On Kapiti Island 3 -New Zealand's premier conservation reserve

Welcome to the Midnight Collective Broadsheet 103

Actively supporting NZ’s endangered wetland birds

Before we go up into the Kapiti forest to encounter more of our critically endangered birds, we are taking a short trip down to the stony beach shoreline, where a Blackback gull colony is right in the centre of its nesting cycle and unusual events were taking place.

The Blackback is not endangered and there are larger nearby colonies. One on pest free Matiu/Somes Island in the centre of Wellington Harbour (Te Whanganui o Tara) has proved a hazard to the local airport and steps have been taken to keep the size of the colony down (by slipping infertile eggs into the nests). Yet this Island colony is well established and its community dynamic proved intriguing.

Here upwards of a dozen nesting birds are spread along around a kilometre of coast, the females happily ensconced amongst the flotsam, well above the high tide mark. They make little effort to conceal their nests, though they will freeze if you venture too close, and only leave at the very last moment. 

All their defensive effort goes into mounting an aggressive aerial guard. Much of the colony flies over to the mainland beaches during the day to feed, (they flock back right on dusk), but there are always watchful birds left with the nesting females who will attack any human who ventures too close. A principal egg predator however, is the (protected) weka, and they hang around the colony; but a Blackback is more than a match for this endemic rail, and even at night the gulls can spot an intruder and will take to the air in defence.

Weka - near extinction in North Island  -foto Ridgway Lythgoe

Right in the centre of this colony however, was a nesting intruder – a lone variable oystercatcher -torea-pango. These birds are much more at risk than the Blackback’s and under siege from introduced pests where nesting on Mainland beaches. (From stoats, rats, dogs, feral cats et al; plus a self-introduced new comer, the spurwinged plover). But this presence provided a real intrigue because why would the blackback’s allow it?

Kapiti Island oystercatcher - gender unknown 

The oystercatcher pairs share the nesting, though there is only one at the nest at a time. We were on the island 5 days and saw the birds together just the once - at dusk - as they switched sitting responsibilities. They are somewhat like pied stilts in this. Assiduous at camouflage, they will spot you well before you spot them, and immediately leave the nest and begin very successful diversionary behaviours, fossicking innocently about, well away from the actual nest site, in order to lead you astray. So good were these two, that it took us forty eight hours before we finally developed the expertise to spot the sitting oystercatcher before she/he spotted us and thereby identify the nest – right out in the open.

I've got my eye on you

Oystercatcher nest

Blackback nest

Their nests are very similar to a blackback nest, and the eggs too are similar though lighter in colour; though you might easily mistake one for the other. But oystercatchers are both canny and feisty. They don’t confront a human, gauging them too large a threat so respond by diverting them. Smaller threats, as you will see in the video they implacably confront.

There is a lone male paradise duck –putangitangi- on the island. He has just lost his long time mate and is  a lost soul without her, perching on a picnic table through the night (which had to be cleaned every morning) before ambling down for company to the gull nesting colony during the day. The gulls were watchful but tolerant of his presence, but the oystercatcher wouldn’t have a bar of him – immediately denying him passageway and constantly swooping at him, and forcing him to fly passed to a roost at the far end of the colony.

So what exactly is going on here. Gulls are scavengers and could easily (a pukeko wouldn’t hesitate!) predate the eggs of the oystercatcher, but showed no interest in doing so. The oystercatcher, likewise could have had a feed out of the many gulls eggs it was surrounded by. And while it launched itself at the gloomy para, it showed no similar aggression to the gulls. 

They obviously know and are used to each. Presumably the gulls benefit from having this feisty cohabitant in residence, while the oystercatcher is in a much safer environment nested within this colony. Yet this is only half the story for these animals are actually building complex relationships. Most of the wildlife programmes you’ll see on TV and elsewhere focus on  predatory behaviours of wild animals. This is what attracts human interest (and lifts ratings) but it provides a very fallacious picture of the real lives of animals. Here on Kapiti, in an environment protected from human intervention and from introduced predators,  we are witnessing interspecies behaviours which both surprise and intrigue; for what is going on in these animals minds? Is it really that different to what goes on in ours? 

The benefit seems mutual and bares some similarity to the Raumati Beach dunelake environment when paradise duck were raising their young. (This wetland has now been destroyed by an expressway). The parents, particularly the females provide early warning signs of danger,  which benefitted (by alarming them) all the birds on the lake. They were also big enough  to confront the chief predator of the youngsters reared at the lake –pukeko. They  kept them at a wary distance.  

Track we were listening to while posting this - Mitchell Torok from 1953 - Caribbean...

Up in a tree so high away up in the sky

Sits a wide-eyed monkey on a limb.

He wonders why the people go to so much trouble

Just to try and be like him.

He doesn't understand that it's a ladys hand, 

That makes a heart feel so sublime.

But before too long he starts to sing their song, 

And then he gets in the conga line.

     
Jill Studd's Blog
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