They are rarely seen during the day. As darkness falls, they come out of their nests, make a repetitious call which sounds like knocking on wood, flap their wings and try to catch insects.
One may mistake the bird for dried leaves as it nests and rests on the ground, amid fallen leaves.
They are the large-tailed nightjars.
Previously, they could be easily found in large numbers at Lawachhara National Forest in Moulvibazar's Kamalganj. However, logging has caused a serious habitat loss to this bird.
Talking to The Daily Star, Bangladesh Bird Club founder and renowned bird researcher Enam Ul Haque said large-tailed nightjar is a nocturnal bird. Its scientific name is Caprimulgus macrurus.
The bird is around 33 centimetres in length, dark brown in colour. They have long slender wings, long tails, short legs and short bills. Nightjars spend most of the day sleeping on the ground, in dried leaves. They lay two eggs between March and May, he said.
The bird feeds predominantly on moths. There are 17,000 species of butterflies and 1.3 lakh species of moths in the world. But their number is fast dwindling, causing a food crisis for large-tailed nightjars, Enam said.
Ten years ago, he said, this bird species could be easily found in Lawachhara forest. “In the evening, we frequently heard the calls of nightjars. But they are rarely seen now.”
Other birds of the large-tailed nightjar family are great eared nightjar, grey nightjar, Indian nightjar and savanna nightjar. Very few large-tailed nightjars and grey nightjars are seen in the country.
Tabibur Rahman, assistant conservator of wildlife management and nature conservation department in Moulvibazar, said deforestation was the main reason behind the food shortage of wildlife in Lawachhara.
Joly Paul, president of Lawachhara Bon O Jibo Boichitro Rokha Andolon, echoed Tabibur.
Nurul Mohmain Milton, general secretary of Environmentalist Journalist Forum, said the authorities concerned should stop deforestation in the forest and protect wildlife like large-tailed nightjar.