Tuesday, March 29, 2011

Wow! Today was our first real migrant fall of the spring. We set our alarm for 2am this morning as we expected low cloud and an absent moon to produce good conditions for an attraction. As we tumbled from the LSA hut it was soon apparent that we were right, but only a few birds were present with about 25 Starling, six Redwing, five Wheatear and about 20 phylloscs attracted. We trapped a Wheatear and two Chiffchaffs and monitored the attraction for the next hour. With little change we set a 6am alarm and returned to bed.

The first bird of the morning was a cracking adult male Black Redstart outside our front door. We then opened the garden net and trapped 12 Blackcap, a Goldcrest, six Chiffchaff and five Willow Warbler. A Golden Plover flying overhead was later found freshly predated in the Gorse.

As we headed to Nant it was obvious that a large fall was taking place. We opened a single 60 foot net and caught 103 birds in the following 90 minutes, the majority of which were Willow Warblers and one of which was a control. A conservative estimate would be that over 350 Willow Warblers passed through the island today.

It really feels like the start of spring now with dozens of Wheatear lining the walls of the island. (c) Richard Brown

This smart first year male Stonechat found the nets at Cristin. With only one pair nesting last year its great to see at least three males at the moment. (c) Richard Brown

The Western Conifer Seed Bug is originally native to Western USA, but was accidentally introduced to Northern Italy in 1999 with an import of timber. By 2007 it had expanded its range over much of Europe from Slovenia to France. A large influx arrived on the south coast of England in 2008. This was believed to be natural range expansion from the original 1999 introduction in Italy. They have also reached as far a field as Japan. The Western Conifer Seed Bug feeds on the sap of developing pine cones, with one of its host plants being Scots Pine, of which there are a few on the island. Amazingly this insect has also evolved to feed on the compounds made by trees to deter herbivores. This is the second island record following one last year. (c) Giselle Eagle

Sunday, March 27, 2011

We've had an exciting few days on the island with several avian highlights.

The 78th Black Redstart to be ringed on Bardsey was caught at Cristin. There are at least two other birds on the island at the moment. (c) Richard Brown

A few Redwing are still frequenting the hillside. In the hand this first-year individual was very distinctive with particularly dark underparts and heavy streaking. The wing was 124mm and, as can be seen from this photo, a good few extra mm were missing from the well abraded tips. These features all point to the subspecies coburni from Iceland and the Faeroes. (c) Richard Brown

Other winter thrushes returning north to breed included a flock of eight Fieldfare. (c) Richard Brown

The first two Willow Warblers of the year were trapped at Nant, the second of which was already wearing a British ring. We'll have to wait and see where this bird was first trapped. (c) Giselle Eagle

Up to 50 Chiffchaff are now passing through each day. The warm days are perfect for large numbers of invertebrates and the birds are making the most of their abundance. (c) Richard Brown

The male Hawfinch continues to feed at the Observatory, making the most of last year's Damson seeds. (c) Richard Brown

This morning we found the first Ring Ouzel of the year at Ty Capel. We were distracted from the Ring Ouzel however when a large female Sparrowhawk chased Polly (see below) into the plantation. A few pained squawks later and we watched as the Sparrowhawk flew with Polly's lifeless corpse onto the mountain to feast. 

Thursday, March 24, 2011

Until yesterday evening there had been 21 records of Hawfinch on Bardsey, four of which had been trapped and ringed. The 22nd was quietly sat next to the generator building and was picked up just as the generator was about to go on for the evening. It quickly found an adjacent mist net.

After the post-juvenile moult there appear to be no differences in plumage between adults and first-year birds.  But we can tell this bird is a male because of the glossy black, purple glossed, outer webs to the secondaries. (c) Richard Brown

This female, caught on Bardsey in 2008, shows a clear ash grey panel across the secondaries. (c) Richard Brown

Wednesday, March 23, 2011

An almost constant band of mist has engulfed the island for the last few days. But the full moon, coupled with the thickness of the mist, has meant that only two Redwings, a Song Thrush and a Blackbird have been attracted. Indeed there have been several times that we haven't been able to see the lighthouse or its beams when stood within 100m of the tower. A few migrants continue to pass through with double figure counts of Chiffchaff and Goldcrest, the first Blackcap and Swallow of the year, and a few Sand Martins and Wheatears.

The first Blackcap of the year was a male in Cristin Garden. We later caught it in the newly refurbished Heligoland Trap (c) Richard Brown

Carreg Bach is just visible in the thick mist which has been covering Bardsey (c) Richard Brown

A Collared Dove somehow found the island through the mist and took to using the feeders at Ty Bach. Only 50 have been ringed by the observatory and we failed to increase this tally as this bird fed around, but not in, our trap (c) Richard Brown

Polly is a Rose-ringed Parakeet which arrived on the island in June 2010. She has survived her first winter and the autumn migrant and over-wintering raptors. Although native to Sub-Saharan Africa and India, there are currently thought to be roughly 30,000 in the UK which, unlike the self-introduced Collared Dove, originated from escaped cage birds. They first regularly bred in the UK in 1969 and have now become abundant breeders in some cities and possibly compete with our native birds for food and nest sites. Our closest breeders seem to be in Merseyside so it is possible that Polly has crossed North Wales although it seems more likely that she has escaped more locally. There is a positive correlation in the UK between parakeet density and the number of detached and semi-detached houses, suggesting that they do best in areas where more bird food is provided by residents. And it is Bardsey's bird tables where she spends most of her time. (c) Richard Brown

Thursday, March 17, 2011

With seven Lapland Bunting proving so faithful to one corner of the same field for a second day, we decided that there was a good chance that the birds could be caught and ringed. Only seven had been previously ringed by the Obs since it started in 1953 so this seemed like a good opportunity to increase our understanding of this seldom trapped migrant. We know that Lapland Buntings overwinter along the coast of Western Europe and predominantly in South East Europe, but there is little evidence to show where the western winterers breed. The closest breeders are on areas of shrubby tundra in Norway but the breeding range of this species is basically circumpolar. Happily two birds proved relatively easy to walk into a waiting mist net.

Both are first-year birds as indicated by pointed tail feathers and generally worn plumage. In the top photo a male is on the left and a female on the right. Fantastic! And they have all returned to the same field today so there may be more in the hand soon. (c) Richard Brown

And back in the field again (c) Richard Brown

The first small fall of Chiffchaffs at Nant provided some entertainment whilst we put the nets up for the coming season. This individual has a bit of a 'pollen horn', a mass of pollen which sticks to the feathers at the base of the bill whilst the bird feeds. This horn was probably amassed somewhere warmer with lots of flowering plants, suggesting that this isn't a bird which has overwintered in North Europe. (c) Giselle Eagle

Wednesday, March 16, 2011

It was almost inevitable that, following the record autumn totals of Lapland bunting in 2010, we were going to get a reasonable number passing back through Bardsey from their wintering grounds on the continent. There have been a few flyovers passing for the last week or so, but yesterday saw the first real arrival with a group of seven taking up residence in one of the hayfields. The field was sodden after heavy rain in the morning but the birds proved very approachable and we got great views as they fed.

It wont be long before some of the males will be looking spectacular. We're really hoping for one in full breeding finery. (c) Richard Brown

Monday, March 14, 2011

Grey Seals are in good numbers at the moment and can be found huddled on rocks or bobbing around the coastline. They spend on average 80% of their waterborne time underwater and 20% at the surface. Each dive usually lasts between five and eight minutes and they have clever adaptations to help them stay underwater for so long. They take large reserves of oxygen down with them, but not in their lungs as we would. Instead the gas is attached to pigments such as haemoglobin in their blood and myoglobin in their muscles, pigments which have a strong affinity for oxygen. By having a much greater volume of blood than a terrestrial mammal of comparable size, and therefore more haemoglobin, Grey Seals can take a lot of oxygen down without having lungs full of buoyant air which would impair their underwater manoeuvrability. Interestingly, when they do surface for air, their heart rates increase from 40 beats per minute to approximately 120. This allows for rapid gas exchange and allows for more time to be spent in search of food.

Grey Seals enjoying the sun (c) Richard Brown

Grey Seals come ashore to breed in the autumn, but it is still not fully understood why they haul out at this time of year. The most likely theory is that they come out to dry out their fur and enjoy the heat of the sun, both of which help to conserve energy. That temperature is important is supported by the observation that they always haul out in areas out of the cold wind.

Watching them in their undisturbed environment is fantastic, and with such large mammals perched awkwardly  on exposed rocks, comedy moments are plentiful.

Yawning Grey Seal (c) Richard Brown

Wheatear numbers are gradually starting to increase and can be seen perched along the walls of the South End and West Coast. The first Chiffchaff of the year was caught and ringed in the Heligoland Trap at the Obs. Small Tortoiseshell butterflies are also on the wing, a good sign that spring is finally here!

Wednesday, March 9, 2011

Spring is slowly starting to arrive with the first migrants being recorded on the island, Chiffchaff and Wheatear. The weather, however, seems less than spring-like, with last night's forecast being for strong winds, rain and low temperatures. We were excited however as these are ideal conditions to dazzle in.

For those of you who have never dazzled before, it involves walking around on dark nights with a torch in one hand and a hand net in the other. Waders tend to partake in a lot of nocturnal feeding in the fields and along the shorelines of the two bays. Once the reflective eyes and/or something vaguely bird shaped is noticed in the torch beam, the dazzler walks slowly towards the bird keeping the torch on it. The bird is then caught with the hand net, and ringed. We had noticed a Woodcock a couple of times on the main track outside the Obs, this was our target bird for the evening. A few meters of stealthiness down the track and a Woodcock shaped object with large reflective eyes was spotted hiding in the bank. With much patience and skill, Rich homed in on it, and with one slow sweep of the net, he caught it.

Adult Woodcock (c) Richard Brown

The paler tips to the primary coverts indicate an adult bird. The feathers are also very fresh and unworn, which would be expected of an adult that has undergone a full moult in Autumn. (c) Giselle Eagle

Although many are resident in Britain and Ireland, Woodcocks are mainly a migratory species and a large influx of winter visitors arrive in the UK every year. The exact numbers are unknown, but estimated at a staggering 740,000 individuals. Ringing recoveries have shown that Winter visitors mainly consist of birds from Finland and Sweden, although recoveries from Russia, Poland and Germany have also been recorded. Woodcock begin their return migration in early March, so it is quite possible that this bird could be heading for Scandinavian breeding grounds some 2500km away.

Me and a Woodcock! The large eyes on the side of its head allows for 360 degree vision. (c) Richard Brown

Monday, March 7, 2011

The morning bird census was all about Corvid passage today. There was a small movement of Raven, but the highlight came in the form of a Hooded Crow which fed with Carrion Crows around the Narrows. As with all Hooded Crows of recent years, this individual proved particularly skittish and was far less confiding than the Carrions it was hanging around with. Hooded Crows are rare in Wales but a few birds have frequented Anglesey recently.

This appears to be a pure Hooded Crow, not showing the extra black areas typical of a Carrion Crow x Hooded Crow hybrid.© Richard Brown

Also of note were at least three male Stonechats. Once a common breeder on the island, breeding numbers have rapidly declined over the past ten years to just one breeding pair in 2010. The pair was successful however, and fledged ten young in three broods. The exact causes of the decline are unclear, but recent harsh winters will have played a major role. Unlike many resident, insectivorous birds, Stonechats rely heavily on invertebrates during the winter and do not turn to fruits and grains for survival.

Male Stonechat © Richard Brown

The remainder of the day was spent repairing the Heligoland Trap in the Obs Garden, which took a battering through the winter. In the last couple of years the trap has caught species such as Ring-necked Parakeet, Wryneck, Subalpine Warbler, Melodious Warbler and Marsh Warbler along with hundreds of commoner migrants, so it was important to fill the gaps where birds were escaping from.

The Heligoland Trap in the Obs back garden. The trap is basically a funnel which directs birds to a trapping area at the end, where our trained staff can collect the birds from a small trap-doored box. The trap was first used on the German island of Heligoland in the early twentieth century. © Giselle Eagle

Saturday, March 5, 2011

Today we saw our 130th species for our 2011 British List, a Whimbrel. Bardsey is rather unusual in having a few Whimbrel which over-winter each year. They seem to loosely associate with the flock of twenty or so Curlew which also over-winter in the area. Typically Whimbrel leave their breeding grounds in Northern Europe and pass through the UK from July until October, heading for their African wintering grounds. They then return to our shores from about late March onwards as they head for their tundra nesting sites. In Britain they breed in Shetland and occasionally on more southerly Scottish islands. It was quite a surprise therefore when a pair bred on the Gwylan Islands, just across the Sound from Bardsey. Especially as they chose to nest in the middle of a Great Black-backed Gull colony. Rather surprisingly they were successful and fledged two young in 2000.

One of our over-wintering Whimbrel Numenius phaeopus phaeopus © Richard Brown

The last Whimbrel we saw was just a few weeks ago in Costa Rica.  However, it was of a different race, Hudsonian Whimbrel Numenius phaeopus hudsonicus. Superficially it looks very similar to today’s Whimbrel Numenius phaeopus phaeopus, the main difference being rump colour, brown in the Hudsonian and white in ours.  While their ranges don’t over-lap (Hudsonians being restricted to the Americas), vagrant Hudsonian Whimbrels have been recorded on a handful of occasions in the UK. With this in mind, we inspect the rumps of Whimbrels on Bardsey very  closely!

Hudsonian Whimbrel Numenius phaeopus hudsonicus © Richard Brown

Part of the daily census is to record which colour-ringed Chough are present on the island. The majority of our birds sport rings of coloured plastic, these being added either on the island or elsewhere in North Wales. Colour ringing is an important tool for monitoring Chough populations, which are restricted in the UK to Wales and Cornwall. The rings allow individuals to be recognised in the field without having to disturb the birds. Sightings of colour-ringed birds have given us much insight into their movements. For example, we now know that in North Wales adult Chough escort their young to Snowdonia, where they deposit them in large non-breeding flocks. The adults then return to their breeding areas whilst the large flock of non-breeders roams widely. 

A few of the Chough currently feeding on Bardsey. The front three are ringed with unique colour combinations so we can monitor their movements on the island and across Wales. © Richard Brown

Friday, March 4, 2011

Bardsey Lighthouse last night with a clear, starry sky behind © Richard Brown

Last night was stunning. Moisture in the air meant that the individual beams of the lighthouse were very clear. The Milky Way was bright in the sky so there was no chance of an attraction. But the morning saw an exciting avian event anyway when an Arctic Skua flew past us on the narrows. Until today the earliest record of this species was 8th April so this was a very early bird indeed. Two Small Tortoiseshells feeding around Ty Bach were also earlier than average and had probably been coaxed out of hibernation by the warmer temperatures of the last few days. Other notable events included Shags nest building on the east coast cliffs and the continued arrival of Razorbills and Guillemots to the waters around the island.

Auks are typically monogamous. The Razorbills we saw this morning seemed to be reaffirming their pair bonds with lots of bill touching and swimming wing to wing. © Richard Brown

The skies around Bardsey remained misty all day. To the east mountain peaks rose above the haze and to the west the sun disappeared early into a dense bank of mist © Richard Brown

Rich spent part of the day fixing not one, but two generators. Although the first one only had to be shook vigorously to fix, the other involved scavenging the old starter motor off an old generator. Covered in grease (Rich) and an hour or so later, it (the generator) too was fixed! 

Wednesday, March 2, 2011

We arrived back to Bardsey on Monday in stunning sunshine. We’ve spent the last couple of days settling into the LSA Hut and Island Life.  Birds are a little thin on the ground but Chough and a Merlin were new to our year list and a couple of Red-throated Divers are spending the days feeding offshore.  The corpses of several waders suggest the winter months were harsh on the island but spring is definitely in the air with Goldcrest, Chaffinch, Robin and Dunnock singing through the day and a brief flyby bumblebee. With the first UK sightings of Sand Martin and Wheatear last week, it’s not going to be too long before they hit Bardsey.

An adult male siskin caught today as we put up the nets at the obs. The black centred greater coverts, the broad, relatively unworn tail and the whitish tips to the tertials all suggest a bird over a year old. The black crown is indicative of a male (c) Giselle Eagle and Richard Brown

Rich checking out the Red-throated Divers and bumping into ten Turnstone heading southwards (c) Giselle Eagle