For our smaller bird species keeping warm in winter can mean the difference between life and death.
Some species however have come up with some ingenious ways of increasing their survival rates - by simply 'getting close to the neighbours'.
Wrens for example are well known for sharing nest boxes in particularly cold winters - over 60 have been counted emerging from one nest box!
Monkmead Wood Volunteer Group try to erect at dozen or so bird boxes every couple of years not just to provide nest boxes for Spring but simply because they are invaluable roosting sites for our smaller species of bird like the Wren during Winter.
It you're able to place a bird box in a quiet place in your garden (not in direct sunlight though) you'd be supplying our wildlife with both a Spring and Winter residence!