With the arrival of spring each year we look forward to seeing the birds that will return to us from far away Africa. The first to arrive is the swallow. This is a blue coloured bird with a long forked tail. It will suddenly cross your garden like a blue arrow, on its way to either a cowshed in Long Wittenham or to a broken down barn in the north of Scotland, or, of course, anywhere in between, especially if it had successfully reared young there last year.
Next to arrive is the dark coloured swift with its long sickle shaped wings, which will keep it high in the sky for most of the time. This is a mysterious bird that deserves a story all of its own.
Almost at the same time the small, blue and white house martins will return to their last year’s nests. To carry out any repairs, or to rebuild, they have to settle on the ground to collect mud from the edges of ponds or streams. This they dislike, as their short feathered legs can easily become wet or dirty. This mud dries remarkably hard and can remain so for several years. Feathers are picked up, or caught in the air, to line the nest with. Two to four pure white eggs are laid. They have to be white to be seen by the parent birds in the dark interior of the nest and where, of course, there is no need for camouflage colouring. On hatching, the egg shells split exactly in half and are dropped by the parent birds on to the ground beneath. From this you can know the number of young in the nest.
The two parent birds are now very busy all day, flying with open beaks over the surrounding countryside to collect balls of insects. On their return they spit them into the gaping beaks of the young ones, who appear to be always hungry.
After about three weeks or so it is time for the young martins to leave the nest. This they are very reluctant to do, as the warm, dark interior of their home seems much better than the unknown bright light of the outside world. To combat this, the parent birds fly up with beakfuls of food, but refuse to pass it over. Finally, in desperation, or hunger, the young martins will launch themselves into the unknown.
You can recognise a young martin’s early flight, as it flies somewhat slower than its accompanying parents, though its wingbeats are noticeably quicker. In early autumn, just before migrating to Africa, you may see the martins, young and old, repeatedly swooping up to the nest sites, the young martins following the patch of white feathers on their parents’ backs. This is to imprint on the young ones memories just where the small nest is, up under the dark eaves, and this information will be retained for when, or if, they return next spring.
If this procedure had occurred in spring, before egg laying, it would have meant that a cock house sparrow had got into their nest for a possible take-over. Martins are terrified of house sparrows and will not enter the nest, if they think one is in there.
In autumn the young martins will stay for a week or two after their parents have left. They will come back to roost in late evenings, but they too will join other martins coming through from further north, and in swirling circles will drift slowly south. This is in direct contrast to their quicker and more direct flight of their spring return.
Their migration route takes them across France and Spain, then down the western side of Africa to where, we think, they spend our winter just south of the equator. They do not nest there, but just enjoy the warmth and sunshine of the southern summer before returning, hopefully, to their nest sites here in spring.
Their deserted mud nests make excellent winter roosting quarters for blue tits and jenny wrens. To my knowledge there are three small colonies of house martins in this village - Mackney Lane, The Croft and Sotwell Street.
So look out for these welcome visitors in late April. It just wouldn’t be summer without them.