This article was written by Doug Rudge, the leader of the Sand Martin pulli ringing project, for the 100th newsletter of the Axe Vale & District Conservation Society:
After ten long years, the ‘Cliff’ was eventually used by nesting Sand Martins late in the summer of 2023 when 10 pairs bred in it… their late arrival that year was likely due to the loss of their natural colony earlier in the season, probably through erosion or flooding. It is known that adult Sand Martins are very faithful to their usual nest sites, returning to them year after year to breed and this may explain why it took so long for them to take up residence at the ‘Cliff’.
In 2024 they returned at the very start of the breeding season and occupied a total of 38 nest chambers. It is reasonable to assume that the increase in the number of breeding pairs was due to other displaced birds from the same nesting site lost the previous year, along with the offspring from the 2023 season. Juvenile Sand Martins return from their first winter in Africa as sexually mature birds so are able to breed straight away, and because they fully moult their feathers over the winter, they even come back looking like adults!
This year there was a significant increase in activity at the ‘Cliff’ with well over 100 nest holes seen to be visited… (although it turns out that not all were actually used!)
We have no way of knowing whether these were adult and juvenile Sand Martins returning from last year, although it would again seem reasonable to assume so; but the massive increase in numbers is significantly more than expected: Sand Martin survival rates from year to year are quite low, with only around 1 in 3 adults and 1 in 5 juveniles surviving to breed the following year! So we would only have expected around 40 nests this year based on an average productivity of 6.75 offspring per breeding pair. It seems likely therefore that a second colony has been displaced locally and that they also used the ‘Cliff’ this year.
As a bird ringer and a member of the Axe Estuary Ringing Group (AERG), based at Seaton Wetlands, I have been leading an enthusiastic team of ringers who are keen to answer some of the questions raised above. The only way to be certain whether individual birds are returning every year is to tag them: to do this we fit small, uniquely numbered metal rings to the birds legs, then attempt to re-trap them in future years to confirm survival rates and longevity…
The absolute best time to ring any bird is as a nestling because you know everything about it – the nest location, number of eggs laid, number that hatch, date of hatching, number that survive to fledge and whether more than one brood was raised in the same nest.
This year there were 87 successful nests, 36 of which had second broods, making a total of 123 broods raised!
We fitted rings to almost all of the nestlings, exactly 500 in total!
Doug fitting the 500th ring
We also targeted adult birds in front of the cliff, catching and ringing 118 of the breeding birds… Three additional ‘adult’ birds were already wearing rings that had been fitted in France last autumn when they were juveniles heading south on their first trip to sub-Saharan Africa (some 2,500 miles away!). We also caught and ringed 18 additional juveniles, suggesting that there may also be young birds from other colonies roosting in the ‘Cliff’ (because we didn’t fail to ring 18 of the nestlings!).
It will be really interesting to repeat this exercise in years to come to see how many ringed birds return. Next year we would expect around 40 returning adults and 100 returning juveniles... I’ll let you know how we get on.
In the meantime, if you would like to see what we got up to, we featured on the BBC Countryfile programme from Seaton Wetlands, which was broadcast on 22nd June 2025 and is available on BBC iPlayer for 1 year. Happy viewing!
