Sunday, July 31, 2011

The last week has been a very busy one for us with the other staff on holiday and lots of Manx Shearwaters to monitor. During the day we have been continuing to ring, measure and weigh the Manxie chicks and during the night we have been ringing and recapturing hundreds of adult birds. The Corncrake's bizarre calls have been a constant but very welcome accompaniment to the nighttime. But with only four or five hours sleep each night we've worn ourselves out and, with the return of the other staff, it's time for our holiday. Nothing stressful, a relaxing break with friends and family. So today we spent over four hours in the car and went chasing some fantastic waders!

First stop was Blacktoft Sands for the stunning moulting adult Marsh Sandpiper that has been hanging around since the 12th July. There are some amazing photos out there but during our time the light was poor and the bird slightly distant for the 400mm lens. Through the scope the views were stunning! This amazingly delicate Tringa is on its way from breeding grounds in Eastern Europe to Africa or way down in the Middle East. From here we headed to Saltholme for rather into the sun views of Semipalmated Sandpiper and Temminck's Stint. (c) Richard Brown

Sunday, July 24, 2011

Reports of unusual nocturnal calls eventually filtered through to Obs staff on Thursday morning. Having possibly been present on the island since monday, and definitely since Wednesday, there was clearly a strange beast calling loudly from below the Obs. Not the typical eerie calls of the Manx Shearwater, this was something different. We turned the generator off as usual on Thursday night but, rather than walk down to the South End, we sat out beneath a beautiful star filled night. The calls that began at about 2300 were amazing! Obviously a Corncrake, they included the typical 'crex crex' call, but also some bizarre rasping notes and a sound akin to a party horn. Rich investigated the bird with a torch and decided to trap the migrant for ringing.

 Clearly the bizarre noises were coming from an adult Corncrake rather than from a practical joke, but the unusual squeaking cries are unlike anything we've heard from Scottish breeders or on recordings. BWP makes no mention of these calls either. Why this bird, rare in Wales, has arrived in late July (when most pairs have already fledged young) and begun to sing through the night is a mystery. Having ringed the bird it was returned to the hay field below the Obs from where it preceded to interrupt the sleep of several guests for the remainder of the night. The bird is still singing as we type! (c) Giselle Eagle

Elsewhere on the island a Redstart remains, over 30 Willow Warbler were logged and single figure counts of Whitethroat, Blackcap, Chiffchaff and Grasshopper Warbler were noted. 

Friday, July 22, 2011

A couple of Grasshopper Warblers, a Blackcap and a Redstart appeared yesterday and today a Mediterranean Gull, an Arctic Tern and a Golden Plover were all new in. Up to 24 Swifts have passed through along with two Sand Martins. But generally things remain quiet.

The first returning Groppers have been typically skulking. This one outside our house in the early hours showed for just long enough to make out the relatively fresh tips to the primaries which suggest that this is a bird hatched this year. The majority of autumn records tend to be of this age, perhaps suggesting, as mentioned below for Willow Warblers, that younger less experienced birds make shorter journeys and stop off more often as they don't accumulate enough fat reserves for long flights. (c) Richard Brown

Despite some quite intensive moth trapping over the last decade or so, it seems there are still many species of common garden moth which are exceedingly rare on Bardsey, or even yet to be recorded. The Bordered Beauty (above) was only the third for the island and the Double Dart (below) was the first. Immigration from the nearby mainland on the recent light northerly winds seems the most likely explanation for why these common moths have just appeared. (c) Richard Brown

We decided to make the most of a quiet afternoon by ringing some Manx Shearwater chicks. With over 15,000 pairs on the island, most with a single chick down a single burrow, you'd be forgiven for thinking this was an easy, straightforward task. But the burrows which the Manxies excavate can be deep and awkward, and a few inconsiderately placed rocks and right angle bends in the tunnels made finding the chicks an epic task. Some of them are becoming quite fat but still have another 25 or so days left in their burrows before they make their first flight. The grey down which covers their body like a giant fleece insulates them well from the damp conditions in their burrow. We take wing length measurements as well as weights and this allows us to calculate their age and how well they are being fed. This particular chick is around 50 days old, and weighed over half a kilogram! (c) Richard Brown

Wednesday, July 20, 2011

A couple of Lapwing, four Whimbrel, six Redshank and 11 Common Sandpiper are the only new waders and a Greenfinch is the only obvious change inland. We celebrated completing the Heligoland trap revamp with a walk down to the beach where we found that the second brood of Ringed Plovers had just hatched.

Approximately 10,000 pairs of Ringed Plover breed in Britain and Ireland, around 80% of the nominate race. The single pair nesting here has done well this year having already fledged three young prior to these three hatching. Sadly the remaining egg has failed. (c) Richard Brown

Monday, July 18, 2011

Strong westerly and northwesterly winds again raised hopes that a few scarcer seabirds might pass by, and they did, at Strumble Head. Here the number of Manx Shearwater logged topped 3,000 but the majority of birds passing were probably of local origin, indeed only a few Common Scoter and Gannets must have come from further afield. A couple of Purple Sandpipers and Dunlin have now joined the small numbers of Whimbrel, Common Sandpiper and Redshank whilst the Curlew flock has topped 50 on a couple of dates. Inland there has been little change but the hard work put into the Heligoland extension seems to be paying off with some nice catches. For example the Willow Warbler, Stonechat and Whitethroat pictured below were caught in a single go.

Willow Warblers have been well studied on Bardsey. This young bird probably hatched on the Island and has begun its partial post-juvenile moult. This bird will probably start its epic migration towards the end of this moult, a full couple of weeks or more prior to the adults departing. The adults undergo a full moult and this is probably why they depart later. But this does not mean the adults will arrive on the wintering grounds later. Studies of fat deposits have shown that younger birds only accumulate enough of an energy reserve to fuel short distance flights whereas the adults, presumably more experienced at feeding, can fuel themselves up for longer non-stop journeys. This may explain why many ringed juveniles are re-trapped on the south coast of Britain having not travelled too far whilst adults are often not seen again, perhaps crossing the Channel in one night. (c) Richard Brown

Although only three pairs of Stonechat are breeding this year, they are all currently incubating third broods. This youngster has been fortunate enough to be born on an Island lacking ground-based predators. This absence may explain why, as of last year, the oldest known Stonechat had been recorded here. A juvenile ringed 1 October 1987 was still alive 4 years 11 months and 15 days later on 16 September 1992. (c) Richard Brown

This young Whitethroat is also undergoing a partial post-juvenile moult. There is good evidence from ringing that young birds may return to the island in subsequent years. For example a bird ringed as a chick on 2 July 1989 was re-trapped as an adult male in May and July 1991 and on 26 May 1992 having crossed the Sahel each spring and autumn. (c) Richard Brown

This particular first-summer Kittiwake has been spotted associating with both Herring Gulls and Oystercatchers. A lot of first-summer Kits spend this time of year in their wintering grounds between the Sargasso Sea and the Azores so this is the rarer of the plumages that we are seeing on the birds around the island. Incidentally the Sargasso Sea is the only sea without shores. (c) Richard Brown

The Poplar Hawkmoth caterpillars continue to grow at a steady speed. They have already undergone three moults, the last being only a week or so ago (above). During the moult their head casing pops off and, once they have emerged from their old skin, they proceed to eat it. When they are about to moult they stop eating and stay motionless on a leaf for a day or two and during this time the head again begins to protrude, soon to pop off. (c) Richard Brown

Friday, July 15, 2011

Well it's been a rather busy week. A trickle of early migrants has included a Black Redstart, a lingering Redstart, which is today at the Obs, a couple of Grasshopper Warblers and probably a few phylloscs joining the Bardsey breeders. Five Whimbrel have joined the Curlew flock and Redshanks and Common Sandpipers continue to pass through. So why so busy? Well we've had another quick dash away from the Island, radio and TV crews have been visiting and the Heligoland extension continues to go well.

Sadly the TV crew from Countryfile didn't have time to get to the Obs. They decided that watching Emyr's pickled fruit was more interesting than the amazing Manx Shearwater chicks we had lined up for them; John Craven didn't even taste Emyr's fruity morsel. This blob of fluff is only 30 days old and in another 40 or so it will be setting out to fly to the waters off South America, without its parents! Now that's interesting! Happily BBC Radio Wales spent plenty of time hearing about these mega birds. (c) Richard Brown

A smaller chick roughly 20 days old. The chicks fatten up at an impressive rate fed on small fish and squid brought in by both parents. Indeed at about 50 days old the chicks will weigh approximately 600g, a third as heavy again as the adult birds. They then lose this weight as they build up their flight muscles for the last couple of weeks before they depart. If this chick survives as long as our oldest known Manx Shearwater, over 50 years, then it will fly the same distance as to the moon and back, twice! (c) Richard Brown

Graylings are now on the wing across the Island. Graylings spend a lot of their time regulating their body temperature, aiming to keep themselves at around 32 degrees. If they are too cold they lean sideways on to the sun to expose as much wing and body area as possible. If they are too warm they stand head-on to the sun, on their tiptoes. (c) Richard Brown

It's looking like a fantastic year for Hummingbird Hawkmoths with sightings on most days. (c) Richard Brown

Rich has been worrying that all our time on Bardsey is leading to us having a small carbon footprint so our quick trip off the Island was designed to rectify the problem. Here's Rich doing a few hot laps in a V10 Lamborghini Gallardo capable of 0-62 in 4 seconds and 195mph. The crappy Porsche was no match. A massive thanks to Ange and Jas for a perfect present. (c) Giselle Eagle

Friday, July 8, 2011

With hundreds of Cory's Shearwaters passing the Southwest corner of Britain and Ireland it didn't seem like too big an ask for one to drift up the Irish Sea a bit. So we've spent a long time staring hopefully out to sea. The only real reward has been the first Balearic Shearwater of the year. A few dozen Black-headed Gulls and twenty-odd Common Scoter passed by with several thousand Manx Shearwater. Inland a young Redstart has been the only new bird of note. 

We've spent the last couple of weeks extending the Heligoland trap in the Obs garden. By lengthening the leading edges we hope to gently coax more birds to work their way into the trap. This male Stonechat, one of only three adult males on the island, was perhaps our first reward. British breeding Stonechats are generally rather sedentary, although a few birds ringed at the nest in the UK have turned up on the Continent. Stonechats breeding elsewhere in Europe, however, are more migratory and this has been reflected by ringing on Bardsey with three birds ringed on migration turning up in Southern Europe. The longest recorded journey of a Bardsey bird was a female ringed in April 1970 which travelled 1603km to Alicante, Spain, before being found freshly dead. (c) Richard Brown

The two Poplar Hawkmoth caterpillars continue to grow rapidly. The eight prolegs and the anal clasper at the rear will be lost during pupation, but the front six are true legs and will form the basis of the adult's legs. The amount of time it takes us to find the boys on just a couple of branches is testament to the amazing camouflage of this species. (c) Richard Brown

Tuesday, July 5, 2011

Another quiet period bird-wise on Bardsey with a few Swifts passing over and a couple of Common Sandpipers frequenting the coast. But we've been treated to a gloriously sunny, calm spell and the lack of wind has resulted in an incredibly flat sea, perfect for searching for cetaceans.

Up to 23 Risso's Dolphins have been feeding just off the West Coast! The tall dorsal fin and blunt forehead makes this species easily identifiable from a distance (top). The calves are born grey, but turn darker as they age to juveniles and as they become adults their skin tone becomes more silvery. White scars cover the skin of all adult Risso's (middle); these are caused by gregarious and rough social interaction with other adults and from squid which, along with octopus and cuttle fish, are the main prey items for this species. While this particular pod had clearly found a good food source (the group was often spread out in a long line, a formation typically adopted when hunting), Risso's Dolphins prefer to feed at night when their prey items migrate closer to the surface of the water. Having said this they are able to dive to depths in excess of 1000 metres. (c) Richard Brown

The Bardsey Sound, the area of sea that stretches from the Llyn Peninsula on the mainland to Bardsey Island, has earned a fearsome reputation over the years, with no less than 45 recorded ship-wrecks between 1812 and 1914. Vessels carrying wine from Spain, china clay from Cornwall and slate from Portmadoc, to name but a few, all fell victim to these treacherous waters. Rich got the opportunity to brave these unforgiving seas in a kayak. 

The waves were immense mountains, the currents unbelievably strong and the floating debris of previous wrecks had to be skilfully avoided. Luckily Rich's experience and skill took him safely through conditions that few kayakers would be equipped to deal with! Many thanks to Kev for recording the perilous journey for future generations to marvel at.

Giselle has her eye in for spotting recently emerged moths at the moment. The wings of moths are clearly not visible on the caterpillars, but they are present as tiny 'wing discs' in the second and third segments of the body. These develop within the body of the caterpillar until they are forced outside of the skin close to pupation. Within the pupa the wings develop and form a structure which is cleverly pleated in a way so that the wings can be rapidly unfolded when the adult hatches. Speed is very important just after hatching as the moths are very vulnerable to predators at this time. The Lackey (above) and Dark Arches (below) were both found at this vulnerable moment. The wings are pumped up through the veins and will dry in a couple of hours from when the moths will be capable of flight. (c) Richard Brown

A further five broods of Swallows were ringed and another pair had built a new nest at the Lighthouse. (c) Richard Brown

Saturday, July 2, 2011

A Common Sandpiper was on the South End this morning and a Garden Warbler and Spotted Flycatcher had arrived in the Withies. At the Lighthouse the House Martins have fledged at least four young and 17 Swifts were feeding around the tower. The highlight has been another visit to the nearby Gwylan Islands.

The main purpose of the visit was to count and ring Puffins. Each monogamous pair raises a single chick deep in an underground burrow. As might be expected on a small island which holds approximately 800 pairs, these burrows have become interlinked and it can prove difficult to feel for the chicks within such a complex maze. We did quite well however and managed to furtle out lots of these smart pufflings. The chicks remain underground for approximately 40 days before taking to see at night; they will probably not return to land for two or three years and will not breed until they are about five. (c) Richard Brown

We also caught several adults. The fantastic blue and yellow portions of the bill are actually made up of horny plates which separate and fall off at the end of the breeding season. The blue plates above and below the eye will also drop off in the near future. (c) Richard Brown

Apparently the people of St. Kilda used to use puffins to flavour their porridge. (c) Richard Brown

Bardsey on another beautiful sunny day with clouds developing over the nearby mainland (above) and the view towards Bardsey as the first pilgrims would have seen it as they departed St. Mary's Well. (c) Richard Brown