An army of citizen scientists across the UK has given scientists from the British Trust for Ornithology (BTO) new insights into the nesting habits of House Martin, arguably our closest nesting neighbor.
Over a two-year period members of the public across the UK were asked to monitor the breeding behavior of House Martins. House Martin is a summer visitor to the UK who spends the winter months in sub-Saharan Africa and returns in April and May to build their cup-shaped nests under the roofs of buildings.
Over the past 25 years, House Martin has declined 39% and is listed as a bird sanctuary, but it’s unclear what drivers could be behind the decline.
By asking the public to provide information about the Martins House, which was nesting on their property or in nearby public buildings, the BTO scientists hoped to gain some insight into how this adorable relative of the swallow did in different parts of the country and whether the breeding success has been different in different parts of the UK.
Your results were very interesting. House Martins arrived in the east earlier and began to breed earlier than birds in the west, possibly due to the drier weather in the east. Birds that used old nests from earlier years or artificial nests also had greater breeding success than those that were built from scratch. Substrate was also important. Birds that built nests on PVC, as opposed to brick, concrete or wood, had much less breeding success – possibly because nests were more likely to collapse on the PVC substrate.
House Martin, Copyright Shaun Harvey, from the Surfbirds Galleries
Martins prison did better in suburbs and in the presence of fresh water. Although the amount of agricultural land had no effect, more hatchlings were produced by birds raised near livestock. Interestingly, there was no evidence that more young were produced in the north than in the south, although the national trend showed a greater decline in house martins in the south.
The study also reported the first triple breeding attempts in the UK while registering pairs of House Martins making three nesting attempts in a single summer further south in Europe that had not previously been observed in the UK.
Dr. Esther Kettel, lead author of the paper, said, “Thanks to the efforts of the thousands of volunteers who took the BTO House Martin survey, we now have a much better picture of what helps House Martins breed successfully, but it is still work to do. “
She added, “What we have learned is that one of the easiest ways to help House Martins in the short term is to provide artificial nesting cups. This can save about ten days of nest building time and give the Martins who use them a head start in the breeding season. “
The BTO House Martin survey was made possible thanks to the generosity of the public who donated to the BTO House Martin appeal.
The full paper can be found here https://onlinelibrary.wiley.com/doi/10.1111/ibi.12888