Thank you all for your detailed and considered
opinions on this observation.
. initially I did think the birds were probably listening
for what dangers (reptilian, mammalian or avian) may be
laying inside the nest box. However, I began to doubt this
theory when I noticed how frequently the male head pressed
the awning strut where he perches near the nest box.
. I searched through 'Australian Parrots' by Forshaw and
Cooper but could find no reference to such behaviour.
. the nesting pair aggressively defend the nest area by
chasing off, and attacking, other Eastern Rosellas which
venture into our back yard to assess the nesting potential.
They ignore other curious birds including the resident
Kookaburra and Pied Currawongs.
. the rosellas certainly do have mite infestations. After
3 fledglings left the box last year I climbed up to open the
box for inspection and was immediately covered with a swarm
of tiny, biting mites. These parasites obviously breed up
during incubation. They were not obvious after only 1
fledgling left the box the previous year.
If I can get some useful photographs of this behaviour I
will attach them to a future email.