Sand martin

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Sand martin, also known as the bank swallow in the Americas, is a small migratory bird in the swallow family (Hirundinidae). It’s brown on top, white underneath, with a thin brown band across its chest. It has a black bill and brown legs. Juveniles have lighter rufous tips on their wing feathers.

What it is and where it lives
- A tiny, quick-flying insect eater that migrates long distances.
- In summer, it breeds across a wide area: Europe, Asia, and much of North America (the Holarctic region).
- In winter, it moves to warmer parts of Africa, southern Asia, and South America.

Name and classification
- Scientific name: Riparia riparia.
- The name Riparia comes from Latin for “riverbank,” reflecting its preference for nesting near rivers and streams.
- It was first described by Carl Linnaeus in 1758 as Hirundo riparia (the riverbank name later became Riparia riparia).

Subspecies and range
- There are several subspecies with slightly different ranges:
- Riparia riparia riparia: Europe, western Asia, and parts of North America.
- Riparia riparia taczanowskii: eastern mainland Asia.
- Riparia riparia ijimae: Sakhalin, the Kuril Islands, and Japan.
- Riparia riparia shelleyi (sometimes called eilata): Egypt and southern Israel.
- A related bird once thought to be a subspecies, the pale martin, is now usually treated as a separate species.

How it looks and how big it is
- Size: about 12–13 cm long (4.7–5.1 inches).
- Wingspan: 26.5–29 cm (10.4–11.4 inches).
- Weight: typically 11–16 grams (0.39–0.56 oz), up to about 19.5 g before migration.
- Distinguishing features: brown back, white belly, white throat, brown breast band, black bill. Juveniles have rufous-tipped coverts.

What it eats and how it behaves
- Diet: small flying insects, especially gnats and other flies near water.
- It is highly social, often nesting close together in colonies.
- It nests in tunnels dug into sand or gravel, usually near rivers, lakes, or oceans. The nest is a straw and feather ‘bed’ at the end of a long burrow.
- Lays 4–5 white eggs around mid to late May. A second brood is common in most places.

Breeding, migration, and habitat
- Sand martins typically arrive at breeding sites in spring, with Britain’s birds appearing around mid-March and those in parts of the U.S. and Canada arriving by April.
- They spend much of the season near large bodies of water, then move south or to lower latitudes as autumn approaches.
- In some regions, arrival and departure times have shifted earlier in recent decades due to climate changes.
- They nest in loose colonies and may roost in large flocks at night during migration.

Conservation and status
- The species is currently listed as Least Concern by the IUCN, though some local populations have declined because of habitat loss and other pressures.
- In Canada, certain populations are considered Threatened because of large population losses in the past.
- Locally in places like California, some populations are also threatened.

Fun facts
- The sand martin is one of the first swallows to return to northern breeding grounds each spring.
- It shares mixed colonies with related species but usually does not interbreed with them.

In summary, the sand martin is a small, agile swallow that nests in sandy banks near water, travels long distances between breeding and wintering grounds, and feeds on tiny flying insects. Its wide distribution means it can be seen in many regions during summer and winter.