For some weeks now swallows have been gathering, in small groups, on the power lines near the river at Hardy Farm. Presumably they are getting ready for their long migration to Africa. I don't know very much about swallows or about their migrations. FoCM Treasurer, John Agar is a keen birdwatcher and offered to pull together some information on these subjects; below are his findings:
The Swallow (Hirundo rustica)
This instantly recognisable bird is regarded as the harbinger of summer. The arrival from winter quarters is generally early April but the vanguard may appear in early March often caught out by unexpected snowfall.
The favoured nest site is inside buildings. It builds an open nest of mud, cemented by saliva and strengthened with plant stalks and straw. The female lines the nest with feathers before laying eggs (4-5) which she incubates alone, between 14 and 16 days being fed mainly by the male. The young birds leave the nest after 19 – 23 days and are fed by their parents for a while. Two –three broods may be reared during the summer.
In late September and early October the birds form up in large groups ready for their return journey to South Africa. Unlike many other migrants they do not put on large reserves of fat since they feed during their leisurely return flight. They move Southward through Britain and across the Channel at its narrow eastern end. They continue South Westward through France and the Iberian Peninsula and across the Mediterranean. This 2000 Kilometre
(1,200 Miles) journey is completed in about 6 weeks and is thought to be made up of 10 legs i.e. 120 Kilometre a day, each of which forms just part of the birds day.
The birds are then presented with (as are many other migrant species) their most formidable barrier, the Sahara Desert. Many birds perish, however a bird with good food reserves and in good condition can cross the 1,500 Kilometre (930 miles) in a couple of days to reach the rich feeding grounds of the Niger River. Having reached this point the birds are only half way through their journey. Having negotiated this most difficult part of the journey they still face danger from predation by, amongst others, tribes-people who trap them for food. However by mid to late November they will be feeding right down on the Cape of Good Hope.
It is amazing to think that the chick from this tiny fragile egg can, with luck, in 4 – 5 months time be 9,000 Kilometres (6,000 miles) away in South Africa especially as it has never made the journey before.
The return journey in spring is much faster and can take as little as five weeks and is made more to the East. It is only in the last 60 years or so with the advent of bird ringing that accurate details of migration have become known. It was thought that Swallows hibernated in the mud of ponds probably due to their habit of gathering in large numbers in trees and reeds surrounding ponds prior to migration. Indeed it was suggested in 1703 that the birds wintered on the moon!
This instantly recognisable bird is regarded as the harbinger of summer. The arrival from winter quarters is generally early April but the vanguard may appear in early March often caught out by unexpected snowfall.
The favoured nest site is inside buildings. It builds an open nest of mud, cemented by saliva and strengthened with plant stalks and straw. The female lines the nest with feathers before laying eggs (4-5) which she incubates alone, between 14 and 16 days being fed mainly by the male. The young birds leave the nest after 19 – 23 days and are fed by their parents for a while. Two –three broods may be reared during the summer.
In late September and early October the birds form up in large groups ready for their return journey to South Africa. Unlike many other migrants they do not put on large reserves of fat since they feed during their leisurely return flight. They move Southward through Britain and across the Channel at its narrow eastern end. They continue South Westward through France and the Iberian Peninsula and across the Mediterranean. This 2000 Kilometre
(1,200 Miles) journey is completed in about 6 weeks and is thought to be made up of 10 legs i.e. 120 Kilometre a day, each of which forms just part of the birds day.
The birds are then presented with (as are many other migrant species) their most formidable barrier, the Sahara Desert. Many birds perish, however a bird with good food reserves and in good condition can cross the 1,500 Kilometre (930 miles) in a couple of days to reach the rich feeding grounds of the Niger River. Having reached this point the birds are only half way through their journey. Having negotiated this most difficult part of the journey they still face danger from predation by, amongst others, tribes-people who trap them for food. However by mid to late November they will be feeding right down on the Cape of Good Hope.
It is amazing to think that the chick from this tiny fragile egg can, with luck, in 4 – 5 months time be 9,000 Kilometres (6,000 miles) away in South Africa especially as it has never made the journey before.
The return journey in spring is much faster and can take as little as five weeks and is made more to the East. It is only in the last 60 years or so with the advent of bird ringing that accurate details of migration have become known. It was thought that Swallows hibernated in the mud of ponds probably due to their habit of gathering in large numbers in trees and reeds surrounding ponds prior to migration. Indeed it was suggested in 1703 that the birds wintered on the moon!
John Agar, 31st August 2009
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