(This is a summary of the talk given at the Annual Meeting)
This has been the second year of my study of swallows in the villages of Alfrick, Suckley and Leigh. Once again I am grateful for the help received from residents, who have had swallows in their buildings. Out of the thirty three adults ringed last year, only thirteen came back to breed in our villages, six of which were female. Two exceptional birds, not only returned, but paired up again, and nested in the same place at Stitchings Hill. Here they reared two broods, quite an achievement after flying to South Africa and back.
Of the other returning birds, some moved sites, but never very far. One pair from Patches Farm split up to form new partnerships, setting up homes at Bridges Stone and Luckolds Farm. The remainder all came back to the original sites and found new partners.
One surprise was the non appearance of any of the youngsters that were also ringed. This is a previously documented fact on young swallows, where only around twenty percent seem to make it back to Britain. Adults do much better, probably because after one migration, they are more experienced at avoiding the hazards en-route.
During 1999, new nests have come to light, and more adults were recorded. By early September forty two had been ringed and another thirteen re-caught, one of which was a controlled bird, that was first ringed as a youngster in 1998, near Telford, in Shropshire. This male took up residence at Brockamin, where altogether eight pairs nested, and hopefully he will make this farm his permanent residence.
Most pairs bred singly, only six sites out of twenty one had known multiple nests. The largest concentration was centred on Alfrick Church, where there are eleven sites within a 1.5 kilometre radius, and holds over fifty percent of the study birds. It is generally thought that because swallows return regularly to the same sites, some of which are quite well hidden, such as a small opening into a garage or stable, that they must be the same ones that nested the previous year. This is sometimes not the case, and these sites are found by prospecting birds, who on finding an old nest present, and no other occupants, take it over and do up this old nest.
Previous research has found that these well constructed cups of mud, may last for many years. The average life of a nest was discovered to be around seven years, but one was found to have been in use for forty-eight years. The lining often contains feathers, usually white, and from poultry. Experiments using coloured feathers placed into the cup, found them discarded in favour of the white ones. Around twenty to forty have been counted in most nests and they are quite important as an insulating layer to help in the incubation of the eggs.
From regular visits to these nests, and noting how many chicks are reared, it is easy to work out how productive this summer has been. Data from twenty-six pairs showed that overall this was 5.5 young each. Another researcher in Scotland arrived at a figure there of 5.4 chicks per pair, but these were mainly from single broods. One other comparison was the percentages of returning adult birds from the previous year. In Scotland it was only 29%, and here somewhat higher at 39%. Further study is needed to see how constant these figures are.
Clutch size is another way of monitoring success. From thirty-six broods, where the number of eggs were noted, an overall clutch size of 4.17 eggs was calculated. If first and second clutches are separated, the figures are 4.44, and lower at 3.89 for second nests. In Scotland this year, where only one brood is the norm, a figure of 4.66 was produced. The weather here can be much more inclement than the south, and daylight hours although longer during summer months, rapidly shorten after August, making feeding that bit harder.
Predation of nests was low, with no indication of the main causes. At one site the inner lining of the nest was found hanging out, at others youngsters were found dead on the floor, even though some house holders had tried to put them back. No logical explanation seems possible to explain this phenomena, unless it is done by the swallows themselves. Using DNA testing it has also been discovered, that not all male swallows are the fathers of their offspring!
It has also been observed that unattached males will also try to split another pair up, a female being more ready to take on a new partner if her first nest fails. Eggs also disappeared from some nests, most probably rodents, but most pairs laid again, and reared young. Only at two nests did complete desertion of the site occur after first broods, but at Brockamin, one bird found a new mate, and moved about half a kilometre to another site. There must have been a split up of the original pair at the new site too, since this was a second brood.
At another nest site, after the first brood had flown, the pair were caught again, the male of which was the original owner, but it was with a different female. My curiosity made me investigate this second pair again, and to my surprise, the successful second brood had yet another new female in residence, showing once more that there must be quite a few movements of these birds, that go undetected, unless they are identifiable in some way such as a ring. If these ringed birds are found elsewhere, it does give the finder, the opportunity of discovering where the bird originated, as the ring itself has” The British Museum, London”, stamped on it.
Only one of the study birds has so far been recovered by someone else. This was a youngster from Luckolds Farm in Alfrick, ringed on 12th June 1999, when it was around half grown, so it probably did not leave the nest site, until another ten days later. It was then found on the 10th July, only two to three weeks after fledging, at Hatfield, between Bromyard and Leominster, weak but alive. What was it doing over to the west, instead of a southerly direction? The eighteen kilometres it flew were nothing to the distances they pursue in the autumn. A flight to Hatfield and back in a day is no distance and could be just for feeding purposes.
This study over the next few years should hopefully throw up yet more surprises, besides giving valuable data on the survival of the swallow, which is held dear to many country people.
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