Environment – Spoonbills are coming

Next time you are near a coastal mudflat or estuary, keep an eye out for giant white birds with long and bizarrely shaped beaks – the royal spoonbill or kōtuku ngutupapa.

You have a pretty good chance of seeing them because over the last couple of years there has been a dramatic increase in sightings of spoonbills around the Hibiscus Coast.

This reflects a steadily increasing population of these magnificent birds across New Zealand as a whole. Good local places to spot them are in the Long Bay Okura marine reserve and Ōrewa Estuary.

Spoonbills have only recently become part of New Zealand’s native wildlife – they were first recorded in 1861, and first known to breed in 1949. In the 1970s there were less than 100 individuals – but today there are more than 2000 in the country. Spoonbills are considered native species because they arrived here (from Australia) under their own steam and have established themselves without any direct human intervention, either intentional or otherwise.

The range of bill shapes in birds reflects their diversity of diet and feeding behaviour. For example, seed eating birds like sparrows and parrots have plier-like bills, while birds that forage in the mud, such as bar-tailed godwits and oystercatchers, have long probing bills so they can get deep into the substrate. But what on earth is the function of that ‘spatula’ on the end of a spoonbill’s beak?

If you get a chance to watch spoonbills foraging (and you should get more and more chances in the coming years), have a good look at exactly how they feed, swinging their bills back and forth. The bills have lots of little sensory pits that detect the movement of their prey. When they detect the presence of food (fish and shrimp mainly) as they sweep, their bill snaps shut and they will then lift their head and flick the food to the back of the bill and swallow it. The extra space provided by the spoon increases the size of the trap.

But they have another trick – the top bill is curved (like an actual spoon), while the bottom bill is flat (like a spatula). Together they form a hydrofoil that swirls and stirs the water around and increases the odds of contact with prey. This is just one of nature’s countless adaptations that give organisms an edge in survival.