Hello Canberra birdos,
We are doing some research here at the Uni of Queensland on satin
bowerbird painting. We've noticed that they use their bills to do
the actual painting rather than using a "paintbrush". Immediately
before they paint their bower walls, they often chew up plant
material which we are guessing increases the supply of saliva which
forms the major part of the paint. Some of this plant material
sometimes gets painted onto the bower walls as well, so this might be
mistaken as using a brush. At our study site in the Bunya Mountains
they usually chew hoop pine needles, although I have seen them using
other species of plant and dirt. There are records in the literature
of them using charcoal. We also have observed them painting just
saliva onto the walls.
Work that's been done here suggests that painting is one of a
multitude of signals that males use in their efforts to attract
females (along with the bower, all the decorations and the song and
dance the males do). Females appear to nibble the paint when they
visit bowers, and one study has shown that the rate at which males
paint their bower walls predicts their mating success. We also think
that freshly painted paint is the important signal in this regards,
rather than the amount of accumulated dried paint. We're planning on
doing another experiment this spring to investigate this painting
behaviour a bit more.
If anyone wants to read up some more on the role paint plays in satin
bowerbird mate choice behaviour and they have access to a library
with journals, our group has published a couple of papers on the
subject recently:
Robson, T.E., Goldizen, A.W. & Green, D.J. (2005) The multiple
signals assessed by female satin bowerbirds: could they be used to
narrow down females' choice of mates? Biology Letters 1:264-267
Bravery, B.D., Nicholls, J.A. and Goldizen, A.W. (in press) Patterns
of painting in satin bowerbirds and males' responses to changes in
their paint. Journal of Avian Biology
With regards David Rosalky's original query about what bowerbirds did
before blue plastic arrived in this country, there are quite a lot of
natural blue things they use. As has been mentioned, rosella
feathers are very popular (and are a preferred item to be stolen from
a rival male's bower), blue flowers from species such as Dianella and
Solanum, and blue berries (typically Exocarpus fruit). They also use
quite a bit of yellow, such as leaves, cockatoo feathers, yellow
flowers (such as Acacia or Dendrobium orchids) and pale yellow
straw/grasses. They often use a few white objects as well, such as
very faded small grass tufts and bones (bird or small possum skulls
and sometimes vertebrae). And as was mentioned by someone else,
brownish items such as cicada skins, praying mantis egg coccoons and
huntsmen spiders are occasionally used. I have also observed that
some populations in the Wet Tropics of north-eastern Queensland use
moss.
Hope this is of interest,
James
--
Dr James Nicholls
School of Integrative Biology
University of Queensland
Brisbane QLD 4072
Australia
Phone: +61 7 3365 7591 Fax: +61 7 3365 1655
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