That was my initial suggestion. Partly because it is a simple
explanation: Got an itchy head? – scratch it. That does not require a complex
thought process. I suggest that the other suggestions all required a complex
thought process of steps of logic as to why the idea might become useful. Sure
they could have been possible if it was a thought out process but only if the
bird was amazingly intelligent and that seemed excessive to me. However if it
was instinctive and beneficial for those reasons, then I would expect all
members of the species, if not genus, if not family, if not order, as well as
many other hole nesting birds to do it.
Head scratching an irritant just makes sense by itself.
Philip
From: Birding-Aus
[ On Behalf Of Geoff Ryan
Sent: Friday, 30 August, 2019 6:26 AM
To:
Subject: [Birding-Aus] Head pressing in Eastern Rosellas
Thanks Mike for doing the HANZAB Vol 5 search. I am now of
the opinion that mite infestation is the most likely explanation for this
peculiar behaviour.
Geoff
Wed 28-Aug-19 7:06 AM
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.
Thanks Geoff
