A curious thing. I haven’t ever seen it in either species of
rosella that usually use the nest box here. Or elsewhere. Your suggestion fits
in the context of mammals, but as far as I know, no birds use scent marking.
Most birds (a few exceptions) have minimal sense of smell and in those cases it
is related to locating food. You haven’t said whether the birds also use the
usual tactic of displaying at the nest box or active fighting with other birds
in defence. That is something other birds will understand.
Maybe your birds have lice….. Or just a quirk of these 2 birds.
Philip
From: Birding-Aus
[ On Behalf Of Geoff Ryan
Sent: Wednesday, 28 August, 2019 7:06 AM
To:
Subject: [Birding-Aus] Head pressing by Eastern Rosellas
Once again we have Eastern Rosellas nesting in a box next to
our lounge room wall. This year we have again observed a puzzling behavioural
pattern by the nesting couple. The lengthy process of nest selection (we have
two boxes in the backyard) involves much 'head pressing' where the bird presses
its forehead on the box, around the box, around the house walls near the box
and particularly on the awning strut, near the box, where they perch. This
behaviour is mainly done by the male but both are involved. Now they have
started laying the male still head presses when he perches on the strut
awaiting the incubating female to emerge.
In my ignorance I think that this may be some sort of
territorial marking - such as smearing some substance from glands in the skin
of the forehead and by doing so laying claim to the nesting area.
I would appreciate your considered opinions.
