June 7, 2024: The barn swallow (*Hirundo rustica*) is a small migratory songbird with distinctive blue upperparts and a deeply forked tail. They build cup-shaped mud nests in sheltered locations each spring, often near human structures.

The barn swallow (Hirundo rustica) is a small migratory songbird recognized for its distinctive appearance and remarkable nesting behavior. Here are key details about the barn swallow and its nest-building habits:

– Size: About 15-20 cm (6-8 inches) in length, including the tail.
– Coloration: Blue upperparts, a rusty-red throat and forehead, and a creamy underbelly.
– Tail: Deeply forked, which is a key identifying feature.
– Wings: Long and pointed, aiding in agile flight.

Habitat and Distribution
– Habitat: Open country, often near water, and human habitations like barns and bridges.
– Distribution: Widespread across North America, Europe, Asia, and parts of Africa. They migrate between breeding grounds in the Northern Hemisphere and wintering grounds in the Southern Hemisphere.

Nest Building
Each spring, barn swallows engage in the intricate process of building their nests. Here’s how they do it:

1. Location Selection: They prefer sheltered sites, such as the eaves of buildings, inside barns, or under bridges. The chosen site typically offers protection from the elements and predators.

2. Materials Gathering: The primary building material is mud, which the swallows gather from nearby puddles, riverbanks, or other moist areas. They often mix the mud with grass, straw, and feathers to add strength and insulation.

3. Construction Process:
– Foundation: The birds start by making a small mud platform, which they gradually build up by adding more mud pellets.
– Shape Formation: They mold the nest into a cup shape, often using their beaks to press and smooth the mud. This shape provides a secure structure for holding their eggs and chicks.
– Lining: Once the outer shell is complete, the nest is lined with softer materials like feathers and grass to provide a comfortable and insulated environment for the eggs and chicks.

4. Reconstruction and Reuse: While barn swallows typically build new nests each year, they may also repair and reuse old ones if they find them suitable.

Nest Characteristics
– Size: The nest is roughly 4-6 inches in diameter.
– Placement: Nests are usually positioned at least 3-6 feet above the ground, secured to a vertical surface.
– Structure: The cup-shaped nest has a sturdy, mud exterior and a soft, insulated interior.

Breeding and Care
– Egg Laying: The female lays 3-7 eggs, which are incubated for about 14-16 days.
– Chick Rearing: Both parents share the responsibility of feeding and caring for the chicks, which fledge about 18-23 days after hatching.

Barn swallows are highly social birds, often nesting in colonies. Their ability to adapt to human structures and environments has helped them thrive across a wide range of habitats.