DARWIN’S FINCHES OF THE GALAPAGOS ISLANDS

I would be remiss if I didn’t dedicate one of my posts on the Galápagos Islands to the bird that ignited Charles Darwin’s interest in the evolution of species:   the finch. It is a small creature, but its impact on Darwin’s treatise and the study of life in general,  is monumental.

There are over 14 different species of finch which all developed from a common ancestor that flew over from the South American mainland.  With no pressure from predators, the Galapagos finch population grew  and is one of the best examples of “adaptive radiation:”

The  diversification of an ancestral group of organisms into a variety of related forms specialized to fit different environments or ways of life, each often further diversifying into more specialized types.

These little birds evolved based upon attributes to best  flourish in different biological niches – small, medium and large seed eaters on the ground and in trees, fruit and insect eaters, nectar drinkers and amazingly even tool users.

Darwin collected many specimens during his Galapagos visit and also drew pictures.  I am always struck how so many naturalists have this artistic ability to painstakingly construct such accurate drawings:

However, despite Darwin’s powers of observation he actually did not realize at first the connection these diverse birds had, and it was only after returning to England and conferring with other naturalists who later visited the Galapagos that Darwin had his eureka moment.  To be fair, Darwin did not have the scientific technology of today, nor the ability to DNA map, so let’s cut him a lot of slack – what he eventually discovered forever changed the study of how life survives on planet Earth.

You can appreciate the giant leaps Darwin had to make to develop his theory of evolution – especially when you see how small and “ordinary looking” these finches are.  I have to admit, at first blush many of the Galapagos finches  I encountered looked very similar to our ubiquitous sparrow.  But this is why Darwin was so brilliant – he was able to make the connection that whether subtle or not, all the slight differences in the different species are critical to their survival.  And more importantly, all these Galapagos finches are related.

Enough lecture – here are a few  of the Galapagos finches I was able to capture with my camera, and true to their lineup,  some are in trees, some in grass and some on the beach.  Unfortunately it is difficult, almost impossible to locate many of the species as they are so small and well camouflaged:

 

Unfortunately I was not able to find the one finch that really captured my fancy:  the woodpecker finch.  For eons we humans held the belief that we were unique in our ability to make tools, only to be disabused of this notion by countless examples of tool users in the animal kingdom.  Who would have imagined, however that a tiny bird, without opposable thumbs could not only expertly use a tool – but could ingeniously create one.

True to its name, the woodpecker finch hunts for food like a true woodpecker, prying up bark by pecking with its bill to find grubs and other insects.  This finch, however does not have the long tongue that real woodpeckers have to probe for deep deeply imbedded insects. Instead, the intrepid woodpecker finch finds a cactus spine or a twig – and if the implement is too long, the finch customizes the length with its beak, manufacturing a perfect tool to extract a tasty meal.  Here’s a video of this from the internet:

 

If you watched carefully, you also got a cameo of another iconic Galapagos inhabitant which is a major subject of a previous Chasing Dreams  post.  Did you see him?

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