABUNDANCE 

 O Berore major decline • Following major decline 



'.': B«Fore minor- decline O Following minordecline 



FICtIRE 59. YEARS OF PRINCIPAL DECLINES IN THE ABIINDANCE OF RIFFEI) tJROl SE IN VVKIOI S 

 RKCIONS OK ITS NOKTIir VSTFRN WP \OliTlI-( FNTU M. R VNCK lOflO-lO]! 



Two indices have been used in lliir- rliart. First, ii.- lias hoeii luentiuiicil before, the occur- 

 rence of scarcity seems to have aroused the most loiuerii and thus affords the best criterion 

 of the fluctuations which have taken place. For the purpose of this discussion the year i)iotted 



