Tuesday 8 July 2014

Rainbirds


Welcome to the Midnight Collective Broadsheet 29
Actively supporting NZ’s endangered wetland birds

One of the rare pleasures of this investigative work is to stumble across the unexpected and we have had two such encounters in the past three days. Here is the first, a riroriro, or grey warbler seen on the track going down to the dune lake.
Spot the riroriro - white undercarriage centre-right
This is the NZ rainbird, whose song reportedly falls away in tone, ending abruptly, if the weather is about to take a turn for the worst. I remember trekking through Whanganui National Park territory as a greenhorn and querying the sagacity of this with a leathery old conservationist of around 75 years. She  looked me up and down as yet one more no-hoper who shouldn’t be allowed near a national park and walked away.

They are little bush birds, used to living in dense podocarp forest and a nightmare to photograph because they are difficult to focus and always on the move, fossicking out insects from the bark and foliage of trees. Rarely seen out in the suburbs like this,  nevertheless here they are -a pair- though we only managed a couple of messy images of one before they zipped away, across the wharemauku.   
Riroriro (in camouflage) - near dune lake
The nests of these tiny animals, that vie with rifleman for the title of NZ's smallest bird, (being little bigger than your thumb), are parasitized by the two native cuckoo’s, -the Shining and Long Tailed. These birds overwinter on South Pacific islands then migrate back to breed here in the spring. They don’t however, do the  legwork themselves, the females laying their eggs in riroriro nests. We have seen a long tailed fledgling, (koekoea) just out of the nest on the Island (Kapiti), with two riroriro parents, desperately trying to keep ahead of its appetite.

Long-tailed cuckoo - koekoea -ill. Keulemans
The long tailed, is the rarest of the NZ cuckoos and it has a loud gnarly cry, which it uses, like its human counterpart, to galvanise its parents into feeding it. This underlines the seeming tyranny of the situation for the fledgling, which throws the riroriro’s own eggs out of the nest, grows to 3 or 4 times the size of the parents. Though the parents could care less. It is their youngster and there is no way it is going to be left to starve.

The process raises intriguing (and intractable) questions about the influence of parenting on a fledgling. When Don Merton was down on Little Mangere Island. in the Chathams trying  to save the  black robins which were down to a last fertile female -Old Blue- (He was famously successful), the initial strategy was to cuckold the nests of tomtits, with black robin eggs. This gave Old Blue the opportunity to lay a further  clutch.  It had to be abandoned when the robins began to show tomtit-like behaviours. These cuckoos however, repeat the behaviour of the parents they have never seen, then the females in addition repeat their mother’s parasitic behaviours without however, ever being trained in the strategy themselves…

And our second surprise? The discovery of marine animals in our small wetland pond over the back of the wharemauku. There seems no obvious way fish can get in here, becasue it has been dry  between March and early April, and yet here they are!! It is also decidedly fetid with cattle having direct access to it. And if this wasn't enough, the expressway has it directly in its sights and is closing in fast from the north. More on all that next week.

Track we were listening to while posting this
The Big O's Blue Bayou  
I'm going back someday come what may to Blue Bayou
Where you sleep all day and the catfish play on Blue Bayou

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