Could the answer not be something far more simple? Just based on what is
available. Beruldsen's book just says "lined with feathers". So that would be
normal. These need not have been white (he does not mention that), and probably
just was whatever species or colour was available at that place and time. If
the Sulphur-crested cockatoos are now abundant and obviously white feathers
are, you would think, easy to find (by being big and white), then simply on
that statistical basis they now use a lot of white Sulphur-crested cockatoo
feathers. It would be odd (or at least hard to prove) if more white feathers
stimulates more nesting. Although using a lot of white feathers could easily be
a risk, as it likely would increase visibility of the nest to nest predators.
Philip
-----Original Message-----
From: Birding-Aus On Behalf Of
Julie Neumann via Birding-Aus
Sent: Friday, 9 February, 2018 11:12 AM
To: Birding Aus
Subject: A query about Eastern Spinebills
I am hoping the brains trust out there will help us to answer this. A friend
has been observing Eastern Spinebills in her garden in the lower Blue Mountains
for many years. She posed these question about their nesting habits:
> My observations on eastern spinebills’ nest-feathering has prompted me to ask
> more questions around “which came first :- the feather or the egg?”. When we
> first moved to the mountains in the early 1960’s, Sulphur-crested cockatoos
> were not seen regularly, & certainly not in the large flocks of today.
>
>
>
> the Spinebill nest in our front hedge a few summers ago was completely lined
> with feathers, & more than 90 % of them were white. so I wonder if
> previously the Spinebills may have used other white birds’ feathers (like
> chooks??), or used a different coloured feather for the main nest-lining &
> side-walls. I also wonder if the abundance of available white feathers these
> days has stimulated successful nesting behaviour in Spinebills, & also of
> course if in areas where large white feathers are not available, the
> Spinebills breed at the same rate as the white-feather-nest-liners. Or if
> the whole white-feather-lining is just a localised behaviour, or just
> happened in our front yard once... it would be very interesting to hear any
> other observations, please.
>
>
>
Julie Neumann
0247393063preferred. 0429130679
<HR>
<BR> Birding-Aus mailing list
<BR>
<BR> To change settings or unsubscribe visit:
<BR> http://birding-aus.org/mailman/listinfo/birding-aus_birding-aus.org
</HR>
|
