this is the lyrics that we use in school. :)

my pigeon house
i open wide
and i set all my pigeons free
they fly all around
way up, way down
and they sit on the tallest tree
and when they return
from their merry merry flight
they shut their eyes and say goodnight
Coocooroo coocooroo coocooroo
coocooroo coocooroo coocooroo
cooroo...