Archive | August 14, 2012

Galapagos: The birds

Mating Swallow-tailed gulls (Creagrus furcatus), the world’s only nocturnal gull species, endemic to the Galapagos. Where else in the world can you photograph mating birds with a 14mm lens? [Canon 7D, Canon 14mm]

A recent visit to the Galapagos has fulfilled my life-long dream to see one of the most iconic and beautiful natural history destinations in the world. It was as good as I hoped it would be; it was also an exercise in frustration. The abundance of wildlife I encountered there was astounding, and the fact that nearly everything that I saw was endemic and loaded with historical and evolutionary significance made for an amazing wildlife experience. I was able to see most of the endemic animal taxa, both vertebrate and invertebrate, and a good representation of the unique Galapagos flora. At the same time, since I was visiting the islands as a tourist and not a researcher, my ability to photograph things was limited (for example, it is forbidden to use flash photography anywhere on the islands, which severely limited my ability to do macrophotography), and of course collecting anything was out of the question. I was itching to go out at night with a headlamp and look for the endemic crickets, and wanted to spend days flipping rocks on the volcanic shores, looking for its rich fauna of littoral crustaceans. Alas, it was not to be, at least not this time. But I did manage to find and document a few very interesting, less-known Galapagos organisms, and I will write about them in the coming days.

Not being able to indulge my obsession with the smaller majority forced me to shift my attention to the big and “charismatic” , and no group of animals is easier to see and appreciate in the Galapagos than birds. I am not too much into birds, in fact my knowledge of these animals is probably more rudimentary than that of any other major group of organisms. It is not that I don’t appreciate their beauty and complexity of their behaviors, it is just that the field of ornithology has always appeared to me too crowded (often with characters so narrowly focused on their binoculars’ narrow field of vision as to ignore the rest of the natural world), and getting up before dawn to watch fleeting shadows in the canopy holds little appeal for me. But the Galapagos Islands presented to me a world of birds that I can wholeheartedly embrace. And while this blog is devoted to pretty much everything BUT birds and mammals, I cannot resist sharing a few ornithological snapshots from my very brief trip to las islas encantadas; I also promise that this is the last time that I write a post about birds.

Darwin’s finches are rather uniform in their appearance, but each species displays a different beak shape and feeding specialization. Males of most species are black, while females and juveniles are speckled grey. A. Large Ground Finch (Geospiza magnirostris)from Genovesa; B. Sharp-beaked Ground Finch (Geospiza difficilis), male, from Genovesa; C. Small Cactus Finch (Geospiza scandens) from Santa Fe; D. Green Warbler-Finch (Certhidea olivacea) from Genovesa.

No birds are more emblematic of the Galapagos than Darwin’s finches. About 14 species of finches are found on the Galapagos, and while very similar in the overall appearance, each species exhibits a specialized feeding behavior, reflected in the morphology of their beaks. It was this variation in the beak shape that gave Darwin supporting arguments to his idea of “transmutation” of species, as he noticed that their morphology changes to best adapt to the local conditions and different sources of food. Since his time we have learned quite a lot about the underlying genetic and developmental mechanisms of the finch’s beak; it was recently discovered that a single protein calmodulin, is ultimately responsible for regulating enzymes that turn on and off genes that control development of different types of beaks.

Galapagos mockingbirds (Mimus parvulus) from Genovesa [Canon 7D, Canon 14mm]

But it wasn’t the finches that first got Darwin thinking about the origin of species on the Galapagos, it was mocking birds. He noticed that birds from different islands differed ever so slightly but consistently in the coloration of their plumage and the shape of their beaks which, combined with the knowledge that giant tortoises from different islands exhibit similar difference, started him on the path towards a crystalized view on the function of natural selection. He also kicked himself for not keeping better track of finch specimens collected from different islands.

Galapagos, located at the confluence of several cold, nutritionally rich oceanic currents, is also chockfull of marine birds that flourish in the carnivore-free, fish-plentiful environment. Most are so unafraid of people that you really need to watch where you step, or you will risk squishing some cute booby chick, or trip over a frigatebird nest. I wish I had more time to spend watching these animals there and, who knows, maybe I would become a twitcher after all.

Galapagos flightless cormorants (Nannopterum harrissi) from Fernandina [Canon 5D, Canon 100-400mm]

Nazca boobies (Sula granti), a male and a chick from Genovesa [Canon 7D, Canon 16-35mm]

Blue-footed booby (Sula nebouxii) from North Seymour [Canon 7D, Canon 14mm]