I’ve been checking from the end of our garden which overlooks Whale Island (a big advantage of having moved to this house earlier this year!) for several weeks now to see if the terns have arrived to breed there (Whale Island, that is – not the end of the garden!) as it’s around the time when I expect them to come.
Whale Island as from the end of our garden – you can see the ‘head / body’ and ‘tail’ of the ‘whale’ where it gets its name from…
Last friday I checked as usual and the island was quiet – no activity, not even a single bird to be seen. Sunday afternoon I go check again and was amazed to see between 3-500 birds circling over and around it! They had arrived – and not in ones and twos over a couple of weeks as I had expected but pretty much all at once!
– Whale Island at low tide as seen by GoogleEarth. You can see the greenish area of dense bush with a rim of bare exposed rock – which is where most of the terns nest.
Whale Island has been known for many years as a breeding site for terns in particular Roseate Terns with a handful of others – in the literature recorded as Bridled Terns, but all I’ve ever seen there are Sootys. Not sure if they were originally mis-identified or whether over the years the Bridled have vanished and been replaced by Sootys. Perhaps both occur and I’ve missed the Bridled and the earlier guys missed the Sootys?? Will need to look harder at all of them.
a photo of a Sooty that I took on Whale Island back in 2003.
The arrival of the terns therefore spurred us into action. I had to get to the island before the birds actually started settling down to nest so as to lay down a path of wooden planks through the low vegetation so that once they’d started nesting it would still be possible to move among the nests to count them and check the breeding success without the danger of stepping on eggs. After a good meeting with the new KWS warden of the Watamu Marine Park – Albert Gamoe – who is an excellent man doing a good job, we planned to go the next morning over low tide to take the planks and to mark out 1x1m quadrats which we would use for sampling the colony.
It was blustery and quite choppy the next morning when I with our centre manager Henry, Alba Baya (research assistant) and volunteers Andrew and Alex headed for the small beach at the end of the Watamu headland to wait for the KWS boat. We had a dozen or so planks of neem wood that we started to cut into short pieces while waiting to use for “stepping stones” around the colony. It took two trips to take us together with equipment and the Warden + two rangers who were manning the boat across to the island and as we approached it we could see the birds circling and wheeling in the air over the rock as well as chasing each other low across the water. There were probably 300+ birds in all, mostly the all white Roseates with the black crown but a handful of Sootys and then probably about 20 Brown Noddys – a species for which in the past we only ever recorded one or two every year – until two years ago when there was an explosion of them with an estimated 1,000 birds on the island! To see 20 again this time suggested therefore that there would be good numbers again this year – beautiful birds which are rarely seen as they are so much pelagic (oceanic) in their occurance.
the Noddys like to sit on the cliff in the lee of the wind and are amazingly approachable – this is taken with just a small digital camera from about 20ft away!
We flushed a lone Fish Eagle sitting at the top of the cliff as we climbed up to get to the flat top of the island – he was probably very happy to have the terns come back as he regularly feeds on both the adults and the chicks once they start hatching. There were no terns on the ground so we were just in time to be able to put the path down and set up the quadrats. Using ‘hot pink’ string left over by some visiting entomologists earlier in the year, we started marking out 1x1m squares and putting down a winding path of 1-foot long bits of plank. This was a long and slow process and it took a good 2 hours to mark out 22 quadrats and lay the path.
Andrew is a GIS expert and so he spent the time with the GPS marking and taking points all over the island so we can draw up a decent map of it.
By the time we finished the tide was well and truly on its way back up and when me Andrew and Alex were picked up by the second return trip of the boat we had to wade out through quite deep water to get to where the boat could reach without being slung onto the rocks.
Altogether a very successful trip – we now just wait for a couple of weeks and then head back to see how the breeding attempt is coming along. One worrying possibility is that there are rats on the island still (there was an infestation 2 years back and I’d hoped they’d have died out by now but there were signs that the rats are still around which we may have to do something about…).