Living with Birds Why do we feed birds? Tweetapedia

You might have read stories in the media that question the value of offering supplementary food to birds. While it's a valid debate that deserves further research, there's clear evidence that garden feeding – especially in winter – does indeed increase survival rates.

In a US study of chickadees (similar to our willow tit), those that had access to supplementary feeding had a 70% winter survival rate versus 30% for those who didn't. What's more, birds that didn't use feeders spent up to two extra hours each day foraging, increasing their exposure to potential predators.

You might worry that birds can become reliant on your offerings, and that stopping suddenly will make them go hungry. But it turns out your natural concerns are misplaced. In the wild, birds juggle several feeding patches at a time. Your garden is one such patch – and if food runs out in one place, they will simply switch to others.

Survival of the fattest

Studies reveal some small birds like blue tits derive less than 20% of their total food from feeders. In the spring and summer in particular, adults will naturally feed a balanced diet to their chicks, so there doesn't appear to be a serious case of dependency.

It's also suggested that winter feeding allows weaker birds to survive that would otherwise have succumbed to the cold. This sounds like a good thing, right? In fact there's evidence that this increased survival may cause an artificial restructuring of bird communities in and around our gardens.

For example, if more individual birds of a common species survive the winter, then this could lead to more competition for nest sites to the exclusion of less bold species that don't visit feeders so readily, such as marsh and willow tit. But then it could be argued that these extra birds are trimmed back by natural predators such as sparrowhawks. You're still feeding the birds, albeit indirectly!

You also have to consider the huge amount of modification that humans have made to the countryside at large. Maybe feeding goes a little way to redress this.