I don’t know what other responses you have had or if you would intend to carry it forward. I think it is a curious idea. Does the correspondent have any serious
supportive evidence? I can’t see it as possible to prove or disprove. Many other birds such as parrots and mynas will often approach their nest in pairs. I think it is just social or each one monitoring that the partner actually arrives safely. I know that
Leaden Flycatchers (probably others) when they change nest duty, it is common for one to fly into the nest and the other leaves at the same instant, departing on the same trajectory. It can almost look like nothing has happened. This isn’t my discovery. Someone
(I’ve forgotten) showed me this, decades ago and I have seen it since. This action certainly appears to be consistent with hiding the fact that there is a nest there but it also mainly minimises the time that the nest is uncovered. Both reasons are probably
advantageous (which one more is hard to guess). The other thing is that Aust Wood Ducks will also often perch on their nest tree with a lot of calling and being really obvious. The Fraser & Gray names book suggests this is where the strange name comes from.
So they show 2 behaviours that in the suggestion involved by your correspondent, appear to be quite contradictory and thus I think it hard to see how the advantage, whilst possible, could be sufficient.
From: Canberrabirds [
On Behalf Of David McDonald (Personal)
Sent: Friday, 1 October, 2021 3:51 PM
Subject: [Canberrabirds] Waterfowl nesting behaviour
Greetings. Every Friday, a neighbour of mine distributes an email on a natural history topic to interested locals. Today’s reads, in part:
Many Waterfowl species will nest in open tree hollows, ingeniously disguising the entrance with flybys where the pair fly close and fast in unison past the hollow with one disappearing into the hollow whilst the second
continues on, attracting an onlookers' gaze.
I had not heard of this behaviour before. Any comments/observations, please?
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