Advancing a 24-Hour Time-Activity Budget for Wintering Atlantic Flyway Canada Geese: Consideration of Nocturnal Behavior
Date
2013-05
Authors
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Journal ISSN
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Publisher
University of Delaware
Abstract
Canada geese (Branta canadensis), both resident and migratory, utilize many
areas in New Jersey as wintering and breeding grounds. Biologists and wildlife
managers are interested in establishing time-activity budgets for geese and other
waterfowl to help determine carrying capacities, daily energy needs, and other
ecological information. In order to accurately create these budgets, it is important to
observe behaviors over a complete 24 hr period, a task not easily achievable due to
constraints of nighttime observation. Therefore, nocturnal activity is often dismissed.
My objectives in this study were to 1) examine whether various Canada goose
behaviors differed between the four time periods of a day (morning crepuscular,
diurnal, evening crepuscular, and nocturnal) and 2) explore the effects of
environmental variables and human hunting disturbance on goose behavior
comparatively between diurnal and nocturnal periods. The behavioral observations for
this study took place in coastal habitats in New Jersey. Observations included 7
behaviors (feeding, resting, comfort, swimming, alert, flying, and walking), 6
environmental variables (temperature, wind speed, cloud cover, tide, ice coverage and
precipitation), and whether or not sites fell within hunting areas and open hunting
season. I analyzed behavioral observations across time periods using multiple analysis
of variance (MANOVA, α ≤ 0.05). I further analyzed individual behavioral
differences between observation periods using univariate analysis of variance
(ANOVA, α ≤ 0.05) with Tukey’s post-hoc pair-wise comparisons. To analyze
environmental variables and hunting, I used backwards stepwise regression to find the best-fitting model. Feeding, resting, and swimming were the most common behaviors.
I found that behavior proportions differed across observation periods (MANOVA, F21,
2777 = 6.32, P < 0.01). Further univariate ANOVA with Tukey’s post-hoc pair-wise
comparisons indicated individual behavioral differences existed between observation
periods. Additionally, I found that environmental variables and hunting lead to
differences in the 3 most common behaviors (feeding, resting, and swimming)
between diurnal and nocturnal periods. The results of this study show that Canada
geese are far more active nocturnally than previously assumed. Further, it showed that
environmental variables and human hunting disturbance have an effect on behavior
and can cause birds to be more or less active during certain time periods. This
information can be valuable for future wildlife researchers and managers in
considering time-energy budgets for Canada geese and acknowledging that nocturnal
behavior should be incorporated into 24 hr budgets.