Janet Baraclough wrote:

snip
I've noticed that cuckoos call cuckoo while perched, but not while
flying.You can hardly ever spot one in a tree and I've never seen
one
on the ground. When they are flying between trees they make a very
different,husky croaking call which sounds roughly like " watchitty
watchitty". If you look then you might see one; quite large and tend
to fly low, short distances only, in a rather stealthy manner.

Dare I risk it?
I'd be chicken not to rise to the bait.
I'll be accused of pontificating again.
(Deep breath)
Cuckoos do have a range of alternative calls. But, early in the
season, the familiar 'cuckoo' is the norm and is uttered ...... both
in flight and at rest.
Depending on which author one refers to, the alternative calls range
from
'a deep wow-wow-wow' through,
'a hoarse coughing whuff-whuff-whuff',
'an explosive bubbling chuckle'
'a long bubbling note',
to 'a mewing note' when eyeing up intended foster parents.
So Janet's 'watchitty-watchitty' is certainly within that spectrum.
But, cuckooing in flight ........ is acknowledged.

Wait for it, wait for it. ;-)

--
ned