In my recent trip report, which described several days in the northern Ruahine Range, I referred to the presence of whio (pronounced fee-oh), also known as New Zealand’s Blue Duck. The bird has evolved in an isolated fashion and is not closely related to other ducks. It’s a strong swimmer, and one of very few birds in the world that lives its entire life on fast-flowing, bouldery mountain rivers. It’s most active during the edges of the days, and sometimes overnight, and it’s named after the feee-oh sound of the male’s call… moreso than the responsive squalk of the female. Whio are not as iconically popular as some of New Zealand’s other birds such as the kiwi or the kea, yet if you turn over a New Zealand $10 note, you’ll see a pair of whio on the back.
Whio are also listed as vulnerable to becoming extinct. They nest for three months a year in caves, log jams and under other vegetation, so the eggs and chicks are vulnerable to both spring flooding and introduced predators. The total population is hard to count, but a current estimate is for as few as 2,500 individual birds, scattered throughout the country and dropping. Being exclusively territorial they’re usually seen in pairs at best, which doesn’t help towards improving numbers. Occasionally, however, there are also good stories.
Its requirement for clean water and a high diversity of aquatic insects means the presence of whio is considered a key indicator of a genuinely healthy river, something that’s all too uncommon in New Zealand today. If you find whio, it means you’ve found a waterway that’s in a fairly pristine state. Keep this in mind next time you’re thinking of leaving a mess that will seep into a waterway, or throwing unwanted food-scraps into a stream, or washing dishes in a river outside a hut or camp-site. You may well be making life harder or impossible for vulnerable species such as whio, not to mention all the insects it relies on.
It’s fortunate to be able to see such birds in the Ruahine Range, but it’s something I’ve taken for granted that I can report having seen them without putting the very birds I’ve seen in danger. Sadly it’s not always the case. Despite being at risk of eventual extinction for several reasons, the whio is, at least, not generally in danger from people of malicious intent simply knowing where they live. From this point on, I’m going to write about lizards.
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