Nightjars and their allies occupy a special ecological niche of insectivorous birds that hunt during dusk and dawn. Unlike bats and owls, they don't hunt by sonar or sound. Nightjars only use vision. This is why they developed many physiological and morphological adaptations during evolution. Nightjars mainly forage on moths and night active beetles. Because they are not selective on their diet, the composition of their diet is depending on the food that is present. Food availability can vary due to temperature, habitat, season, humidity, etc.

Nightjars have large eyes, and each has a viewing angle of 180°. Whey they open their beak, they can look passed it to catch insects more accurate. The internal structure of the eyes is adapted to. Their retina has a large amount of bars and cones and behind the retina there is a tapetum lucidum. Other adaptations focus on the 'processing' of food. Whiskers on their upper mandible help catching prey. The widened oesophagus helps with storage and canalisation of prey. The feathers of nightjars are soft like owls. This makes gives them the ability to fly silently through the night.

During our research of 2012 we investigated the food availability for Nightjars for the first time. Food availability was measured by a standardized way in multiple biotopes. Also pallets and droppings were collected for further investigation. This part of our research was realized by LIKONA and two students of the University of Hasselt, who completed this project as their bachelor-thesis Biology.