So that’s how it does it

Long time readers of this blog will recognise, in the photo below, the nest-box and the critter loitering in the entrance. Every June/July for the past five or so years an Australian Owlet-nightjar (Aegotheles cristatus), pictured, roosts for several weeks in this nest-box near our house.  The smallest of Australia’s nocturnal birds it is extremely curious and if we happen to walk past the nest-box during the day it immediately pokes its head out of the entrance to see what is going on.

The nest-box in question is built for a Rosella (so the guides tell me). It is much deeper than it is wide. I also have in trees near the house two Owlet-nightjar nest-boxes which are much wider than they are deep but nothing has ever inhabited them. I have often wondered how the Owlet-nightjar could sit looking out of the nest-box opening for long periods of time. I assumed that it had feet like a White-throated Treecreeper.

The White-throated Treecreeper (Cormobates leucophaea) spends its life scaling the trunks of trees looking under bark for the insects on which it feeds. A look at the photo (right) shows that the toes are particularly large compared to the size of the body, perfectly adapted for the task of cling to vertical surfaces. In addition, their legs and feet are controlled by special tendons so that when a bird bends its legs the feet automatically close. In this way the treecreeper can sleep whilst attached to vertical surfaces. The photo below shows a treecreeper that often sleeps under the eaves of our house.

But a careful look at the ONJ photo shows its feet (with little toes) gripping the opening of the nest-box. Evidently it does not have the feet/toe locking mechanism of the treecreeper but in an effort to check out the neighbours simply perches on the edge of the nest-box entrance and crams its body through the opening.

Being a busy-body comes at a cost.