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Delichon

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The genus *Delichon* consists of four species of small birds known as house martins. These birds are part of the swallow family, specifically the Hirundininae subfamily. This group includes all swallows and martins except for the river martins.

Mehlschwalbe Delichon urbicum
Mehlschwalbe Delichon urbicum

House martins are highly specialized aerial hunters. They are known for their unique physical traits and their ability to build complex nests. They play an important role in their ecosystems by controlling insect populations.

DelichonUrbicaFBI
DelichonUrbicaFBI

Physically, these birds are described as chunky with "bull-headed" appearances and short tails. They possess dark, blackish-blue feathers on their upper bodies. This contrasts with a bright white rump, which is the patch of feathers above the tail. Their underparts are either white or grey.

Delichon urbicum lagopodum 1894 (cropped)
Delichon urbicum lagopodum 1894 (cropped)

A key identifying feature of the *Delichon* genus is the presence of feathers on their toes and tarsi. This distinguishes them from many other swallow species. Their size varies by species, with the common house martin being the largest at 18.3 grams. In contrast, the Nepal house martin is the smallest, weighing approximately 15 grams.

One of the most fascinating aspects of house martins is their nesting behavior. They are classified as "mud nest builders." This means they construct closed mud bowls to house their young.

Delichon dasypus -Hokkaido -Japan -collecting nest material-8b
Delichon dasypus -Hokkaido -Japan -collecting nest material-8b

Scientists believe this nesting style evolved to reduce competition between males. Because mating occurs inside the nest, the narrow entrance makes it difficult for other males to enter. This allows the birds to live in dense breeding colonies. Both parents participate in building the nest, which they line with grass or feathers. After laying a clutch of two to four white eggs, both parents help incubate them. The female typically handles most of the incubation, which lasts between 14 and 16 days.

Delichonurbicaegg
Delichonurbicaegg

The genus is divided into four distinct species with different habitats and behaviors. The common house martin is a widespread migrant that breeds across Europe and northern Asia. It often winters in sub-Saharan Africa. The Siberian house martin, which was split from the common house martin in 2021, breeds in northeast Asia. The Asian house martin prefers mountainous regions or sea cliffs. Finally, the Nepal house martin is a resident species that stays in the Himalayas year-round.

Delichon dasypus -Taiwan-8-4c
Delichon dasypus -Taiwan-8-4c

While most species migrate, the Nepal house martin does not need to travel for warmth.

History shows how our understanding of these birds has changed through scientific study. The genus *Delichon* was established in 1854 by American naturalist Thomas Horsfield and British entomologist Frederic Moore. They created the name to accommodate the Nepal house martin. Interestingly, the name "Delichon" is an anagram of the Ancient Greek word *chelidôn*, which means swallow.

Delichon urbicum lagopodum 1894 (cropped)
Delichon urbicum lagopodum 1894 (cropped)

Over time, researchers have used DNA studies to refine how these birds are classified. For example, genetic evidence shows that the common and Asian house martins are closely related, even though they breed in different areas. These studies help scientists understand the evolutionary links between different types of mud-nesting swallows.

House martins are highly skilled at catching insects while flying. They primarily hunt for small prey like flies, aphids, and winged ants. They also eat beetles, lacewings, and other small insects.

Mehlschwalbe Delichon urbicum
Mehlschwalbe Delichon urbicum

By feeding higher in the air than other swallows, they avoid direct competition for food. This specialized feeding niche allows them to coexist with species like the barn swallow. However, they are not without danger. Fast-flying birds of prey, such as the hobby, are known to hunt them.

Falco subbuteo kobuz2
Falco subbuteo kobuz2

They are also most vulnerable to predators when they descend to the ground to collect mud for their nests.

In recent years, house martin populations have faced several challenges. In parts of central and northern Europe, numbers of the common house martin have declined. This decline is linked to several environmental factors. Poor weather patterns and the use of agricultural pesticides can harm their populations. Additionally, a lack of available mud for nest building can prevent them from breeding successfully. They also face competition from house sparrows, which often attempt to take over nest sites. Despite these pressures, none of the four *Delichon* species are currently considered threatened.

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🖼️ Images & Media (8)
File:Mehlschwalbe Delichon urbicum.jpg
Mehlschwalbe Delichon urbicum.jpg
File:Delichon urbicum lagopodum 1894 (cropped).jpg
Delichon urbicum lagopodum 1894 (cropped).jpg
File:Delichon dasypus -Taiwan-8-4c.jpg
Delichon dasypus -Taiwan-8-4c.jpg
File:Delichon nipalense (close-up).jpg
Delichon nipalense (close-up).jpg
File:DelichonUrbicaFBI.jpg
DelichonUrbicaFBI.jpg
File:Delichon dasypus -Hokkaido -Japan -collecting nest material-8b.jpg
Delichon dasypus -Hokkaido -Japan...
File:Delichonurbicaegg.png
Delichonurbicaegg.png
File:Falco subbuteo kobuz2.jpg
Falco subbuteo kobuz2.jpg
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