We have many Least Bittern at Reserva Don Luis and they can be heard calling early morning or early evening from their preferred habitat of water and rushes. They are very shy and will rarely fly instead preferring to forage at the bottom of the reeds. If disturbed they will sometimes fly or will stand completely still with their head and bill erect to blend in with the reeds. They seem able to lengthen and narrow their body shape in response to disturbance.
They are members of family Ardeidae with the other herons and are similar to the Stripe-backed Bittern. They are one of the smallest herons in the world at 25cm but are good hunters as their low body weight allows them to climb through the reeds undetected. They prey on small amphibians, small fish and insects.
One is most likely to see its underparts which are white with light brown streaks. Its face is brown with a dark crown There is a large dark patch on the back which is black in males and dark brown in females. The bill is long and pointed and varies in colour but is usually yellow with green tinges. The legs and feet are yellow and the eyes are yellow although they can appear to have a blue tinge sometimes.
Male Least Bittern