23. Moorhens rediscovered on Tristan
The last part of my masters in Biology was already dedicated to Tristan da Cunha. I made a zoogeographical analysis of the origin of the seabird fauna of the islands, using literature and museum specimens. When I visited the Natural History Museum in Leiden to look at old skins, the curator said to me:
"Ah, Tristan da Cunha, that is interesting. That is the island of the legendary Moorhen that never existed!"
What? How dare you! Of course it existed! I knew about all those people who ate them and found them so delicious! It was then and there that I decided to bring the Tristan Moorhen back and rehabilitate it. I dug into old sources to find eyewitness accounts and tried to trace specimens. To my surprise, I found a short note about birds collected on Tristan in the Zoological Museum of Cape Town, mentioning two Moorhens found between 1908 and 1910 by Mr Keytel, at a time when Island Cocks were already considered extinct. They were sent to me by Professor Winterbottom, in a package all the way from South Africa to the Netherlands. However, they turned out not to be Island Cocks. One was a Common Moorhen, the other one a Red-garted Coot, both probably vagrants from South America. The birds were sent back to Cape Town.
Precious little is left of the collected specimens, only three skins. One in the American Museum of Natural History (which I suspect to be a Gough Moorhen), and two in the British Museum. To my surprise I found a short note about Tristan Moorhen bones in the Museum of Cambridge University. I had to see those! So I went to England with three intentions. I was going to Tring to look at the skins, to Cambridge to look at the bones, and to Utoxeter to visit Michael Swales at Denstone College.
The bird collection of the British Museum in London had just recently been moved to Tring, to the northwest of London. Many skins were still unpacked. There should be two skins from Tristan, one in the collection of type specimens, the other one in the special collection of extinct species. A type specimen is the one that has served for the description of the species, so there is never more that one. They can never be replaced so curators guard them very carefully. The type specimen of the Tristan moorhen was hermetically sealed in a plastic bag, and I was not allowed to take it out. So I could not measure anything. The second bird, in the collection of extinct birds, could not be found. Perhaps it was still in one of the unpacked boxes. There was a third skin, but that one I found suspicious. On the label was written "Moorhen from the Cape Colony". A more recent label read: "This is not the Cape Coot, but probably comes from Tristan da Cunha". Later, someone had added in pencil: "yes". So this one could have come from either Tristan or Gough. I was soon done with the skins in the British Museum.
I spent a long evening with Michael Swales, listening to all his adventures on Gough Island and Tristan. He showed me hundreds of slides, even including some of Moorhens. But most of these were rather blurred, the birds being too quick all the time. They looked like brown streaks against an intensely green brackground. He did not mention the birds he released on Tristan.
In Cambridge I stayed with Mr Benson, a friendly, white-haired, deaf old man, who should have retired a long time ago, but was still taking care of the bones and skins in the museum. This is also where I got hold of a copy of the catalogue of Bullock's auction sale in 1819. Most of the skeletons were dubious, and looking at ambiguous notes on the labels, could either come from Tristan, or from Gough. Three turned out to be real, originating from the birds Sclater had used for his description of the species. There were also a few skeletons which definitely came from Gough. They where all without skulls because in preparing a skin the skull remains inside. I carefully measured everything I could, and perhaps I found a small difference in size, the Tristan birds being of a slightly lighter build than those from Gough, but don't ask a statistician. I published my findings in the Bulletin of the British Ornithological Club (Beintema 1972), edited by Mr Benson. As a budding scientist, this was my very first scientific publication in an international journal.
At the International Ornithological Congress in Berlin, 1974, I met Sir Hugh Elliott, Tristan's first Administrator, with whom I had corresponded about Moorhens earlier. He had seen my paper in the Bulletin of the BOC, and he told me he had a surprise for me. He had just heard that live Moorhens had been found on Tristan, coincidentally almost in the same year my paper had appeared, in 1972.
From October 1972 till November 1974, Mike Richardson had been Medical Officer on Tristan. Mike was not only a doctor, but also a keen birder. He climbed to the Base more than seventy times to collect data on the bird life, and he went to Inaccessible, Nightingale, and Gough several times. When Mike arrived on the island, the people told him that in March of the same year, they had seen Moorhens in an isolated, hardly accessible valley called Longwood, on the other side of the island. Mike visited the area three times, in April and December 1973, and in February 1974. He collected five specimens, which are now in the British Museum.
The area where the birds were found covered about eight square kilometres, and Mike estimated there were about 200 Moorhens. It was difficult to see them, but they were clamorous, and he could hear them calling all around him. He could not find any nests, but a male collected in December had swollen testicles, indicating mating time. In February and April he saw young birds, so he concluded the birds had an extended breeding season. It is the same with the birds on Gough, which may breed at any time of the year.
He looked at the stomach contents of the birds he collected. He found vegetable matter, including seeds, and grit and little stones, which birds in general use for 'chewing' their food after swallowing it. Furthermore, he found eggshell fragments and squid beaks, indicating that the birds would scavenge in seabird colonies. Spilled remains of squid are especially found around the nests of the Yellow-nosed Albatross. In the Longwood valley rats were very numerous, and Mike thought he saw prints of cats (which have never been seen since), so the conditions for the survival of Moorhens did not look at all promising. How was it possible that these birds were doing so well while the old ones were driven to extinction? What was their origin? I thought they very well could be survivors of the original stock which, through severe selection, had learned to run away from rats or cats.
The alternative explanation was that these Moorhens were descendants of the birds Michael Swales had brought to Tristan in 1956. In a correspondence with the Percy Fitzpatrick Institute in Cape Town he revealed that he had released eight birds not far east of the Settlement. I wondered how likely it was that a handful of Moorhens would have walked all the way across the mountain to the other side of the island, and, being from Gough, and therefore not adapted to predators, survived and multiplied, where the old ones could not. And if they lived there unnoticed for almost twenty years, they may as well have been there unnoticed for eighty years, as the area is seldom visited. So the identity of the birds Mike saw remained unclear. My favourite theory was that they were descendants of the original stock who had learned to deal with the rats. Michael said it was his successful reintroduction.