Farm expansion threatens unique New Zealand bird
Endemic bird species are no longer abundant in New Zealand, but those that survive include many interesting specimens. Take the wrybill, for instance.
Energetic, skilful, confident and decidedly pugnacious (when nesting), this little ‘pale plover’ (Anarthynchus frontalis) is unique in at least one aspect.
Known in Maori as the ngutu parore (‘tensed lips’), the wrybill is the only bird in the world with a beak that is bent sideways – always to the right.
If you want to see them, you need to pick your visit carefully because they conduct an annual mass inter-island migration to and from breeding sites – albeit within New Zealand.
According to New Zealand Birds Online (NZBO) the wrybill breeds only in the braided rivers of the South Island, where it uses its laterally curved beak to reach insect larvae under rounded riverbed stones.
Breeding over, almost the entire population migrates north to winter in the harbours of the northern North Island, notably the Firth of Thames and Manukau Harbour.
Between January and July the wrybills form dense flocks at high-water roosts, and by far the easiest place to see them is at the Miranda shorebird site an hour southeast of Auckland.
Finding them on their riverbed breeding grounds in the Canterbury area is much more challenging. All their life stages are predominantly grey, and they become ‘highly cryptic’ among the greywacke shingle of the riverbeds.
Threats and numbers
NZBO says counting wrybills is difficult, but estimates a total population of about 5000, and declining. More than 40% of them will winter at Miranda on the Firth of Thames.
As with so many of New Zealand’s shockingly long list of extinct endemic species, the main threats faced by wrybills are predation by introduced mammals, plus native birds. Nest flooding is also an issue.
But a big new danger to the nesting wrybills is ‘agricultural encroachment’ by land-hungry farmers. Environment Canterbury says some 12,000 ha of river margins were ‘taken’ for intensive farming between 1990 and 2012. And the practice continues.
NZBO now lists the wrybill at ‘nationally vulnerable’.
Natural Images © 2017