Fossils, Finches and Fuegians: Charles Darwin’s Adventures and Discoveries on the Beagle

In his general notes on what wildlife he had seen in Monte Video, Charles recorded that:

Birds are abundant on the plains & are brilliantly coloured. Starlings, thrushes, shrikes, larks & partridges are the commonest. Snipes here frequently rise & fly up in great circles; in their flight, as they descend, they make that peculiar buzzing noise, which few which breed in England are known to do. On the sand-banks on the coast are large flocks of Rhynchops [scissor-beaks]; these birds are generally supposed to be the inhabitants of the Tropics. Every evening they fly out in flocks to the sea & return to the beach in the morning. I have seen them at night, especially at Bahia Blanca, flying round a boat in a wild rapid irregular manner, something in same manner as Caprimulgus [nightjar] does. I cannot imagine what animals they catch with their singular bills.

When next he encountered Rhyncops he had more to say about the function of their beaks.

During the last few days before departing on the Beagle’s first cruise, Charles’s most notable achievement was, after a long chase among the rocks at the Mount, to shoot through the head a large female capybara, in structure a huge guinea-pig, in habits a water rat. She weighed ninety-eight pounds, and could not readily be preserved apart from a tick crawling on her skin. He also found two more new species of turbellarian worm under dry stones on the Mount, collected some elegant snakes and frogs, and as usual captured a host of spiders and beetles.

CHAPTER 8 (#ulink_755baea3-e7bf-5c15-91a1-ad2ae0abf4bf)

Digging up Fossils in the Cliffs at Bahia Blanca (#ulink_755baea3-e7bf-5c15-91a1-ad2ae0abf4bf)

The Beagle was now ready to proceed on her first cruise to the south, surveying the coastal waters between Buenos Aires and Bahia Blanca. At first the steep waves in the shallow water at the mouth of the Rio Plata caused so much spray to break over the ship that Charles had seldom felt a more disagreeable sensation in his stomach. In more open water after rounding Point Piedras, matters improved, and on 24 August in ten fathoms of water slightly north of Cape Corrientes in latitude 37

26´S, Charles found ‘incredible numbers’ of the very simple animal that he had encountered earlier in the voyage, north of St Jago (see p.54) and off the Abrolhos Islands, and had been unable to identify. This time he was able to describe in some detail the anatomy of these arrow worms or chaetognaths as they came to be called, and twelve years later published a short paper about them.

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Two days later, in latitude 38

20´S, Charles found some of what he called corallines, the insignificant but exceedingly numerous little organisms of doubtful nature that encrusted rocks and fronds of seaweed like a moss growing on the surface, to which he had been introduced by Robert Grant at Edinburgh (see p.6). On examination of the specimens under his microscope, he immediately and correctly identified them as closely related to what would today be called ‘bryozoans’ of genus Flustra