June 26, 2017 at 1:00 pm
Following our Poll last month, we actually sat down to have a closer look at why penguins are actually black and white. And we compiled our results into an 8 minute video. Below there is both the video and an illustrated transcript with links to some of the sources we cite.
Penguins. Surely most people automatically associate that term with flightless, upright waddling and most importantly, black and white birds. We all know them from hundreds of movies, cartoons and documentaries.
And while it is safe to assume that the penguins’ preference for fish as food is common knowledge, it is also surprising that many have at least a vague idea about what the penguins’ black-and-white attire is good for. Blending in an Camouflage.
Many, many sources ranging from the popular to scientific spectrum state that the penguin’s black back makes the bird more difficult to spot while at sea. When seen from above they disappear in front of the dark blue of the ocean, while their white bellies help them to blend in when seen against the bright sky from below.
According to this idea, the black-and-white plumage helps penguins to be invisible to predators and prey alike.
But… is that so?
To answer this question, let’s go back to where this idea comes from.
This gentleman is Abbott Handerson Thayer, a prominent painter in the United States of the late 19th and early 20th century. He also had a knack for natural history; he was particularly fascinated by animal colouration.
He described a phenomenon known today as “countershading” which is pretty widespread throughout the animal kingdom. In a paper published 1896 in the ornithological journal Auk, he pointed out that many animals are
“painted by nature, darkest on those parts which tend to be most lighted by the sky’s light, and vice versa”.
But it wasn’t Thayer who first mentioned countershading in the context of penguins. In 1892, four years before Thayer’s paper came out, a book titled ‘Animal Colouration’ was published by Frank Evers Beddard, an English zoologist and – weirdly enough – earth worm expert. In it he discusses countershading in animals:
“the white under-side of […] of aquatic birds such as the penguins, are stated […] to be inconspicuous when seen from below and against the bright sky.”
Even though Beddard makes it sound as if it’s not his own idea, it seems his is the first written account of what may be the purpose of countershading in penguins.
And, at a first glance, it seems logical, right? That is, until you really start to think about it.
And funny enough Beddard himself called it straight away when he goes on to say…
“It appears however that this really not the case. If snowflakes […] are watched as they fall from the sky, which is naturally overcast and dull, they appear almost black.”
Let me illustrate what this weird snowflake analogy means for penguins.
Here are a few photos of penguins seen from below.
See where I’m going with this?
Unless you shine a bright light at penguins from the deep, their white bellies will do nothing to prevent them from appearing as a dark shadow.
So what about the black backs? The advantage, according to many books and articles is that the birds are harder to see from above. But, when you look at underwater footage of penguins, they often do not really blend in with the environment that well.
Here are some birds that are true masters of the art of camouflage…
..whereas penguins, even under murky conditions, are still quite visible. To be quite honest… penguins do a far from stellar job when it comes to blending into the marine environment. If they were serious about it, shouldn’t they all blue rather than black and white?
So, I think we should have serious doubts that penguins are black and white primarily for camouflage purposes. Sure, it helps under some circumstances, but that seems more like a by-product. Which brings us back to our initial question.
Why are penguins black and white?
In 2009, Hannah Rowland from the University of Liverpool compiled a comprehensive review of the function of countershading. And she points out a whole string of factors that may all play a role for the black and white colouration in penguins.
Dark colours absorb far more light energy than light colours. This means that the black backside of penguins is more efficient in absorbing heat from the sun than their white front. According to Rowland, penguins have been observed to use that to their advantage, by turning their backs to the sun when cold, and their white undersides to the light when hot.
That would also work when the penguins are resting at the surface in often cold water. In Galapagoa penguins, Dee Boersma (in Bernard Stonehouse’s ‘The Biology of Penguins’) observed that penguins floating at the surface had dry backs allowing them to absorb solar radiation. At the same time, she mentions that while “it is tempting to suggest that the penguins can offset loss of heat to the cold water absorbing solar radiation” her data did not allow testing of this hypothesis.
But the same can be said about the camouflage idea – it has ever come under scientific scrutiny.
Dark feathers have been shown to be stronger and resist more abrasion and wear. Especially if birds are exposed to airborne particles, having black feathers may make the plumage more resistant to abrasion. While Rowland suggests that this may not apply to penguins, it seems she overlooked the fact that penguins spend long periods on land, often pretty dang exposed to the elements and associated abrasive forces.
Coloured feathers are also more energetically costly to produce than white feathers, which could be another reason behind the colour of penguins. With regards to the other explanations for the penguins’ black backs – thermoregulation and protection from abrasion – it makes sense that the penguins’ undersides are white. At sea only the part of the plumage that faces the sun is black. And on land, the penguins generally lay down on their tummies or huddle together backs exposed. So the parts that play no role in absorbing radiation or withstanding the elements don’t need to be black. So why waste energy to generate pigments for the belly feathers?
It has also been suggested that the black and white colouration of birds may actually be beneficial for recognition of conspecifics. This can be helpful when it comes to locating and capturing prey. For example, if a penguin notices a swirl of black and white bodies zooming around a cloud of something, that may be indicative of that something being quite edible.
So why are penguins black and white?
Well, quite honestly, we don’t have a definite answer – or an answer that has ever been scientifically tested. However, if anything, it seems that the common assumption that it’s all about camouflage doesn’t have enough legs to stand on. It takes a lot more, not to be seen.
March 21, 2017 at 4:05 pm
What do catastrophic floods in Peru have to do with tawaki from Jackson Head?
Torrential rainfall in the Andes has wreaked havoc in Peru, killing 72 people and rendering thousands homeless. While many media outlets were quick to pin this catastrophe to the weather phenomenon El Niño, it’s actually not quite that. No yet, anyhow.
We witnessed the devastating effects El Niño had on tawaki from Jackson Head a mere two years ago. Many chicks died of starvation while their mothers desperately tried to find enough food on long, far-ranging foraging trips. In the end the breeding season turned out to be a pretty bad one with only a quarter of the chicks surviving until fledging. Then, last season, a stoat invasion befell the tawaki population pushing the breeding success down to close to zero.
If we are indeed on the verge of another El Nino, the penguins could be facing a third bad season in a row. So, when confronted with the terrible news from Peru, a visit to NOAA the world’s authority with regards to El Niño was in order. The first sentence of the current El Niño report is a bit of a relief “El Niño neutral conditions continued during February”. But…
…the Peruvian catastrophe shows all the hallmarks of an El Niño with much higher ocean temperatures than normal. What keeps it from qualifying as El Niño is that these warmer temperatures are offset by cooler waters further west along the equator. Some scientists have therefore dubbed the situation a ‘coastal El Niño’. And not only that. Further down the NOAA report it reads that after the March-May period “there are increasing odds for El Niño toward the second half of 2017 (50-55% chance)”.
If the severity of the ‘coastal El Niño’ at play in Peru now is an indication for what might happen towards the end of this year, the Jackson Head tawaki have to brace themselves for another tough season.
December 29, 2016 at 6:55 pm
Well, here’s a little secret for anyone who’s planning to watch the upcoming next movie in the Alien franchise. The scene pictured below is not on an alien planet – it’s Milford Sound. And there are two tawaki breeding colonies in the frame, Sinbad Gully and Harrison Cove. The latter one, of course, is our main Fiordland study site.
So a great opportunity to let the person sitting next to you know of your insider knowledge and tell them about the Tawaki Project. (Perhaps you may want to wait until the movie is over before spreading the word about our work.)
December 24, 2016 at 11:18 am
Doing research is one thing, sharing the knowledge you’ve gained another. Far too often, scientific results are published in scientific journals that nobody reads or has access to. As much as we try to spread the word about the fantastic creatures that tawaki – and other NZ penguin species are – a lot of our time is used up with data analysis, writing reports and trying to secure funding for upcoming field seasons. But this time we were incredibly lucky to share our experiences with two professional story tellers. Richard Robinson‘s incredible photographs capture the beauty of our flippered friends and Bill Morris‘ fantastic account about penguins in New Zealand will no doubt help to raise much needed awareness for a seabird that in our country is taken for granted and, as a result, often underappreciated.
Go and support their work! Buy the latest issue of New Zealand Geographic!
December 22, 2016 at 3:53 pm
The Tawaki Project’s Fiordland season wrapped up in the current issue of the Advocate South (also known as Fiordland Advocate).
July 2, 2016 at 8:24 pm
In the face of environmental change, the tawaki is at last receiving the scientific attention needed to protect one of the world’s rarest penguin species.
Many New Zealanders know the little blue penguins that live and breed along most of our mainland coastlines, and we hold the yellow-eyed penguin that adorns our $5 bill in our hands every day. But faced with a photo of a Fiordland crested penguin/tawaki, most of us likely wouldn’t recognise it as another native species. Tawaki belong to the group of crested penguins that boast striking yellow feathers above their eyes. Unfortunately, most crested penguin populations have been declining during the last century, and tawaki do not seem to be an exception. The population is estimated to range between 5,000 and 6,000 birds, and at some sites their numbers are believed to have declined by as much as 30 percent over just 10 years.
But there is considerable uncertainty about the numbers. Unlike other crested penguins, who breed in densely packed colonies, tawaki breed in scattered colonies, mostly in forests along the rugged coastlines of South Westland, Fiordland, Stewart Island/Rakiura and outlying islands. They are true forest penguins that epitomise the wrongness of the penguins-on-ice stereotype. It also means that it is no mean feat finding – and counting – these penguins in the remote and wild areas they inhabit.
Their nesting habitat ranges from sea level to 100m elevation, and they like to breed in impenetrable vegetation. Some pairs have even been found breeding in sea caves with access only through submerged entrances. This means it is next to impossible to get accurate estimates of tawaki populations throughout their entire range.
In 2014, Robin Long surveyed a 60km stretch of coastline between Haast and Milford Sound to identify and accurately census tawaki breeding colonies in the area. She found at least 870 pairs – a stark contrast to the 150 pairs reported in a 1994 survey. However, this likely represents an underestimate in the earlier census rather than an increase in actual penguin numbers. By repeating her 2014 survey during the next 10 years, Robin will record changes in penguin numbers, which will be used to extrapolate trends of the entire tawaki population.
Determining tawaki population size and trends is one thing. Coming up with conservation measures to ensure the survival of the species is another. It is equally important to determine which key threats affect the penguins and what options we have to mitigate these threats.
Tawaki breed on land but find their food at sea. On land, introduced predators – stoats, possums and dogs – may prey on the penguins and their offspring, while human activities can disturb breeding birds and cause them to abandon sites. At sea, rising ocean temperatures probably disrupt prey availability, fisheries may compete for resources or result in accidental bycatch, and pollution in the wake of proposed oil exploration could also become a major problem for the tawaki.
To date, very little is known about tawaki ecology. For decades, the inaccessibility of their breeding sites was a major barrier for scientific investigation. However, by using new technologies to observe and track the penguins, two research groups from the West Coast Penguin Trust and Otago University have joined forces to fill in significant gaps in our knowledge about the species.
Using motion-sensing cameras at nest sites, the trust is carrying out a study to determine the impact of introduced predators on tawaki. In the past two years, thousands of videos have been recorded. Although most video clips show penguins preening or gathering nest material, occasionally intruders – stoats, possums and rats – enter the scene. While it appears that possums and rats keep a respectful distance from the breeding birds, stoat attacks on chicks caused some monitored nests to fail.
The Tawaki Project is studying the penguins’ marine biology. Using miniaturised GPS dive loggers, Otago University researchers Thomas Mattern and Ursula Ellenberg study tawaki’s foraging ranges and diving behaviour. First results indicate that climate substantially influences the birds’ foraging success, but apparently this depends largely on the region in which the penguins breed. During the strong 2015 El Niño, tawaki from Jackson Head, Haast, had to travel hundreds of kilometres to find food for their chicks while others in Milford Sound could obtain ample food without leaving the fiord.
Both projects will significantly expand our knowledge of tawaki and provide much needed information for fact-based management of New Zealand’s unique and enigmatic forest penguin. To find out more, see www.tawaki-project.org and www.bluepenguin.org.nz.
June 11, 2016 at 4:44 pm
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.
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.
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.
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.
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…
February 3, 2016 at 4:51 pm
Although this season’s field work is long over – and, in fact, tawaki are currently going through their annual moult after a grueling and fantastic season (depending if you’re a penguin from Jackson Head or Harrison Cove, respectively) – we only now managed to compile or field report for the season. It can be found as PDF on our Download page and is easily reconginzed by the awesome and overwhelmingly green cover shot.
We have a good excuse for the late publication though. We have been busy with other penguin work on the Otago Peninsula where we trialled novel camera loggers on Yellow-eyed penguins. And despite a few organisational set-backs the trials went well and provided us with truly fantastic underwater footage of a penguin searching for and catching prey. Not strictly tawaki but too awesome not to share it here:
September 18, 2015 at 11:25 pm
Finally a break in the weather. Up until lunchtime we had fish swimming past the living room windows of our Neils Beach domicile. But within half an hour or so it all disappeared and made room for blue skies. And sunshine, actual real sunshine! Miracles do happen!
In the morning Ursula and Junishi drove down to Queenstown to pick up Klemens Pütz from the airport. Jun will be heading back to Dunedin. Klemens will take care of the Jackson Head tawaki tracking when we head over to Milford Sound in about two weeks.
Hotte and I borrowed a ute from Geoff Robson, the owner of Greenstone Helicopters who has been supporting the Tawaki Project since its beginning. We headed out to Jackson Head after lunch. Over the course of three hours we did a nest check run at Popi’s Plaza and the Hilltop area. No more nest failures to report, which is great! The sun did its thing to make the bush bashing actually an enjoyable past-time.
Ursula and Klemens only returned to Neils Beach around 10pm so that we had to scrap the idea of deploying more loggers tonight. However, with Klemens we have a true penguin tracking pioneer in our team so that we can work in two groups and get twice the amount of penguins fitted with loggers in the next few days.
September 17, 2015 at 7:51 pm
We’re swamped down in Neils Beach. A heavy rainfall warning is in place for Westland with 130mm expected to fall until tonight. Not good news for us – and probably not good news for the penguins either.
Around midday a gap in the clouds opened up and the sun even peeped through it for a moment. But when it counted – in the evening – the rain returned with full force and reached almost biblical proportions.
Deploying data loggers in these conditions is really difficult. The adhesive side of the tape we use to attach the devices to the penguins will inevitably get wet and won’t stick that well. Once the tape is stuck to the devices it can withstand weeks in ocean water. But use damp tape during deployment and you have a recipe for disaster.
On top of that a tsunami warning after the earthquake in Chile, rough seas and swollen creeks made it simply impossible to reach the tawaki colonies of Jackson Head.