Observations on Great and Lesser Frigatebirds (Fregata minor and F. ariel).

The Frigate bird is an iconic species in Seychelles - soaring on the breeze a large dark bird with its characteristic arched wing profile silhouetted against the bright blue sky - it has been adopted as a symbol by 3 islands in the central archipelago. Both species can be seen quite regularly in the central archipelago, though neither breed here, their nearest large breeding colonies being situated on Aldabra.

Aride island hosts the largest roost in the central archipelago with a seasonal peak of some 4,500 birds. Skerrett et al (2001)[1] states that small roosting populations also occur on Cousin and Bird Island. I lived on Cousin (1990-91) and clearly recall Frigatebirds roosting in a single casuarina tree, ignoring all others, north of “Anse Fregate”. That tree latterly fell however and I do not know whether the small roosting population on Cousin persists today. What I do know however is that Denis harbours a regular if small roost of some 40- 50 birds. Both species are represented though as is normal throughout the central archipelago the great out number the lesser.

On the Saturday morning of my last visit to the island I observed 6 frigatebirds stunting and swooping at not too high an altitude over the runway so I took some photos in the hope that the results would be good enough to differentiate between the species for the blog.

The photos are not the best – standing looking almost directly upwards, trying to zoom on and photograph rapidly moving birds not being one of my strong points! – but they are sufficient however to discern identifying characteristics.

The lesser frigatebird adult has the abbreviated white chest and inner wing patch, whilst the adult male great frigatebird is entirely black save for its red throat patch (barely visible in the sidebar photo).

Interestingly I was also able to photo two immature great frigate birds one white-headed and one buff-headed. Skerrett et al (2001) state that the white-headed birds are from the Aldabra colony whilst the buff-headed sub-adults originate form breeding colonies even farther afield! Click on the images below to enlarge.

[1] Skerrett et al (2001). Birds of Seychelles. Helm Field Guides, London.

A familiar and punctual friend – the Danaid Eggfly (Hypolimnas misippus).

During my island visit last weekend I encountered a familiar friend the diadem butterfly or Danaid eggfly. During the mid-90s I worked on Cousine Island and recall seeing this beautiful butterfly, the male of which has a very distinctive wing decoration of 3 large clear white spots on a sooty brown background (see photos in sidebar), in successive Aprils. When I subsequently moved to Mahe I was struck by the fact that I again saw the butterfly over several years on successive Aprils.

This seasonal punctuality has continued on Denis I had regular sightings of the species last April flitting rapidly along the woodland fringe at Belle Etoile and then I had the opportunity to photograph a female in the hotel gardens (see sidebar). This last visit to Denis I encountered two separate males exhibiting territorial and display behaviour and was also able to get some good shots of one of them hence enabling this post. The species is dimorphic with the female being a mimic of the plain tiger butterfly (Danaus chrysippus) but also showing variations in form.

Gerlach and Matyot [1] state that the species is seasonal with adults flying from December to April - but they also note that they are most commonly observed in March-April.

H. missipus is a common butterfly with a pan-tropical distribution and polyphagous eating habit. It is known to feed on species of Asystasia, Portulacaceae and Ipomea all of which are common and abundant on Denis and so it seems likely that this beautiful butterfly will grace Denis for many Aprils to come.

[1] Gerlach, J. & Matyot, P. (2006): Lepidoptera of the Seychelles islands. Backhuys Publishers, Leiden, The Netherlands.

Flycatcher – Breaking News

I have fantastic news to report! I received a call from Rachel Bristol, the Flycatcher Project Officer, yesterday confirming that we now have our first fledgling Flycatcher on Denis!!! This represents a major breakthrough – it is after all the first Paradise flycatcher to fledge from a translocated population and the first real sign that we are making progress with the species and its long term conservation[1].

It also comes as a significant relief as some dozen previous attempts had proven unsuccessful. Some failures were due to infertile eggs but several chicks have also been lost to unidentified causes though we strongly suspect our old enemy the Mynah bird!
The problem is without constant observation of the nest it is very difficult to ascertain a specific cause of a breeding failure. A few years ago when I was in Government employ we monitored Seychelles white-eye nests to assess causes of breeding failure using special cameras. Rachel and I have discussed this option and she will be seeking funding to try and finance a couple of cameras so that we can get a better understanding of the factors involved. In the meantime however the Mynah remains suspect number 1 and we mean to address the problem ASAP.

The chick that has fledged is from one of the nests filmed by SBC during their visit last month (See post of April 3rd). This chick hatched on Monday the 30th of March (See post of April 9th) and was expected to fledge on the 13th or 14th of April.

When I visited Denis last week however, I spent about 30 minutes in the territory and found no evidence of a chick and feared the worst. Rachel came up the next day and also could not find a chick plus she also observed two adults nest-building nearby giving a strong indication that the previous breeding attempt had failed. So I left the island on Saturday disappointed and believing that we had lost another chick. Thankfully however Rachel has subsequently observed the fledgling being tended to by its mother – the new nest being built actually belonging to another pair in an adjacent territory!

So great news… and hopefully just the first fledgling of many, though we are now approaching the end of the breeding season, we can look forward to next season with much more hope.

I don’t have any photos of the fledgling yet but hope that Rachel or Catherina may be able to get some… keep checking back for updates on our the first Denis island Paradise flycatcher!!!


[1] This transfer of the Seychelles Paradise Flycatcher was been a collaborative effort. Approval was granted by the La Digue Development Board. Donor funding was received from the UK Darwin Initiative. The overall project leader is Dr Jim Groombridge. Project partners include: Nature Seychelles, the Seychelles Department of Environment, the Durrell Institute of Conservation and Environment, the Royal Society for the Protection of Birds, Wildlife Vets International, RARE UK and the University of Kent.

Seychelles Magpie Robins – the next generation.

During my last two visits to Denis I have had the opportunity to follow up on the status of some our sub-adult magpie-robins. As reported previously we have faced some problems with SMR breeding attempts. Mynah birds have caused real problems – destroying nests and taking/attacking chicks – whilst we have also now had two chicks born with leg abnormalities which have lead to their demise.

There have also been successes however – in particular the two juveniles that Catherina has raised by hand. Catherina’s “babies” named Charlie and Spencer are both well able to fend for themselves and appear to be prospering. They have not forgotten their adoptive mother however and frequently turn up at her place begging for food! During my previous visit I was walking with Catherina towards her place when both birds approached her on the path and began begging. It was amazing to watch as they followed her to her house and then apparently accepting each other’s presence began feasting on the bowl of insects and grated boiled egg she provided them (see photos in sidebar).

I also during that visit encountered the juvenile in territory 1 it very obligingly posed in a nearby bush for photos and the brown barring on its white wing patch which identifies it as a sub-adult is clearly visible (see photo in sidebar).

This last weekend I visited the island again and encountered the territory 1 juvenile and its parents on several occasions. They were notable because the behaviour of the birds was unusual. I first noticed them as I walked from the airport, having just arrived, to the main hotel building. The juvenile was perched amongst some giant tortoises in the tortoise park this is quite normal as SMRs have learnt that the large reptiles disturb the ground where they pass often revealing insects which the birds eat. What was unusual was the constant “churring” call that the adult was making. This call is typically a sign of aggression or stress in the bird. Over the next two days I repeatedly heard churring coming from this territory and then on Saturday morning I observed both adults in pursuit of their offspring! It turns out that the adults are now undertaking another breeding attempt and clearly have decided that one juvenile in the territory is enough!

This behaviour is in fact normal for Magpie-robins but can of course put the ousted sub-adult under a lot of stress – so we will monitor this sub-adult (ringed orange/orange). If it establishes a small sub-territory adjacent to its natal area we will set up an additional supplementary feed station to cater for its needs.

Keep checking back for updates…

Infrastructure and Land Use

Flying out of Denis the other week I was able to take a few aerial photos of the island as we banked away – whilst not the best due to the slightly fogged windows of the plane they are however sufficient to give an impression of the layout of infrastructure on the island. It is therefore opportune to give readers an overview of the island’s Land Use Plan (LUP).

The Environmental Management Plan for Denis (2008-2012) is based upon LUP which sets out five categories of land usage listed and set out in the photo graphics below:

Zone A: Primary Production Area: designated for intensive human activity, infrastructure placement and production landscapes.

Zone B: Secondary Production Area: designated primarily for production landscapes and low-density tourism/residential infrastructure.

Zone C: Conservation Management Area: designated primarily for management to attain conservation/biodiversity objectives.

Zone D: Ecosystem Restoration Area: area designated for restoration to island’s natural state. All other activities are subordinated to that end.

Coastal Zone: Land within 25m of high water mark – designated for management to optimise natural vegetation cover, structure and function for specific defined ends depending on locality – no permanent infrastructure.

The graphics below show the land zonations and also the main areas of infrastructure of human activity (simply click on the photos below to enlarge). The photos in the sidebar can be used to better interpret the second graphic below.

The LUP is the foundation upon which other aspects of the EMP (such as Biodiversity plan and ecotourism plan) are logically built.

Key:

Yellow: Staff accommodation & related infrastructure.

Blue: Workshops, generator house & fuel storage.

Pink: Livestock areas.

Dark Green: Vegetatble and fruit production.

Light Green: Hotel complex and guest villas.

Brown: Incinerator and solid waste sorting area.

Observations on the Seychelles Paradise Flycatcher…

The Paradise flycatcher (Terpsiphone corvina) is classified as Critically Endangered on the IUCN Red List of threatened species. The first ever translocation of this species was undertaken to Denis in November 2008 when 23 birds were released on the island over a period of two days.
In my previous post (Friday April 3rd) I recorded that SBC had come to Denis to do a film and radio shows on the Flycatcher introduction project. During their visit they were able to film two nests with birds incubating eggs and whilst I was with them I took the opportunity to take some photos and make some observations. We can not venture close to the nest so I was at the maximum zoom and digital enhancement the camera could offer. This coupled with heavy shade in this area means my photos are not the best they are sufficient however to highlight the observations.

Nest Structure:
The two nests showed an interesting variation in design. The first was constructed on the fine end of a down-hanging branch of a young Takamaka tree and looked rather precarious, the nest secured in position by being interwoven with a couple of leaf stems. The second was in the fork of a young sapling-like “upshoot” from an otherwise fallen Indian almond tree; but it looked all together more solid, being secured to the three woody stems of the fork.
The nests were also notable for their adornment with white materials. One appeared to have small pieces of white cotton, presumably plucked direct from the wild plants that still grow on the island. The second, meanwhile, was clearly festooned with white feathers. Rachel Bristol advised me that the birds in the source colony on La Digue also typically decorate the exterior of their nests with white materials. The only reason I can think of for this (and this is pure speculation) is that it may serve to break up the outline of the nest in the dappled light that typically penetrates through canopy making it harder for potential predators to discern.

Incubation, Nest Guarding and Chick Feeding:
During the SBC filming on that Saturday evening and Sunday morning we observed the the females incubating and then the male guarding the nest from a nearby perch when the female left it periodically. On the Monday morning however I returned to the nests and noted in one that the male tended to the nest directly including sitting in it. As I watched I realised that the male was in fact bringing insects to the nest meaning that the egg must have hatched in the last 24 hours. Over the next 20-30 minutes I also observed the female bring insects confirming the hatching.

Whiskers on Flycatchers:
On examining my photos a few days later what struck me was the prominent “whiskers” displayed by both male and female birds. The Flycatcher feeds predominantly by “hawking” i.e. the taking of insects on the wing. This requires high precision and fine last-second adjustments as obviously the prey will attempt to avoid being taken if they possibly can. I can only imagine that the whiskers enable the final adjustments through tactile stimulation to catch prey when they are perhaps too close to be properly seen.

Click images to enlarge. i). Male at nest. ii). Female bringing insect to the nest. iii). Whiskers evident on the female and (iv). male.

Seychelles Broadcasting Corporation visit Denis Island.

Last weekend Denis played host to a team from both SBC TV and radio. The primary reason for their visit was to record programmes about the introduction of the Seychelles Paradise Flycatcher (Terpsiphone corvina). 23 Flycatchers were transferred from La Digue to Denis in November of last year in the first ever transfer of this critically endangered species (see posts of 5th and 16th January for more information)[1]. Prior to the transfer the only breeding population of the bird was restricted to the island of La Digue where its habitat is coming under increasing development pressure. It is very important to establish additional breeding populations of the species on other islands so as to reduce the risk from stochastic events such as storm, fire or disease that a single population in a restricted area is prone to.

To assist with the coverage I asked Rachel Bristol the Project Officer responsible for the flycatcher transfer to also visit the island so she could give the necessary interviews. Filming and recording went very well with the cameramen getting really good footage of females on two separate nests and a male in close attendance in one territory.

In addition to covering the flycatcher project, film and interviews were also taken on the progress of the Magpie-robin project, the woodland conservation project and more generally about the natural history of the island – including footage of bee-eaters perched along and flying over the runway.

The SBC crew also visited the new “Belle Etoile” Villas, filmed them and interviewed the Hotel Resident Manager Mr. Paul Horner about this new initiative for the national tourism programme “Check-in”.

The natural history filming was for the national environmental TV series “Karnen Lannatir” whilst the radio recordings were for the weekly radio show “Nature Watch”. Whilst drafting this post I have just spoken to Lucille Adrienne who produces the radio show and she advised me that she has sufficient recording for 3 and possibly 4 fifteen minute spots – including good recordings of the song of the Flycatcher and the bee-eaters so that should make for an interesting listen. The programmes will go out on SBC MW as of next week at Thursday 11:30 hrs and repeated Friday 17:15 hrs.

This latest media coverage is another plus for GIF’s Public relations and outreach programme that seeks to raise awareness of the achievements of the ongoing work on Denis Island. Our sincere thanks go to: the SBC crew Mr. Jerome Dogley, Mme. Lucille Adrienne, Mr. Claude Vidot and Mr. Guilmer Philoe for their interest in the environmental work on Denis Island; and Mme. Lena Desaubin from the Department of Environment for facilitating arrangements.

[1] The transfer of Flycatchers to Denis was: enabled by the agreement and cooperation of the La Digue Development Board, and the partnership and support of UK Darwin Initiative, Nature Seychelles, the Seychelles Department of Environment, the Durrell Institute of Conservation and Environment, the Royal Society for the Protection of Birds, Wildlife Vets International, RARE UK and the University of Kent.