Did you know... House Martin

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Wednesday, 11 November 2009 09:04

Did you know... House Martin

These short profile articles called „Did you know…“ should not only serve for presentation of some of my bird pictures but also as an ID card of each individual bird with basic facts about the described species as well as some interesting information that you maybe did not know…I do not say that I know these facts better but internet is a powerful tool of today and it is sometimes worth just to enter the name of the bird into the search engine and read through the found articles. It is also kind of ornithology class for me as I am still rather a birding beginner.

The very first species we have a look at closely is the House Martin (Delichon urbica) and it is simply because this bird came across my way during one late summer day. After one of my numerous morning birding trips around the village I live in and which was rather poor photography-wise but quite interesting birding-wise, I met these birds when entering the gate of our house. They were swirling above my head and some of them were sitting on the high voltage wires. My poor knowledge of birds allowed me just to recognize that the bird I was looking at was not the common Barn Swallow (Hirundo ructica) but one of the other two species from the Hirudinidae Family that can be seen in our country i.e. either the House Martin (Delichon urbica) or the Sand Martin (Riparia riparia). In my case I was looking at the flock of House Martins (Delichon urbica) that can be distinguished from the other „swallows“ by the presence of white rump and on top of that the Barn Swallow has also more incised tail compared to House Martin. When looking at the nests, House Martins in most cases build their nests outside of buildings below the roof ledges, which is the remainder of their former habitats on rocks. The nest is ball-like structure made of dried mud and littered with feathers and grass-blades inside with small circle entrance in the top part of the nest. House Martins often nest in larger colonies where the nests are so tightly arranged that the wall of one nest can support or even be a part of the neighboring nest. Unlike House Martin, the Barn Swallows build their nests inside the buildings and the nests have a shape of open shallow bowl with wide entrance. Sand Martins prefers more natural habitats and hollow the burrows in steep clayey or sandy flanks.

Some interesting facts

During migration the House Martin can fly as long as more than 200 km in a single day and among the passerines one of the swallows is even a record-holder - the American Purple Martin (Progne subis) was recorded to had flown over 800 km in a single day during the Spring return to the nesting area! Our European House Martin migrates during the daytime and that is because these birds hunts for insects. Otherwise the long-traveling birds usually migrate during the nighttime. Also the birds migrating only within the realm of Europe usually fly during day.

To build a nest House Martins use a mud, which means that dry spring can cause troubles and the birds can be delayed with the nest building. To make their spring return even more difficult the House Sparrows sometimes takes over the House Martins´ nests. As the Martins usually lose the „fight“ for the nest with Sparrows, their only effective defense is to build the nest entrance so small that it is too tight for Sparrows to get in.

Compared to Barn Swallows that hunt insect low above the ground, House Martins hunt insect in higher levels – the average height of hunting is 21 m above the ground but they can hunt so high that we can hardly see them with a naked eye – out of the breeding season the hunting level is usually more than 50 m above the ground. During the breeding season the feeding area usually does not exceed 450 meters from the nest. During bad weather conditions they hunt low above the ground and above the water surface. The usual prey encompasses flies, aphides and ants.

The European population of House Martin is estimated to be 20 – 48 million individuals (another source says 60 – 300 million); population in Czech republic is estimated to be ca. 600 000 – 1 200 000 pairs of House Martins.

Eurasian Hobby (Falco subbuteo) is the main threat for House Martins and because these passerines are most vulnerable when collecting the mud for building nests, they always do this activity in a group to have better control on what happens in the air above. Thanks to its great aerial skills House Martin are in most cases able to evade most of the air predators.

The average length of the life is up to 5 years for House Martins but there are records of birds aged 10 and 14 years.

During the flight the House Martins beat the wings at the average rate of 5.3 beats/second, which is slightly faster than Swallows (4.4 beats/second)

During migration in 1974 several hundred thousand House Martins have been found died or dying in Swiss Alps and the surrounding areas – these birds have been caught by severe weather with low temperature and heavy snowstorms.

At the beginning of the breeding season the weather condition at the breeding grounds can still be quite severe – to survive, House Martins must herd. In one case altogether 14 birds have been found sheltering in a single old nest.

House Martins are sometimes attracted by hot-air balloons – they swirl just above the balloons and probably use the hot air as a kind of elevator to get a lift as in a thermal.

Sometimes House Martins choose unusual places for nesting – one nest have been found on the ferry crossing 22 km distance eight times a day between Danish Copenhagen and Swedish Malmo. Similarly several nests were found on a local ferry in Denmark – the ferry was operating across 13 km long passage and the round trip took 2 hours. The adult birds visited the nests only at the terminals when the ferry opened the gates.

Basic facts

Order: Passeriformes

Family: Hirundinidae

Genus and Species: Delichon urbica

Body length: 12 - 13 cm

Wings span: 26 – 29 cm

Weight: ca. 18.3 g

Nesting: Usually twice in a season – in May and August the female lays 4-5 white eggs brooded by both parents for another 14 – 16 days until the young are hatched. Both parent feed the chicks for another 22 – 32 days when the birds leave the nest. The young birds from the first brood are known to feed the second nestlings. The nesting is successful in ca 90% and 60 – 80% of young birds lives to their maturity.

Migration: Autumn migration to South during September to the wintering grounds in Africa and spring return to the breeding grounds in the second half of April.