Where on Earth do British House Martins go?

01 May 2013 | No. 2013-18

It is one of ornithology’s greatest mysteries but also one that the British Trust for Ornithology (BTO) hopes to answer using the very latest that technology has to offer.

It is not known where in Africe House Martins
winter, or how precisely they get there

The House Martin is well known to many people; from April to September it lives cheek by jowl with those lucky enough to have this energetic little bird nest under their eaves. In recent years, however, the number breeding here in the UK has fallen by two-thirds, leading to the species being amber listed as a bird of conservation concern and in need of some help.

Whilst we know a lot about the breeding ecology of the House Martin in the UK, once September comes and this enigmatic bird heads off for the winter it virtually disappears from our radar. It is not known where in Africa House Martins winter, or how precisely they get there.  If we are to start to understand what is driving the decline of this wonderful species, then it is these questions that we will need to answer.

This summer, the BTO aims to use the latest technology to discover the routes that House Martins take to Africa and to answer that great ornithological mystery, exactly where do they spend the winter months? BTO researchers plan to do this by fitting a tiny (shirt button-sized) device known as a geolocator. Weighing less than a gramme, the device contains a clock, a calendar and a light sensor, together with enough memory to store all of the data collected from the day it is fitted until the day it is retrieved.

By comparing daylight length, as measured by the light sensor, with the time and date recorded, scientists at the BTO are able to determine where on the planet the device was at any given time. This information will then reveal the wintering areas, together with the location of possible stopover and refuelling sites, precise migration routes and the timing of the migration through Europe and Africa.

Paul Stancliffe of the BTO commented, “I have long dreamed of being able to follow a bird like the House Martin on its migration from Britain to Africa, to get a glimpse of the places it is passing through and the places that it chooses to stay and rest for a while before continuing on its journey. It is very exciting to think that we are on the brink of new discoveries that should help these delightful birds and provide them with a more optimistic future.”

He added, “This technology comes at a price and we need help to secure enough of them to make the project worthwhile.  Anyone interested in seeing how they might be able to help can find out more by visiting www.bto.org. Each device costs £170 and we hope to be able to fit them to at least 20 birds.  We need help to support the scientists developing this project."

For more information please visit http://www.bto.org/volunteer-surveys/house-martin-survey/movements

Notes for Editors

  1. The BTO is the UK's leading bird research charity. A growing membership and up to 60,000 volunteer birdwatchers contribute to the BTO's surveys, collecting information that underpins conservation action in the UK. The BTO maintains a staff of 100 at its offices in Thetford, Stirling, Bangor (Wales) and Bangor (Northern Ireland), who analyse and publicise the results of surveys and projects. The BTO's work is funded by BTO supporters, government, trusts, industry and conservation organisations. www.bto.org
  2. Despite many thousands of House Martins being ringed in Britain each year, their African wintering grounds are completely unknown. This is partly because the species is poorly-known in the non-breeding season, as relatively few are observed in Africa compared to the millions that winter in the continent. This has led to speculation that they might spend long periods feeding at high altitude, including above the rainforest, where they remain unnoticed. 

    Although there have been some recoveries of British-ringed House Martins in Europe and North Africa, their migration strategies and routes north of the Sahara are also poorly understood. Fortunately, new developments in tracking technologies provide an opportunity for us to finally answer this long-unanswered question.

Contact Details

Paul Stancliffe
(BTO Media Manager)

Office: 01842 750050
(9am to 5.30pm)
Mobile: 07585 440910 (anytime)
Email: press [at] bto.org

Images are available for use alongside this News Release.
Please contact images [at] bto.org quoting reference 2013-18

The BTO has an ISDN line available for radio interviews.
Please contact us to book an interview
Office: 01842 750050 

Related content