Nature Notes 5.

Just back from the island, it was a brief 24 hour stay primarily to give a presentation and walk for some guests, so a quick summary of salient points noted below:

• Sooty tern (Onychoprion fuscata) update. I stopped by the sooty tern project for an hour or so mid-afternoon on Saturday but only observed a couple of circling flyovers by birds. On Sunday morning however I met Vicki and Georgia at the observation platform and they had quite a lot to recount – most notably that they had observed a pair of terns landing that had courted and mated in the project area… this is most encouraging!!! In addition they had observed a bird attempt to court and mate with one of the plastic models – which goes to show that models clearly do provide the correct kind of stimuli!!! Whilst I was there on Sunday morning I observed a bird circle and land in the location … unfortunately I couldn’t stay and take photographs… but that will be a focus of mine during my next visit.
• Observations on a Seychelles warbler (Acrocephalus sechellensis). Much along the lines of my post of June 8th , whilst pursuing one matter – in this case whilst sitting under the observation platform in the shade waiting hopefully for a Sooty tern to land – various other points of interest presented themselves. First my attention was drawn by the familiar clicking of a warbler’s bill as it took insects. The bird was very close by in a clump of low herbaceous vegetation consisting primarily of the spinach plant “Payater” (Amaranthus dubius). This was clearly a very fruitful area for it as it remained in this small clump for a good 20 minutes feeding busily on insects taken from the underside of the leaves. On a few occasions it took a prominent perch and looking above would launch itself straight up to aerially intercept a flying insect. It also paused in a more secluded site to preen. Judging from its behaviour, the somewhat mottled plumage on its breast and the less than rich brown colouring if its eye I got the impression that it was a subadult – probably recently departed from its natal territory and currently “floating” or in the process of establishing a territory for itself.
• Ant-lions (Myrmeleon obscurus). Then looking down at the ground beneath the platform I became aware of several characteristic funnel traps of ant-lion larvae in the sand. These funnels with there very loose surface of sand are easily disturbed by passing insects such as ants. At the nexus of the funnel hidden just below the surface the ant-lion larvae lies in wait. When it senses the disturbance of sand in its “funnel” it shoots sand out from the centre knocking the unfortunate prey down into the centre where it is caught and consumed by the waiting predator. I watched fascinated by the occasional shots of sand that were sent out from the centre of each pit.
• Carpenter bees (Xylocopa caffra). Finally whilst waiting under the platform I tried to get a photo of a female carpenter bee that was drawn by small flowers in the undergrowth. This has become something of a task for me… I have wanted to do a post on the carpenter bee for quite some time but I can’t seem to get a good photo of the female. I have several good photos of the male but the female with her black body and characteristic single large yellow band is another matter all together!!! The males move slowly from one flower to the next often pausing and hence allowing photos to be taken. The females however whilst much more readily noticed with their distinctive colouration and low rumbling buzz are very flighty seemingly never pausing long enough for me to get a decent photo… I shall endeavour to persevere…
• Blue-cheeked bee-eaters (Merops persicus). Moving away from the Sooty tern project… regular readers will be aware of the presence of the beautiful blue-cheeked bee-eater on Denis for the last 6 months (See my post of May 23rd for the full account) and our interest in recording when exactly the last individuals leave the island. It had been thought that all the birds had left after the first week of this month – but during the tour I was giving on Sunday morning I observed two hawking from prominent perches on the island’s southern beach and then later repeatedly heard one near the hotel complex… so a few stragglers yet remain. We will continue to monitor.
• Flycatcher news (Terpsiphone corvina). Great news from Mervyn working on the Flycatcher project! A second bird has now fledged successfully giving us much hope for the future.
  

Outreach Programme – Launch of Denis Island Newsletter.

I have posted in the past about various aspects of our outreach programme under the islands 2008-2012 Environmental Management Plan. The raising of public awareness both at home and overseas is an important component of the overall sustainability of the island’s environmental initiatives – and this blog forms part of that outreach.

In recent months we have had some excellent national media coverage on the TV, radio and in the press. We also, thanks to the assistance of the Seychelles Broadcasting Corporation, have had some great international coverage on CNN. This has all been very encouraging and has resulted in positive feedback.

We are also active on the island as well; GIF personnel provide walks and talks for hotel guests and the island has also constructed an information centre which now just awaits the arrival of posters and pamphlets on the island’s environment in English and French for it to open.

Now last week we launched an Environmental Update Newsletter for circulation on the island in Guests’ rooms and in the hotel complex. The intention is that there will be an issue every 2 months that will give clients the opportunity, at their leisure, to learn about the islands wildlife and environmental projects.
Simply click on the images below to enlarge and read the first Newsletter.

Sooty tern project – update and Post by Prof. Chris Feare

I have been to the island 3 times in as many weeks largely due to the need to follow up on preparations for and implementation of the island’s sooty tern project (see my post of 19th May for background information). Professor Chris Feare, the world expert on the species, is in the Seychelles at the moment having come out to oversee the project set-up on Denis. Our two volunteers, Georgia French and Vicki Willits, have also arrived and work is now ongoing.

Following on from our findings last year the models and loud speakers have been set out in the project area. One loud speaker has also been mounted half-way up the trunk of a coconut tree facing out to sea along the prepared entry flight path in order to attract birds that may be flying along the coastline. The southeast monsoon has been late to establish this year and this has a bearing upon the behaviour of Sooty terns – with fewer birds over-flying the island than we would normally expect. The wind has however now set in and we hope that bird numbers will pick up in the next week or two. Despite this, landings have been relatively good with in fact more landings reported in the first week of work this year than throughout the entire season last year! This is very encouraging and underlines I feel, that the lessons learnt regarding the birds’ preferences last year are now reaping benefits in our work. Of particular note was the landing of a pair of birds which then commenced a courting display – exactly what we are hoping for!!!

Chris Feare has kindly written a post (see below) for this blog that sets our work in the broader context of his long term study of Sooty terns in the Seychelles archipelago:

"While Sooty Terns do not command the iconic status bestowed upon some of Seychelles’ rare endemic birds, such as the Seychelles Magpie Robin, Seychelles Warbler and Seychelles Paradise Flycatcher, the Sooty Tern is in fact the Seychelles’ most numerous bird. It breeds in huge spectacular colonies on Bird and Aride Islands, and on the more remote islands of Desnoeufs in the Amirantes, Goelette Island of Farquhar Atoll and Wizard Island of Cosmoledo Atoll. Despite remaining so numerous, Sooty Terns have faced a number of threats since man settled the islands in the mid-eighteenth century. These include the collecting of enormous numbers of their eggs, alteration of the habitats of their nesting islands and the introduction of mammalian predators such as rats and cats. As a result, several former breeding colonies now lie deserted, particularly those on smaller islands close to the main centres of human occupation.
Concern for the species led to their receiving various forms of protection but these are extremely difficult to enforce on remote and often uninhabited islands, and some of the earlier conservation attempts were based on insufficient knowledge of the birds’ biology and behaviour. My own studies of Sooty Terns in Seychelles, now spanning 37 years, along with investigations of colonies elsewhere in tropical oceans, have provided information on their needs and lifestyle that can contribute greatly to their conservation. For example, we know from recent events on Bird Island that restoration of prime habitat, by removing old coconut plantations and encouraging the development of indigenous herb vegetation such as purslane, can lead to a dramatic recovery in numbers. Controlled harvesting of their eggs can also play a part by placing a value on the birds while at the same time regulating the number of eggs that can be taken and the islands upon which harvest is permitted. And eradication of alien predators benefits all indigenous animals, not just Sooty Terns.
Sooty Terns are long-lived birds: on Bird Island ringing studies have revealed several birds 34 years old. In the absence of disturbance, adults usually return to nest on the same island year after year. In an attempt to re-establish a colony on an island known to have supported a large colony 200 years ago, an experiment is currently taking place on Denis Island (see recent blogs). Here, a small area of forest has been cleared and plastic models and broadcasts of Sooty Tern calls are being used, with some success, to attract birds to the island. Once settled, we hope they will continue to return and breed.
Despite our increased knowledge, however, Sooty Terns still hold many mysteries. In particular, we do not know where they feed while they are breeding. Nor do we know where they go when the leave Seychelles after breeding. Ring recoveries in southern India and in northern Australia suggest that they travel far. But we shall not get a better picture of their movements until tiny satellite transmitters, suitable for attachment to Sooty Terns, are available. Only then will we be able to determine whether another of man’s activities, intensive fishing of tuna, presents a threat to these magnificent birds. Sooty Terns do not eat tuna, but they are totally reliant on these predatory fish to drive smaller fish, like sardines, to the ocean surface where they become available to the birds. So if the Sooties prove to feed where tuna are being over-fished, the birds’ populations will be threatened no matter what conservation measures are in place on their nesting islands."

100 posts – one thing leads to another

This post marks a landmark for the Denis Island Environmental Update blog – it being the hundredth post since I started the blog in July 2008. The blog was established primarily to provide information to hotel clients many of whom return periodically to the island and expressed an interest in being able to follow up on our projects on the island during the time in between their visits.

It did occur to me when starting out that whilst I would initially have plenty to write about it would be difficult after a while to find new and different matters to cover. In fact the opposite has been the case, every visit to the island seems to provide numerous new topics to report on and it is not lack of subject matter but rather lack of time to write them that effectively limits the number of articles I am able to post. Frequently I leave the island with a list of 6 or 7 new topics for potential posts but many fall by the wayside as they are replaced by new options from a subsequent visit before I get the time to actually write them up.

A perfect example of subject overload happened during my visit a week ago. I noted on arrival a sudden and widespread commencement of nest building by the island’s Brown noddy colony (see post of 31st May). I spent some time photographing the birds nest-building in the coconut trees at the entrance to the main hotel complex. Following this I decided to go and try and photo the birds gathering nest material on the beach crest. As I approached the beach however I noted a white tern alighting on a branch next to its chick with a beak full of fish so I was then distracted by this and occupied by attempts to get a photograph that captured the moment of food transfer from adult to chick. I failed to do this but decided to wait for the return of the adult and try again. After a few minutes a white tern did indeed fly into view bearing fish but this was a different adult flying to another chick higher up in the same tree. Whilst trying to feed the chick a small fish was dropped and fell to the ground. This nutritious morsel was immediately picked up by a moorhen which in turn ran off in the direction of a scaevola bush. I suspected that it also had young to feed and I now set off to try and capture that image. The moorhen did indeed have two chicks hiding in the bush and it thereafter sectioned up the fish to feed to its young – paying me no attention whilst I remained still nearby. I stood partly behind the scaevola bush so as not to make the birds feel threatened whilst I photographed the feeding. It was whilst standing there that I noticed that the flowers of the bush were alive with large numbers of a fly with very distinctive red-eyes – so having never previously observed such an aggregation I photographed these insects so as to enable their identification at a later date.

After this I returned to my original plan of going to the beach crest to photo noddies collecting nesting material. I positioned myself on a beach chair and waited for the right opportunity. I was soon photographing several noddies busy gathering casuarina fronds on the beach when I noticed a ghost crab approaching me along the beach. These animals are normally very wary and difficult to photo but as I was stationary on the seat the crab appeared not to notice me and continued to approach so I took the opportunity to photo it also. As it passed along side me I turned in the chair to try and get a better shot but this movement alerted it to my presence and it immediately sought refuge down the nearest crab burrow. I kept my camera trained on the burrow entrance however as I was confident that this burrow belonged to another crab which meant the new arrival would rapidly be forced out by the resident. Sure enough the crab soon appeared at the entrance but seeing me shot back down. This happened a couple more times and I waited, confident that the crab would soon have to emerge and I would have another opportunity to photo it up close. What happened next however really did surprise me and was the first time I had ever observed such behaviour. The crab did indeed re-emerge but this time clasping the resident crab, which was a bit smaller, in its pincers. It then proceeded to castaway the smaller crab and return back into the burrow which it had obviously found so much to its liking that forcible eviction of the owner was the next logical step!!!

I then just walked 30 metres down the beach and encountered 15 Greater crested terns – the highest count I have ever recorded on Denis – better yet they very kindly contrived to position themselves such that I could fit them all in the frame of a single photo thereby providing proof of the new record!

So through the simple idea of taking a photo to complement a post on Brown noddy nest-building one thing had led to another over a period of 30 minutes or so to encounter five other potential articles… so what to write about next?

Focus on warblers…

The Seychelles warbler (Acrocephalus sechellensis) is an iconic species for Seychelles conservation. In the 1960s the entire global population of only 20-25 birds was restricted to a small area of mangroves on the tiny island of Cousin. This led to the purchase of Cousin by the Royal Society for Nature Conservation in 1968 and the subsequent management by the then International Council for Bird Preservation (now BirdLife International).
The purchase of Cousin in order to save the warbler is often considered the dawn of modern conservation in Seychelles. In the following years natural vegetation was allowed to regenerate on Cousin and the Seychelles warbler population expanded and spread throughout the island. In 1988 warblers were introduced from Cousin Island to Aride and then to the neighbouring island of Cousine in 1990. Both introductions proved to be successful in particular the introduction to Aride where birds were reported to be nest-building within a day of their release on the island! The population of warblers on Aride today numbers more than 2,000 birds and the world population now likely over 3,000 – a most remarkable success!
58 Warblers were introduced to Denis Island in 2004 and follow up surveys of the island population 2005, 2006 and 2007 have shown a steady expansion of the warbler population on the island. The introduction of the warbler to Denis contributed to the downgrading of the threatened status of the species to Vulnerable under World Conservation Union (IUCN) criteria.
Logistical problems meant the island was unable to host researchers in 2008 to follow up on the monitoring of the population but I am happy to report that a survey of the population will be undertaken in 2009 so keep a look out in the coming months for updates on the status of the Seychelles warbler on Denis Island.