Winter Activity Patterns of Black-Capped Chickadees in Interior Alaska

• Published in: The Wilson bulletin (Wilson Ornithological Society) 1976-03, Vol.88 (1), p.36-61
• Main Author: Kessel, Brina
• Format: Article
• Language: English
• Subjects: Bird banding; Birds; Cloud cover; Luminous intensity; Photoperiod; Snow; Solar radiation; Temperature; Temperature measurement; Weather
• ISSN: 0043-5643

Daily activity patterns of Black-capped Chickadees (Parus atricapillus) were studied about an artificial feeder near Fairbanks, Alaska, from September to May, 1960-1967. The daily light cycle was the dominant environmental factor determining the daily activity period. Activity days were longer relative to daylength before the winter solstice than after. Light intensity was the second most influential factor. Chickadees began activity in the morning at lower light intensities than those at which they ended activity in the evening, and they began and ended activity at lower intensities during the last half of November and the first half of December than at other times of year. At cold temperatures, chickadees had shorter activity days than when it was warmer, but their feeding intensity was greater; they apparently conserved energy by reducing activity during cold periods. Even after accounting for the effects of light intensity, chickadees began activity in the morning earlier on clear than cloudy mornings. Solar radiation tended to result in shorter activity days during early and late winter, but longer activity days during mid-winter. Snow and wind appeared to have only slight effects on activity patterns. The relative influence of several of the environmental factors appeared to change during the winter, and each factor exerted more influence on the timing of first activity than of last activity.