Glenhead nest sites in the early nineties. The one with an asterisk used to be two nests but became the only nest regularly used each year after the roof works —
Swifts at Glenhead 2013 © Andrew Rodger 2013
Since 1990 I have been involved with two properties where large swift colonies were affected by building works, which disrupted their breeding patterns or altered the building in a way which precluded the continued use of established nest sites. In the period following the works, steps were taken to try to re-establish these colonies but progress was slow and often discouraging.
At Glenhead there were steady signs of swifts returning. After the works to the roof in 1995 and the subsequent repairs to the nests, there had been a single nesting pair with followers and since 2010 there had been two breeding pairs. Groups of five or six swifts were a common sight around the building during the summer. Allowing for the juvenile non-breeding period, we had hoped to see more, perhaps followed by an exponential increase as more swifts reach maturity. In preparation for this we designed and installed durable nest boxes on the house and in the byre gable to see if swifts could be persuaded to expand the colony to this nearby building, in the hope that it will make them less vulnerable to the interventions of the owner's agent, who seemed intent on blocking the original nest sites.
Not far away at Cloan the colony of swifts was completely lost in around 1990. The owner tried to re-establish a colony by providing wooden boxes, obtained from the Hirsel as there was not the market then that there is now for boxes. No swift activity was seen and, eventually, the boxes rotted and were taken down.
However in 2006 we erected a triple box at Cloan, adjacent to the original nest sites and a call CD was used to encourage interest from the nearby swift population in Auchterarder.
Swifts were seen around the building for the first time in ten years during the 2007 summer and one of the nests was being used in 2008.
The nests were inspected every year in September and April and it was always the nest on the right which was used each year. Frequently I found a thick comfy mattress of moss containing coaltit eggs, on top of which the swifts had nested.
There was often straw and cow hair from the nearby fold of Highland cattle. We assumed these could have been brought in by the swifts. Straw is usually an indicator for starlings but fortunately, we think the height of the nest above ground deterred starlings. Even so, we taped the nest doorways in the autumn and removed the tape at the end of April, to try to reduce the risk of another bird taking the nests over.
We no longer have access to the Cloan nest sites but at the time of my last visits it was known that one nest was in regular use for breeding and both the others had trial nest rings on the floor, which seemed promising. Hopefully the new owner will encourage the swifts.
The Glenhead story is not quite as happy. Though there was one nest site in regular use, the other sites which had initially been taken up again by swifts were lost to house martens which had built mud nests on the underside of the bottom slates, preventing access by swifts. The house martens had come from a nearby building which had a long established colony which had been disrupted by windfarm works. Hitherto there were no house martens at Glenhead but their ingenious adaptation of the swift nests meant there was nothing the swifts could do and they became established. The swifts tried to win back their nest sites but the house martens were well organised and drove the swifts away from the building. Though some interest had been shown in the terracotta nest in the byre gable, there were no swifts nesting there by the 2016 season. The owner's agent was not sympathetic and on more than one occasion people had been sent up with instructions to block the holes, so it is possible that there are now no more swifts at Glenhead.
A record of these sites was maintained up to April 2017 when we lost access to the buildings.