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Bird feeders actually improve bird health

A new study from Lund University in Sweden reveals that providing food to small birds during winter not only fills their stomachs, but also helps them maintain better health. This is because the energy they save from feeding can be utilized to fight infections instead of being expended to maintain their body temperature.

Small birds have a remarkable ability to lower their body temperature by several degrees during winter nights, in an effort to conserve energy. This physiological adaptation is crucial for their survival, given the limited food resources available during the cold months. 

However, when birds become infected, their bodies respond by raising their temperature, a natural defense mechanism that clashes with their need to save energy.

Hannah Watson, a biologist at Lund University, explained the focus of the research: “We investigated how access to food during winter affected the balancing act between maintaining a low body temperature in order to save energy, and the possibility of raising body temperature in order to fight infection.”

The study, published in the Journal of Animal Ecology, found that birds with access to food during the winter were able to maintain a slightly higher body temperature at night compared to those who did not have access to feeding tables. This indicates that they had gathered enough energy to survive a winter night without needing to lower their body temperature as much.

How the study was done

To further investigate the effects of access to food on the birds’ immune response, the researchers exposed them to a simulated infection. Surprisingly, all the birds exhibited the same fever temperature, regardless of their access to food. However, birds without access to extra food were forced to expend more energy to raise their body temperature high enough to battle the infection.

“We had expected to find that the birds that had access to birdfeeders would have more energy to fight an infection, and that as a result they would exhibit a stronger fever response,” said Watson. “Our results, however, show the opposite – birds that did not have access to a reliable source of food had the strongest reaction to infection. This enabled them to reach the same fever temperature as the birds with extra food.”

What the researchers learned

In the face of climate change and increasing human activity, wild animals are being exposed to new pathogens they have never encountered before. 

Bird feeding can have both positive and negative effects: birds that visit feeding tables may be exposed to a higher risk of infection due to the spread of pathogens, but at the same time, their immune defenses could become more tolerant to new infections. 

Therefore, understanding the factors that influence animals’ capacity for an effective immune response, such as access to food during winter, is crucial for conservation efforts.

“A lot of people like to feed the birds. Our study shows that this can have a positive effect on the capacity of our small birds to fight an infection,” said Watson. 

This research highlights the importance of providing food to small birds during the winter months in order to bolster their health and resilience against infections.

What more we know about feeding habits of birds

Birds have diverse feeding habits that are influenced by factors such as species, habitat, and season. During the winter months, birds face various challenges due to harsh weather conditions and limited food resources. Consequently, they adapt their feeding habits to survive and maintain their energy levels.

Here are some key aspects of birds’ feeding habits during winter:

Food scarcity

In winter, the availability of natural food sources such as insects, fruits, and seeds decreases. Birds must search for food more intensively or change their diet to include alternative food sources.

Diet flexibility

Many birds exhibit flexibility in their diet during winter to cope with food scarcity. For example, insectivorous birds may switch to consuming seeds or fruits, while some seed-eating birds might include insects in their diet.

Foraging strategies

Birds employ different foraging strategies to find food in winter. Some may join mixed-species foraging flocks, which increases the chances of locating food sources and provides protection from predators. Others might cache food during the fall season to rely on during winter.

Energy conservation

With limited food availability, birds need to conserve energy. They do so by reducing their activity levels, roosting together for warmth, and, as mentioned in the previous answer, lowering their body temperature during winter nights.


Many bird species benefit from human-provided food sources such as birdfeeders during winter. Common foods provided in birdfeeders include seeds, suet, and fat balls, which supply birds with essential nutrients and energy. However, it is important to maintain hygiene at birdfeeders to minimize the spread of diseases.


Some bird species avoid the harsh winter conditions and food scarcity by migrating to warmer regions with abundant food sources.

Understanding the feeding habits of birds during winter months is essential for their conservation, as it helps us develop strategies to support their survival in the face of changing environments and human-induced disturbances. 

Providing supplementary food sources, such as birdfeeders, and preserving their natural habitats can play a significant role in sustaining bird populations during winter.


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