Nature Notes 2

Just back from a weekend visit to Denis, much of the time was spent with an SBC film and radio crew so more good media coverage which I will post about later.
It’s been awhile since I was on the island so there is a lot to report, other work commitments permitting I hope to have several posts up for readers over the next few days. I’ll start off with a few notes on various natural history observations:

• Fody Feeding Frenzy – there is a palm tree at the entrance to the hotel which is in flower and causing great activity amongst Madagascar fodies. The inflorescence was teaming constantly for 2 days with squabbling fodies. Despite watching quite closely I am still not sure upon what exactly the birds were feeding. They appeared to be particularly interested in the flowers, perhaps taking pollen/nectar but also perhaps feeding on insects drawn to the flowers. Their attention was however not restricted to the flowers perhaps feeding on insects or young parts of buds elsewhere on the inflorescence. Regardless they were numerous, combative and very vocal… so there must have been something good there!
• More Mynahs!!! – I am reluctant to mention mynahs again having posted extensively on them recently (see post of March 17th) but I got the distinct impression that their numbers are on the increase particularly around the hotel. I also encountered our king Mynah (Lerwa marten) again in its usual locale at Belle Etoile and though he continues to be shy I got a better photo of him (see sidebar) though it was at long distance.
• Grey Heron - the bird I first reported on February 15th is still on the island (might it perhaps be taking up permanent residence?) and it continues to be wary. I saw it at Belle Etoile and I was able to take a few long distance photos; but when I tried to be clever and maneuver myself closer by using some thick vegetation for cover it knew exactly where I was. So having belly-crawled to my near perfect vantage point and just brought the camera up to my eye the heron took flight north… clearly still smarter than this observer!
• Bee-eaters still with us… - interestingly some blue-cheeked bee-eaters (Merops persicus) are still with us. Having arrived in large numbers in November of last year a few have remained ever since. It’s hard to tell how many remain on the island. I saw 6 together “hawking” over the runway in the afternoon but also encountered individuals around the hotel and along the southeast coast. I would guess there are approximately 10-12 on the island.
• Crested terns – these beautiful birds are still to be encountered at Pte Mme Guichard or the offshore rocks on the southern point but there appear to be only six at the moment.
• A new restaurant visitor – finally in my post of February 23rd I talked about the nature and different rare species that guests could see, simply while taking breakfast on the Restaurant verandah. Well we can now add magpie-robin to the list. On Sunday morning I watched a magpie robin fly into the restaurant perch on a table and begin to sing! It then spent the next 30 minutes or so in and around the area. It is a single male that has taken up residence around the main hotel building apparently establishing a close relationship with the gardening staff following them closely when they rake in the morning and feasting on the insects there work exposes!

Denis Island contributes to knowledge on migratory birds…

Over the preceding few months I have periodically posted on our observations of migratory birds. Denis’ position on the north of the Mahe plateau makes it a very interesting location for migratory birds as for many it may represent their first landfall in some 1000 miles of flying over the Indian Ocean! This strategic position makes the island a magnet for exhausted or storm blown birds. Despite this bird records from Denis are rather sparse simply because there have rarely been ornithologists on the island for any extended period. Over the last year or so however the combined activities of various researchers visiting for different projects, the presence of Catherina, my periodic visits and the interest of an island resident have allowed us to start building up a generalised picture of what birds are visiting the island or actually overwintering on the island.

We are not yet undertaking any standardised monitoring as we lack sufficient personnel to do this, so observations are purely ad-hoc or opportunistic nevertheless they are not without value. The Seychelles Bird Record Committee (SBRC – you can connect to their site via the link in the sidebar of this blog) is the agency that compiles records of birds in the archipelago as per the objectives bulleted below:

• To collect information and records relating to the status of all birds observed from the islands of Seychelles and their surrounding ocean (EEZ).
• To assess reports of all birds considered to be of less than annual occurrence within the Seychelles EEZ and to permanently maintain the original bird record submissions made by observers together with all Committee comments and votes.
• To publish summary details of all accepted records, encourage publication by observers of first records for Seychelles and to maintain a national list of bird recorded in Seychelles EEZ.
• To provide all persons or bodies interested in the study of birds in Seychelles with scientific data pertaining to bird sighting records.
• To increase awareness of and interest in the birds of Seychelles both nationally and internationally.

I liaise periodically with Adrian Skerrett of the SBRC regarding sightings on Denis and on occasion he may request that the observer(s) submit a record sheet if the sighting is of a species that is not considered an annual migrant to the archipelago. The record sheet is then assessed by the SBRC which if it deems there is sufficient evidence to substantiate correct species identification will accept and publish the record. In this vein I have received notice from Adrian that the following recent sightings from Denis have been accepted by the SBRC:

• Purple Heron (Ardea purpurea) – One immature bird sighted at Belle Etoile, Denis Island on the 3rd October (by Catherina Onezia). This is the 35th record for Seychelles.
• Ferruginous Duck (Aythya nyroca) – One adult male at the pig farm, Denis Island 25-27 November 2008 (by France Hoareau and John Nevill). This is the 4th record for Seychelles.
• Eurasian Hobby (Falco subbuteo) – At least one and up to three at the airstrip and over the coast 24-27 November (by Mickey Mason, Catherina Onezia and John Nevill). This is the 20th record for Seychelles, all from late October to early January.
• Yellow Wagtail (Motacilla flava) – One adult male, probably race beema at the pig farm, Denis Island on 9 December 2008 (by John Nevill and Anne-Marie McDevitt). This is the 29th record for Seychelles, reports spread fairly evenly through the months of October to May.

Of course to get a record accepted it is a great help to have photographic evidence! Thanks to the wonders of modern digital photography this is becoming increasingly possible – see sidebar for photos of the species in question.

The records of the major influx of Amur Falcons (Falco amurensis) to Denis in November of last year have also contributed (amongst many others) to the species now being recognised as an annual migrant to the archipelago. There is an interesting summary of records, pertaining to the mass influx last November, from all over the archipelago to be found on the SBRC website. Simply click on the link below to go direct to the summary:

http://www.stokecoll.ac.uk/sbrc/latest/amur%20falcons.pdf

SMR News 7: A population status review…

On the 25th of June 2008 20 Magpie robins were flown to Denis on a chartered Twin Otter. 16 of the birds came from Fregate and 4 from the island of Cousin[1]. Translocation is a highly stressful experience for the birds and fatalities are not unexpected. The birds all arrived in apparently good condition however including the four from Cousin, which had experienced a sea crossing from Cousin to Praslin that morning prior to their flight to Denis.

A soft introduction method was utilised with the birds being kept by pairs in aviaries that were positioned in appropriately wooded and tranquil locations around the island. Veterinary expertise was on hand courtesy of the Durrell Wildlife Trust as Jersey Zoo, UK. The birds were released on a staggered schedule 2-3 weeks after arrival. Sadly one bird was lost whilst in captivity, a young female, that succumbed to a lung infection the type of which is linked to lowered immune response due to stress – i.e. most likely a casualty of the introduction process.

The released birds however, settled in very quickly, territories were soon formed and males could be heard singing from strategic vantage points high up in the casuarina trees.
Since their arrival the birds have received individual and dedicated care from Catherina Onezia, the GIF Project Officer. Catherina checks on the condition and activities of the birds and provides each territory with a special supplementary food mix 3 times-a-day.

The first egg was recorded on the 4th August and it hatched the on the 23rd! A fantastic start! Unfortunately the chick was later found dead below its nest possibly the victim of a Mynah bird attack.

By the end of December (i.e. 6 months after introduction) there had been a total of 13 nesting attempts recorded. 9 attempts failed:1 pullus was lost (as mentioned above) 2 nests were destroyed by Mynah birds the others failed at the nest building or egg stage. 4 were successful but two of the fledglings were lost – one due to an apparent abnormality with its legs and the other to unknown causes. So by the end of the year the islands population stood at 21 birds – an overall increase of 1. Compared to some past introductions elsewhere this was a very good beginning as a few birds can be lost in the early stages of an introduction before the population stabilises.

The number of nesting attempts is very encouraging and shows that the birds are in good condition and finding the habitat on the island suitable, but the number of failures in breeding is a cause for concern and certainly we need to investigate ways of improving the success rate. I have covered in detail (in my posts of 17th February and 17th March) the issues we are facing with the Indian Mynahs and how evidence is growing that they may be the main problem.

Catherina eventually had to take the injured chick (from the 17th February post) into fulltime care but the bird prospered there and has subsequently been released as an independent bird – the second chick Catherina has successful raised by hand!

At time of writing the island population now stands at 22 birds, including the loss of an adult to unknown causes, so there has been some additional breeding success this year. Let’s hope that we have turned a corner and that 2009 will be year of steady population growth! Keep checking back for updates…

[1] The SMR introduction was the result of a multi-partner cooperation in a project led by Nature Seychelles, supported by SMART (The Seychelles Magpie Robin Recovery Team – a multi-partner initiative) and in particular Fregate Island Limited.

Eurasian Hobby (Falco subbuteo)

Regular readers will recall in November that the island experienced an amazing influx of migratory birds. Denis played host to some 500 blue-cheeked bee eaters and 40 or 50 Amur falcons and 2 or 3 specimens of a larger bird of prey that at the time I was not able to properly identify though they were suspected to be Eurasian hobbies. I had taken a lot of photos and in December had the opportunity to go through them with Adrian Skerrett of the Seychelles Bird Record Committee (see link to SBRC website in sidebar). A couple of the photos were sufficiently good to be able to confirm the presence of Eurasian hobbies amongst the influx of Amurs.

It also answered the question that had arisen about the predation of bee eaters and a turtle dove that was reported during this period on the island. Amur Falcons, although recorded on occasion to take small birds, typically take insects and small vertebrates like lizards. I observed such behaviour repeatedly with birds swooping down on to the runway and capturing small prey. For the falcons to be taking bee eaters and the significantly larger turtle dove seemed surprising. Eurasian hobbies however are known bird predators and the one instance I was able to photograph of a raptor with a freshly killed bee eater was indeed a Eurasian hobby.

The Indian Mynah (Acridotheres tristis) – a growing problem…

In my post of February 17th I recorded that a Magpie robin chick had been attacked in its nest by four Mynah birds working in unison! The male did his best to defend the chick but it was this territory that had lost the female only a day or two before. As such the male was alone and whilst he fought with two birds the other two swooped on the nest to attack the chick! The chick was saved by the intervention of Catherina who fortunately was working in the territory at the time and ultimately she has taken it into her care in order to raise it by hand. This kind of cooperation between the mynahs speaks to their high intelligence. I recall in the mid-nineties seeing four mynahs working together on Cousine island to drive a Fairy tern (Gygis alba) from its egg which they then promptly broke and consumed.

The mynah bird appears to be the main problem that faces the magpie robins on Denis with at least two other nests known to have been destroyed by mynahs and at least one chick fatality that suggested mynah involvement.

The Indian or Common Mynah (Acridotheres tristis) is an introduced or Invasive Alien Species (IAS) to Seychelles. Its native range is central and southern Asia and it is widely distributed throughout the Indian subcontinent. It is believed to have been introduced to Seychelles via Mauritius in the late 18th century either as caged bird or possibly as an early and misguided attempt to control crop pests.

The mynah is a highly intelligent and adaptable bird and exploits all terrestrial habitats in the central archipelago from reef flats exposed at low tide to the highest peaks. Though predominantly a ground feeder, the mynah is able to exploit diverse local and temporary food sources. In Seychelles they have been identified as competitors with (for nest sites and food) and/or predators of (chicks and eggs) threatened endemic land birds such as the magpie-robin, Seychelles white-eye (Zosterops modesta) and Seychelles Scops owl (Otus insularis).

Since its introduction the species has spread progressively throughout the central archipelago. Its date of arrival on Denis is not clear but was sometime in the 20th Century as Fryer did not record the bird on the island in either of his visits (1905, 1908) but Stoddart did record it as present during his visit in 1977. Today at a very rough estimate there are some 300 – 400 mynahs on Denis. They can be best seen in the late afternoon feeding on the runway when as many as 150 birds may be seen at one time spread across the entire length of the strip.

The problem now is how do we go about controlling the mynah population? This is far from easy for various reasons. The mynah population has been controlled in the past on Denis using poison. This was done in 2002 in tandem with the rat eradication project that year. The birds were habituated to being fed in a certain location over a period of several days and then the food source was poisoned. This was very effective but was only possible at that time because the island had no rare native birds. Today particularly with the Magpie robin and Fody (and to a lesser extent the Warbler and Flycatcher) we cannot risk using poison for fear of killing one of these rare birds either by direct or secondary exposure to poison. The other options are trapping or shooting but these too bring difficulties.

Traps cannot be left unattended as again non-target species may be caught; as such trapping methods used must be i). ones that do not inflict injury or harm in the process of capture, and ii). must be permanently manned such that non-target birds can be promptly released; and again the mynah’s extraordinary intelligence also comes into play. Whilst working on Cousine Island in the 90’s I instituted a bounty system on the island such that staff were paid SR100 for each mynah they caught. SR100 was worth a lot more then than it is today and consequently staff devoted quite a lot of time and effort to the capture of the birds. In particular I recall Mme. Juliana Souffe catching birds using a simple walk-in pull-string trap that she baited with open papaya fruit. She set the trap up across a track from the kitchen where she spent several hours a day and when a bird went in she simply pulled the string and bagged a bird! After initial success however this method ceased to work. The birds worked out the link of the string to the trap – so Juliana changed the string to a transparent nylon fishing line and latterly buried it from the trap under the sand but the birds still worked it out. What was particularly alarming however was that birds did not just learn to avoid the trap and resist the temptation of the mouth-watering fruit inside – an adaption that one could perhaps expect. Rather they worked out that the string and not the trap was the dangerous item… so they would happily enter a trap which had no line attached and feast on the papaya but would not enter a trap which had a line attached…. now that is frighteningly intelligent!!!

Shooting poses other problems. Firstly it can be very difficult to get permission for a firearm, even an air rifle; secondly the mynahs work it out!! On Cousine we got permission for an air rifle in 1995 and initially were able to shoot a few mynahs. Then however after awhile if you walked around with the rifle you never saw a mynah, but when you didn’t have the gun you saw them everywhere! In other words they had associated the gun with the danger rather than just the human! We could of course seek help from the military or a police unit to get a marksman over with a 2.2 rifle but such activity is not compatible with a hotel resort in full operation – so what to do?

We have actually identified a company in Australia that makes a specialised mynah trap which has certain features which are supposed to overcome the wits of these brainy birds. So I have asked the island owners to order a couple so we can try them out. Let’s hope we can get them in the not too distant future and that they may prove effective in gradually getting the mynah population under control!

Denis Island’s environmental work gets global media exposure…

In my post of 17th November 2008 I wrote about the filming of our environmental projects by Seychelles National TV company the SBC. This was subsequently aired and I gave links to the footage on YouTube in my post of 12th January.

The work however did not end there. Srdjana Janosevic who led the filming on Denis submitted the footage to CNN’s World Report programme and an edited version appeared for several days on that global network over the weekend before last. It is fantastic for Denis and GIF to receive such global coverage and really puts a massive tick in the Outreach Programme Box under the island’s Environmental Management Plan.

Our sincere thanks go to Srdjana for her interest in our work and her endeavours in getting the images out to the widest possible audience. Indeed we hope to get her back out to the island in the coming months to film another of our projects.

You can connect to the CNN coverage by following the link below:

http://www.cnn.com/video/#/video/international/2009/03/02/wr.feb.28.bk.b.cnn

Also simply click on the images below to enlarge the stills from the footage.

A Unique Morning on a Unique Island…

The last weekend that I was on Denis - I took the opportunity on the Saturday morning to go round and check on various aspects of ongoing works. I nearly always take the same route when I do this starting in the Old Settlement in the northwest of the island and then basically going clockwise round the island through the various areas and habitats.

That Morning, having just checked the tree nursery, I encountered one of the male magpie robins in the garden of the estate manager it was busy hunting out insects in the grass and then was kind enough to take a nice photogenic perch which I took advantage of.

About 10 minutes later in the northern estate woodland I encountered a male Seychelles Fody in breeding colour (see post of February 19th below) and it also obliged me with a photo-opportunity.

Having gone through the workshops and generator house area, I progressed on to the “farm” where the pig sties, cattle shed and solid waste incinerator are situated. I then headed south towards the runway with the intention of going down the east coast through Belle Etoile. Before reaching the runway however I heard the distinctive call of a Seychelles Paradise flycatcher high up in the Indian almond canopy. It’s a beautiful clear call which catches the attention it being a still recent addition to the island’s birdsong. The bird was 50 or 60ft up and that coupled with the dappled light made getting a decent photo difficult. The bird was however very responsive to being “whistled in” and tantalised me with the hope of a better shot for some 20 minutes before I gave up. During this time I also briefly saw the female. It was fantastic to see a territorial pair of this critically endangered bird seemingly content in their new home on Denis and offering hope of a brighter future for the species.

About an hour later I was well down in the south of the island heading towards the southern promontory when I heard the familiar “chit” alarm call of a Seychelles warbler. I whistled back and the male soon came down into a nearby young papaya tree to call in response and another photo was taken.

I went on that morning to see a grey heron, a beautiful flock of crested terns and a group display of Madagascar fodies – all in a morning’s walk around Denis!

It was not until I went through the photos the next week however that I realised the significance of that morning. Denis is the only island in the world where one can see the “endangered*” Seychelles magpie robin, the “near threatened*” Seychelles fody, the “critically endangered*” Seychelles paradise flycatcher and the “vulnerable*” Seychelles warbler! Nowhere else harbours this combination of rare endemic species and what makes it all the more remarkable is that all four species have been introduced by man to the island since 2004!

This has all been made possible by the investment of the island owners beginning with cat and rat eradication in 2000 and 2002 respectively. What more evidence is needed to show the importance of private sector investment or the benefit that such investment can bring?

*: Classifications as per the IUCN Red List of Threatened Species.