Origin of nightjarnight + jar: from the whirring noise made by the male
any of a family (Caprimulgidae) of goatsuckers; esp., the common European nightjar (Caprimulgus europaeus)
Any of various chiefly nocturnal, insectivorous birds of the family Caprimulgidae, especially those in the genus Caprimulgus. Also called goatsucker .
Origin of nightjarnight jar 2 ( from their harsh calls )