Winter’s cold bite forces birds to expend more energy just to maintain their body heat. Unlike mammals, birds do not have thick fur or layers of fat to insulate them. Instead, they rely on their feathers to trap warm air close to their bodies, but even this natural insulation can only do so much when temperatures drop below freezing.

To stay warm, birds fluff up their feathers and shiver, but these actions require energy, which they must replace by eating more food. If they cannot find enough nourishment, they risk hypothermia, which
can be fatal in extreme weather conditions.

With daylight hours drastically reduced in winter, birds have far less time to search for food. During the warmer months, they can forage from dawn until dusk, but in winter, they may only have a few precious hours of light to locate enough sustenance to last through the long, cold night.

This time pressure means that any disruption to their feeding patterns—such as a sudden snowfall covering available food sources—can have devastating consequences. Birds must carefully balance their time between searching for food and staying alert to predators, making winter survival
even more demanding.

Winter depletes many of the natural food supplies that birds rely on. Insects, a vital protein source for many species,
are either hibernating or frozen beneath the soil, making them almost impossible to find. Berries and seeds, which sustain many birds in autumn, are quickly consumed, leaving only scarce pickings for the remainder of the season.

As a result, birds must rely more heavily on human-provided food sources, such as bird feeders stocked with seeds, suet, and mealworms. Without these extra resources, many birds struggle to meet their daily nutritional needs.