Yellow-billed Cuckoos lurk through all levels of the forest in search of caterpillars.  Cornell Labs description of sound:    Male Yellow-Billed Cuckoos make a distinctive series of hollow, wooden-sounding ka-ka-ka-ka-ka-kow-kow-kowlp-kowlp-kowlp-kowlp syllables. The whole series is quite slow and gets slower toward the end; calls can last up to about 8 seconds. . I could not find a good video with the bird calling.  Click on the button to hear the bird.