CONTENTS 
ADSEYACE cecesccvressccccrcccsccnacvenssccevesecsesccecees 
Introduction sessccsnccsccccccecccccrccccanccccsesescccecs 
PiiCOHdUte quads Reed ddpddew awed oeae ake eubume ee heews 
The call-count method ..csccccccececccrccscccesesece 
Weighting factors Seca tiled |g sinauecye wh wie eens 
Long-term trends seccccccscccccccssccccscssnccececee 
Trends in the breeding-population index = 1960 ..cscecses 
Eastern management unit cccccccccsccrccrscscscccscces 
Central management unit SeCKCHO SHER RO SOO RAE CHE AHES 
Western management unit Scene ereeeesereseeereeeneeee 
Discussion of population-index CYeENdS saecccccovcsese 
"Literature cited capanocgrbecateies ta rieie pe gsvaay eta led aieadets ts oh a icareme 
1il 
lv 
Ww 
| ml > > oa > Ww 
