crow is not cuckoo

काकः कृष्णः पिकः कृष्णः को भेदः पिककाकयोः

वसन्तकाले संप्राप्ते काकः काकः पिकः पिकः।

कुवलयानन्दं

kaakaH krishnaH pikaH krishanaH ko bhedaH pikakaakayoH.

vasantha kaaley samprapthey kakah kakah  pikah pikaH

kuvalayaananda 

കാകഃ കൃഷ്ണ: പികഃ കൃഷ്ണ: കോ ഭേദ: പികകാകയോ:

വസന്തകാലേ സംപ്രാപ്തേ കാകഃ കാകഃ പികഃ പികഃ

the crow is black in colour and  so also black is cuckoo.

  when the spring arrives the crow is crow and the cuckoo is cuckoo

till the arrival of spring the birds have not much to sing and they are hardly heard... most of the sound we hear till then will be the crowing of the crow. the crow and the cuckoo are in their infancy strange lookalikes and the mother cuckoo even commits the deceit of laying her eggs in the nest of a mother crow who hatches the baby cuckoo thinking it also as her own offspring. But by the arrival of the spring season the cuckoo baby gains enough strength to fly and she soars in the skies to sing  her heavenly notes.  The poor crow can only make its usual crowing noises... Similarity in form can be deceptive...at the proper time the quality shows.