Whis­tle on the water

The whio duck is down to the last 3000 in­di­vid­u­als, and it’s our job to pro­tect them.

Element - - Ecology - By So­phie Bar­clay

The whio has al­ways been an iconic bird for the an­glers, tram­pers, white water rafters and kayak­ers of Aotearoa. But those less fa­mil­iar with the pris­tine wa­ter­ways of our con­ser­va­tion es­tate may know only the blue duck, in all its azure glory, as the less fa­mous bird on our ten-dol­lar note.

Once whio were found all over the coun­try. But a lethal cock­tail of egg-munch­ing stoats, re­lent­less for­est clear­ance, water qual­ity de­cline and gen­eral hu­man in­ept­ness has dec­i­mated pop­u­la­tions, leav­ing less than 3000 in­di­vid­u­als. Un­for­tu­nately, the whio’s pref­er­ence for high­coun­try rivers means we can’t just whisk them off to pest-free, off­shore is­lands to re­pro­duce in undis­turbed bliss.

In Fiord­land, DOC has caught more than 400 stoats since De­cem­ber. Te Anau Bio­di­ver­sity Ranger An­drew Smart says that in ar­eas lack­ing stoat con­trol, eggs, and some un­lucky mother ducks, were eaten af­ter only nine days on the nest (out of 35). Be­cause fe­male adults are more likely to be caught, it’s hard for pop­u­la­tions to re­cover. Not a sin­gle duck­ling made it to the river when stoats weren’t con­trolled, com­pared with nine the year that stoat trap­ping was im­ple­mented.

Re­search has led to stoat trap­ping in eight ‘se­cu­rity sites’, high pri­or­ity ar­eas for whio con­ser­va­tion. The goal is to con­serve 400 breed­ing pairs – 50 at each spot – by 2016.

Whio Op­er­a­tion Nest Egg is an­other in­ge­nious at­tempt to ramp up num­bers. Eggs are pinched from un­wary whio who re-nest, whilst col­lected eggs are in­cu­bated, reared and then re-re­leased, ef­fec­tively dou­bling num­bers. Blue duck usu­ally mate for life, but there are the odd un­scrupu­lous whio to be found. “We’ve had birds that di­vorce quite reg­u­larly. We’ve got a male who we call ‘Hugh’ af­ter Hugh Heffner, and he gets a new, younger part­ner nearly ev­ery year,” says Smart. Whio live for an av­er­age of 10 years in the wild.

Whio are highly spe­cialised birds, with adap­ta­tions for a life in rapid­filled rivers. Their gi­ant, webbed feet can fold back into ‘grooves’ in their legs to make them more stream­lined, whilst their blue-grey colour cam­ou­flages them amongst river boul­ders. Whio are unique to New Zealand.

Whio rely on aquatic in­sects such as stone­flies which thrive in good water qual­ity, and are there­fore an ideal in­di­ca­tor of a river’s health, says Robert Hood, Pro­gramme Man­ager at Ruapehu. They have a rub­bery vac­uum cleaner on the end of their bill, used for hoover­ing up in­sects and lar­vae which live un­der the rocks, which they sieve out into their mouth.

Hood ad­mires the whio’s abil­ity to thrive in “a very tough en­vi­ron­ment”. Born into dan­ger­ous sur­round­ings, duck­lings are very vul­ner­a­ble to pre­da­tion, flood events and be­ing swept down­stream. Luck­ily, adult whio are dili­gent and ob­ser­vant par­ents.

Whio are more en­dan­gered than the kiwi, so Whio Aware­ness Month is a good ex­cuse to don your tramp­ing boots and head river­side to catch a glimpse of these cu­ri­ous ducks in their nat­u­ral habi­tat.

“We’ve got a male who we call ‘Hugh’ af­ter Hugh Heffner, and he gets a new, younger part­ner nearly ev­ery year”

DOC Te Anau Bio­di­ver­sity Ranger An­drew Smart

Pho­tos: Alan Gib­son

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