Swallows in a natural nest site – a first for Northumberland

By Ian Kerr

A thriving Swallow population has long been a feature of my regular patch, Holy Island, and 2014 has proved by far the best year since I started monitoring and ringing the species more than a decade ago.
At least 78 broods, involving a minimum of 270 young, fledged around the village, harbour, St Coombs Farm, Snook House and the Lough. Many pair produced two broods and a small number of nests produced third broods although it was impossible to say if the same pairs were involved.
Whatever the circumstance, the 2014 breeding season far surpassed the previous record year of 2009 when 56 pairs fledged around 150 young.

The most productive site was the complex of fishing sheds near the pier where two linked buildings had 16 nests, about half inside and the others on the outside, including for the first time on ledges installed by fishermen to help the Swallows.
Elsewhere, pairs also used the refuge box at the Causeway, World War Two bunkers near Beal Point and the sluice gates at Longbridge End and the double-decker hide at Lowmoor Point, all within Lindisfarne National Nature Reserve. They were not included in my totals above as I had insufficient data on their success.
Excitingly, for the first time a pair used a natural site, the first record of its kind for Northumberland. This nest was in a crevice under an overhanging turf at the top of an eroding low boulder clay bank near Emmanuel Head, the eastmost point of the island. At high tides the waves would be just eight feet below the nest.
The nest was discovered by a friend, George Moody, summer warden for Lindisfarne’s Little Tern colony, who noticed it while doing his ‘day job,’ collecting shellfish on the local rocks. A family party of five Swallows was nearby.
When I visited the site a few days later these birds had disappeared. The nest was well-concealed, its mud almost the same colour as the background. There was heavy splash underneath indicating its success. When I climbed up I found a fully-feathered dead chick in the cup which must have perished at about time its siblings fledged.
As mentioned, high tides wash the base of this bank and the nest would not have survived a good easterly blow which often sends waves crashing against it, washing out large chunks of clay and rock. Fortunately for this pair, the weather during the breeding season was kind and mainly westerly.
The nest was the first I had ever seen in a natural site and so I circulated the pictures and details widely to seek comment.


Sharrock (1976), Gibbons et al (1993) and Turner (2006) have all stated that natural sites are very rare in Britain although obviously at one time in the remote past before building were available they must have been the norm. However, two NRG ringers were able to come up with instances of natural sites.
Keith Bowey recalled that in the early 1970s in County Durham a pair nested on the side of a horizontal branch on a large Beech tree on the outskirts of Sunderland. There were also claimed to be instances of cliff sites near Marsden being used but no details, dates or circumstances appeared to be available.
Also in the 1970s, Martin Davison found Swallows nesting near the entrance to a sea cave north of Oban on the west coast of Scotland. Shag and Rock Dove were nesting further inside.
Angela Turner has speculated that the very high population on Holy Island in 2014 may have forced this pair to resort to using a natural site. The nest was about 250m from the nearest more normal site, the wooden hide at the Lough. This year it produced five broods of Swallows and two broods of Pied Wagtails.
As a result of her comments, I searched the rest of the sea banks at Emmanuel Head and also the cliffs at Coves Bay just to the north. There search revealed nothing apart from a very tired Short-eared Owl which may have arrived against strong westerly winds.
It is possible that there was intense competition for nests at the Lough. In early August, I found a brood of four young about ten days old which I had intended to ring dead on the floor under one nest. The nest itself was undamaged, the young had been left intact and two other Swallow broods a few feet away were untouched. All that seemed to rule out a predator. Perhaps this was a case of an aggressive male attempting to take over the nest by evicting the young.
I will certainly be checking the bank site next spring in case these birds return. Finally, following Angela’s thoughts, I wonder if we are missing other Swallows using the many miles of cliffs around Britain, particularly in good breeding years?
I was asked to write a short report on this unusual nest site for the BTO ringers’ blog. This resulted in the additional information that two Swallow nests had been found during 2014 on sea-cliffs in Devon.
House Martins seem much happier than Swallows to use cliff sites. There used to be a thriving colony at Howick, Northumberland, which faded out during the 1990s. However, Mark Holling tells me that there are still small sea-cliff colonies between the border and North Berwick.

References:-

Sharrock, JTR (1976) The Atlas of Breeding Birds of Britain and Ireland. T & AD Poyser.

Gibbons, DW et al (1993) The New Atlas of Breeding Birds of Britain and Ireland 1988-1991. T & AD Poyser

Turner, A (2006) The Barn Swallow. T & AD Poyser.

 

Advertisements