What is "singing hawk"

Singing \Sing"ing\, a. & n. from Sing, v. Singing bird. (Zo["o]l.)

1. Popularly, any bird that sings; a song bird.

2. Specifically, any one of the Oscines.

   Singing book, a book containing music for singing; a book of tunes.

   Singing falcon or Singing hawk. (Zo["o]l.) See Chanting falcon, under Chanting.

   Singing fish (Zo["o]l.), a California toadfish ( Porichthys porosissimus), called also midshipman; -- so called because it produces a buzzing sound with its air bladder.

   Singing flame (Acoustics), a flame, as of hydrogen or coal gas, burning within a tube and so adjusted as to set the air within the tube in vibration, causing sound. The apparatus is called also chemical harmonicon.

   Singing master, a man who teaches vocal music.

   Singing school, a school in which persons are instructed in singing.