Seeds and tallow balls not only saturate the small birds, but also make them much healthier, according to new research from Lund University. Feeding during the winter months makes the birds healthier because they do not need to put as much energy into fighting infections.
When the birds were exposed to a simulated infection, they all had almost the same fever temperature. Instead of conserving energy to get through the winter, birds without access to extra food had to use more energy to fight the infection.