Foot Trembling Behaviour

In search of the New Zealand robin

It was on an undergraduate ecology field trip in the Nelson Lakes National Park that I first encountered this curious little bird. I found myself assigned to a group of bird-lovers who were convinced we should spend our three days in the field studying the bird’s so called 'foot trembling'. I wasn’t so sure.

The New Zealand robin is inquisitive and territorial, and will often come to investigate passing trampers. So if you are out in the bush and you happen to spot one, take the opportunity to sit down for a rest and watch this endearing little bird. If you stay still, they will gladly come within a meter or two, and are always happy to clean up any spilt biscuit crumbs. If you wait until the robin begins foraging you might just see their unusual foot trembling behaviour.

All varieties of New Zealand robin do their foraging on the forest floor, pecking for worms and small insects in the leaf litter. Between jabs at the ground with their beaks, they can be seen standing still, tilting their head back and forth, while twitching one of their skinny legs. The theories suggest that they do this to stir up insects, somehow disturbing them with the vibrations from their trembling leg.

A robin mid-foraging

'We're biting off more than we can chew' I said. ‘How were we going to find these birds in the first place, let alone get close enough to study them? Maybe we should do something on trees or lichen,' I suggested, 'they tend to stay still at least.'

In the end, I was outvoted and we set off into the nearby mānuka scrub to track this bird I'd never seen before, with the aim of observing its behaviour. I needn’t have worried about locating subjects for our study. It can't have been more than half an hour after entering the bush that one of my avian inclined teammates recognised the robin’s call.

Our research wasn't able to shed much light on the true purpose of the robin’s foot trembling, but it was certainly fun bashing around in the bush for three days, recording the comings and goings of these native birds. Even more, it was a chance to actually spend some time experiencing some of our unique native fauna, that all too often we barely glimpse as we power on to our destinations.