At Barnham Broom we are lucky enough to have some rather special residents…
House martins are small birds, dark blue-black on top and white underneath with a forked tail. They are summer migrants, spending their winter in Africa and generally returning to the UK around April.
Unfortunately house martin numbers are now in rapid decline in the UK and they are currently amber listed as Birds of Conservation Concern. The British Trust of Ornithology (BTO) have launched a two-year survey aiming to assess these graceful birds and get to the bottom of the problem.
What's going wrong?
Characteristically house martins spend the majority of their time on the wing and build closed dome-like nests up under the eaves of housing. Because they feed on airborne insects, their appearance in the UK correlates to the weather. A cool wet spring during the peak migration period would dissuade much of their primary food source and severely slow the birds' progress.
In 2015's season of Springwatch, which aired on the BBC in June, it was reported that in 30 years numbers have plummeted by a huge 57%. It was suggested that the birds' decline was due to the lack of resources for them; it is thought a large factor is modern housing. House Martins love to build their nests up under eaves and with more UPVC and less wood being used in construction, the beakfuls of mud the birds use to build aren't sticking to the walls. This coupled with fewer green areas to collect the wet mud from is seriously impacting numbers.
What's being done?
This year the BTO launched a nationwide square survey where volunteers have been visiting 2,000 – 3,000 pre-selected 1km squares throughout the UK. The Barnham Broom complex in Norfolk is lucky enough to have had house martins nesting onsite for years. It is usual for these birds to reuse their last year's nests but this year, for the first time, the birds are nesting outside reception and the information room as well. One of the volunteer spotters for BTO arrived onsite to take stock and met with the manager of the property Shirley Carr. Because the Barnham Broom house martins are part of an active colony that returns every year, the representative was interested in counting the numbers there.
House martins leave England from the end of the summer into early autumn and retrace their migratory path. Though the main breeding season runs from May to August it isn't too unusual to see some chicks still in their nests in September, so keep your eyes open when you're staying at Barnham Broom. The next stage of the survey takes place in 2016 when the BTO will be observing individual sites in order to gather information on nesting activity.
How can you help?
Because house martins are finding it hard to build on the side of housing, we can help out or offer encouragement by providing artificial nests to try and counter the problem. These are widely available now in shops and online and simply attach under the eaves of your roof to create a nice sturdy home. Remember that house martins are communal nesters so you'll need five or six for them to take notice. It will help if you provide a little area of wet mud – perhaps piled in an upturned bin lid – that way the birds will be able to pick through and add to the artificial nests, plug any holes and make it their own. They may even be encouraged to build their own nests alongside the artificial ones.
Image: https://commons.wikimedia.org
You can buy an artificial house martin nest box from garden centres, online or from the RSPB. Alternatively find out how to make one on the RSPB Website.
