Rainbow Bee-eaters, Merops ornatus, are amongst our prettiest birds and I always look out for them hunting on the Town Common or in parklands beside Ross River – even, occasionally, in my own garden. I know they nest in holes in sandy river banks but I never thought about where or how they might spend the nights outside of the nesting season until one of my readers sent me an email asking whether I knew about them roosting in a “huge aggregation” beside Ross Creek in the city. I hadn’t known, of course, and was quite surprised by both the communal roosting and the inner urban location.
It took me a week to find an opportunity to see for myself. The location was a narrow fringe of trees at the edge of Ross Creek, on the South Townsville side (in front of the Telstra building), and when I arrived half an hour before sunset the birds were already beginning to fly in. Numbers built up steadily over the next 45 minutes, most of them in one wattle tree but a few in nearby mangroves. As the evening grew darker and cooler they huddled closer together and deeper inside the tree, making an accurate estimate of numbers impossible; 50 or 100 might be a fair guess, and more may still have been arriving when I left.
A bit of time on the net revealed that the communal roosting behaviour is well known and the urban location not too unusual. In a study of their roosting habits around Darwin by Bellis and Profke, for instance, we read,
While breeding, Rainbow Bee-eaters tend to roost in pairs or in their nest (Fry 1984). Non-breeding birds, however, roost in trees in colonies of 30 or more birds (Warham 1957; Kloot and Easton 1983; Garnett 1985; Saffer and Calver 1997). Birds travel to the roost from their foraging grounds between 15 to 60 minutes prior to sunset, eventually settle down before dark and leave at dawn the following morning (Lord 1933; Warham 1957; Kloot and Easton 1983).
Bellis and Profke counted up to 300 birds in one roost, while Graeme Chapman (also in NT) estimated 1,000 at one Mataranka site. (His page is worth visiting for his wonderful photos, too.)
Rainbow Lorikeets share this roosting behaviour and are such a common sight around the city at nightfall that I automatically assume that a flock of greenish birds heading for a tree at dusk is a flock of lorikeets. I will look more carefully in future!