Elf owl (Micrathene whitneyi)

For back yard birding at its best, it’s hard to beat Arizona’s Sierra Vista, home to the Southwest Wings Birding and Nature festival. As many as a dozen different kinds of hummingbird spar like wartime flying aces around the feeders, while Mexican jays utter shrill warning calls at a diamondback rattlesnake lurking below.

But for a really special back yard bird, I must wait until dusk. Local birder Tony welcomes me and my old friend Chris, and as darkness falls we sit and wait, hoping it will make an appearance.

Our eyes are fixed on a nest-hole a few metres above our heads, home to the world’s smallest raptor: the aptly named elf owl. Barely the size of a sparrow, this bird is just 13-14cm long, and weighs a mere 40g.

Moments later, right on cue, a quizzical face appears at the entrance. This is the single survivor of two chicks, waiting impatiently for its parent to bring back food. But the adult has a very different agenda: it knows the youngster is now ready to leave the nest. So it calls loudly from a distance, trying to tempt its recalcitrant offspring to take the plunge.

That night the young owl stayed put, but the following evening Tony saw it fly for the very first time. Tiny it may be, but this pint-sized predator is now busily wreaking terror on even smaller creatures of the night.