- Homoeothermic animals exposed to low ambient
temperature must increase metabolism to maintain body temperature. The amount of heat
production required depends on the external temperature, the effectiveness of the animals
insulation (e.g. subcutaneous fat, hair coat and piloerection, feathers and fluffing up).
Increased heat production to maintain body temperature involves a cost in terms of energy
- In general, adult waterfowl with intact insulation
from plumage and an adequate energy supply (e.g. stored fat, available food) are able to
maintain their body temperature despite low ambient temperatures.
- Downy waterfowl are less able to maintain body
temperature on exposure to low ambient temperature, and there are considerable species
differences in this ability.
- Anything which interferes with the insulation of
the bird (e.g. oil, detergents, wet-feather) considerably compromises the ability of
individual waterfowl to maintain body temperature on exposure to either low ambient
temperature or cold water.
- Maintenance of body temperature in low ambient
temperature is dependant on increased metabolism and therefore an energy supply. If food
is unavailable and stored reserves are used up, death may result from a combination of
starvation and hypothermia.
- Low ambient temperature, in particular a sudden
drop in temperature, is associated with both rapid icing of fresh water bodies and salt
precipitation in saline water bodies.