Encouraging birds into our gardens – Roosting

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All birds, like us, rest and sleep. This period of inactivity is called roosting.

Some birds roost alone, while others roost in groups varying in size from small to very large. To be honest, you probably won’t want to encourage birds to communally roost extensively in your garden. Just think back to the times when you parked your car under the shade of a large tree, only to return to find it blanketed in guano. Accommodating large communal roosts with the provision of large trees and other likely roosts (preferably away from buildings and streets) may be more of an urban planning issue than one you need consider in your own garden. However, you can accommodate roosting by individuals and small flocks within your garden. Birds roost in a variety of places. They do not build nests to sleep in. Nests are built solely to contain eggs and chicks. Many birds sleep perched on branches or in tree cavities. Shorebirds may sleep out in the open on beaches. Waterfowl such as ducks and geese can sleep while floating on the water, but also sleep on shorelines. Waders, such as heron, may sleep in shallow water. Kiwi sleep in burrows during the day. The jury is still out on whether migratory birds sleep while in flight. Birds may face a number of challenges while roosting such as how to avoid being eaten, falling out of a tree and dying from cold. Unlike mammals, birds are able to rest one brain hemisphere at a time, keeping the other alert for predators. Passerines have evolved a handy trick to keep from falling from their perch. They have flexor tendons which extend down the back of the tarsus bone to their toes. When a passerine alights on a perch and bends its legs, the flexor tendons automatically lock their toes around the perch. This grip can only be released when the bird straightens its legs. Birds utilize a variety of strategies to stay warm: fluffing their feathers, tucking their heads under a wing, huddling together, seeking shelter in the cavities of trees, cliff faces, manmade structures, etc. Some species even lower their metabolism in order to conserve energy. Some birds communally roost and evidently the reasons for this are still not fully understood. Possible advantages of communal roosting are increased warmth, protection from predators through increased vigilance and enhanced foraging efficiency come sunrise (if the early bird gets the worm, it may help to sleep next to said early bird and accompany him in the morning). Disadvantages include getting pooped on by neighbours, increased conspicuousness to predators and competition for food. It may be that communal roosting confers no advantages and only occurs because of limited acceptable roosting sites or proximity to a favoured foraging ground. In other words, a large group of birds may be in the same place at the same time because it is where they want to be, not because they want to be with each other, much the same way people congregate in shopping malls. So what can you do to help facilitate a good night sleep for the birds in your garden? Provide them with trees and bushes among which they can nestle above the ground, safe from predators and sheltered from the elements.