I write this with a heavy heart (I get too invested, I think). After closely monitoring this hollow for months, I saw galahs fledge, and the gang gangs take over the hollow and lay an egg within a week of the galahs exiting. Day in, day out, they incubated their egg, and I marvelled at their patience. But inside me was a flutter of concern - because last year, their 1-2 weeks old nestlings were predated by krefts gliders. A week ago I watched the female settle into the hollow for the night, chucking her head, indicating she was readying to regurgitate and feed her new hatchling. Last night, however, I observed neither adult enter the hollow, and both flew off at 8pm. Fearing the worst, I went down again today. There was the pair, intensely 'grief grooming' (well, that's my words for their behaviour). The male entered the hollow for a couple of minutes, then they both flew off. TomT looked inside the hollow with a pole camera, and our fears were confirmed. The hollow was empty, the nestling had disappeared. But the parents were at the tree every time I visited today - early in the morning, late in the evening. Quietly talking, or chewing, or grooming.
This is the third hollow that I've been observing this year that failed. As I'm only monitoring three hollows . . . the loss truly feels great . . .
ps - @MichaelMulvaney - I believe the female is actually Madonna (see her head colouring in the unclear third photo); and the feather colouring from last year's photos indicates she is the same female from the hollow last year