Hunting for wasps and chickens – Bats, Birds and the elusive Galliwasp

My week on Montserrat was busy – I had to meet the various teams of environment department workers who were responsible for the different biodiversity programmes.  I was to meet an old friend of mine, Laverne, who almost single handedly had introduced and fostered use of GIS on Montserrat.  And I wanted to get a grip on the species I was looking at.

The biodiversity action plan was to focus on endemic species in the Central Hills.  My colleagues from Kew Gardens were getting a good handle on the plant species – had conducted transects across the hills and were finding new species almost all the time.  I had a quick job to manipulate their existing data into a format that could be transferred to their master database in London.  There was a guy called Steve who I started referring to as the batman; he was crazy about bats and had a complicated way of recording all his information.  The island conservation team more or less let him get on with it.  Bats are one of the few land mammals in the Caribbean that are endemic – given the chain reaches out in the ocean there are not many other ways to extend your species’ range unless you fly.  The result is that there are several endemic species and subspecies of bats in all the islands and Montserrat is no exception. I chatted with the batman a couple of times by email  but there did not seem much point in changing the way he did things for the sake of local conditions.

Then there were the birds.  I worked with Geoff from RSPB to decide how we would best tackle this.  I showed him the seabird databases I had developed in the South Atlantic, but we agreed this was a different case.  Here they were not trying to count every bird on a rocky outcrop, but to try and sample some shy species in forest undergrowth; most notably the Montserrat Oriole whose numbers had declined sharply after the eruptions.

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The Centre Hills from our village

The two other species of interest were different.  The first was an enigma.  It was like hunting the snark, like the blind man in the dark room looking for the black cat …. that isn’t there.  It was the Montserrat galliwasp.  A galliwasp is not, as you might imagine, a kind of insect, but a lizard.  For a smooth lizard it is slightly flattened, wide bodied even.  My description is all from books.  I didn’t see a galliwasp in the week I was there.  In fact it had been several years since anyone had seen a galliwasp.  The last time had been about five years ago and the poor creature in questions was in the jaws of a small dog so was not going to do anything to relieve its critically endangered species status.

So I designed a database that was to do a couple of things; one was allow anyone to log reports of people seeing a galliwasp – whether being eaten or not at the time.  The second was that a series of remarkably complex study sites were being set up to see if they could attract galliwasps in to be studied.  I never saw one of these sites themselves but it was described to me in great detail.  They sliced up the site into segments of long grass and short grass, corrugated iron they could hide under, scrubby vegetation.  I was to create a complex database that would describe all the habitats and the number of galliwasps of what sex, age, length and height.  All this for something which had not been seen alive for a generation.

The Other Mauritius – Lessons in Island niches

We gently negotiated the shallows close to the island and pulled up against a wooden jetty.  We disembarked and stretched our legs, and of course the first thing we did was look back to the mainland from where we had come.  We were taken by the tall slim guy to a collection of huts inland from the jetty.  In a small room that he called a museum, we were given an introduction to the foundation and its work.  He was very eloquent, speaking in both French and English to the mixed group.  The foundation had been set up in the 1970s to restore populations of various animals and plants that were on the verge of extinction.  The museum was devoted partly to those that had got away – those species who were already extinct before the foundation was able to do any good.  But they were rightly proud of their success stories.  After all I had seen for myself the released populations of Mauritian kestrels and pink pigeons in the Black River Gorges National Park. One of the most fascinating exhibits in the museum was a model of the Giant Skink, and animal that has been estimated to have been extinct since the 1650s.

It looked like any skink I have seen, the neat little lines of scales along its back, its slightly rounded but sleek looking head and the beady black eyes.  But the model, a life size, is nearly a metre long.  This would have been more like an iguana than the little friendly lizards that run up and down the walls of many a tropical house.  We also learnt of the Rodrigues and Mauritius Tortoises, with the most enormous necks to reach up to the fruits in the shrubs around.  Another magnificent sculpture gives an idea of what incredible creatures these must have been , before they too became extinct once man colonised the Mascarenes.

Sober to reflect on the losses but we also wanted to see the success stories, so we started our tour of the island.  First of all, our meticulous guide wanted to explain the importance of the vegetation.  He had a good reason too:  He was trying to make us understand a little as to why animals on Mauritius had become endemic species.  He showed us all manner of plants whose seeds had washed up on the shores and they had colonised the difficult volcanic and limestone rocks.  Many travelled in coconuts, hence the palms, some may have come by wind or inside birds guts or stuck to their exteriors.  Then the animals have arrived somehow – perverse in some cases.  Maybe it was plate tectonics which had separated species from their continental brothers, or perhaps bizarre cast away stories of animals stuck to branches, seeds or whatever.  But once on their own little island kingdoms they could become masters of both their environment and fellow creatures.  Each tried to find a niche.  The vegetation was dry and scrubby but quite thick.  The ground cover was available to a large number of creatures, but if by evolution you could breed in longer necks, some animals gained an advantage in reaching the further branches and have more food just for themselves.  This explained the anatomy of the tortoises.

There was evidence that some plants had evolved to take advantage of their relationships with the tortoises.  Some plants ensured their succulent leaves, flowers and fruits were at the tops of their structures; only reachable by one tortoise.  Fruits in particular could be passed through the tortoises’ digestive systems and excreted with all the other rich manure – a perfect place for a new plant to get a grip in a difficult rocky environment.

Then came a difficultly for some of these plants.  When species went extinct, the symbiotic relationship was broken, and the plants found it difficult to reproduce.  MWF are trying to overcome this now by introducing species which fit certain ecosystem niches.  In the case of the old tortoises they have introduced the only giant tortoise that still exist in the Indian Ocean, the Aldabara Giant Tortoise from the Seychelles.  They have long necks (not quite as giraffe-like as the Mauritian ones they replace), and are starting to assist in restoring the vegetation on the island back to how it might have been in the old days.