 |
"This guest of
summer, the temple haunting martlett, doth approve by his loved masonry
that the heaven’s breath smells wooingly here" (Macbeth, William Shakespeare) |
Introduction
House martins are summer visitors to the UK, arriving mainly in April and departing in October for wintering grounds in tropical Africa. They are widely distributed throughout the UK and nest colonially, usually on buildings – even in highly urbanised environments such as London. House martins are easily recognisable by their white rumps and blue-black and white plumage.
Nationally the population appears to be undergoing a slow, shallow decline, although firm evidence of the rate and extent of such a decline is lacking, and there is significant variation from site to site, a factor demonstrated in London. There was a notable range expansion into the Inner and East London boroughs bordering the Thames between the late 1960s and the 1990s, contrasting with some apparent contraction of range in outer South London boroughs. Figures from the BTO-administered Breeding Bird Survey (BBS) show a significant decline in London between 1994-99, and there are indications of a decline in passage birds, especially in the autumn, and later arrival of birds in the spring.
Conservation Considerations
There are three major environmental factors in the conservation of house martins:
 | Availability of suitable nest sites (usually on buildings) and an adequate supply of wet mud with which to build the actual nest |
| Weather conditions, especially relatively warm and sunny conditions with moderate rain, which favour easy availability of flying insect food |
| The ability of the locality to supply a diversity of insects in order to allow chicks to be reared successfully |
Human interference to nests, predation by domestic animals in particular and factors operating in the African wintering grounds all influence breeding populations. Current conservation activity for house martins is limited to advice (RSPB promotes a house martin information leaflet for householders) and survey.
Future Action
In London, sites for breeding house martins are exclusively on buildings, and the availability and viability of suitable sites is unlikely to be directly affected by Habitat Action Plans.
Availability of wet mud This is a determining factor in the ability of the species to build nests, and may be influenced by actions in certain Habitat Action Plans, notably the Tidal Thames, and possibly also Gardens, Canals and Wastelands. Any actions, which lead to the continued or increased availability of wet mud at river margins and bodies, may be of value.
Availability of airborne insect food This is also a limiting factor, and habitat management leading to conditions which maintain or increase the numbers and range of such insects will be valuable, especially where such habitats are in the vicinity of buildings which may provide nest sites. All Habitat Action Plans may be relevant, with Canals, Tidal Thames, Woodland and Wastelands being of greatest potential.
Other potential actions Key among these is the need to raise public awareness to the presence, status and needs of house martins and encourage the provision of artificial nest boxes. There is an associated need to discourage illegal destruction of nests, and publicise ways of containing droppings where these are a problem to householders. Continued survey and monitoring would be valuable and could be done in conjunction with other London-wide species surveys.
Further Reading
RSPB (1998) House Martins. Information leaflet, RSPB.
Contact
The contact for this Statement is RSPB
|
Steve Gilbert |
tel 01273 775333 |
house martin © RSPB Images