House martin: the bird profiles

Want to attracts house martins to your garden? Can you tell a house martin from a barn swallow? Here’s everything you should know about the house martin.

House martins (Delichon urbica / Delichon urbicum) are one our most common swallow species. In summer, you should be able to spot them in residential areas, nesting in the eaves of buildings. With typical, swallow-like manoeuvres, they tend to dart through the skies in search of food, performing entrancing acrobatics above bodies of water. Read on to find out more about this wonderful species.

House martin: key facts

How to recognise the house martin

You are most likely to spot a house martin in flight, showing off its pointed wings and forked tail–typical swallow characteristics. What is more, in flight, the house martin’s bright white, monochromatic underside will starkly contrast to its shining blue-black body.

How to tell the difference between male and female house martins

It is very difficult to distinguish between male and female house martins. The only notable difference is the colour of the throat. A female’s throat is dirty-white, whilst a male’s is pure white. Unfortunately, this is difficult to spot for the untrained eye, and impossible, even for experts, if the bird is in flight.

How to recognise a young house martin

Young house martins are the spitting image of their parents, so you should be able to spot their white bellies and darker bodies from an early age. Be aware, though, that unlike their parents’ metallic blue plumage, a young house martin’s feathers are dark and dull. In addition to this, a young house martin’s stomach is somewhat dirty, and its throat is darker than an adult’s.

How to recognise a house martin egg

House martins lay between three and five eggs per brood, each about 2cm in size and pure white. Females lay the eggs in an enclosed nest, built of clay, which is attached to a building. The inside of the nest is padded with fine blades of grass and feathers.

How to tell the difference between house martins and barn swallows

Barn swallows are another common swallow, often in close proximity to house martins. In fact, the two sometimes hunt insects together. But don’t worry: they are easy to distinguish. Barn swallows have dark throats, brown-red faces, and their underbellies are far from white. Further, a barn swallow’s tail is long and thin, where the house martin’s forked tail is short and stubby.

Note: At long distances, you may be able to spot a difference in their altitudes. House martins hunt insects at about 20 metres, while barn swallows usually only climb to seven or eight metres. However, this is not iron clad, and there is a chance the house martin will try his luck at lower heights.

What is the perfect habitat for house martins?

House martins are very flexible home makers, found in mountains as well as city centres, they are happy in many open and semi-open habitats. Most important for the house martin, is an abundant supply of insects, so they prefer to be near water. They also make a point of looking for suitable nesting sites, which are often found on the eaves of buildings or on cliff faces.

Where do house martins build their nests?

Be it against natural rock, on the eaves of buildings, or under a concrete bridge or balcony, house martins always build their nests on overhangs. The nests are made of clay, and are hemispherical with a small entrance hole. Old nests are often reused both by swallows and other cave nesters such as house sparrows or tits.

House martins like to breed in colonies, so it is likely that several of their nests will be built next to one another.

When is breeding season for house martins?

House martins breed between April and September. The mother and father incubate the egg alternately for 14 to 16 days. After hatching, young house martins are fed lots of flying insects by both parents until they are large enough to leave the nest, which can take up to 30 days. The chicks will take their first flights near the nest, and, in these first weeks, are supported with food by their parents. Soon enough though, these young squabs will be on their own, as house martins often breed twice within a single season.

Where do house martins spend winter?

House martins are only found in the UK during breeding season. Since, they are dependent on flying insects, they would starve to death in the UK over winter. As such, late in the year, they migrate to the rain forests of Africa, south of the Sahara.

What does a house martin’s song sound like?

The house martin’s song is not particularly melodic. It consists of an unstructured, chattering and chirping. Although it doesn’t live up to the melody of other songbirds, the song is at least bright and eager. In flight, you might also hear a happy “Prrrriet”.

Help the house martin!

House martins are finding it increasingly difficult to build nests. In fact, they are often driven away so that their nests can be destroyed. If you want to offer the native birds a home, read on for assistance on birdhouses, food and best practices.

What do house martins eat?

House martins feed exclusively on flying insects, so you don’t need to fork out on a bird feeder to please them. Really, all you can do is follow the motto: insect protection is bird protection. Avoid using insecticide sprays and try to buy products that promote sustainable and ecological agriculture. This will help provide a habitat and food for house martins down the line.

If you would like to go one step further, and bring more life to your garden, grow a meadow of native flowers and herbs. It will attract insects and birds alike. To go the extra mile, try planting bird-friendly native shrubs to make your garden as natural as possible.

Which birdhouses are suitable for house martins?

House martins are happy to use birdhouses, but they must be the right type: hemispherical and completely enclosed, aside from a small entrance hole. Essentially, it must be just as they would make in nature. If you find one, try attaching it to the wall of your house or garage, and be sure to clean it once a year to avoid accumulating dirt and parasites. This will increase the birds’ chance of survival. The best time to clean the house is towards the end of winter, just before the swallows return from their migration in April.

Tip: A board to collect faeces underneath the nesting boxes is a must to avoid dirty facades!

How can I support house martins even more?

If you would prefer house martins build their own nest, be sure to have lots of clay soil. Clay is not easy for house martins to find, and can be in short supply, especially during dry spells. A small puddle in the garden will do wonders. And if your soil is sandy, try offering clay soil in a small bowl with some water.

If you have another bowl to hand, setting up a bird bath is a must. On hot summer days, bird baths are loved by all garden birds. Be sure to clean it regularly though, to prevent the spread of infectious disease. On hot days, the risk of pathogens is high, so it is best to clean the bird bath daily during summer.

If you are gripped with bird fever and would like to learn more about garden birds, take a look at our other articles on the yellowhammer and magpie.