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Adaptations Of The Gray Catbird Dumetella Carolinensis To Long Distance Migration: Energy Stores And Substrate Concentrations In Plasma, Richard Marsh

Richard Marsh

The major body components (water, lean dry, and fat) were measured in the carcasses of Gray Catbirds from which the flight muscles had been removed. Birds were collected from May through October near Ann Arbor, Michigan and during September and October near Gainesville, Florida. Additionally, the glycogen content of muscle and liver and the concentrations of glucose and triglycerides in plasma were determined in catbirds sampled during fall migration in Florida. Catbirds attained maximum body masses of ∼50 g in Florida, largely due to the addition of fat. Relatively lean birds (∼3-4% body fat) in spring through fall weighed approximately …