The Collaborative International Dictionary
Laughing \Laugh"ing\, a. & n. from Laugh, v. i. Laughing falcon (Zo["o]l.), a South American hawk ( Herpetotheres cachinnans); -- so called from its notes, which resemble a shrill laugh. Laughing gas (Chem.), hyponitrous oxide, or protoxide of nitrogen Laughing goose (Zo["o]l.), the European white-fronted goose. Laughing gull. (Zo["o]l.)
A common European gull ( Xema ridibundus); -- called also pewit, black cap, red-legged gull, and sea crow.
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An American gull ( Larus atricilla). In summer the head is nearly black, the back slate color, and the five outer primaries black.
Laughing hyena (Zo["o]l.), the spotted hyena. See Hyena.
Laughing jackass (Zo["o]l.), the great brown kingfisher ( Dacelo gigas), of Australia; -- called also giant kingfisher, and gogobera.
Laughing owl (Zo["o]l.), a peculiar owl ( Sceloglaux albifacies) of New Zealand, said to be on the verge of extinction. The name alludes to its notes.
Wiktionary
alt. A South American hawk (''Herpetotheres cachinnans''), so called from its notes, which resemble a shrill laughing. n. A South American hawk (''Herpetotheres cachinnans''), so called from its notes, which resemble a shrill laughing.
Wikipedia
The laughing falcon (Herpetotheres cachinnans), also called the snake hawk (erroneously, since it is not a hawk), is a medium-sized bird of prey in the falcon family ( Falconidae), the only member of the genus Herpetotheres. This Neotropical species is a specialist snake-eater. Its common and scientific names both refer to its distinctive voice.