Prospecting for “Golden” Hollows

Forest Red-Tail Black Cockatoo atop a natural nesting hollow in Boddington

‘Tis the season for prospecting, for commodities richer than gold.  When Black Cockatoos go searching, for hollows large and old.

So what are the nest requirements for Black Cockatoos and how do I know they are prospecting?

Here’s what makes a good nesting tree:

• Predominantly Marri, Wandoo, Salmon-Gum, Karri or Tuart (Red-tails almost always nest in Marri)
• Ancient (>150 years old)
• Diameter at breast height (DBH) greater than 50cm
• Senescent (over mature and declining in health, causing dead branches)
• Hollow bearing
• Adequate food plants within 6-12km and water within 2km
• Hollow mostly vertical
• Hollow entrance width > 15cm
• Hollow depth >50cm
• Height of entrance – generally 5-6m avg. for Carnaby; >8m Forest Red-tail

How do I know when they are nesting?

• September to January is the approximate nesting window for Carnaby’s, although Forest red-tails can breed all year round.
• Early rain can indicate that the birds are going to nest early.
• When looking for a suitable nest, birds will be seen in pairs, and you may see one of the pair sitting alone on a branch near the entry of a potential hollow, while the other inspects the hollow.
• The female may chew around the rim and enter and leave the hollow.
• Once an egg/s is laid and whilst the chick is young, the female will stay mostly on the nest, leaving only a couple of times a day to be fed by her male and drink.
• When the chick is older, the female will leave the nest more frequently to feed.
• If a female is seen alone or with her male rather than in a flock, it is likely that she is near her nesting hollow.

If you do observe any of the above behaviours please notify our Black Cockatoo Project Officer Megan LeRoy via email megan.leroy@peel-harvey.org.au or phone 6369 8800.  Megan can come and confirm nesting and may be able to use a telescopic camera to look in the hollow.

Some other Facts about our Black Cockatoos:

• Carnaby’s start to breed at 3-4 years of age
• Females return to natal areas (the place they were born) to breed
• Carnaby’s lay 2 eggs (only 1 generally survives); Forest Black Cockatoos (Red’s and Baudin’s) lay one egg only
• Incubation is 30 days; with fledging 70 days from hatching
• Carnaby’s breed every year, Forest Black Cockatoos every other year (generally)
• The chick stays with the parent for its first year
• They need water within 2km of nesting, and food within 6-12 km
• Can travel 50-150km to breeding sites
• Older/dominant pairs get the best hollows; younger pairs gets seconds

More information on Black Cockatoos breeding ranges can be found at: https://birdlife.org.au/projects/southwest-black-cockatoo-recovery/breeding-range-survey-swbc

This project is supported by the PHCC through funding from the Australian Government’s Environmental Restoration Fund.