LONG-TERM TRENDS OF CHICKADEE POPULATIONS IN WESTERN NORTH-AMERICA

被引：9

作者：

BRENNAN, LA ^{[1
]}

MORRISON, ML ^{[1
]}

机构：

[1] UNIV CALIF BERKELEY,DEPT FORESTRY & RESOURCE MANAGEMENT,BERKELEY,CA 94720

来源：

CONDOR | 1991年 / 93卷 / 01期

关键词：

CHRISTMAS BIRD COUNT; PARUS-ATRICAPILLUS; PARUS-GAMBELI; PARUS-RUFESCENS; POPULATION MONITORING;

D O I：

10.2307/1368614

中图分类号：

Q95 [动物学];

学科分类号：

071002 ;

摘要：

We evaluated population trends of Black-capped (Parus atricapillus), Chestnut-backed (P. rufescens) and Mountain (P. gambeli) chickadees in the Pacific Northwest of North America using 41 years (1944-1985) of data from Christmas Bird Counts. Most (7683%) locations showed no significant trends (long-term increases or decreases in numbers of chickadees detected per observer hours) for any of the three species. Five to 14% of the locations had significant declines and 10 to 13% had significant increases. The recent range expansion by Chestnut-backed Chickadees in the Sierra Nevada of California was not accompanied by declines in Mountain Chickadee numbers. Chestnut-backed Chickadee populations no longer appear to be increasing in the Sierra Nevada; however, some populations in the San Francisco Bay region of California are apparently still increasing.

引用

页码：130 / 137

页数：8