Looking back to Chiloé, where Darwin roamed

Juneau naturalist studies a temperate rainforest similar to Southeast Alaska

Posted: Sunday, December 23, 2007

Charles Darwin visited Chiloé Island in 1834 and 1835 on his now-famous voyage around the world in the Beagle. I don't think he liked the island very much. About the climate he said: "In winter the climate is detestable, and in summer it is only a little better." He found the forest beautiful but gloomy, impenetrable, impervious, blackish-green, and generally silent. The poor but industrious people had been "negligent" in clearing the forest, which was "a heavy drawback to the prosperity" of the island. And he showed no signs of learning anything there that contributed to the later development of his then-radical ideas.

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Poor Charles! He really missed lots of good things on Chiloé. Winters are indeed wet and windy, but this is no big thing for visitors from Juneau. And summers can be sunny, dry, and hot. The forest is certainly thick and dense, and often very muddy, but full of bamboo thickets and spectacular flowering trees and vines. Juneau folks have lots of experience handling mud, but we don't have the scarlet, white, pink, and yellow flowers on the trees and shrubs. His impression of a silent forest is mystifying; in spring and summer the songs of birds can be heard everywhere. And by now, much of the forest has been cut and burned, for agriculture and for plantations of exotic trees, so presumably Darwin would be pleased.

The south-temperate rainforest of southern Chile, including Chiloé, represents a curious composite of different worlds. Most of the trees are broad-leaved, evergreen, and closely related to species on the other side of the world in New Zealand and eastern Australia, and even southern Africa. They are living evidence that all the southern continents were once joined into a huge super-continent called Gondwanaland - there are even fossil trees of similar types in Antarctica.

Many of the native birds, on the other hand, are related to North American species. A visitor from Alaska would immediately recognize the austral thrush as a sort of brown robin, and the austral pygmy owl is almost identical to our own northern species. The common Chilean swallow is similar to the related tree swallow up here. A few wide-ranging species, such as kestrels and great horned owls, are even the same as here at home.

However, many other native birds are related only to other Latin American species. The bird communities of Chilean rainforests are distinguished by a high degree of endemism - that is, many of the species have very small geographic ranges that are restricted to the south-temperate rainforest, or even just part of it, and they occur nowhere else in the world. Some of these species belong to a Latin American family of birds called tapaculos. There are four kinds of tapaculos in the Chilote rainforest, and my favorite one is the chucao tapaculo.

When Darwin visited Chiloé, he noticed "an odd red-breasted little bird" that ran around on the forest floor uttering peculiar noises. That's the chucao tapaculo, but its breast is orange, not red, and its plumage nicely matches the colors of many of the fallen leaves on the ground. My introduction to chucaos came as I was crawling around on the soggy ground, counting seedlings of bird-dispersed trees for a preliminary study. A chucao walked right up next to me, checked out my activity - and was probably hoping that I'd stirred up some nice, juicy grubs in the leaf litter.

Chucaos run very fast through the dense understory on the forest, changing direction frequently, so they are very hard to follow. But at times, they approach humans very closely, as I saw in my first encounter. I later had one come and sit on my notebook while I sat taking notes on the parent birds' behavior at a nest.

Country people still tell the old myth about chucaos: When you leave the house in the morning, if you hear a chucao call on the left, that is bad luck and you should go back immediately and stay home. But if it calls on your right, then it is OK to proceed upon your business for the day. For me, however, chucao calls from all sides were good luck and very much OK.

My research team eventually found a chucao nest and I saw the chicks for the first time. There were two of them (the usual number), and they were almost ready to leave the nest. They already had plumage like their parents, except for an "afro" of extraordinarily long down on top of their heads. The long "hairdo" flopped down over their eyes in a most engaging way. I was captivated. That was years ago, and I've seen hundreds of chucao chicks since then, and I still chuckle at the sight.

So here was this totally cute little bird whose populations also happen to be threatened by potential extinction because of loss of the forest habitat. How could I not study it? Thus, for the next 15 or so years, I became sort of a migratory bird - conveniently leaving the grubby Juneau fall for the austral spring, with its long days and only occasional rain. But there's just as much mud, and as many fallen tree trunks, and as thick an understory as there is around home, and you'd think I'd have enough sense to locate a new study in something besides rainforest!

Over the years, my field assistants for the chucao project came from Alaska and other parts of the U.S., Canada, Argentina, Australia, and Chile. It often takes a team of observers to find chucao nests, because they are usually in cavities and well hidden in the dense vegetation. We documented nest success of many nests, and banded chicks and adults, each with a unique color combination, so we could estimate survival by re-sighting them later. We also learned that chucaos are restricted to areas with dense cover of vegetation, so as more and more land is cleared, they not only lose habitat but also have trouble moving around the landscape. They depend on 'bridges' or corridors of dense growth to move among the fragments of forest that still remain. Without those bridges, chucaos in isolated forest patches often fail to get mates and that local population may die out altogether.

We have provided enough information to design a conservation plan for this bird in this landscape. The same plan will also serve several other endemic species that are similarly dependent on wooded connections between patches of suitable habitat. Survival of these species now depends on attitudes and policies within the country. So their fates are uncertain.

This year in Chiloé, I found three nests of the chucao, just for fun. As usual, the nests were very well hidden, but under big piles of dead fern fronds instead of in tree cavities. There was no way to dig down to the nests themselves without destroying their concealment, so I did not get my "fix" of seeing the comical chicks.

It will be hard to say goodbye to this place. I have enjoyed the view of the Cordillera of the Andes to the east (on clear days) and the volcanoes on the mainland to the north (ditto). I'll miss the gaudy, red, bird-pollinated flowers of the notro tree and the wild fuchsia bushes with their red and purple flowers dancing in the breeze like diminutive ballerinas. The tiny Darwin's fox and the small deer that bolts through the understory will be just memories. Most of all, I will miss my little chucaos and all the good fellowship of the folks who share the field station.

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