SEASONAL AND DIURNAL BODY-MASS FLUCTUATIONS FOR TWO NONHOARDING SPECIES OF PARUS IN SWEDEN MODELED USING PATH ANALYSIS

According to the hypothesis that has been invoked most frequently to explain seasonal fattening patterns for birdsthe adaptive winter-fattening hypothesisindividuals respond to worsening foraging conditions by increasing body mass and energy reserves. Two hypotheses have been proposed equally frequently to explain daily weight gain patterns for birds: according to the state-dependent foraging hypothesis, energy reserves should be amassed early …