Larus atricilla

from The Collaborative International Dictionary of English v.0.48
Laughing \Laugh"ing\, a. & n.
   from {Laugh}, v. i.
   [1913 Webster]

   {Laughing falcon} (Zool.), a South American hawk
      ({Herpetotheres cachinnans}); -- so called from its notes,
      which resemble a shrill laugh.

   {Laughing gas} (Chem.), nitrous oxide, also called
      hyponitrous oxide, or protoxide of nitrogen; -- so called
      from the exhilaration and laughing which it sometimes
      produces when inhaled. It has been much used as an
      anaesthetic agent, though now its use is primarily in
      dentistry

   {Laughing goose} (Zool.), the European white-fronted goose.
      

   {Laughing gull}. (Zool.)
   (a) A common European gull ({Xema ridibundus}); -- called
       also {pewit}, {black cap}, {red-legged gull}, and {sea
       crow}.
   (b) An American gull ({Larus atricilla}). In summer the head
       is nearly black, the back slate color, and the five outer
       primaries black.

   {Laughing hyena} (Zool.), the spotted hyena. See {Hyena}.

   {Laughing jackass} (Zool.), the great brown kingfisher
      ({Dacelo gigas}), of Australia; -- called also {giant
      kingfisher}, and {gogobera}.

   {Laughing owl} (Zool.), a peculiar owl ({Sceloglaux
      albifacies}) of New Zealand, said to be on the verge of
      extinction. The name alludes to its notes.
      [1913 Webster]
    

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