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Monday, May 4, 2015

Islanders and Aliens

Happy Star Wars Day! (May the Fourth... as in, "May the Fourth be With You..." get it?).  What better day to talk about aliens... but not the Yoda kind.

The invasion of Guam by the brown tree snake was novel in one way - the invader was a snake.  If you'd replaced it with, say, a mongoose, or a stoat, or rats or macaques, or perhaps feral dogs or cats, however, you would've gotten a story which has played out across the Pacific, from the Galapagos to New Zealand to Hawaii.  Expand your search further, and you would have seen similar losses in the Caribbean, the Seychelles, Mauritius, and the Mediterranean.  The story plays out like this:
  1. Island has unique wildlife, found nowhere else on earth
  2. Island is visited by humans
  3. Humans introduce domestic animals and/or invasive pests
  4. Island looses unique wildlife, now found nowhere on earth
To be sure, extinctions occur on the mainland also, both because of invasive enemies as well as other causes (habitat loss, hunting, etc), but islanders seem to be especially vulnerable.  Part of it is that islands are small, and so the populations that live their tend to be small.  Makes sense - smaller the land mass, smaller the number of animals it can supports, easier it is for predators to kill all of said animals off.  Because the landmass is smaller, the animals that inhabit them also tend to be more specialized, which works great when conditions are stable, but is very problematic when they suddenly change.

Island animals, especially those that evolved in the absence of predators, also tend to be naive in the face of danger, a tameness that some visitors mistake for stupidity.  No bird exemplifies (or exemplified, emphasis on past tense) this more than the dodo, a hulking, turkey-sized pigeon-like bird from Mauritius, off the east coast of Africa.  Unaccustomed to the indignities of being hunted, the dodo waddled up the first sailor with a club, and was driven to extinction shortly after its discovery.  

The dodo calls to mind another problem that many island birds face when dealing with invasive predators - many are flightless.  It seems silly at first - flight is the most awesome advantage birds have over mammals.  Why give up that gift?  The fact is, flight is expensive.  It takes a lot of energy for a bird to fly, and it requires specialized muscles and feathers that are - biologically - costly to maintain.  Fear is biologically expensive, too.  Imagine if you ran away from every single thing you saw that could be possibly dangerous - strangers you see while out walking, cars, unfamiliar dogs, unexplained noises - you'd run yourself ragged in no time.  Time spent running is time not spent eating, or mating.  If an animal has no predators in its environment, it makes sense to loose this fear, and if there is plenty of food on the ground, and no need to get up high, why bother flying?  Current flightless island birds include the kakapo and kiwis of New Zealand, the flightless cormorant of the Galapagos, and the steamer ducks of the Falkland Islands.  

It all makes perfect sense when you look at it naturally.  The problem is that we've made this an increasingly unnatural world, and it's getting harder for specialized, predator-naive animals to survive.  Invasive predators have eaten their way through populations of many island birds around the globe, driving some to extinction.  Others are found only in captivity now, stranded in zoos and breeding centers until a safe release site can be located.  Sometimes, this means waging costly, difficult eradication campaigns to cleanse habitats of invasive pests.  In other cases, it means playing Noah's Ark and trying to establish new populations of birds on predator-free islands (which, ironically, involves introducing non-native species... again).

Some islands birds are lost and gone forever - the moas of New Zealand, the elephant birds of Madagascar - and nothing (at least right now) - can bring them.  For others, however - species which are still hanging in the balance - there is still time, still a chance to pull them back from the brink.  

Guam and the other Mariana Islands have birds in both categories.

Saturday, May 2, 2015

Zoo History: Empire of the Brown Tree Snake

"But behavior, even in a pea-brained reptile, is surprisingly flexible.  On Guam, the snake forages as easily on the ground as in the trees, and it will consume anything that smells of blood... What scientists thought was one serpent is in effect two: the native and the colonist, the preinvasive and the postlapsarian."

- Alan Burdick, Out of Eden: An Odyssey of Ecological Invasion

By the 1960s, ornithologists studying the Pacific island of Guam knew that something was wrong – they just didn’t know what.  Before the startled eyes of scientists, the unique bird life of Guam – many of them species birds found nowhere else on earth – began to vanish, one species flickering out after another.  No one could agree on what the problem was.  Some said it was remnants of the pesticide DDT, still active in the environment years after its use.  Others suggested habitat loss, or maybe an introduced disease. 

The only known was that the southern third of the island was virtually devoid of bird life, and the line on “birdlessness” was steadily advancing.

In the 1980’s, biologist Julie Savidge was studying the extinction crises when she came across something she didn’t expect to find – a snake.  Guam had snakes, but they were tiny, worm-like things, not the large, active, muscular creature she found.  The species was identified as Boiga irregularis, the brown tree snake, known throughout Indonesia, New Guinea, and the Solomon Islands… but not on Guam.  Intrigued, she shifted her attention to the snakes and noticed a disturbing pattern – where the snakes appeared, the predator-na├»ve island birds disappeared.  She summed up her findings in a 1987 paper, “Extinction of an island forest avifauna by an introduced snake.”

In its native haunts, the brown tree snake is a modestly-sized, fairly cryptic species, a tree dweller that preys on arboreal birds (birds which have coevolved in the presence of the snake and are equipped to evade it) and is in turned preyed upon by monitor lizards and birds of prey.  On Guam, the snake found paradise – no predators, and prey that had never seen a snake as a threat before.  The damage was devastating – three of Guam’s endemic birds were eaten out of existence, whereas others now only exist in zoos and breeding facilities.  The brown tree snakes of Guam became different from those of Indonesia or New Guinea – bigger, more adaptable, more aggressive.  They eat the birds, yes, but have also learned to scavenge, everything from raw meat to canned dog food to bloody tissues.  Up to 40 snakes may be found on an acre of forest.  Here on Guam, Dr. Jekyll became Mr. Hyde.

How did the brown tree snake get to Guam – and, recently, onto other Pacific islands – in the first place?  It’s suspected that the brindled white-eye, Guam broad-bill, and other island birds are the last casualties of World War II.  During the war, American warplanes island-hopped around the Pacific, and it is likely that when they did, they carried stowaways.  Brown tree snakes can go a long time without food or water, allowing them to comfortably wait out a ride.  A female can store sperm for months, allowing a single gravid female to colonize an island.

Birds, lizards, and bats aren’t the only victims of the brown tree snake’s expansion.  It’s destroyed local poultry industries.  It’s been known to enter houses and bite people as it forages for food – the species is moderately venomous.  Most irritatingly, it has caused thousands of power outages.  Highly arboreal the snakes climb power poles, and their combined weight can bring the wires down.

There has been little success in controlling the brown tree snake.  Introduced diseases, poisoned baits, physical removal, snake-proof barriers – all tried with limited success.  Some scientists have quietly written Guam and other snake-infested islands off, focusing more on what can be done to prevent the expansion of the snake’s growing range.  Of all the islands in the Pacific, the most heavily guarded is Oahu, in Hawaii.  Hawaii is the crossroads of the Pacific in terms of commerce and transportation – from here, the snakes could get anywhere.  So far, a tiny handful of brown tree snakes have been captured on Hawaii (often with the help of trained dogs), but they are not believed to be established… yet.
The US government uses posters like this to help people identify and report spreading brown tree snakes

The fight to limit its spread continues, but it is still to be seen what island is the next to fall to the brown tree snake.

So, how does this all count as “Zoo History?”  Later this month, we’ll be showing how zoos have been involved in the struggle to save Guam’s remaining bird life from extinction.

Friday, May 1, 2015

Mariana May

This month, I'm going to try to do something a little different with the blog.  For the first time, I'm going to have a monthly theme, focused around one topic, a topic which many zoos and government agencies have been dealing with for years, but one which hasn't received too much attention from most people (certainly less than global climate change or poaching).  That topic is the avian extinction crisis of the Mariana Islands.

Though governed by the United States, the Mariana Islands are the most far-flung parts of the country, lonely crescent of islands south of Japan, north of New Guinea.  As with many islands far removed from land, they are home to unique creatures found nowhere else on earth... and that unique wildlife - especially the bird life - is under siege.  For the ornithologist, the Marianas must have seemed an Eden of friendly, beautiful birds, evolving in a world free from danger.

Every Eden, as we'll see tomorrow, has a snake, however...

Wednesday, April 29, 2015

Book Review: Last Flight of the Scarlet Macaw

"Belize draws the eccentric, the madcap, and the downright mad.  In this colorful human menagerie it takes some doing to stand out, but there is one woman who manages to delight, enrage, captivate, frustrate, and inspire her fellow Belizeans more than anyone else.  She's the proprietor of the Belize Zoo.  Her name is Sharon Matola."

Despite the title, the scarlet macaw doesn’t feature too prominently in Bruce Barcott’s piece of environmental journalism.  Macaws do appear in it – as do jaguars, harpy eagles, and Baird’s tapirs, to name a few animal costars – but only in the role of a catalyst for the story.  Instead, the book is the tale of Belize, an obscure Central American country, largely ignored by the rest of the world.  It is this indifference, this lack of attention, which has allowed some shady deals to unfold over the years, including a proposal for the construction of a dam which would destroy some of the most pristine habitat in Central America.

Unfortunately for government ministers and dam investors, some people were paying attention.  Among them was Sharon Matola, the founder and director of the Belize Zoo.  Matola created the zoo – founded with the leftovers from a wildlife documentary shooting – with the twin purposes of housing non-releasable native wildlife and introducing Belizeans about their wildlife heritage.  When Matola learned about the proposed dam and what its impact would be on the wildlife of Belize, she (respectfully) called attention to the issue.  When the government tried to intimidate and silence her, she gathered allies – both in Belize and around the world – and fought back.

The book is a fun ramble over a series of topics – from tropical ecology to the Matola’s biography, the history of Belize to the history of dams.  For most of the topics involved, if you’re looking for a specialist source of information, you can find a better one – that’s not what this book is.  Instead, it’s a front-row view of a scene that’s unfolding all over the world – striking a balance between environmental protection and economic development.

In some ways, the expose of the Chalillo Dam isn’t the best example, because Barcott goes to show it’s such a corrupt, uneconomical, impractical project that it should’ve been dismissed immediately.   If it had been perhaps a better project, one that would have made a real improvement in the lives of local people, the story would have been different.  In either case, the book does force the reader – especially the North American or European nature lover – to re-examine their feelings about the environment-economy debate in the developing world. 

Just playing devil’s advocate – the more we learn about the dam through the eyes of the author, the sketchier the whole thing seems.  Still, ignoring this particular case, it does raise questions.

Proponents of the dam point their fingers at Matola and her allies and accused them of meddling at best, of neocolonialism or (in the case of Matola and other Belizean citizens) treason at worst.  “This is our country, our people are poor, and we need this,” they say, “What right have you to dictate to us what to do in our own nation?”  They do have a point – it’s easy for us to place more value on scarlet macaws than on sustenance farmers.  Besides, we’re saying these things after having already destroyed most of our own ecosystems (including damming a heck of a lot of our own rivers) – what gives us the right to judge?  But on the other hand, if the governments charged with the task of protecting wild animals and wild habitats won’t do their job, then who will?

Monday, April 27, 2015

Where in the World?

Happy World Tapir Day!  (Giraffes get a day, penguins get a day, everyone gets a day, it seems).  Today, the world - or at least the very tiny percentage of it that cares - celebrates the world's five (or four - still some argument) species of tapir - solitary forest-dwelling ungulates from Central and South America... oh, yeah, and Southeast Asia.

Hmmm... about that one.

One of the most fascinating aspects of animals' natural history is the question of what animals end up where.  Why are all the tapirs in Latin America, except a single species - the Malayan tapir - found clear on the other side of the world?  For that matter, if you have tapirs in South American rainforests and Asian rainforests, why not in African rainforests?  Then again, why do the African and Asian rainforests have apes, but not the South American?  One species of alligator is found in the southeastern United States and is very common; the only other one in the world is found in China, and is critically endangered.  What gives?

The science of the distribution of animals around the world is called zoogeography.  It tries to answer these questions, and sometimes it succeeds.  Sometimes it's a story of ancient geology - seas rising and falling, mountain ranges and canyons appearing, continents drifting - for the later, consider North and South America, which were once entirely separate land masses before they collided together, allowing animals to cross between the two.  In other cases, more active exploration leads to animals appearing in strange places - consider the various island animals, carried out to sea on floating rafts and colonizing new islands.  Sometimes, a species was once widespread around the globe, and then disappeared as conditions changed, leaving only a few remnant populations.  And sometimes we have no idea... yet.

Part of it may have to do with chance, too.  Perhaps tapirs would do very well if they were introduced to the Congo.  Maybe gorillas or orangutans would thrive in the Amazon - plenty of other species do just fine when they are introduced (often by human intervention these days) into a new environment.  And maybe not - maybe they wouldn't be able to find appropriate food items, or maybe there is some other variable that would prevent them from establishing themselves.  There have been plenty of experiments - some disastrous, some harmless, some bizarre - in introducing animals around the globe.

Tapirs probably aren't destined to be added to that list any time soon.

Friday, April 24, 2015

From the News: Kansas City Zoo gives up palm oil to save orangutans

I die a little every time I go to the grocery store.  Living on a zookeeper salary, I try to do my shopping on the cheap side, but I do have a sweet tooth that I am totally owned by.  No fancy, expensive desserts for me, but a box of donuts or a carton of ice cream to get me through the week is essential for my mental (if not physical) well-being. Unfortunately, almost all of the inexpensive options contain palm oil.  My love for wildlife and my love for cheap pastries are thrown into sharp conflict.  Depending on how rough the week has been, wildlife doesn't always win.

So kudos to Kansas City Zoo for doing what I don't have the strength to do - make a break from palm oil.  Hopefully, more zoos, aquariums, museums, and other wildlife facilities will follow in their footsteps.  After all, there are substitutes we can use for palm oil.  There is no substitute for an orangutan.

Orangutans at the Kansas City Zoo.

Wednesday, April 22, 2015

Earth Day Quiz

On Earth Day, we celebrate our planet and all of the biodiversity found on it, as well as those who are working diligently to save it.  I came across this editorial on The Huffington Post by Dr. Cristian Samper of the Wildlife Conservation Society, reminding everyone of the role that zoos and aquariums play in protecting our natural world.  Enjoy!

Instead of my normal monthly Sporcle quiz, today I'm sharing a short "What Animal Are You?" quiz that Google produced to celebrate Earth Day.  I'm not sure how I feel about winding up with giant squid, but maybe you'll make more sense out of whatever animal you get.