Examples from the Web for chook
A softer, more musical rendition is given when the birds are well bunched and feeding, which came to my ear as "chook."Life Histories of North American Shore Birds, Part 1 (of 2)|Arthur Cleveland Bent
Achun well knows all this, and he has determined to have Chook Aloong displaced.The Truth about Opium|William H. Brereton
A great blackbird flew out with a loud “chook, chook,” and the red of the haw on his yellow bill.
A great blackbird flew out with a loud "chook, chook," and the red of the haw on his yellow bill.