Bird Bulletin 8

Crested Terns. These beautiful birds are still with us and indeed I recorded my highest count for Denis yet, on Friday 10th October, with 14 birds perched on the southern rocks.

Bridled (re)Terns. Having recorded a bridled tern roost of 200 – 300 birds on the island October through December last year, I have been on the look out at the southern point of the island where the bulk aggregated last year but without success. Then on Saturday 11th I was undertaking the first beach check of the new hawksbill turtle season when I noticed all five buoys off the west of the island were being used as perches by bridled terns. This gave an inclination that birds might be returning and sure enough further down the coast in the branches of a prominent casuarina tree I counted 15 bridled terns and 10 lesser noddies. The southern point of the island however still shows no sign of bridled terns and so I will keep monitoring this small roost area to see if it expands as the weeks pass.

Frigate birds. I have still to go and check properly on our Frigate bird roost as the right time usually clashes with other commitments but on the evening of Friday 10th I saw 29 Frigates flying very low over the island towards their southwest coast roost area.

Blue pigeons. I have written at length on the blue pigeons on the island in other posts (most notably the August 10th post entitled “Natural Recolonisation 1”) and the population continues to do very well. On Saturday 11th I saw two fledglings together accompanied by an adult in a small Morinda tree. The various ornithological reference works do state that the birds will occasionally have a clutch of two eggs, though I have personally never seen this, but this sighting seems to suggest the successful fledging of a clutch of 2 on Denis.

King Myna. The Myna birds on Denis have taken to imitating the call of the Magpie robins already causing me stop more frequently to verify whether I am indeed hearing a robin or not. I have also seen on 3 or 4 occasions recently, at Belle Etoile, what is known as a “King Myna” – i.e. a Myna bird which has no feathers on its head or neck thus revealing the yellow skin all over its head to quite startling effect.

Fairy Tern and Tropicbird Progress (3).

So back to our breeding seabirds for an update. Firstly the Fairy terns:
the first juvenile looks well and fully-fledged with only the lack of the purple band at the base of its bill to distinguish it now from an adult.
the second juvenile took me by surprise by flying off as I approached! It circled for a while and then returned but I kept my distance so as not to disturb it again. The bird still has clear juvenile barring on its wings and has not developed yet its full tail plumage but is clearly developing well.
Finally our egg has hatched and we have new young chick on the branch I have opted to name this bird “Fred” and will keep you informed of his/her development.

As for the tropicbirds:
· It does appear that the first nesting site has been abandoned.
· The adult is still at the second site and appears to be incubating.
· Our chick, to be known hence forth as “Tina”, has attracted a great deal of attention and feedback following my posting of its picture on the blog. Tina appears to be doing well with evident of growth over the last week.
Because of the relatively low number of breeding pairs of Tropicbirds on Denis I have decided to map the known breeding sites and will seek feedback from island staff to make it as comprehensive as possible before posting at a future date.

Sooty Tern Summary 2008 (Part 2).

This post follows on from my post of 21st September.

Once the area had been selected the next issue was to identify an appropriate form and source of models. As part of the scientific basis of the project we wanted to offer the birds a variety of stimuli in various combinations so as to properly assess their preferences. We investigated various options and ultimately went for 3 types:
· Moulds were made in the UK to enable the production of fibreglass models in Seychelles.
· 2-dimensional models were made out of plywood and painted
· Plastic models of crows were bought in UK and repainted and tails added to resemble sooty terns.
Unfortunately for some technical reason, that frankly still escapes me, the moulds and particularly their rubber interiors were not suitable for the local production of fibreglass models. So we were left with two types.
The sound system used to broadcast colony noise was purchased from a company that makes sound systems to scare pest species off crops in Europe. This was modified to play the noise of a sooty tern colony.
These different options plus control plots were combined with variations in vegetation management to generate 8 different stimuli combinations each repeated twice over the project area.

Vicki Wheeler and Tori Yates arrived at the end of May and set out the project with Chris Feare and the help of the Island Manager Camille Hoareau.

Observations were taken at set times (day and night) from a viewing platform constructed at one side of the project area. The interaction of Sooties with the trial area was recorded in terms of time spent overflying the area, height of flight and of course landings within the area. Tori and Vicki were equipped with night vision glasses to assist their nocturnal data collection.

Without going into specifics (because there are papers to be written and much more work to follow over the next 2 to 3 seasons), the area was successful in engendering interest amongst overflying sooty terns including numerous landings and demonstrating a clear preference for certain parameters.

At the end of the season models were re-positioned to reflect the favoured formulation and some 30 were re-painted as juveniles to give the impression of a successful small colony. I was supposed to follow up on this closely for another month but unfortunately broke my arm at that time and didn’t visit the island for a period of 5 weeks. However, occasional sightings by at least three individuals confirmed that the new formulation was particularly successful with 5 -10 birds seen to land at a time and numerous birds circling low overhead.

So with the results of the first season now gathered, it is for us to refine our approach accordingly for next season and hopefully optimise the scope for the establishment of a small breeding colony. It was certainly a most encouraging first year!

Bird Bulletin 7

Sunbird sighting: following on from my post of 15th September (in BB 6) Catherina has again sighted the male sunbird in the same location (to the north of the island) on both the 2nd and 3rd of October. Now we want to know from which of our nearest neighbours, Bird or Aride islands, the bird has originated. Catherina has also been able to get a reasonable view of the rings and I have communicated the combination to ICS, the agency that manage Aride island to see if it is one of theirs. I must also contact Nature Seychelles to see if the bird is one of those they introduced to Bird Island a couple of years ago. I will keep you informed and if the bird is indeed from Aride it will be an interesting addition to our knowledge of the species and its status on Denis (see my post dated of August 23rd for more information).

Seychelles Magpie Robin Update: love is blossoming on Denis! Well at least amongst the Magpie Robins with two more pairs appearing to establish. Most notable is the movement south of the single female from the area adjacent to territory 3 down to join the lone male there to form a new pair (see maps in side bar). Also the younger female that was co-habiting in with two other birds just south of the runway has apparently left this area, leaving anew pair behind her, and commenced floating. It is to be hoped that she will next turn up with one of the males on the northeast coast. This would result in the current optimum number of 9 pairings and hopefully engender more breeding activity. News from other territories includes:

• T1 appears to be nest building again following the earlier loss of its chick.


• T3 are feeding their fledgling.


• T4 is currently incubating with hatching presumed imminent


• T5 is nest building after an apparent failure at egg stage of a previous breeding attempt.
  
  Following a request for a larger map I have posted the map showing territory changes here in the body of the text. Simply click on the map to see it as a full screen version.

Crested Terns: Are still with us with eleven seen together on the southern rocks on October 3rd.

Purple Heron: I have been in contact with Mr Adrian Skerrett in his capacity as chairman of the Seychelles Bird Record Committee (see link in sidebar) and he confirms that Catherina’s sighting, recorded in my post below, is the first substantiated record of the species on Denis. Catherina will submit a completed record form and photo to the committee for their final confirmation in order to make the record official.

Migratory Birds Report 1

As promised, as the northern hemisphere winter draws in, Catherina and I have been monitoring the occurrence of migratory birds on Denis so as to begin to establish a proper baseline of occurrence. The northern location of Denis within the Seychelles archipelago makes it an important landfall for migrating birds to either rest up en route or to stay and overwinter.

Turnstones (Arenaria interpres) and Whimbrels (Numenius phaeopus) are present all year round but numbers have increased noticeably in recent weeks. The turnstones occur in small flocks all round and on the island so overall numbers are very hard to assess. The Whimbrels however tend to aggregate particularly on the reef flats that fringe the island’s east coast and number currently between 80-90 birds.

A common sandpiper (Actitus hypoleucos) is to be seen on the east coast since September 17th and individuals of both lesser and greater Sand Plover (Charadrius mongolus & C. leschenaultii) have been seen during September. There are 3 or 4 Grey plovers (Pluvialis squatarola) on the island and its keening call is commonly heard at Belle Etoile.

On October 3rd however, Catherina saw and photographed a beautiful Purple heron (Ardea purpurea) at Belle Etoile possibly the first confirmed record (I will check on this) for this species on Denis.

Fairy Tern and Tropicbird Progress 2.

The first thing I did on arrival on Denis this week was to go and check on the fairy terns we have been following and it was good news all round.

• The first juvenile shows good development since my last report with tail feathers now fully developed “she” must be approaching full fledging.
• The second juvenile has grown dramatically! Gone is the fluffy ball of a chick from the last report and the development of proper plumage is now apparent.
• Meanwhile the fairy tern egg remains safe and sound on its branch under the attentive incubation of its parent.

Later that day I went in search of the three ground nesting tropicbirds that I first reported as a new occurrence on Denis on Sunday the 14th of September (Post entitled “Another landmark in the restoration of Denis Island”) and here also we have progress:

• The first nest area was vacant and no egg, or evidence of an egg, was apparent so the status of this “nest” is not clear. The depression left by the adult was still visible as was the presence of droppings; so the adult may have yet to lay its egg or it may be that it has abandoned the site.
• The adult was still present in the second location and I assume that it is incubating though I have yet to see an egg.
• However on going to the third site at the southern point of the island I was delighted to find a beautiful tropicbird chick. The chicks are absolutely stunning (see photo in sidebar) when young and hopefully as a ground-nesting population establishes will provide a great addition to the island’s ecotourism product. More importantly however this is the first confirmed tropicbird chick to hatch on the ground following the eradication of rats in 2002, this marks another landmark in the rehabilitation of the Denis Island ecosystem.

Managing for the future. The hot dry spell we have been experiencing on Denis recently reminded me that on other islands where I have worked in the past measures are taken to enhance locations for tropicbirds to nest. These measures focus on limiting the amount of exposure to direct sunlight by appropriate placement of palm leaves and providing greater security to the site by ringing it with stones. The latter measure in addition to providing the adult with a greater sense of safety and concealment may also serve to protect freshly hatched chicks from crab predation when adults leave to gather the chick’s first meal. It may be that the first site, if it turns out to have been abandoned, has been exposed to too much direct sunlight for the adult to cope with. So I will broach the topic with the island management in the coming days to see whether we can manage some potential nest sites in the vicinity of those already established in attempt to attract more adults into nest.

Nature Watch (2)

Dry weather: Flying in to Denis Thursday morning (2nd October) the colour of the vegetation immediately drew my attention. We have been experiencing a dry spell in the central archipelago for a few weeks and of course this is always more pronounced on the low-lying islands which by the nature of the their topography attract less precipitation. The island presents a much less verdant spectacle from the air than usual with the greens somewhat faded and many of the grassed areas showing brown. The exception to this is the foliage of the Indian almond trees in the forest which appear to be sporting a fresh growth of leaves.

Obviously dry weather has implications for the island’s entire ecosystem, in particular it typically results in a consequent reduction in insect populations. The Seychelles warbler and magpie robin are both insectivorous birds and dry weather will result in a reduction of their food source. For the warblers this will typically mean a cessation of breeding activities until the next decent period of rainfall. For the magpie robins they will rely further upon the thrice-daily stocking of their feed stations by Catherina. It is for this very reason that Catherina’s work is so important. The foundling population of robins on the island require support to maintain them in good breeding condition. It is essential for the future prospects of the population that it get off to a good start with breeding success such that numbers can increase and make the population more resilient to natural perturbations in the future. In addition to this we are taking other measures to enhance their feeding habitat and I will cover that in the next posting of the SMR news in the coming days.

That afternoon I undertook my usual walk around the island to follow up on various issues. On reaching the grassland area called “Belle Etoile” on the island’s east coast I was struck by how the grass had died back revealing features and contours of the terrain that are normally smothered by thick herbaceous growth.

I checked on the small colony of wedge-tailed shearwater burrows, that I first mentioned in my post of 18th August “Re-colonisation 2”, and was pleased to note several new burrows further down the coast. This is very encouraging and I will keep monitoring the colony in the hope of establishing proof of breeding in the coming months.

I then continued south to check on the status of the ground-nesting tropicbirds - I will post on their status and that of the fairy tern chicks we have been following in the coming days.

As I write this we are experiencing a sudden cloudburst which will certainly help to revive the vegetation and I understand from the national meteorological office that they are forecasting a normal transition into the rainy season in the coming weeks. It can’t come too soon for Denis.

Humpback whales: on the 7th of September I posted on the sighting of 3 humpback whales offshore. On the 25th and 26th September hotel guests were treated by a much closer visitation by a mother and calf which spent the best part of 2 days within a few hundred metres of the Northwest coast of the island with the mother adding to the spectacle by occasionally breaching.

I have now (11:00 hrs Friday 3rd October) just been advised that whales are again visible today off the island’s southwest coast. See my post of August 20th entitled “Marine Megafauna” for information on the fantastic wildlife to be seen in the waters around Denis.