Nature Watch 3

Flying in on Tuesday 4th October Denis was picture perfect – there had a been some rain in the preceding week and the foliage showed a fresher green whilst the sea was as still and clear round the island as I have ever seen it. As we circled before final approach over the shoals to the northwest I looked down in the hope of seeing some wildlife in the water The water being so clear I had high expectations but on the approach I was disappointed to only see one turtle surfacing for a breather.

On arrival I made my usual check on the fairy tern juveniles that I have been following over the last couple of months and I will post on that later.

In recent weeks I have been undertaking thorough beach checks each time I visit in order to count turtle tracks (see post of October 22nd). It takes a good couple of hours to walk round the island and it is hard work with the sand very soft and fine in places and trees down blocking the way in others. It is also however a great opportunity to take in the beauty of the island and make various natural history observations.

Walking the beach on Thursday (6th) morning on the southwest beach I noted a turtle close in shore head above the water checking out the beach. It is normal for hawksbills to survey a beach before coming ashore, I assume to assess whether it is safe. The animal only being about 10 metres or so offshore, I hid behind a tree and kept still hoping it may soon emerge to nest. Whilst watching it cruise around in the shallow water my eye was caught by movement further offshore – there was a second animal about 40 metres out also surveying the beach. Over the next 5 minutes I realised there were at least 4 (and I believe 5) hawksbill turtles all within 50-60 metres of the shore all apparently assessing the beach as a suitable nesting site!!! I waited for some 20 minutes convinced that one would emerge at any moment but without luck. The need for me to finish my rounds in time to catch my plane off the island meant I had to move on but I am certain that 2 or more of these animals will have nested soon after.

One frequently encounters hermit crabs on the beach during a turtle track count and as per previous posts (see posts of July 16th and September 10th) recent GIF research has indicated that the populations on the island may be limited by a shortage of suitable shells for the crabs to grow into. Casual observations seem to support this as I encounter very large numbers of small crabs in neritas spp shells etc… but much fewer larger ones in turbo shells. Furthermore many of the larger hermits have clearly outgrown their shells. When a crab fits well into its shell its large chela (claw) and one leg should fill and close the shell aperture, effectively “closing the door” and protecting the animal from attack when it retreats within. I am however frequently finding specimens where several and even all the limbs remain exposed when the crab seeks refuge and this presumably makes the animal much more vulnerable to predation from species such as the crab plover.

Also during my rounds I have been paying closer attention to the old shells washed up at high tide and I have been photographing specimens which are still in reasonable condition to enable species identification and I hope to start making occasional posts on this in the coming weeks.

Check back regularly for further observations, news and updates!