Bird Bulletin 5

SMR update:

I have received good news from Catherina regarding the progress of the Magpie robin population recently introduced to Denis (see posts of: 15th August; 4th, 15th, 20th, and 30th July) I will post in detail on this in the coming days so check back regularly.

Sooty tern project:

I will soon be resuming my visits to Denis with one of the primary objectives being to make observations of the sooty tern project trial area before we pack the equipment away for the year - so check back for the latest news.

Migrant birds:

As summer in the northern hemisphere draws to a close we can look forward to visitation by various species of migrant birds. Denis’ geographic location as the second most northerly of the Seychelles archipelago means it is ideally situated to receive migrants. Now with Catherina resident on the island, and more frequent visits scheduled on my part, I hope we can begin to establish a much more complete list of our annual visitors. If so I will add the migrant birds list as a recurrent feature on the Blog.

Vegetation 1 – Coastal Vegetation

When De Trobriand discovered Denis in 1773 he found it luxuriantly vegetated with a 50/50 patchwork of forested and grassland areas. The soil in the interior he described as rich and dark and though he found no standing water he recorded that he felt a shallow well would readily find it. Within 70 years of this discovery however, the vegetation on Denis had been changed almost beyond recognition, being described as agricultural land, the likely crops being maize and cotton. Further changes in land use followed through the years leading ultimately to the patchwork of secondary habitats that we find today.

The coastal vegetation on Denis plays a vital role in the island’s ecosystem. The hardy plants that grow there serve to:

• bind the sand against the eroding action of the sea,
• protect the interior vegetation from the worst rigours of sea winds and salt spray,
• provide a habitat for various animal species including nesting grounds for marine turtles.

The coastal vegetation on Denis is dominated by three indigenous species: Scaevola/Veloutye (Scaevola sericea), Bay Cedar/Bwa D’amand (Suriana maritima) and Beach Gardenia/Bwa Kassan (Guettarda speciosa).

Scaevola is the most common and familiar beach shrub throughout the central archipelago and it forms dominant stands along the majority of the northwest and north coasts of Denis. Scaevola is unmistakeable with its characteristic large glossy, bright green leaves, 5-petalled white flowers (with all petals restricted to the lower half of the flower) and round white fruits. Scaevola provides a sheltered habitat for nesting turtles and the tawny hermit crab. Whist the blue pigeons on Denis also show a taste for its berries.

Bay Cedar can be found intermittently along the west and southern coasts and forms quite thick stands on certain areas of the East coast where perhaps it is too exposed to the southeast monsoon for Scaevola to form dominant stands.

Beach Gardenia typically grows as a tree on Denis and can be found scattered along the west and northern coasts of the island whereas on the east coast it forms extensive dominant stands a feature which is to the best of my knowledge peculiar to Denis and suggests a concurrence of factors that particularly favour its growth and propagation.

The coastal vegetation at the southern point of the island exhibits an interesting community of species. Here Scaevola grows along with Bay Cedar, Tournefortia argentea and mature specimens of Pisonia grandis. This transitions, as one moves inland, through beach gardenia, into mixed stands of Cordia subcordata, Thespesia populnea and Pisonia. This combination and succession of species speaks to stability in the habitat and enquiries have revealed that the area has not been disturbed within living memory. This coupled with descriptions of the island from the 1880s onwards as having a band of coastal vegetation surrounding the interior production landscapes suggests that this area may be as close to a relict of the original coastal vegetation as remains on Denis and is therefore of particular research and conservation interest.

Bird Bulletin 4 - “About Terns”

A key element in re-habilitating Denis’ ecosystem is developing an understanding of what the island was like in its pristine state. De Trobriand’s original description is very informative but not down to the species level of seabird. It is reasonable to conclude however that terns formed a major component of the original seabird colony.

• Brown Noddy (Anous stolidus): breeds in quite large numbers on the island. No census has been undertaken as yet, but practically every coconut crown in the hotel grounds has at least one pair during the breeding season. How dense the populations are in the areas of coconut-dominated forest needs to be assessed, but Denis has the potential to be one of the major breeding colonies in the Seychelles. Though no birds are yet actively breeding on the ground, as they do in some other colonies, what is noticeable is the number of chicks that continue to receive parental care and now fledge successfully despite falling from their nest, something that would never have happened prior to the rat and cat eradications.
• White Tern (Gygis alba): quite abundant and to be found breeding all year round on Denis. Again we currently have no indices as to the actual population on the island, though there is considerable anecdotal evidence to suggest that numbers have increased considerably since rat eradication in 2002. In recent months however there have been a large number of chicks and juveniles that have been left to starve suggesting a problem with the food supply.
• Lesser Noddy (Anous tenuirostris): are quite likely to have bred on the island in the past, large numbers (C 30,000) are to be seen roosting on the island and there are reports of occasional individuals breeding but I have yet to be able to confirm this. It is to be hoped that a breeding colony will establish itself on the island in the coming seasons.
• Sooty Tern (Onychoprion fuscata): known to have bred on the island in the past (see posts dated : July 2nd and August 17th 2008 for updates on the ongoing project to re-establish a colony on the island). This season has seen numerous landings of birds in the trial area including 5 birds on a single occasion. This bodes well for years 2-4 of the project.
• Bridled tern (Sterna anaethetus): In Seychelles Bridled tern breeding colonies are typically associated with rocky habitats and thus Denis may not be suitable for breeding. The birds however certainly frequent the island with at least 200-300 observed roosting in casuarinas on the south and south western coasts from November 07 through to February 08.
• Roseate Tern (Sterna dougallii): though we have no records, it is possible that the Roseate Tern used to breed on Denis as it once did on the neighbouring Bird Island. Certainly they are seen round the island, I most recently noted a pair, on the 24th July 08 soaring in the breeze over the southern point of the island and then swooping low over the water and calling distinctively.

NATURAL RECOLONISATION (?) 3 - The status of the sunbird on Denis Island

The Seychelles Sunbird (Nectarinia dussumieri) is endemic to the central Seychelles archipelago and is often cited as the endemic species that has best adapted to, or perhaps even benefited from, man-induced habitat changes.

The status of the sunbird on Denis Island, however, is not so clear. Fryer, recorded sunbirds as present on the island in 1907[1] as did Stoddart following a visit in 1977. Hill however, found no sunbirds and described the species as “apparently extinct” following a survey in 2001. Discussion with island residents revealed anecdotal sightings of the bird in the mid-nineties from the areas called Bois D’Argent and “Miray Bondye” and somewhat less credible claims of the birds being regularly seen at the site of the old hospital (see map3).

In July 2007 however there was a confirmed sighting of a single male sunbird (Feare, C. and Nevill, J) at the abandoned house at Miray Bondye. It was suggested at the time that the bird may have come from Bird Island where a population of Sunbirds had very recently been introduced, but the bird seen by Dr Feare and myself had no rings therefore discounting this option. Dr Feare was able to take some partial photographs of the bird in a tree canopy (see sidebar).

Perhaps the species has been reduced to and maintained very low numbers on the island, for reasons that are unclear as suitable habitat appears to be relatively abundant, resulting in only occasional sightings. Or perhaps the population was extirpated in the past and has recently re-colonised or is subject to occasional visitation from Aride Island. Regardless the status of the population is unclear and numbers, if there is indeed a resident population remain very low.

The opening of an environmental information centre on the island, in the coming months, will provide a basis to better engage guests and staff in the search for and hoped for confirmation and whereabouts of a population on the island.


[1] In fact Fryer recorded the sunbirds as being of the Aldabran species (N. sovimanga) though this is now widely accepted as an error.

Marine News 1 - Marine Mega-fauna

Denis is the second most northerly island in the Seychelles archipelago and lies only a few miles from the edge of the Mahe plateau where the seabed drops from some 50 metres rapidly down into the dark oceanic depths. This means that Denis is often surrounded by upwellings of cold nutrient-rich water from off the plateau. This in turn leads to algal blooms, followed by plankton through a procession of life up through the marine food chain. In the 1820s and 30s whaling barks from the United States plied their trade in the waters north of the Seychelles bank hunting sperm whales and they would use Denis Island on occasion for re-victualling.
Denis itself sits on a shallow shoal which extends for an area some 10-12 times the size of the island to West and North West this shoal and its shallow habitats also serve to attract marine life such as dolphins.
With these possibilities in mind Denis Island and GIF teamed up with the Marine Conservation Society, Seychelles (MCSS) and a Masters student from the University of Bremen, Yvonne Dartsch, to undertake a preliminary survey of the occurrence of whales and dolphins around Denis Island.
Yvonne’s study looked at species occurrence relative to water depth, weather patterns etc… and also combined different monitoring methods such as visual sightings and sonar recordings.
Yvonne is still writing up her thesis but I do have some preliminary results on her sightings records that she left with me on her departure. During some 400 hours of observations Yvonne and her assistants, including Shannon Switzer who we have to thank for the accompanying photos, sighted 74 groups of dolphins and whales, including:
· 55 groups of Bottlenose dolphins
· 13 groups of Spinner dolphins
· 1 group of Risso’s dolphins, and
· 2 groups of False Killer whales.

These species were found in water depths from 7- 1000 metres but most frequently on the plateau in depths between 20 and 40 metres only. Group sizes varied between 1 – 200 individuals, with Yvonne stating that finding herself amongst a pod of some 200 or so False Killer whales was a truly extraordinary experience.

Sightings of Bottlenose dolphins were particularly common giving the impression that a pod may be resident around the island. Also of interest were the frequent sightings of Manta rays which when coupled with turtles etc… give broad appeal to divers visiting Denis.

Natural (Re)Colonisation 2 – the Wedge-tailed Shearwater (Puffinus pacificus).

I first visited Denis Island in 1998 with Dr Don Merton to undertake the first preliminary assessment of rats and cats on the island. Don, who works for the Department of Conservation in New Zealand, is the man who pioneered rodent eradications on islands and during the time we spent on Denis we surveyed the rat and cat populations and tested their bait type preference etc…

I clearly remember our night time surveys around the pig farm where the beam of a torch would reveal the glittering eyes of literally dozens of cats that gathered there to feed in the evening. Whilst our walk-in traps all caught rats each night – the density of these predators on the island being extraordinarily high!

It was thus particularly surprising, to me at least, to hear the call of a lone wedge tailed shearwater in the woods one evening. I subsequently made enquiries with some of the island staff and they confirmed that though wedge tails (known locally as “Fouke”) did roost occasionally on the island they did not breed.

That they did not breed is to be expected, as the Fouke excavates and lays its eggs in subterranean burrows that it vacates during the day whilst off fishing. This species is therefore particularly vulnerable to rats and simply can not co-exist with them in the long run.

Rats were finally eradicated from Denis in 2002 and during the subsequent years the number of roosting shearwaters has increased particularly on the ground in certain coastal stands of Scaevola. November 2007, however, marked a major landmark in the rehabilitation of Denis when Island staff found a small colony of wedge tail burrows on an isolated portion of the east coast. I checked the area and was able to confirm the presence of the birds in the evening; but though likely at that time I did not succeed in finding proof of breeding.

Wedge-tails can be breed at any time of the year but have a very definite seasonal peak with chicks hatching November/December and taking 10-12 weeks to fledge. I will be looking out for the birds in the coming months and hope to be able confirm the re-establishment of a breeding colony on the island. Should shearwaters breed on the island this will be a major breakthrough in the rehabilitation of Denis and further justify the investment started 10 years ago by the island owners.

Bird Bulletin 3

News from our neighbours: I had the opportunity to communicate with Jo Savy on our nearest neighbour Bird Island last week and was able to follow up on a couple of the issues I have posted on recently.

• Jo confirmed the presence of a Barn Owl on Bird (see post of Monday 4th August) but feels that it is an occasional visitor rather than resident. This further increases the likelihood that this bird or others are visiting Denis also, so we must increase our vigilance in this regard.
• I also asked whether they had any Blue Pigeons (see post of Sunday 10th August) and Jo answered in a similar vein, saying they have indeed on occasion sighted an individual blue pigeon on Bird, but that they do not consider it to be a permanent resident but rather an occasional visitor from Denis. It’s 4 or 5 years since I last visited Bird but from what I recall of the vegetation there, it would appear suitable for blue pigeons. Surely it must only be a matter of time until the species establishes a population on this most northerly outlier of the Seychelles archipelago and thereby completes a remarkable recovery story.

Sooty Tern Project: I have received preliminary results on the Sooty Tern project from Vicki and Tori following their return to UK at the end of July. During their observation periods they observed 24 landings including one of 2 birds simultaneously. Their findings are very clear cut with 22 of said 24 landings (i.e. 92%) occurring within a single combination of stimuli – i.e. a combination of models, sounds and vegetation type. These very clear results will allow us to much better target our management of the area next season. During their last few days on the island Vicki and Tori altered the layout of the models in line with their findings to see if this would better attract birds at the end of the season. Unfortunately, I was supposed to follow up with observations during August but breaking my arm has put paid to that and I have yet to visit Denis during this month. Catherina however has opportunistically taken observations when she passes the area during her SMR survey work and reports having seen five birds together on the ground on the 30th July with another 10 or so circling only a couple of metres in the air above them. This is very encouraging and with fine tuning coupled with an area which will be much more suitably vegetated in general next year gives us good reason to believe that the project can be successful within the next 2 to 3 years – let’s hope so!

Good ideas catch on fast and this project has attracted attention. I understand a second island will be attempting this project next year. So we look forward to a brighter future for the sooty tern in the central archipelago in the coming years.

Magpie Robin News 2

Catherina, the GIF Environmental Officer on Denis, has got back to me with more information on the status of the newly-introduced Seychelles Magpie Robin (SMR) population on Denis. Firstly Catherina reports that all 19 birds appear to be in good condition and adapting well to their new home. As reported on the 30th July (Bird Bulletin 2) Catherina had identified two territories that had commenced nest building activities, well that is now the case in 4 territories (see map 2):

Territory 1: the nest has been constructed in a natural cavity in a Casuarina tree.
Territory 2: the nest has been constructed in a dead Casuarina.
Territory 3: the nest has been built in the crown of a coconut tree.
Territory 4: the exact position of the nest has yet to be identified but the birds activities indicate that a nest is under construction.

Interestingly all the nests are utilising natural locations rather than the numerous nest boxes that have been put up in each established territory which shows that sufficient nesting sites are available in the woodland habitat.

Nesting activities, of course, form part of breeding behaviour and close observation of the birds’ activities will, over time, indicate whether egg incubation or later chick feeding has commenced. However in the case of territory 3 I can be more specific, as Catherina has been able to position herself so as to observe the interior of the nest and is able to confirm that there is an egg in the nest as of the 4th of August!!!

Now of course, we mustn’t count our robins before they hatch! In recent years SMRs have laid a significant number of sterile eggs – some have postulated that this may be related to in-breeding depression though we cannot, at this stage, quantify this and many would argue that through a process of evolutionary selection small island bird populations are not prone to such factors. So firstly we do not know if the egg is viable. Secondly, the development of young birds (egg through fledgling) is fraught with dangers – including possible predation (see bird bulletin 2, 30th July). So we must be cautious and not be overly disappointed or discouraged if we don’t soon see chicks. However what is undoubtedly true is that the SMRs have adapted very rapidly and well to their new home on Denis Island and have clearly found it to their liking. Remembering that the birds were only transferred to Denis on the 25th June (see post of Friday July 4th) and were only released from their aviaries during the period 13th to the 18th July (see post of Sunday July 20th) ; to have nests and at least one egg in the first week of August is very encouraging indeed. Long may it continue!

Check back regularly for more news on SMR progress.

BREAKING NEWS!

I have received word from Catherina on the magpie robin population including some most exciting developments. Once I have received the full details I will post accordingly so check back here periodically!

Close encounters of the feathered kind…

Having lived for four years on sea bird colony islands (Cousin 1990-91, Cousine 1993-96) and then in my former capacity as Director of Conservation in the Department of Environment (1996 – 2002) I have encountered a lot of injured or sick birds, abandoned chicks etc... :

• Otherwise healthy seabirds, in particular lesser noddies, brown noddies and white terns, are often to be found with irreparable injuries such as badly broken wings.
• In certain years the sticky seeds of the Pisonia tree can reap a grim harvest.
• A failing of the monsoon wind can leave literally thousands of chicks abandoned to starvation by their parents that are forced back out to sea to seek food for their own survival.

We have negligible capacity nationally to treat injured wild birds, so ones with badly broken wings are best despatched with a swift blow to the back of the head (techniques vary but the end result is much the same). This is the kindest thing to do as otherwise the birds face a period of slow starvation and then being eaten alive by crabs and/or lizards when they become too weak to evade these scavengers. Many birds can be saved from the sticky Pisonia seeds provided they are found and cleaned early enough and sterling work is undertaken on the various island reserves when seeding coincides with the nesting season. Abandoned seabird juveniles should generally be left where they are found, or if appropriate put on the nearest prominent perch, as adults will often continue to tend to young that have fallen from their nests.

As a conservationist at heart it can be very distressing to have to terminate birds. In particular I find dealing with injured white-tailed tropic birds the most difficult. I am certain that this large and particularly beautiful bird has sufficient intelligence to “know the score” and I distinctly recall one such bird looking me directly and pointedly in the eye seconds before I despatched it.

Still as with the Pisonia seeds not all encounters end badly and in the last 8 months I have had two encounters that have generated good photo-opportunities and are worth recalling.

In December 2007 we had several crested terns on the island including adults still accompanied by their sub-adult offspring. I noted over a period of days that one sub-adult was partly entangled in something and was hence limited in its ability to move and fly. After seeing it struggling on consecutive days I resolved to try and catch it. This was not easy because we have a couple of sandstone outcrops just offshore in the lagoon and the bird was still able to reach these refuges. Anyway with some forethought, careful manoeuvring and patience I was able to catch it and remove what turned out to be discarded fishing line that had entangled around its legs and one wing. With this removed the bird was returned to full mobility and with an indignant squawk and rather vicious peck removed itself from my otherwise unwanted attentions and flew off to join the others.

Then in July I was in the hotel media room when there was an abrupt thump on one of the windows, I looked out to see that the victim of this unfortunate impact was a rare Seychelles warbler. The bird was stricken and lying agape on the ground and my initial thought was that things did not look good, particularly as there was evidence of blood around its mouth. I gathered it up carefully and took a minute or so to examine it for other overt signs of injury – there were none. Within a couple of minutes it began flexing and gripping with its claws, so I placed it on a sheltered perch in a nearby bush and observed from a distance. Over the next 30 minutes or so, it slowly recovered, ceased gaping and became incrementally more aware of its surroundings. Several further minutes were spent motionless, followed by a brief preening before it suddenly, and apparently no worse for wear, flew back off into the bushes.

NATURAL (RE)COLONISATION 1 – The Seychelles Blue Pigeon

The natural area of occurrence of species is a controversial subject in the local conservation community as it has potentially substantive ramifications for ongoing conservation action plans. In an ideal scenario species would only be introduced (i.e. re-introduced) to islands that they had previously naturally occurred on. The reality however is considerably more complex. The lack of a comprehensive baseline of the original occurrence of species, the dire status and urgent need of many species and the available islands with habitats suitable to support them have required a much more pragmatic approach. These are issues that have been pertinent to the introduction, of the Seychelles warbler, fody and magpie-robin on Denis Island. The pragmatic approach, however, has been prevalent in recent years and continues to improve the status of key rare endemic species.

Not all species require introduction however, man-induced changes to an ecosystem whether they be production landscape changes or attempts at ecosystem restoration create habitats and niches for species that can then establish themselves through “natural” dispersal. A good example of this is the Blue pigeon (Alectroenas pulcherrima) on Denis Island. De Trobriand did not mention any land bird species in 1773 when he first described the island and the pigeon was not recorded in 1907 or 1977 surveys of the island. Today however the blue pigeon is a common sight on Denis with nest building behaviour and juveniles regularly seen. Though no systematic survey of the blue pigeon population on the island has been undertaken a minimum of 23 birds were observed together in a single fig tree in march 2008 and it is estimated that there are at least 50 to 100 birds on the island.

So what has brought about this natural arrival and population growth on the island?
The blue pigeon, an endemic to the Seychelles central archipelago, has an interesting history. It is good to eat and has been heavily exploited in the past with clear evidence of a corresponding reduction in population and range of the species. However a combination of legal protection, public education and improved standards of living has greatly reduced, if not eliminated, this practice and the population has demonstrated rapid growth since the mid 20th century.

Crook (1960) cited the species as “not very rare in these islands”, but this comment was made in the context of endangered birds in the archipelago such as the magpie–robin and warbler which were very rare at that time with global populations of less than 50. Penny (1974) stated that pigeons could still be seen where mountain forest persists, most commonly on Praslin but also in remote parts of Mahe, Silhouette and Fregate. Beamish (1979) noted that numbers seemed to be increasing “particularly on Mahe and also fairly common on Fregate, Silhouette and Praslin.” Skerrett et al (2001) provide considerable information stating that:

• in 1980 the bird was rarely seen below and elevation of 200m but by 2001 it occurred to sea level.
• it was then fairly common on Mahe, Praslin, La Digue and other large wooded granite islands – Curieuse was naturally re-colonised in the 1980s, this being linked to an increase in woodland habitat on the island.
• that it was introduced to cousin in 1990 and that it now breeds there successfully[1].
• Aride Island was naturally re-colonised with the first record in October 1990.

The colonisation of Aride is of particular interest because this is the nearest (56km south) granitic island to Denis and therefore logical source of origin for its population.

Hill (2001) records blue pigeons as present on Denis but does not comment on its relative abundance. This suggests that somewhere between 1990 and 2001 that birds colonised Denis from Aride. This is a very narrow period of time particularly when one would normally assume that the population on Aride would first establish itself and expand to fill the available habitat on the island before emigration to a distant island like Denis would occur.
The current relative abundance of blue pigeons suggests that Denis was colonised shortly after Aride and/or that immigration of birds to the island is ongoing. Denis does appear to be a particularly suitable for Blue pigeons. Even in the mid-20th century when the island’s surface area was dedicated to coconut production visitors noted that an unusual number of broad leaved trees were allowed to flourish within the plantation. The coconut plantations on Denis were abandoned in 1982 and broadleaved trees flourished in the aftermath, developing closed canopies in significant areas of the north east quarter of the island. Today Denis has extensive areas of broadleaved woodland (approximately 50 hectares with another 20 hectares under restoration) including a lot of fig trees, the fruit of which is particularly favoured by blue pigeons. The birds can also be commonly seen feeding on the fruits of the abundant scaevola bushes that fringe the coast of the island. So with abundant food sources on a relatively large predator free island the birds can be expected to prosper.

But should they be there? There are arguments for and against:

• the island is clearly within flying range of the species as proven by the recent natural colonisation of Denis.
• but would the natural vegetation have supported a population of the birds? the original vegetation of Denis consisted of Pisonia dominated broadleaved forest interspersed with grassland areas and the avifauna was dominated by huge sea bird colonies. De Trobriand, the discoverer of Denis certainly doesn’t mention them, but then again his description of the island is limited. Certainly the closely related Comoro blue pigeon has prospered in similar ecosystems.
• the absence of the birds throughout most of the 20th century might be interpreted as meaning the birds were never there but the late 19th and early 20th century saw a diminished population in numbers and range – so if the birds had been extirpated on Denis through human consumption and/or the extensive habitat change on the island during that time, there would have been no ready source of re-colonisation.

There does not currently appear to be any definitive information; and whilst I am personally inclined to believe that Denis does form part of the natural range of the species the population has clearly benefited from the development of man-made secondary habitat on the island.

What can be said, however, is that the blue pigeon is today present and prospering on the island, it is a protected species and a welcome addition to the island’s ecotourism product and current vegetation management regimes mean its population is likely to further expand over the next 5 – 10 years.


[1] From personal observation I can confirm that a breeding population of blue pigeons was established on the neighbouring island of Cousine in the mid-1990’s – nest and juvenile found in 1995.

Bird Bulletin 2

Great news received from Catherina – as of 30th July 2 pairs of magpie robin have commenced nest building in their newly established territories. This shows that the birds have settled and found their new home appropriate to their needs. Catherina will keep the birds under close scrutiny in order to ascertain whether breeding has commenced. Check back regularly for updates!

Invasive species are considered the primary threat to the native biodiversity in Seychelles and it is the removal of mammalian predators from Denis (cats in 2000 and rats in 2002) that has enabled the introduction of rare species like the fody, warbler and magpie-robin to the island. There are however other invasive species issues that are of concern to the magpie robin introduction on Denis.

The Common Myna (Acridotheres tristis) – introduced quite early on in the human history of the Seychelles, the Myna is a highly intelligent and adaptable species that can utilise a broad ecological niche. The species has spread throughout the central archipelago and is a common sight on Denis. The Myna poses a double threat to the magpie robin as a competitor for nesting sites and as a potential predator of eggs and nestlings. As such we will, in the coming months, be exploring means of controlling the Mynas in order to facilitate the establishment and expansion of the robin population on Denis.

The Barn Owl (Tyto alba affinis) was introduced to Seychelles in the 1950s in a misguided attempt at rat control. The barn owl prospered however on the much easier pickings of roosting seabirds. The decline of the white tern (Gygis alba) on many of the granite islands, has been attributed to barn owl predation. The barn owl has also been connected in the past to the loss of 2 or 3 magpie robins on one island. The barn owl however has not previously been recorded on Denis and it was hoped that the isolation of the island may keep it safe. It was with considerable concern therefore that I read in a recent addition of the NPTS publication “Birdwatch” that a barn owl has taken up residence on Bird Island, the nearest island to Denis. What’s more Bird is in fact more isolated from the central archipelago than Denis! Barn owls kill seabirds in a distinctive manner that can be identified from the remains of their prey and they also develop favoured locations for feeding so we have now incorporated the examination of dead white terns into our normal observation routine such that should a barn owl arrive on Denis we can take the appropriate measures to protect our native bird populations.