Glossy Black-Cockatoo food plants

To: "birding aus" <>
Subject: Glossy Black-Cockatoo food plants
From: "Judie Peet" <>
Date: Tue, 12 Mar 2002 20:25:51 +1100
Hi Alan, Anthony, Carol and David,
Re Glossie food in the central west of NSW: Thanks for the interesting info everyone. It all goes to give a clearer picture of the needs of the Glossy Black-Cockatoo.
I get thoroughly confused by the Allocasuarina/Casuarina distinctions - except for remembering that Allo has black seeds and Cas has grey.
All mature casuarina cones will open their valves to discharge their seeds if picked and put into a paper bag for a while. The time depends on the species, but it's usually just a few days. Left on the plant, cones will ripen and discharge seeds from opened valves of woody cones. Glossies only eat cones that are "pre-ripe" - that is, when the seeds are developed, but the cones are still fairly soft and sappy.
There are huge variations in cone behaviour, such as between the two shrubby casuarinas in Goonoo (43 kms N/W of Dubbo) and Buloke - a tall tree. A. diminuta and A. gymnanthera have flowers, unripe fruit, ripening fruit and hard woody fruit - all at the same time (they flower/fruit continuously) - and Buloke (A. luehmannii) which flowers in about March, takes about 9 months for fruit to ripen, discharges the seeds around December to February, and then drops the empty cones.
What this amounts to for the Goonoo Glossies is a permanent, reliable food source from the shrubby casuarinas, and a seasonal supplement from the Buloke. (These three species are the only casuarinas naturally occurring in Goonoo.)
There are continuous stands of River Oak along many of the watercourses and drainage lines in the central west, and sometimes "chewings" - ie, crushed cones, are found beneath them. River Oak holds onto its cones for a long time after ripening to the woody stage and discharging seeds, but the woody cones will fall off readily, unlike A.diminuta and A.gymnanthera which keep a firm hold on old cones. Interesting plants, eh?
Back to the birds: What has been bothering me is that observers who find chewed cones of River Oak might assume that Glossies had done the chewing...and this could give rise to mistakes in records of preferred  Glossie habitat and presence.
Ahhhh, by the way Carol, re Fairley & Moore's explanation of the Allo/Casuarina thing - River Oak has dull grey seeds, but sharp pointy protuberant valves, which makes it...? ( Arrgh! This way madness lies...) I don't think the CONES are too small for Glossies, but I think the SEEDS are. River Oak seeds are really tiny, less than 1/2 the size of A.diminuta seeds which come from a cone of only about 10mm long. Getting at River Oak seeds would be a lot of energy output for little return.
If anyone does see Glossies feeding on River Oak I'd be most interested to hear about it.
Thanks again to everyone who has responded to questions about what my favourite birds like to eat.
Regards, Judie Peet (Dubbo NSW)
(The only thing certain about bird watching is that nothing's certain!)
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