Animal Cry
Animal Sound, Animal Noise, Chirp, Tweet, Roar, Bark, Meow
noun
The chirp voice is a sound an animal makes. Sure, it works for birds (which chirp), but it also works with most other animals as well. So, we call this an animal cry.
なきごえ
The readings are those that you learned with the kanji. 声 gets changed to ごえ, though, so take note of that in your head. Perhaps you can imagine an animal that does a "GOEEEEE" cry.
きりんの鳴き声を聞いたことがありますか。
Have you ever heard what a giraffe sounds like?
外からコウイチの声が聞こえると思ったら、小鳥の鳴き声だった。
I thought I heard Koichi outside, but it was a little bird's chirps.
自動販売機の下から子犬の鳴き声が聞こえるんです。
I hear a puppy barking under the vending machine.