the crow of a male pheasant
雊 centers on the distinctive call of a male pheasant: its crowing sound. The meaning is narrow and specific to that bird's vocalization.
雊 combines 句 (a bent shape, also associated with sound or phrase) and 隹 (a short-tailed bird). The character likely expresses the idea of a bird's call, specifically a pheasant's crow.
On the left, 句 suggests a phrase or sound; on the right, 隹 is a bird. Picture a male pheasant opening its beak to let out a loud crow: 句 (sound) + 隹 (bird) = the crow of a male pheasant.
For コウ, imagine the pheasant's crow echoing like a deep 'coo' sound: coo -> コウ, the call of the male pheasant.