Monday, 14 September 2015


No, not a typo!  I'm not going to talk about the second most striking bird that you find in parks-and-gardens in these WEA islands. That's the Goldfinch Carduelis carduelis [male R] which comes to visit our front yard (when I'm paying attention, which is rare enough when it comes to checking off the bird-life on the farm) most years. So many of the common Irish birds are LBJs [little brown jobs] that are only namable by experienced twitchers, that it's nice to have something so distinctive as C. carduelis. The most striking bird you're likely to encounter hereabouts is Alcedo atthis, the kingfisher, but that is sufficiently rare that it inspires poets.  But that's here and now.  Today we are going back nearly 200 years and to the other side of the world.

On 2nd October 1836 Charles Darwin returned home from his circumnavigation in HMS Beagle with steamer trunks of specimens to unload and sort. He had been collecting wherever and whenever the Beagle touched land and he could secure Cap'n Fitzroy's permission to go off with shot-gun, nets and killing-jars. In January 1837, he offloaded his Galapagos bird specimens on the Zoological Society of London, confident that they would be able to identify and classify the skins. The Society was, in this case, represented a self-taught taxidermist and naturalist called John Gould who had started his working life at 14 as a gardener and son-of-a-gardener. Gould was probably too polite and deferential to say that Darwin had made a bags of collecting these birds. Famously, for example, he had failed to record the island on which each bird had been killed.  On a global scale, the microcosm of a small archipelago was 'essentially the same', so the that's all the leg-tag for each bird recorded.

Darwin told Gould that they were blackbirds but Gould identified them as finches [L print from a drawing by Gould of the cactus finch Geospiza scandens] a different family altogether. He also realised that they were a) different from anything he'd previously seen or read about but b) they were also strikingly diverse among themselves.  Frustrated by the lack of geographical information supplied by Darwin, Gould applied to Captain Fitzroy and other members of the crew to see if they had better provenance data for their specimens of the same species.  Eventually Gould was able to sort the finches into 12 separate species and show that each one appeared to be endemic to a single island.  That biogeographical information is given in the text-books as a key insight which drove Darwin down the path towards his 1859 book The Origin of Species. The fact that distinctive species could evolve . . . but only if isolated from other potentially interbreeding individuals, was a corner stone of the theory of evolution by natural selection. We can thank John Gould for organising and codifying the key information: if it had been left to Darwin, the theory would have been a lot longer a-coming.

They are called "Darwin's" finches in one of the many unfairnesses of scientific naming. It's not always the firstest who gets tribbed, it's often the one who has mostest influence. The finches are re-churned as the example of evolution in action because there are conveniently finite in number of species and each obviously different in the size and shape of beak. It is thus easy to tell a neat story about how the diet drives specialisation and isolation drives speciation. David Lack and dozens of graduate students have filled in the details about how population density fluctuates in each species year by year in tune with extremes of weather and interactions with other species in the same ecosystem. Evolution is thus comprehensible as dynamic and exquisitely sensitive to local conditions. In fact, it was the status of the Galapagos mockingbirds Mimus spp. which blew Darwin's mind open to the possibility of evolution.  Here, according to Gould, were four distinct species: Mimus parvulus [all over the islands but forming distinctive sub-species on each]; and three other sister taxa Mimus macdonald [Española/Hood], Mimus trifasciatus [Darwin/Culpepper], Mimus melanotis [Chatham/San Cristóbal] which were limited to a single island and had evolved into separate species there. Equally important, for the mockingbirds but not for the finches [p.22], clearly and closely related species could be identified on the South American mainland 1000km to the East.

The only rational explanation for this diversity was that species were not immutable. Which is a truth universally acknowledged today [except in the bible-belt] but in Darwin's day was both novel and shocking; so I'll write it again: "species are not immutable!!!".  John Gould was a name in his day, famous for publishing a set of gorgeous illustrated bird books, and for setting the taxonomic biology of Australian wildlife off onto a scientific footing. [L. 1976 commemorative stamp].
But he is largely forgotten now . . . except on The Blob.  John Gould was born >!today!< 14th September 1804 in Lyme Regis, so he must have been known to Mary Anning but may not have registered her because his family left the county to gardens elsewhere soon afterwards. He died, shortly after a visit from painter John Everett Millais inspired the painting The Ruling Passion, in London on 3rd February 1881.  So he was an almost exact contemporary of Darwin (1809-1882) his collaborator and colleague.

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