Land of the Lost: The Nene of Hawai'i

For the first-time traveler to Hawai'i, a word about the birds. There are two groups of birds, the species native to the Hawaiian Islands, and the introduced, or invasive species. There are also two groups of birds, the ones you are likely to see during your trip, and the ones you won't. It's unfortunate, but the two lists are pretty much the same. The native birds of the islands are under assault, and most of them never were a good fit for urban environments where island visitors spend most of their time. The natives have been decimated by disease (often transmitted by mosquito, another island invasive), habitat loss, predation by rats, mongoose, and cats, hunting, and competition from non-native birds. The state bird of Hawai'i, the nene (Branta sandvicensis), is the most iconic example of a native that was almost driven to extinction. A close relative, the Giant Hawaiian Goose, once lived on the island, but is now extinct. I wrote about the nene a few months ago, and the following is an abridged version of that post.

Perhaps 500,000 years ago, a pregnant Canada Goose, or a small flock of geese took a wrong turn. A really wrong turn. Somehow, flying along the coast of North America, the leader maybe decided to take a short cut, and it went poorly. Soon the shoreline was lost to view, and for days, not a single bit of land could be seen. I can imagine the flock becoming smaller and smaller as the weaker members fell behind and were lost.  After days of nothing but ocean, an island came into view. The tired geese landed and began looking for food. None of the plants were particularly familiar, but some proved edible and a few of the geese survived. For all we know, some of them rested up and left for further journeys, but a few stayed around. They took up residence on the volcanic island in the tropics of the Pacific Ocean, a vastly different environment than their summer home in the Canadian Arctic. The isolated volcanic edifices are today called the Hawaiian Islands.

During the millennia that followed, different flocks of geese took up residence in different ecological niches, such as lava flows, grassy slopes, and woodlands. Isolated groups began to diverge, and before long at least three species developed on the islands. One of them, the Giant Hawaiian Goose (species name not yet established), was big, almost four feet long. A lack of predators on the island made flight an energy-intensive but unneeded luxury, so the wings became smaller as the bird evolved to larger size. The goose was flightless. This worked fine for a long time, but humans ultimately arrived on the islands, and probably exterminated them, either by hunting, or by introduction of egg-eating rats, or by habitat destruction.

The second species was the nene-nui (Branta hylobadistes). It was also a big bird, but had larger wings so that it was still capable of weak flight. Like the Giant Hawaiian Goose, it became extinct soon after the arrival of humans on the islands. It has been characterized as a bird in evolutionary transition, in the midst of losing the ability to fly, but it went extinct first. Possibly because it couldn't fly well.

I didn't mean that as a flippant remark. Evolution is a process that has provided the incredible diversity on our planet, and isolated islands have provided the crucible in which much of the planet's diversity has arisen. But birds and other animals that have adapted to very specific situations are vulnerable when those situations are changed. The two extinct Hawaiian geese species were secure on the Hawaiian Islands, but the arrival of humans changed their environment too much and too fast. They were certainly easier to capture than a bird that could escape by flying.

The flying goose, the one that survived was the nene (Branta sandvicensis). The nene's wings were smaller than its Canadian ancestors, because it didn't need to migrate thousands of miles during the change of seasons. But it retained enough flying ability to escape from the island's human invaders. It differed from the Canada Goose in several other respects, including longer legs, reduced webbing between its toes, and a more erect posture. It is adapted to living on lava flows and grasslands, and was less dependent on wetlands than other geese.

It survived, but no longer thrived. Rats ate their eggs and chicks, and later on cats and mongooses were brought to the islands. The species was devastated, dropping from an estimated 25,000 when first European contact was made in 1778 to thirty individuals in 1952. A captive breeding program began, and populations were established on their ancient habitats on Maui and Kauai (where mongooses were never introduced). The wild population is now around 1,950 with another thousand or so in captivity. They are still highly endangered, but their prospects are slowly improving. They have been named the state bird of Hawaii.

I've seen the nenes (pronounced "nay-nay") on Maui at Hosner Grove (the top picture), and on the flank of Kiluaea in Hawaii Volcanoes National Park on the Big Island (the other two pictures). It is awe-inspiring to observe the descendants of a few very unlucky Canada Geese (or lucky?) who made a wrong turn 500,000 years ago and survived a terrifying journey over a very large ocean. I'm glad we're trying to help them survive, instead of driving them to extinction.

Are you interested in learning a bit more about these fascinating creatures? Here is a link for a National Geographic article on the evolution of the Hawaiian geese and their Canadian cousins, and the scholarly article of the research into the vanished species:

 http://news.nationalgeographic.com/news/2002/02/0206_020206_canadiangeese.html

 http://www.pnas.org/content/99/3/1399.full

A Bird Shangri-La No More: The Moas of New Zealand

Note: because the subject matter of this post overlaps with things I usually cover at Geotripper, I'm posting it in both blogs, with just a few editorial adjustments.

Blogging always involves a little bit of free association, where inspiration comes from numerous unrelated events over the course of a few days. I've started my fall semester, and I've met 170 new people over the last week. I've given introductory presentations that describe the reasons a person might want to pursue studies in geology and the earth sciences including a rundown of some of the interesting fossils that have been found in the region. So, I've been thinking about the past, the very deep past of millions of years ago.

Then, I've been blogging here about some birding adventures overseas including trips in Switzerland, Italy, and Australia. While looking for bird pics, I came across the picture below of some Moa replicas that we saw at a New Zealand wildlife park. Replicas, because Moas no longer exist in our world. But once there was a Shangri-La for the birds, a paradise on Earth, in New Zealand.

12 foot fiberglass Moas lurking in a Gondwana forest in New Zealand

New Zealand was a paradise for birds because the island mass separated from other continents prior to the mass extinctions of the late Cretaceous. Small mammals were present, but on the islands they were never much of a threat to the birds, and eventually they went extinct, except for some bat species. With the loss of the dinosaurs and the mammals, the only vertebrates in position to dominate the terrestrial ecosystems were the, uh, dinosaurs. The avian dinosaurs. With no reptilian or mammalian predators, the birds were able to evolve a flightless lifestyle (flight is an expensive energy proposition if it is not necessary for survival). Eventually a number of very large birds evolved, including eleven species of Moas. The largest stood over 12 feet tall (3.6 meters). The Moas were mainly plant-eaters but predators existed on the islands as well, including the extremely large Haast's Eagle (Harpagornis moorei) with a wingspan of nearly 10 feet (3.3 meters).

The Moas in the picture above aren't real. I've added a shot of an Emu from the wildlife park we visited as a stand-in for the large, flightless birds

The trees on the island provide another link to the past. Some of the huge tree ferns in New Zealand evoke Jurassic forests of the long-sundered Gondwana supercontinent. The ferns in the photo below line the opening of a 75-foot deep explosion pit at Orakei Korako Geothermal Area on the North Island. I've never such huge ferns before.

The ancient tree that captured my imagination the most was the Kauri tree (below), one of the bulkiest trees on the planet, rivaling even the Sequoia trees in my own backyard of the Sierra Nevada. The most mature trees are not quite 200 feet high, but their trunks remain thick practically to the crown. Their history extends back into Jurassic time. They once covered large portions of the islands, but unfortunately their wood is strong, mostly knot-free, and attractive. Something like 95% of the original forests have been cut down, and old-growth forests are exceedingly rare and precious. The trees are now protected by law, but ironically, dead trees in swamps are not, and the wood is durable enough that some of the trees from the swamps are still utilized legally, despite having been dead for hundreds or thousands of years.

Unfortunately, the arrival of humans on the islands around 700 years ago spelled doom for the avain Shangri-La. Slow-moving, with no defensive instincts, they were hunted to extinction in just a few decades after the human invasion. When they were gone the large raptors lost their primary food source and went extinct as well. Of the flightless birds, only a few species of the Kiwi, the threatened small forest dwelling bird, survives today.

A New Zealand Fan-tail, one of dozens of endemic bird species found in Kiwi land

Geology and paleontology are disciplines for creative and imaginative people. They recreate for us past worlds full of strange and wondrous creatures that are long gone from today's world. There are enough samples of DNA from the extinct Moas that there is a slight hope of bringing them back as living species, but that's probably a long time in the future, if ever. We must live instead with their echoes and the cultural memories and stories of the descendants of the people who once lived among them.

Bird of the Day: What Happens if a Canada Goose goes on a Tropical Vacation? nene!

Perhaps 500,000 years ago, a pregnant Canada Goose, or a small flock of geese took a wrong turn. A really wrong turn. Somehow, flying along the coast of North America, the leader maybe decided to take a short cut, and it went poorly. Soon the shoreline was lost to view, and for days, not a single bit of land could be seen. I can imagine the flock becoming smaller and smaller as the weaker members fell behind and were lost.  After days of nothing but ocean, an island came into view. The tired geese landed and began looking for food. None of the plants were particularly familiar, but some proved edible and a few of the geese survived. For all we know, some of them rested up and left for further journeys, but a few stayed around. They took up residence on the volcanic island in the tropics of the Pacific Ocean, a vastly different environment than their summer home in the Canadian Arctic. The isolated volcanic edifices are today called the Hawaiian Islands.

During the millennia that followed, different flocks of geese took up residence in different ecological niches, such as lava flows, grassy slopes, and woodlands. Isolated groups began to diverge, and before long at least three species developed on the islands. One of them, the Giant Hawaiian Goose (species name not yet established), was big, almost four feet long. A lack of predators on the island made flight an energy-intensive but unneeded luxury, so the wings became smaller as the bird evolved to larger size. The goose was flightless. This worked fine for a long time, but humans ultimately arrived on the islands, and probably exterminated them, either by hunting, or by introduction of egg-eating rats, or by habitat destruction.

The second species was the nene-nui (Branta hylobadistes). It was also a big bird, but had larger wings so that it was still capable of weak flight. Like the Giant Hawaiian Goose, it became extinct soon after the arrival of humans on the islands. It has been characterized as a bird in evolutionary transition, in the midst of losing the ability to fly, but it went extinct first. Possibly because it couldn't fly well.

I didn't mean that as a flippant remark. Evolution is a process that has provided the incredible diversity on our planet, and isolated islands have provided the crucible in which much of the planet's diversity has arisen. But birds and other animals that have adapted to very specific situations are vulnerable when those situations are changed. The two extinct Hawaiian geese species were secure on the Hawaiian Islands, but the arrival of humans changed their environment too much and too fast. They were certainly easier to capture than a bird that could escape by flying.

The flying goose, the one that survived was the nene (Branta sandvicensis). The nene's wings were smaller than its Canadian ancestors, because it didn't need to migrate thousands of miles during the change of seasons. But it retained enough flying ability to escape from the island's human invaders. It differed from the Canada Goose in several other respects, including longer legs, reduced webbing between its toes, and a more erect posture. It is adapted to living on lava flows and grasslands, and was less dependent on wetlands than other geese.

It survived, but no longer thrived. Rats ate their eggs and chicks, and later on cats and mongooses were brought to the islands. The species was devastated, dropping from an estimated 25,000 when first European contact was made in 1778 to thirty individuals in 1952. A captive breeding program began, and populations were established on their ancient habitats on Maui and Kauai (where mongooses were never introduced). The wild population is now around 800, with another thousand or so in captivity. They are still highly endangered, but their prospects are slowly improving. They have been named the state bird of Hawaii.

My travels in Hawaii were part of the inspiration for my new-found love of bird watching and bird photography. I've seen the nenes (pronounced "nay-nay") on Maui at Hosner Grove (the top picture), and on the flank of Kiluaea in Hawaii Volcanoes National Park on the Big Island (the other two pictures). It is awe-inspiring to observe the descendants of a few very unlucky Canada Geese (or lucky?) who made a wrong turn 500,000 years ago and survived a terrifying journey over a very large ocean. I'm glad we're trying to help them survive, instead of driving them to extinction.

Are you interested in learning a bit more about these fascinating creatures? Here is a link for a National Geographic article on the evolution of the Hawaiian geese and their Canadian cousins, and the scholarly article of the research into the vanished species:

 http://news.nationalgeographic.com/news/2002/02/0206_020206_canadiangeese.html

 http://www.pnas.org/content/99/3/1399.full