“No, but I do eat reptiles.”
(Ano koe de tokage kurau ka hototogisu;
“With such a sweet voice, do you devour lizards, o lesser cuckoo?”)
You can’t judge a book by its cover. People and things often have aspects that are not immediately apparent from how they look or are usually seen to act. If the only thing you know about the lesser cuckoo is its much-celebrated song, you may be startled by its predatory diet. This phrase may accordingly feel most appropriate when a benign or pleasing surface appearance hides something more disturbing, but in usage it seems to just as easily apply when something is more pleasant than expected.
The final term of this phrase is the noun 時鳥 (hototogisu), the “lesser cuckoo,” here apparently directly addressed by the speaker. The phrase said to the cuckoo begins with determiner あの (ano), “that,” prefixing the noun 声 (koe), “voice.” This is marked by the particle で (de) technically as the means by which an action is performed, although here technically it marks a quality of the cuckoo that is contrasted with the following action. The cuckoo’s action is the verb 食らう (kurau), “to eat,” sometimes with violent connotations (note that an attack or other unpleasant situation is also something you can 食らう; it’s not always the “eater” doing violence to some other recipient). The object of the verb, unmarked by any particle, is the noun 蜥蜴 (tokage), “lizard,” perhaps especially the Japanese skink. Finally, the space between the phrase and the address is filled by the interrogative particle か (ka).
Careful readers (or really, anybody who’s studied enough Japanese for the final hototogisu to ring a bell) may notice that this is a 5-7-5 beat poetic phrase, i.e. a haiku. It was supposedly an actual response by Edo-era poet 宝井其角 (Takarai Kikaku) to seeing a cuckoo eat.
A similar phrase calls out the carnivory of a pheasant eating a snake: 蛇食ふと聞けばおそろし雉子の声 (hebi kuu to kikeba osoroshi kiji no koe)
In modern orthography, animal types are often expressed in katakana (e.g. tokage would be トカゲ), and hototogisu may be written with various kanji combinations, often 杜鵑, but for purposes of this phrase 蜥蜴 and 時鳥 are considered correct.
(“Ano ojisan, kaotsuki wa kibishishou da kedo, hanashite mireba youki de yasashii hito da. Masa ni ano koe de tokage kurau ka hototogisu da.”)
[“That guy looks really strict, but if you try talking to him it turns out he’s cheerful and very nice. Very much a case of how appearances can be deceiving.”]