Is there any evidence of the black-billed and yellow-billed cuckoo hybridizing?
Saw two cuckoos today with Tom Barber at one location in his birding block, one
which sounded like a yellow-billed and had some slight masking behind the eye
but also had a buffy neck like a black-billed. The sighting was brief and the
bird's beak was blocked from view by leaves, so we didn't have the opportunity
to confirm that obvious field mark.