Dollarbirds, cicadas and mynas

We received this report from Peter of Seymour about Dollarbirds beside the Goulburn River:

“On 2nd January, as I was walking along the river bank, I came across a loud gang of magpies and with it the call of a bird I didn’t immediately recognise. As I approached, the magpies flew off and a Dollarbird flew out of the trees above. Moving closer, I saw a Dollarbird chick on the ground (see photo above), presumably the target of the magpie gang. The chick had the plumage colour of the adults but a pale bill and gape. As I reached for the chick, I was treated to a wide-gaped threat and strident calls, with adults also calling nearby. I put the chick up into a branch and there it stayed – and was still there next morning. The adults were also around and both the adults and chick were calling.
 

I returned a couple of days later with Alan, a keen local birdwatcher, and we found the chick back on the ground but still apparently healthy. We then spotted a second chick at the entrance to a horizontal hollow branch high in a River Red Gum (see photos). Alan described how he had seen Dollarbirds nesting in similar hollows along the river in previous years. In particular, he spoke about the adults feeding the chicks with cicadas that are noisily abundant along the river in summer.

 
 
 
 
 
To confirm his observations, a Dollarbird landed on a branch with an insect in its beak and typical cicada wings protruding either side. Dollarbirds travel from Indonesia and New Guinea to Australia to breed over summer. At least in this area, cicadas seem to be a valuable food source and may be sufficient reason for Dollarbirds to travel so far south to breed.

Cicada exoskeletons

However, there is a sinister note to this story. Many Common Mynas were also present along the river bank. In an article on the Greengrocer Cicada in the December edition of the Victorian National Parks Association magazine Park Watch, John Kotsiaris notes that:
The other main threat to the green grocer, in my view, is the Indian [Common] myna bird; a very cunning and aggressive invasive species which was introduced into Melbourne in 1862 to control insects in market gardens. When male green grocer cicadas are attacked by a bird you will know about it. [The cicada] will let out a long, loud buzzing “eeeeeeeeeeeeeee!”. I have found that almost always [it] will be in the beak of an Indian myna.

So, the question is: are Common Mynas a threat to a critical food source for the breeding Dollarbirds? Or are there enough cicadas to go round?”

PS. As far as we are aware, the Dollarbird would be a rare sighting in the Flowerdale-Strath Creek area, and we would be pleased to hear from anyone who has seen one.