Birds will also change their behaviour during the colder months to conserve energy.
You might see birds shivering in a similar way to us. Shivering is effective for them, but it isn’t really a long-term solution to the cold.
On those crisp sunny days we often get in winter, you might see the birds facing away from the sun and fluffing themselves up. They do this to absorb and trap the heat from the sun.
Finally, birds might even gather together, sometimes large flocks in small spaces can be seen huddling together for warmth. If available, they will roost in shrubs and trees, empty bird houses and other spots that have residual heat from the day’s sunlight.