Arguably the most iconic of our summer visitors from Africa, the Swallow is a truly amazing bird and a joy to watch. In the same family as House Martins, Swallows are easy to distinguish from this slightly smaller species by their longer forked tail and lack of white rump – which is an obvious feature in the House Martin. Swallows feed exclusively on flying insects, so the only way to encourage them into gardens is by providing suitable nest sites – e.g. leaving a small access point into a garage or outbuilding where there are dark and cool ledges for them to build a nest on. In addition, a supply of wet mud will give the birds a ready supply of their main nesting material.
Swallow diet and food
Entirely flying insects caught on the wing.
Swallow nesting and breeding habits
The Swallow’s association with mankind is of course very much about the species’ adapting to use manmade structures for nesting. Indeed, thousands of years ago it is likely that the Swallow’s population was much smaller as it was reliant on natural structures – e.g. the entrance to a cave – for nesting. The nest site is typically a ledge or timber beam in a barn, garage or other outbuilding. However, Swallows will sometimes choose the most unlikely site which might, for example, be a ledge in the small porch of a house. Overall though, the Swallow is normally looking to fly into some sort of building, then locate a suitable platform to build its nest on which is out of the way of predators – so often high up in the roof area – and also relatively dark and cool in temperature. The nest is built of wet mud (which then hardens to form a solid structure) and combined with plant materials, then lined with dried grass and feathers. There are two to three broods per season with around 4-5 eggs in each. The female incubates the eggs, though both parents feed the young.
Behaviour traits of Swallows
Swallows are a true joy to watch when feeding, with their effortless manoeuvring seeing them twist and turn over meadows and expanses of water in order to catch flying insects – which is the only food they eat. The Swallows which nest in the UK spend the winter in South Africa, with some flying over the Sahara on their long journey and others taking a slightly longer route around the west coast of Africa. For the birds which choose the former, the flight across the Sahara has progressively become more hazardous with the ever-increasing spread of desertification – and with this even less food to sustain energy levels and virtually no water to drink.
Swallow history and population trends
Although the Swallow has declined in numbers across much of Europe, the UK population is reasonably stable when viewed over many decades. However, the population does fluctuate considerably from year to year, and largely because of weather – too cool and wet and there are less insects to feed to young, and too hot and dry means wet mud can’t always be collected for nest building.