Penguin observations

In late October, last year’s tawaki chicks usually start popping up in the breeding colonies. In some years, there are heaps of them, but this year we only saw a handful which suggests that the survival of last year’s chicks cohort wasn’t particularly good. La Niña and the associated warmer ocean temperatures in the Sub-antarctic resulting in lower productivity and less penguin food may have made life exceedingly difficult for many young penguins.

However, a few tough ones did show up on the Shelter and Seymour Islands this year while we were there. Like the fellow below.

Even though the grey beard provides one-year-old tawaki with a rather distinguished old man’s look, the short, pale crest gives their young age away. And as most juvenile tawaki, this one had not a clue what he was supposed to do. It seems as if he (for it is a boy, look at the honker!) wandered aimlessly through the forest and ended up at the least populated eastern side of the East Shelter Island. Eventually he found his wee little nook to plonk down in and contemplate what to do next.

Often, the cool-down period for a tawaki family after a chick-feeding event is the exact opposite of action packed. Especially if the chick (or chicks) in question are nearing fledging and need a lot of food.

In tawaki, not only is it the mother that has to find, catch and bring home all this food. She also has to regurgitate (nothing but a fancy word for “vomiting”) all the nice tucker for her offspring. It is left to everyone’s imagination how exhausting the whole process is.

No wonder then that after the chick has been fed the social life of the adult tawaki seems to happen in super-slo-mo.

An unusually crowded caravan of tawaki at the Northern Landing on East Shelter Island.

Although there are an estimated 110-120 tawaki breeding pairs on the island, you hardly ever see more than one or two at a time.

On one hand, this is due to the fact that there are four main landing sites as well as a handful of smaller landings. So the 240 or so breeding adults distribute themselves quite a bit.

On the other hand, tawaki have experienced considerable hunting pressure over that past 600-800 years. So emerging from the bush in large numbers is a bad idea as it would make a penguin hunter’s life very easy.

One side effect of this is that filming tawaki is a real challenge and requires a lot of patience. But, according to the film crew that worked with us in Doubtful Sound/Patea, this made spotting tawaki so much more exciting and rewarding.

Mini-crèche (by crested penguin standards) of tawaki chicks in a tree root cave on East Shelter Island. As the chicks get older their parents leave to their own devices during the day. Chicks from nests that have neighbours, start to wander over to see what the kids next door are up to.

Here we have the youngsters from nests SE14a, SE14b and SE15 having a bit of a sit in at number 15’s nest bowl.

A tawaki road block on East Shelter Island, Doubtful Sound/Patea.

While working with the local penguin population – filming for a major documentary series and continuing our research on the side – we frequently had to cross the island. The track passes along one of the manliest and most populated (7 nests!) tree root caves on the island.

One day we were making our way back to our boat landing, when we ended up in a stand-off with a troupe of penguins that emerged from said cave, I suppose for a breath of fresh air (with 9 chicks not potty trained the cave is a rather smelly affair).

There we were, three humans and four penguins just eyeing each other up for several minutes. It was a rare and special moment where we could be really close to the birds without them making a hasty retreat.

The
tawaki of Doubtful Sound breed in vast caverns under washed out tree
root systems. These caves sometimes extend several metres under the
forest floor. And th epenguins not only breed in there. They also return
to moult.

Over 3-4 weeks each bird looses about 150,000 feathers – more or less at once – and grows an equal amount of new ones. The old feathers are shed and form huge piles. A feather pile from a single bird is impressive. But if you have 6, 8 or more tawaki moulting in one of these caves together, you get an underground winter wonderland.

By now, the majority of tawaki have returned to the New Zealand mainland to go through their annual moult. Many of the birds return to their breeding colonies to hang out with their partners while they patiently wait for last year’s feathers to be replaced with a flash new plumage.

However, many young birds and non-breeders that don’t have a partner or nest site to return to, make landfall wherever it suits them best.

For example, last year of the five penguins we managed to track throughout their pre-moult journey, only three came back to Gorge River. The other two decided to enjoy a change of scenery and went through their moult in Dusky and Sutherland Sound, respectively.

Admittedly, that’s still very fiordlandish. So how about this guy who was spotted by Alyssa Sutton at Birdlings Flat on the southern end of Bank Peninsula, Christchurch?

A (presumably) moulting tawaki at Birdlings Flat, Banks Peninsula

At a first glance, it appears that the bird may have taken the wrong turn and ended up on the wrong side of New Zealand’s South Island. In fact, in the past, tawaki found moulting on Banks Peninsula have been picked up by well-meaning people who then shipped the birds over to the West Coast by road because the penguins “clearly did not belong here”.

But who are we to judge where tawaki belong? These birds can travel 6,000 kilometres in 8-10 weeks, so that a tawaki could circumnavigate all of New Zealand in half that time. Tawaki moulting along the Otago coast line is perfectly normal; they are even trying to breed there (http://bit.ly/2DXC6kE). And the Banks Peninsula is not that much further.

The ocean around the southern half of New Zealand’s South Island is dominated by the Southland current which flows down the West Coast, around Stewart Island and then up the Southland and Otago coast towards the Banks Peninsula. It is a very productive area that many seabird species forage in. As such it makes a lot of sense for tawaki outside of the breeding season to make the most of these productive waters.

So if you encounter tawaki anywhere on the South Island’s coasts at this time of the year… it’s where they belong. And unless the birds are severely injured or look terribly thin with the breastbone sticking out (e.g. http://bit.ly/2DKGbFO) – they don’t need our help.

So much for ‘once chicks fledge they will not touch try land again for almost a year’. This tawaki chick from Rollers Beach, Stewart Island, obviously had different plans. After its first splash in the big blue, it found itself a nice little rock not far from the cave it hatched in. It then spent the better half of a day perched there preening extensively and enjoying the life in fresh air (as opposed to the ammonia contaminated, dank gas not really qualified to be called ‘air’ inside said cave).

Ultimately, however, high tide forced the young one to get wet again… and start the adventure of its first year at sea.

A recently fledged tawaki chick is raking a break after its first dip

Don’t be fooled by the grey beard; this fellow is only a couple of months old.

The penguin equivalent to taking a shower

Inevitably, the incoming tide washed the wee one of its perch

The moderate earthquake that hit Fiordland last week is reminder that tawaki have chosen a particularly precarious stretch of coast to breed. The species’ entire breeding distribution follows one of New Zealand major geological boundaries, the Alpine Fault.

Tawaki breeding range (red), Alpine Fault and our three study sites. Maybe we should be worried too?

Here the Pacific Plate meets the Indo-Australian Plate, two of the earth’s major tectonic plates. Or more specifically, the Pacific Plate moves over its counterpart, pushing it downwards while lifting itself up  – forming the Southern Alps in the process. It’s a pretty lively zone where earthquakes are a common occurrence. So tawaki live in a pretty shaky region.

That wouldn’t be half so bad, if they would breed in earthquake proof burrows. But a lot of them don’t. Many tawaki establish their nests under rocks or boulders, sometimes along the course of old landslips which in itself is a reminder of the violent forces of earthquakes. As researcher, it is a pain to find your way through this jumble of rocks because not every stone you step on is as stable as it seems. Even larger boulders may give way and start to roll when you try to climb over them. Obviously, that is the last thing you want as there might be tawaki breeding under that very same rock.

It does not take much to imagine what an earthquake might do to this tawaki nest

What does this mean for tawaki when there is an earthquake?

Well, first of all, as stated before earthquakes are a common occurrence along the Alpine Fault. So we can probably assume that a lot of the rocks the penguins have decided to breed under have been shaken into place already and are unlikely to be moved by another wee quake.

However… there is a very big earthquake waiting to happen. The Alpine Fault has ruptured four times in the past 9 centuries, which is about one big earthquake every 225 years. And the last rupture dates back to 1717 – almost 300 years ago. So the next big one is overdue. In fact, geologist estimate the next rupture of the Alpine Fault to occur in the next 50 years. And it will create a massive earthquake of magnitude 8 or more, at least as violent as the 2015 Nepal earthquake. If not more so. To put that into perspective, the devastating earthquake that hit Christchurch in February 2011 was of  magnitude 6.3.

Predicted isoseismals & consequences for the next Alpine Fault rupture (source: http://bit.ly/1DZWvK1).

The predicted epicenter is about half way between Jackson Head and Harrison Cove. Actually the isoseismals (blue lines in the graph above) forecasting the spatial distribution of seismic activity, neatly cover the core breeding areas of West Coast and Fiordland tawaki. So penguins occupying this stretch of coast will be in for a wild ride indeed. And it is safe to assume that the rocks under which tawaki are breeding will move once more when that happens.

If the quake hits during the breeding season tawaki might indeed be in trouble. In this case, a lot of penguins attending their nests may be crushed by shifting rocks or buried under the rubble of landslides. With such a big earthquake, tsunamis are probably to be expected as well so that birds not breeding under rocks may get washed away. So it could be quite bad. But tawaki would have to very unlucky for that to happen.

Two adults in front of their nest at Jackson Head. Will these rocks stay where they are in a quake?

How likely is it that tawaki will be at home during quake?

Tawaki spend most of their lives at sea. So the timing of the quake would have to be spot on and coincide with the penguins’ breeding season (August to November) or moulting (February), the only periods of the year the birds spend substantial time on land. This means that the penguins are only in the region for four months every year. That’s only a 1:3 chance of tawaki witnessing the quake first-hand. It’s more likely that they come back from their migration to find their breeding site layout altered substantially.

If it happens during the breeding season, will it be enough to wipe them out completely?

Highly unlikely, as there will be a lot of non-breeders and juveniles as well as foraging parents at sea and therefore likely spared from quake-related misfortune. And at sea, those birds can handle all kinds of turmoil…

https://vimeo.com/109104158

Last night word reached us that Inger Perkins from the West Coast Penguin Trust made a disturbing discovery while analysing footage from a trail camera deployed last season at Jackson Head.

Using motion triggered trail cameras the trust investigates the impact of terrestrial predators on tawaki at Jackson Head and Gorge River. We are closely collaborating with the trust and maintain the cameras while we’re in the field.

At Gorge River, trust cameras have already recorded how penguin chicks fall prey to stoats, which in New Zealand have wreaked havoc with all kinds of birdlife in the past century. At Jackson Head, however, it is mainly possums that tend to visit penguin nests apparently without causing them any grief.

And as such, analysing the video data has been an enjoyable affair that provided some neat insights into the family life of tawaki. That is, until Inger stumbled across said disturbing footage which raised the question whether Bigfoot or the Yeti might be roaming New Zealand’s West Coast:

https://vine.co/v/iwEhwtYiuJz

(Actually, it’s just a very cheerful Klemens Pütz triggering one of the cameras after checking on one of our GPS logger birds.)