House martin populations are flourishing at Lower Mill Estate in the Cotswold Water Park, reflecting Habitat First Group’s commitment to providing homes for both people and wildlife.
The enormous decline in House martin populations in England (69% between 1967 and 2015), prompted Lower Mill Estate to do something to help these birds which are now an Amber listed species of conservation concern. In 2005 the Estate put up 60 artificial House martin nest boxes. These boxes were soon used, and year on year the number of House martins arriving to nest at the Estate each summer has increased with over well over 150 nests now recorded annually.
House martins start arriving at Lower Mill Estate from wintering sites in Africa in March/April. Weighing only around 19g with a wingspan of just 26cm, this annual journey is a remarkable feat. Once they arrive they begin repairing old nests or building new nests, using around 1000 mud pellets to make each nest, and they go on to have 1-2 broods of young before leaving again in September/October. The Estate encourages residents to leave old nests in place as these will be preferentially used by returning House martins and take only a few days to repair ready for use, rather than the 2-3 weeks it can take to build a nest from scratch.
Despite coming to the UK to breed each summer little is known about these birds when they leave our shores. The British Trust for Ornithology (BTO) records show that over 400,000 House martins have been ringed in the UK since 1909 but only one of these British-ringed birds has been recorded south of the Sahara in southern Nigeria.
Ian Woodward, BTO House Martin Survey Organiser, said, “Our House Martin population has been in steady decline since the early 80s and we don’t really know at this stage what is driving the fall in numbers. However, it is likely to be a combination of factors that could include restricted nest site availability, limited food availability during the breeding season, limited access to the muddy areas that are needed for nest building, and problems affecting survival during migration or winter in Africa. Thanks to our amazing volunteers who took part in the House Martin Survey, we are currently undertaking research to look at some of these potential factors.” He added, “Given the extent of the decline, any action homeowners can take to protect and encourage nesting martins will be important whilst further research is ongoing.”
The Lower Mill Estate colony of these birds is now thought to be one of the largest in the UK and this is most likely due to the design of the houses and their enviable setting amongst lakes and rivers, which provides plenty of nesting sites, nesting material and flying insect prey to support the House martins. Dr Phoebe Carter, Chief Ecologist for Habitat First Group says, “The Estate continues to monitor the House martin population annually and takes measures to protect and enhance this significant colony as part of our ongoing commitment to building alongside nature. We are proud to have been able to give a helping hand to such a wonderful species”.
For further information about the nature conservation efforts at Lower Mill Estate and their sister site Silverlake, Dorset please contact Dr Phoebe Carter firstname.lastname@example.org.
Information about House martins
- Latin name – Delichon urbicum where Delichon is an anagram of Chelidon, Greek for Swallow, and urbicum refers to ‘City’.
- Species information available from British Trust for Ornithology (BTO) and RSPB websites; bto.org and www.rspb.org.uk
- Information about the BTO House martin survey can be found at https://www.bto.org/volunteer-surveys/house-martin-survey
Photo credit Bob Iles.Back to news