• Bank swallow is one of the smallest swallows, its length is 12–13 cm, but it is larger than the common swallow. Its mass is 11–16 g.
• Male bank swallows loudly call and fluff their head feathers to attract females to the burrow. As the work nears completion, solitary males do this especially actively.

The European sand martin has a short black beak for catching insects, and the young have a short yellow beak with a white spot at the base. The adult’s legs are short and dark, used for walking on the ground and digging burrows. The species' plumage is characterized by brown upper body feathers and a brown stripe on the chest, with a white lower body; the tail has a slight notch. The wings are long and pointed, enabling fast and maneuverable flight. The embryo is protected by a hard white shell.