binotonousadj.

/bʌɪˈnɒtənəs/Etymology: < Latin bīnī (see bin- prefix) + tonus, Greek τόνος tone n. + -ous suffix; ? after monotonous.
the world > animals > birds > [adjective] > making a sound > relating to birdsong
1813 G. Montagu at Pettychaps—Lesser During the breeding season their [sc. the Lesser Pettychaps] binotonous cry is incessant.
1847 in J. Craig
This entry has not yet been fully updated (first published 1887; most recently modified version published online March 2021).