Study Discovers Where Garden Birds Sleep At Night

Photo by Kevin Yates on Unsplash

A university study is uncovering the night-time secrets of some of Britain’s favourite garden birds.

The University of Gloucester says that finding out where garden birds sleep at night during the winter is “one of the last great mysteries of the animal kingdom”.

The research will also be used to provide data to help address the decline in the numbers of garden birds, such as the robin and blackbird, in the UK. The study follows a national assessment which showed a 37% decline in woodland birds since 1970.

The birds must endure up to 16 hours of cold and darkness when they cannot feed, and selecting the right place to sleep is crucial to surviving the long winter months.

The team involved in the study, including six students from the University’s MSc Applied Ecology programme, are using VHF radio tracking to find where the birds roost in the evenings, the first such study to do so according to the university.

Researchers worked with the Gloucestershire Naturalists Society to document the night-time roosting habits of four popular garden species – the European robin, Eurasian blackbird, great tit, and dunnock.

Senior lecturer in practical ecology at the university, Dr Mark O’Connell, said: “Our findings suggest that none of the birds we were tracking flew large distances to get to their roost sites, but were using vegetation in local areas where they were located during the day.

“It was clear that there were differences between the species in roosting behaviour, particularly in relation to variation in height of the roost site and the vegetation types used.”

The European robin was found to roost within eight metres of its roost site from the previous night. The Eurasian blackbird, great tit and dunnock tended to roost up to twenty metres away from their previous roost location.

The study also found that the European robin and the great tit prefer sleeping spaces no higher than four metres above the ground, but the Eurasian blackbird and great tit choose sites that were more than six metres high.

And it seems that the species all preferred different places to sleep. European robins favoured laurel trees, and Eurasian blackbirds roosted in various habitats including sycamore, bamboo, bramble, laurel, and evergreen pines. Dunnocks preferred ivy-covered tree stumps, bramble, hawthorn, and a range of garden shrubs, while great tits roosted in beech and sycamore, and occasionally laurel.

The results of the study will be used to help inform and support the management of woodland areas to protect species.