oh! i am disappointed! the 杜鹃 and the 布谷鸟 are not different birds at all! 布谷鸟 being the common name, clearly onomatopoeic (the bird's call is bu gu, bu gu - you guessed it, it's the cuckoo. and no, cindy, that's not you it's calling. we have not forgotten you and the owl.) the 杜鹃, cuculus poliocephalus poliocephalus, is well-known for laying its egg in other birds' nests. in fact there's even a riddle in the exeter book that is about this very business.

Mec on þissum dagum deadne ofgeafu
fæder ond modor; ne wæs me feorh þa gen,
ealdor in innan. Þa mec an ongon,
welhold mege, wedum þeccan,
heold ond freoþode, hleosceorpe wrah
swa arlice swa hire agen bearn,
oþþæt ic under sceate, swa min gesceapu wæron,
ungesibbum wearð eacen gæste.
Mec seo friþe mæg fedde siþþan,
oþþæt ic aweox, widdor meahte
siþas asettan. Heo hæfde swæsra þy læs
suna ond dohtra, þy heo swa dyde.

a loose and poetic translation from craig williamson:

I was an orphan before I was born
Cast without breath by both parents
Into a world of brittle death, I found
The comfort of kin in a mother not mine.
She wrapped and robed my subtle skin,
Brooding warm in her guardian gown,
Cherished a changeling as if close kin
In a nest of strange siblings. This
Mother-care quickened my spirit, my natural
Fate to feed, fatten, and grow great,
Gorged on love. Bating a fledgling
Brood, I cast off mother-kin, lifting
Windward wings for the wide road.

the ancient chinese were well-aware of this characteristic of the cuckoo, so it is hard to reconcile their knowledge with the legend simultaenously held that the 布谷鸟 is the incarnation of a murdered prince 杜宇, whose call is a plaint and a warning. there isn't a corresponding legend in england, but the cuckoo does feature affectively in old english poetry, whose mournful calls are heard in the elegies seafarer and the husband's message. at least those are the ones i can remember. probably there are many more.