Field work

You might have seen some of our recent social media posts, that had little to do with penguins flashing yellow eyebrows. These posts also had little in the way of rain forest settings or involuntary mud baths we had to take while working with penguins.

We are collaborating with colleagues in Chile to help doing with Humboldt penguins what we have been doing with tawaki for the past few years – figure out where the penguins go while at sea and what they are doing there. The overarching question of this project is to which extent Humboldt penguins breeding on Isla Choros in the Humboldt Penguin National Reserve in northern Chile would be affected by the development of a major port for a huge copper mine on the mainland just 30 km from the island. We suspect it may not be good.

So, last month, Thomas went over to Chile for a pilot study on the island. Humboldt penguins are known to be quite skittish and prone to abandon their nests when disturbed, so first step was to figure out, how to deploy tracking devices and recovering them a few days later, without wreaking havoc in the colonies.

In the second week of June, a team of four – Thomas, Alejandro Simeone from Andres Bello University in Santiago, plus students Max and Karen – made their way to Punta Choros, two hours North of La Serena. With the help of a local fisherman/tourism operator, the team was transported across to Isla Choros where they spent the next two weeks camped out in the desert.

The first few days were spent searching and mapping suitable penguin nests for the project. There are two breeding seasons each year in Humboldt penguins, and we had arrived for the winter breeding season. Unfortunately, we were about two weeks early as most nests that we found were either still on eggs or chicks had just hatched. That limited the number of nests Thomas deemed suitable for GPS logger deployments.

What he was looking for were closed nests, with a single entrance, and chicks that were at least a week old. Adult penguins with chicks had already established a bond with their offspring and were less prone to abandon their nest if disturbed. And after being fitted with a device, it was always best to release the bird into a cul-de-sac nest where they could not bolt out the backdoor while the Adrenalin was still through the roof.

Over the next ten days, the team managed to deploy 12 devices on birds of which they were able to recover 10 units. In one case, the bird carrying a logger seemed to have abandoned the nest after it was raided by vultures. Since that deployment occurred at night, it seems unlikely that the disturbance facilitated the raid. So hopefully it wasn’t our fault. The other was a case of bad timing; we deployed the device too late, and the bird did not return to its nest before the team had to leave the island. In both cases, the loggers will eventually fall off.

Over the next ten days, the team managed to deploy 12 devices on birds of which they were able to recover 10 units. In one case, the bird carrying a logger seemed to have abandoned the nest after it was raided by vultures. Since that deployment occurred at night, it seems unlikely that the disturbance facilitated the raid. So hopefully it wasn’t our fault. The other was a case of bad timing; we deployed the device too late, and the bird did not return to its nest before the team had to leave the island. In both cases, the loggers will eventually fall off. Of the ten devices we got back, nine had fantastic foraging data. The tenth bird did not leave its nests during the entire 5 days of carrying a logger presumably because its partner had died at sea. Set netting by-catch is a major issue for Humboldt penguins.

Of the nine penguins for which we managed to obtain data, eight followed a more or less strict one-day-at-sea-one-day-at-the-nest routine. But one female decided to go on a four day sojourn up the coast before returning to feed its chicks.

In the data of the one-day-trip performing penguins, a pattern seemed to emerge. Penguins breeding on the eastern side of the island, tended to forage closer to the coast, while birds that landed on the western side, principally foraged 15-30 km from the mainland. What is a bit unfortunate, is that while the eastern side is where the majority of penguins breed we only managed to track three birds from there. All other birds were from western nests, simply because they were a bout a week ahead in terms of breeding. Taken by itself, our data may be interpreted such that the proposed port development may have a lesser effect on the penguins because they tend to forage further offshore. But given the higher nest densities in the east, it seems that foraging closer to the coast may be much more important than our data suggests at this stage.

In December, it is Ursula’s turn to bring Tawaki Project expertise to Chile and build on this pilot study to get a better idea of the plight of Humboldt penguins in northern Chile.So later on this year, it is Ursula’s turn to bring Tawaki Project expertise to Chile and build on this pilot study to get a better idea of the plight of Humboldt penguins in northern Chile.

While we’re still trying to catch up with posting stuff about the last breeding season, the Tawaki are already starting to come back to go through their annual feather change.During a brief visit to Milford Sound last weekend, to check our transponder bridge, surveillance cams, and re-bait our trapline, we came across this plump young female. Together with her partner she had chosen this lovely spot amongst the ferns to hang out while growing her new dive suit.

During a brief visit to Milford Sound last weekend, we came across this female about to go through her annual feather change. As new feathers are produced, the old ones get pushed out giving the birds a rather fluffy look. Interesting Tawaki almost double their weight in preparation for their annual moult. As new feathers are growing and thousands of old feathers a falling out, she will soon look like an experiment of a fire cracker and down pillow gone wrong. Don’t be alarmed if you see such a penguin. It’s perfectly healthy and doesn’t need any help! Best give them lots of space since they cannot go foraging for food but need to live of their fat reserves while they have holes in their dive suit.

Fantastic to see the first candidates returning so fat and healthy from their epic pre-moult journey. Over the next few weeks more and more tawaki will return to Southern New Zealand to moult. Let’s hope they’ll all find similarly lovely and safe retreats to hide away for their personal annual lock down.

A penguin’s day usually starts pretty early. Tawaki often leave their nest before sunrise. With light levels still below par when it comes to foraging, the birds often spent the first hour or two at sea to have extensive preening sessions…

…or going for a run with the mates.

Filmed with a PenguCam on breeding female from Seymour Island, doubtful Sound, Fiordland, NZ

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.

Tawaki breeding in the open are pretty rare. Open nests that can be viewed from some distance away eve rarer.

But that is exactly what a camera man trying to film breeding tawaki wants.Well, nest SE70c met all the required criteria and, thus, became the hero nest for a documentary shoot that we supervised for the last few weeks.

The few clips we’ve seen were amazing. But it’s another couple of years until the will be broadcast. We, for one, are counting the days!

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 breeding season this year is a bit weird.

While in Milford Sound chicks are already ganging up in crèches – something the young ones do when 3-4 weeks old – the penguins in Doubtful Sound are all over the place.

Some nests have big chicks that don’t have any next door neighbours old enough to cuddle with yet. So dad will have to do. In other nests, the chicks have just hatched.

It would seem that the La Niña conditions over the last winter have thrown a spanner in some of the penguins’ works so that they had to work overtime (as in ‘find more food’) to prepare for breeding which made them return a few weeks later than normal. Others, however, apparently managed to come back as planned.But why do we see this in one fjord, but not the other?

As we said… all a bit weird this year.

Last September we deployed our new miniature penguin camera on a breeding female tawaki from Milford Sound/Piopiotahi. The results were incredible.

After the penguin spent the day foraging in the fjord, she returned the same night allowing us to recover the camera. The device recorded roughly 2.5 hours of footage and provides a fascinating insight into the foraging behaviour of tawaki.

While the camera was rolling the bird caught more than 50 individual fish larvae, simply by picking them up in a sort of drive-by fashion – blink and you miss it.

Particularly fascinating were the captures of three squid. When viewing the footage, it really seems like a bad idea for squid to squirt out ink when under threat. Commonly believed to be a strategy to confuse potential predators, for tawaki the ink seemed to indicate that there is prey to find. Squirting proved counterproductive for the cephalopods.
Also fascinating to observe were the pursuits of sprats directly underneath the surface. The agility of the sprat allowing them to do sudden U-turns seems to give the fish a fighting chance.

From a penguin perspective, it is extremely cool to see that all the prey captures occurred from below, where the prey item was clearly visible against the light backdrop of the water surface. So much for the countershading theory…
We plan to deploy more devices this coming season to get a better understanding of the prey composition and the varying foraging strategies of the penguins. So stay tuned!