Tuesday, 28 June 2011

Sand martin sex. Where do they do it?


It is almost exactly 10 years ago that I handed in my PhD on sand martins. What better way to mark this milestone than with some Riparia riparia-related news.

I got a press release yesterday from the Wildfowl and Wetlands Trust spreading the word about a sand martin colony at the London Wetland Centre in Barnes. They have installed a CCTV camera in one of the nests, providing “amazing close-up views of their nesting habits and their chicks”.

“The centre’s sand martin nest bank currently houses a colony of 40 breeding pairs. One of the cameras is located on the front of the bank so that visitors can watch the sand martins in flight and – in true Springwatch fashion – another is sited inside a nest tunnel with views of the sand martins raising their young. A large screen located inside the bank enables visitors to watch the fast, agile flight of these pretty birds and also to see and hear them on their nest, chattering to each other and their young as they bring food for their growing family. As well as the on-screen action visitors can learn more about sand martins’ behaviour, habitats and migratory patterns.”



It makes me feel a little old to think that back when I worked on sand martins in the 1990s, CCTV was a pretty new idea, at least when it came to studying wild animals. I remember thinking about inserting cameras into nests, mainly to find out if this is where mating (or, more accurately, copulation) takes place.

In spite of the fact that lots of people had studied sand martins before me, it remained something of a mystery where this species actually got down its reproductive business. Indeed, I spent hours carrying out essentially unproductive focal watches and scans of telegraph wires in the beautiful rural village of Szabolcs, where thousands of martins would happily sit and, I assumed, occasionally mate. I got a great insight into village life, but not much dirt on sand martins!

So, as I say, it would have been nice to look inside nests, where sex – though undoubtedly a cramped affair – might have been taking place. But the cost of CCTV equipment back then was prohibitive and the idea of working my way through stacks of analogue tapes was not appealing. More than that, perhaps, it would have been a logistical nightmare to get a camera into the nest of a wild bird without it moving on elsewhere. Ornithological wizard Tibor Szep, who kindly let me study “his” sand martins on the fabulous Tisza River in Hungary, had somehow managed to get weighing scales into a wild nest to measure the growth of chicks but it required an extraordinary level of interference. “Nest materials with nestlings were dug out and placed in a specially designed nest box called a Riparibox,” he and his colleagues wrote in their 1995 description of the “Use of an electronic balance with bank swallow nests”.

So I didn’t bother, concentrating instead on getting desperate male sand martins to mate with a dead female propped up outside the colony (don’t ask). Now though, with CCTV equipment so affordable and artificial banks like that at the London Wetland Centre obviating the need to do any disruptive digging, it’s pretty simple to get this kind of sneaky insight into what goes on inside the nests of holed up birds like the sand martin. I’ve asked if there have been any copulation sightings in the run-up to egg laying. It might make a short communication somewhere.

I’ve been meaning to go to the Wetland Centre for years and now, if I needed one, I have my excuse. As Simon Barnes noted in his Wild Notebook in The Times on Saturday, seeing sand martins in a city is (with a nod to Scott Fitzgertald) “like seeing a flock of sheep turning into Fifth Avenue.” Looking forward to it.