Diurnal flight time of wintering Canada geese: consideration of refuges and flight energetics

Abstract

We monitored individual radio-equipped Canada geese (Branta canadensis) associated with a federal refuge to assess flight activities from late fall through spring. The number of flights per day was lowest in late fall when most geese remained within the refuge and highest in spring when they moved increasingly beyond the refuge area. The only significant seasonal difference in flight time occurred between late fall and late winter 1986. Over all seasons, diurnal flight time averaged 9.4 i?? 2.4 min (SE) and ranged from 0 to 33 min. Geese spent more time flying in afternoon periods during late winter 1986 and early winter 1987. Because of low goose populations on the refuge and abundant food resources in 1986-87, flight activity was probably lower than in most other years. Conservative estimates of average daily energy expenditures for flight ranged from 65 kJ/day in late fall to 200 kJ/day in early winter and were as high as 450 kJ/day. Additional energy costs for flight, when expressed as a percentage of daily energy expenditures, increased from fall (3%) to spring (10%). Highest estimates total daily energy costs (2987 kJ/day, equivalent to 178 g corn) appear to be within reasonable estimates of daily energy consumption. During periods of severe cold or limited food availability, however, additional energy demands for flight (e.g., due to disturbances or long foraging flights) may become important in the daily energy balance of individuals.