The Channel Islands: California s Galapagos

Scorpion Harbor, Santa Cruz Island, Channel Islands National Park | Photo: Jake Pfaffenroth, some rights reserved

The archipelago is a little world within itself, wrote the naturalist Charles Darwin about the worlds most scientifically famous cluster of islands. The official mission of the HMS Beagle was to explore and chart the coastlines and islands on the Pacific side of southern South America, but its perhaps best known for its five-week stop at the Galapagos, an archipelago built from volcanic rock that erupts from the sea some 600 miles from the coast of Ecuador.

A visit to the Galapagos is perhaps the closest thing to a holy pilgrimage for biologists, and for good reason. While it would be quite some time until Darwins theories regarding evolution and natural selection would germinate, the seeds of the idea were planted here.

But after spending a week exploring the islands looking for flightless seabirds, massive tortoises, seagoing iguanas, and those famous finches, I began to wonder whether there was anything inherently special about the Galapagos in the first place. After all, other archipelagos are home to equally impressive and strange collections of wildlife. Islands are important laboratories for biodiversity, places where natural selection has produced some of our planets strangest creatures. But the Galapagos? Perhaps their specialness was simply an artifact, an accident, a side effect of the fact that they were on the Beagles itinerary.

I never dreamed that islands, about fifty or sixty miles apart, and most of them in sight of each other, formed of precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted, wrote Darwin of the islands, yet the same could be said about an archipelago thats perhaps more familiar to Angelenos: the Channel Islands, sometimes referred to as the Galapagos of North America.

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The Channel Islands have their own examples to rival the Galapagos, says USGS biologist Katie Langin. While at Colorado State University, she completed her PhD studying scrub jays on Santa Cruz Island - the one off the coast of Santa Barbara, not the identically named one in the Galapagos. The Island scrub jay is descended from its mainland counterpart, the Western scrub jay, but its been flitting among the oaks and pines of Santa Cruz island for at least a million years, slowly changing in fits and starts, adapting to its seaside habitat.

Island scrub jay | Photo: U.S. Fish and Wildlife Service

If that sounds at least superficially like Darwins finches, thats no accident. The thirteen types of Galapagos finches, all descended from a mainland finch, are famous for the ways in which their beaks are adapted over the last two million years for the types of foods they eat. Some eat seeds, some eat bugs, and one, the vampire finch, even evolved a beak that pecks holes onto seabirds from which they slurp up the oozing blood.

But the parallels run deeper. We did not go to the island seeking evolutionary divergence within the species, Langin says. Her fieldwork, at first, was intended to monitor the population and identify what factors may have been contributing to its decline.

But after her first field season, once she was back in Colorado, something was nagging. She knew that mainland scrub jays had evolved slightly different beaks depending on their diets. Those that lived in oak-dominated landscapes had shorter, stouter beaks, perfect for extracting food from inside an acorn. Those that forage among the pinion pines of Utah, Colorado, and elsewhere have slightly longer, narrower beaks, useful for breaking into pinecones.

So on a whim, she decided to see whether the island jays might show a similar pattern. My jaw dropped, she said. Even with a small sample size, the differences were apparent.

And these differences dont play out across thousands of miles like they do on the mainland. Santa Cruz island is home to three distinct pine forests, separated by oaks. In some cases, oak trees and pine trees sit just a few yards from each other. And yet, by the time shed captured and assessed nearly a quarter of the whole species, the pattern was clear. Despite sharing a single island, the birds had evolved slightly different beaks thanks to their different diets. Just like Darwins finches.

Theyre not the only ones.

Endemic island skunks show up on two of the Channel Islands, unique deer mice can be found on all eight. Three islands have their own night lizards, another three have endemic fence lizards, four have endemic salamanders, and Santa Cruz boasts its own gopher snake.

Catalina Island fox | Photo: Chris Clarke/KCET

Then there are the foxes. Six of the eight Channel Islands are home to a unique type of fox, found nowhere else in the world. The foxes together comprise a single species, separated from its mainland ancestors some ten thousand years ago, but each island is home to its own unique sub-species.

Galapagos iguanas follow a similar pattern. Some mainland iguana rafted over to the islands around 4.5 million years ago, its offspring eventually branching into two groups: the yellow, cactus-eating terrestrial iguanas, of which there are three species, and the dark black, algae-eating marine iguanas. The iguanas have different adaptations to their very different ways of life; each islands iguana population is just a little bit different. The terrestrial iguanas of Isabela Island have a pinkish tint, for example, while the marine iguanas on Floreana have red bellies. Those on Espa ola Island show off reds, greens, and blues, earning them the nickname Christmas iguanas.

The Channel Islands arent unique either. The Hawaiian archipelago is home to a staggering variety of endemic birds, plants, insects, spiders, and even two mammals. Instead of finches or jays, the Hawaiian Islands b

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