Birds of Marlpit Community Garden August 2016
Groups of swifts have been flying over the Garden lately. These birds are the most aerial of all our birds, never intentionally alighting on the ground, feeding on flying insects, they do nearly everything on the wing, even mating! They sleep on the wing, circling higher and higher into the sky in the evening and dozing for a few seconds at a time as they glide along through the night.
The only thing they cannot do on the wing is
nest! They collect feathers and straws in the air and glue them together with their saliva to make their nests, which are nearly always in human structures such as under the eaves of houses and in church towers. This is causing a few problems now as we block up the eaves of older houses and new ones are built without suitable nest sites. It is possible to buy special nest boxes for swifts to counter this. The young can remain in the nest for anything between 37 and 56 days, and are able to catch their own food as soon as they leave the nest, as it would be extremely difficult for the adults to feed them whilst both are flying. They don’t breed until four years old, and during this time they will fly continuously, never alighting anywhere.
Their feet are unusual for birds, with all four toes pointing forwards, adapted to clinging to vertical surfaces such as house walls, since they never land on the ground or perch on the branches of trees.
Swifts are only summer visitors to Britain, as it is only during summer that there are enough flying insects here to sustain them. They arrive in May and depart in August, migrating south quickly and arriving in their wintering quarters in Africa by mid-August.
Other birds which are seen over the Garden and which look superficially similar to swifts as they also feed on flying insects are swallows and house martins. They can be easily distinguished however. Whilst swifts look uniformly dark from a distance (though if seen close up it can be seen they have a white chin), swallows have creamy white underparts and upper parts of a beautiful iridescent blue, with red faces. They have long tail streamers, rather than the short forked tail of swifts (the streamers are longer in males than females, and shorter in juveniles). Swifts have curved scimitar shaped wings, and fly with rapid wing beats interspersed with glides. Their wings are longer and their bodies shorter than swallows, and their flight is faster.
Swallows are mainly birds of farmland, and a few are often present in the Garden. They usually nest in buildings such as barns, making nests of mud lined with feathers and grass. Like swifts, they are summer visitors wintering in Africa, but arrive earlier, in April, and leave later, in October.
Closely related to swallows are house martins. Like swallows and swifts, they also nest almost exclusively on human habitations (though occasionally on natural cliffs), with house martins making round nests under the eaves of buildings out of mud. Although it is illegal, many of these nests are removed by householders because the birds leave a mess of droppings beneath them. They usually nest in colonies with several nests close together.
House martins are shorter than swallows, with short forked tails and a more fluttery flight. Like swallows they have dark blue upper parts, but they have prominent white rumps which enable them to be easily distinguished.#
They also winter in Africa, although their exact wintering quarters are unknown. They breed over a long period, with some having young in the nest in October. In Britain the population has fallen by 44% in the last 25 years.Chris Keene