By Matt Walker
Editor, Earth News
Snapshots of life inside a starling roost
Bird experts have gathered a unique insight into the secret lives of starlings, one of the UK's most intelligent and iridescent birds.
By placing high definition and infrared cameras inside a starling roost, the experts have been able to watch how adult birds bully juveniles and how starlings struggle to keep warm.
Starlings are best known for their acrobatic flocks, known as murmurations, which occur this time of year, but until now their roosting habits have been less studied.
Leading UK starling expert Chris Feare and a film crew working with the BBC Autumnwatch programme set out to capture a day in the life of a British starling.
The team was interested in finding out more about where these birds feed, and most importantly, what goes on inside their roosts, where thousands of birds gather to spend the night.
To research the birds' roosting behaviour, the team placed a series of miniature high definition cameras on the wooden structure of Aberystwyth pier, known to be frequented by the birds.
They also added infrared cameras to film in the dark, and thermal imaging cameras that detect the body heat of the birds and where in the roost is most warm.
Cosy or cold?
The cameras revealed that adult starlings dominate juveniles in the roost.
The adult birds jostle for the best positions and roosting sites.
In doing so, they shove the juvenile birds out to the more drafty, exposed roosting sites.
Thermal imaging cameras record how warm it is inside a starling roost
As a consequence, the juvenile birds all huddle together, while the adults roost alone.
The cameras also revealed that overall, roosting does help the birds stay warm at night.
Mr Feare and his team were also able to hear starlings engaging in some remarkable mimicry: mimicking the calls of tawny owls, curlews, moorhens and blackbirds among others.
Such opportunities to film roosting starlings are becoming more rare.
In recent years, numbers of the birds have fallen by up to 70%.
The decline is believed to be due to the loss of permanent pastures, the use of pesticides and a shortage of food and nesting sites.
Watch the investigation into starling roosting behaviour on BBC Autumnwatch, broadcast on BBC Two on Thursday 18 November at 20.30BST.