Friday, July 29, 2011

"Stranded" Emperor Penguin comes ashore in New Zealand

An Emperor Penguin was first spotted June 19 on the beach in New Zealand, 2,000 miles from it's usual Antarctic habitat.

It was the first Emperor in 44 years to be found ashore in New Zealand, so it caused quite a stir.  But in a situation like this, people jump to faulty conclusions.

I visited an Emperor Penguin colony in Antarctica, and studied Adelie Penguins in Antarctica for three breeding seasons--so I'll provide "between the lines" commentary on the Emperor story.

Lines from the Guardian UK story are in italics; my comments are in blue:

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A young emperor penguin stranded on a New Zealand beach after an epic detour from Antarctic has been moved to a local zoo amid growing fears for its health.

It's common for young animals to wander widely. Wandering allows a species to find new feeding or breeding areas.  It's also a way to increase genetic diversity by spreading genes around the globe.  It's a process called "dispersal," --found one way or another in all species.

Of course, wandering might be risky for the young animals involved--particularly it's a problem finding a mate--but in the long run it's good for the species.  And, a wandering animal might be lucky.  The first Polynesians dispersing in canoes to Hawaii hit the jackpot.

But veterinarians and conservation officials have become so concerned about the bird they have decided to intervene.

A lot goes into the decision to intervene--and not necessarily the health of the bird.  First of all, the Emperor may be causing a public uproar.  People or dogs might abuse the bird.

Secondly, officials may want to look like they are doing something--not "neglecting" the bird, which people assume (perhaps incorrectly) is in distress.

Finally, bringing the bird to a zoo might increase publicity and visitation at the zoo--so the zoo might benefit more than the bird.

Bringing the bird to a zoo could expose it to disease or the stress of capture.  It might have been best to simply move it to an uninhabited island nearby.

The penguin... had been eating sand and small sticks of driftwood, which it had tried to regurgitate.

Adelie penguin chicks commonly eat small pebbles, and regurgitate them.   It's possible they eat pebbles (as do many birds) to help them grind up their food--since birds have no teeth. 

Or, they may eat pebbles to adjust their buoyancy.  Penguins have a lot of fat, but fat is lighter than water, and penguins have air trapped between their feathers.  Emperors dive at least a thousand feet deep--so they need to eliminate extra bouyancy.  Eating sand or pebbles may be their way.

When the reporter says the bird "tried to regurgitate," it sounds like the penguin was in distress.  But it's a normal behavior.  Penguins easily regurgitate--that's how the adults feed young.  Regurgitation by no means indicates the bird is sick.

However, at Hallett Station, where I studied penguins, there was junk strewn about the rookery.   Some chicks did pick up bits of toxic metal, causing mortality in a few cases.  Others were able to regurgitate the toxic pieces.

Update:  Barbara, in a comment at the end of this post, provides additional information about the sand.  A large mass of sand was visible in x-rays, compacted and not easily regurgitated. 

Colin Miskelly... said it made sense that a penguin might mistake sand for Antarctic snow, which emperors eat for hydration...

The kidneys of penguins aren't powerful enough to excrete the salt they take in with their food (or when they drink sea water).  However, penguins do have a special "salt gland" over each eye, discharging a salty fluid that drips off their beak.* So penguins can drink salt water.  We can't assume this bird was thirsty.

Adelie penguins do eat snow while in the rookery, but it's not clear this is a necessity.  Adult Emperors are probably familiar with sand, and wouldn't confuse it with snow.  But this young bird was a "teenager," and as we know, teens will sniff or ingest almost anything for a thrill.

...but he had no explanation for the bird eating wood.

Antarctic penguins normally have no experience with wood.  Antarctic beaches are entirely free of driftwood and junk.  So, they wouldn't know the difference between pebbles and bits of metal or wood.  If a penguin feels a normal urge to eat pebbles for digestion or adjusting buoyancy, they might pick up anything from the beach.

The penguin appeared to grow more lethargic as the week progressed, and officials feared it would die if they didn't act.

In the Antarctic, the beach or an ice flow is a safe place to snooze.  The only mammals on land there--seals--don't bother penguins, so an Antarctic penguin on a NZ beach would be very non-challant.  You could walk up to a penguin, and it would remain resting, unless you got too close.  People couild easily imagine such a bird was sick.

Miskelly was one of three experts who helped lift the penguin from the beach into a tub of ice and then onto the back of a truck.

Emperors are supremely adapted to cold, so they are stressed by the temperatures you'd find in New Zealand.  Some penguin species are found as far north as the equator, but they always live in areas of cold ocean currents.  Other threats,besides heat and ingesting junk:
  • Predators and people:  Antarctic penguins have no fear while on land, because there are no land predators in the Antarctic. 
  • Disease: Antarctic penguins in captivity are prone to lung infections from common molds.  Zoo habitats for penguins are kept as sterile as possible.
Christine Wilton, the local resident who discovered the penguin while walking her dog, was back at the beach on Friday to say goodbye.

"I'm so pleased it's going to be looked after," she said. "He needed to get off the beach. He did stand up this morning, but you could tell that he wasn't happy."

This illustrates how people jump to conclusions.  Public opinion creates pressure for officials to do something, even if it's not necessary.

Miskelly said experts at the zoo were considering sedating the penguin and putting it on an intravenous drip as they tried to nurse it back to health.

After penguin chicks leave the rookery, very little is known about what they do or where they go, until  they return several years later to breed.  So--rather than "saving" this bird from no real danger, it might have been better to protect it from disturbance and study its behavior.

The article presents no evidence that the bird was really sick.  All the Emperor needed was to be left alone, or transported to an uninhabited island, where it wouldn't be bothered.

Update: Based on Barbara's comment below, that the danger to the bird from sand was real, zoo experts may have been justified in treating the bird in captivity.

Nevertheless, given the large expense of this effort, one wonders whether investing instead a similar amount towards solving more basic threats--such as global warming--might have been more helpful for Emperors.

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*  You can see the location of the salt glands in this photo of an Emperor skull.  When the bird was alive, the glands were located in the deep grooves over each eye socket.

1 comment:

  1. After having seen images of the x-ray of Happy Feet I am quite convinced that this penguin would not have survived without any intervention. Yes, emperor penguin chicks often accumulate small pebbles which they are able to regurgitate. But a gut-full of sand (compacting as it was drying out) is not easily regurgitated. The quantity of sand in the penguin's stomach was immense!!
    There is no way that this bird was preparing for the moult. Juveniles moult in December, not June or July. Moreover, it was far too skinny to be ready to moult.
    For the sake of the bird, I am glad that DOC intervened. Leaving him on the beach, even at some island, would have been its demise.


Comments are welcome.