Bardsey's Wildlife

Thursday, 3 April 2014

Nightime update
With large numbers of warblers still on the island by yesterday evening, it was perhaps no surprise that a sizeable lighthouse attraction was underfoot. The steady movement of migrants through the island, coupled with the settling of low cloud and drizzle in the early evening, meant that it was a rather busy night!

At about 2240 last night, the small shapes of migrants illuminated by the lighthouses' beams could be seen over the South End. By 2320, Obs staff had converged on the South End, and within half an hour, the flood lights were ready for action- pointed downward to illuminate the ground, their purpose to bring the dazzled birds away from the lighthouse. These birds can then be caught, thus saving them from eventual exhaustion from repeated impacts against the lighthouse.

At closer quarters, it could be seen that there were between 300 and 500 birds circling the top of the lighthouse: this total comprised a mix of phylloscopus warblers, Blackcaps, Wheatears, Manx Shearwaters, and a single 'Eared' Owl, which darted through. During the next few hours, a trickle of birds were enticed down from the mayhem above, and were captured by means of hand nets. In total, 40 birds were caught, which were then ringed in the early hours, before release. Amongst these were some rather smart birds...

A total of five Wheatears were trapped, this one being the only obvious Greenland-race bird. With a wing length of 110mm, a weight of 29.5 grams, and a tarsus length of 28.6 mm, the biometrics of this adult male leucorhoa gave the impression of a small thrush in the hand, rather than a Wheatear!

Some video footage from the attraction (the small dots are the birds, although you will have to try and picture there being about 100 times the number seen in the video!):

Daytime update

It was clear that, by morning, a large number of migrants had been forced to make landfall on the island, with Blackcaps and Willow Warblers bursting out of every crevice and gorse bush on the island. A small amount of light rain throughout the morning kept many birds on the island, although it was very much apparent that most migrants were moving through quite rapidly.

The first Grasshopper Warbler of the year was heard reeling away in the New Plantation, representing the second earliest record on Bardsey; the earliest was seen on the 1st of April, 1999. Two Firecrests remained mobile around the Nant area, whilst hirundine passage over the coast comprised three Swallows, 22 Sand Martins and two House Martins. Warbler numbers reached their highest figures so far this year, with minimum totals of: 150 Blackcaps, 204 Willow Warblers, 45 Chiffchaffs and 15 Goldcrests. A grand total of 60 Wheatears was also the year's highest total so far.

Willow Warbler

This rather stunning Oak Beauty was attracted to the Lighthouse beams last night. This species has not been recorded on Bardsey before. The larvae feed on a range of deciduous trees, and so this moth is likely to be a vagrant

The male Oak Beauty sported a fantastic pair of bipectinate antenna. Antenna are extremely sensitive, generally used to detect female pheromones from a distance. Members of the lepidoptera family Saturniidae (for example, the Emperor Moth) and many other families can detect female pheromones from distances of up to 2km.

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Click to see inside!

Edited by Mike Archer, Mark Grantham, Peter Howlett and Steve Stansfield and published by T & AD Poyser, this fabulous book describes how much has changed since the first edition of Bird Observatories in Britain and Ireland was published in 1976. There are detailed accounts of the history and work carried out at each of the 18 observatories, with personal accounts by wardens and staff of the excitement of discovering a rarity, watching thousands of migrants attracted to a lighthouse after dark, and the pleasure and experiences that working at some of the country’s most remote and beautiful locations can bring. Click the picture of the book to see inside or to buy your copy.

Migrants

Being sited on the main migration route of many species, Bardsey (or Ynys Enlli in Welsh) is a well-known site for migrant birds, turning up many scarcities and rarities, as well as large numbers of common migrants. The island’s list now stands on 326, after the recent addition of Citrine Wagtail in October 2012.

Although Bardsey’s reputation for rare birds may not quite match that of some observatories, it is almost certainly the best site in Wales for rarities. Among Bardsey’s rarer visitors are the first Summer Tanager (1957) and Yellow Warbler (1964) to have been recorded in Britain and Ireland, as well as American vagrants such American Bittern, Sora, Kildeer, Spotted Sandpiper, Grey-cheeked Thrush, American Robin, Song Sparrow, Dark-eyed Junco, Red-eyed Vireo, Black-and-white Warbler, Common Yellowthroat, Rose-breasted Grosbeak and Blackpoll Warbler. To add to this impressive list of rarities, Black-winged Stilt, Lesser Yellowlegs, Lanceolated Warbler, River Warbler, Western Orphean Warbler, Booted Warbler, Blyth’s Reed Warbler, Eyebrowed Thrush, Thrush Nightingale, Red-flanked Bluetail, Isabelline Wheatear, Black-eared Wheatear, Collared Flycatcher, Blyth’s Pipit, Pine Bunting, Rock Bunting, Yellow-breasted Bunting and White-throated Sparrow have all been recorded.

Besides the rarities, Bardsey regularly attracts large numbers of weary migrants during 'fall' conditions in Spring and Autumn, largely a consequence of the fully operational Bardsey Lighthouse. In 2011, for example, a single grounding of migrants resulted in over 1000 Willow Warblers making groundfall on the island in August. In the not-so-distant past, a single attraction of 40,000 Redwings occurred in late October at the end of the last century.

Breeding birds

Bardsey is home to some 26, 000 pairs of Manx Shearwaters, which can be heard on dark nights from mid-March to August. They breed in their excavated burrows, which are scattered all over the island. Chough is the most important species of conservation concern, with between four to eight pairs nesting around the coastal cliffs most years, and a wintering flock of up to 50 individuals. A pair of Peregrines breed on the island, and a 1-2 pair of Ravens also nest most years. There are several species which nest only occasionally, such as Sparrowhawk and Little Owl, along with Afro-Palearctic migrants like Sedge Warbler, Blackcap, Chiffchaff and Willow Warbler. Up to ten pairs of Stonechats can nest in the isolated gorse patches around the island, along with many Linnets and Meadow Pipits. Corncrakes were once a common breeder on the island, although since 1970 there have been no confirmed pairs nesting. In recent years the likes of Lapwing, Yellowhammer, House Sparrow and Starling have also all become extinct as breeding species. In contrast, Shelduck, Puffin, Long-eared Owl, Grasshopper Warbler and Goldcrest have been added to the breeding bird list since 1998.

Ringing

Ringing is a very important part of the observatory’s role on the island. Since 1953, the observatory has ringed over 315,00 birds of 198 species. The highest number ringed in a single year was 1988, with a total of 11, 301 birds ringed of 93 species. There have been many days in the observatory’s history when several hundred birds have been ringed in one day; these occasions have mostly involved breeding seabirds, although these numbers can also easily occur with migrant species.

Lepidoptera

A total of 561 species of moths have been recorded on the island. Bardsey is not an overly good location for scarce moths, although the existence of Thrift Clearwings (Nationally scarce) has been established on the Thrift plants around the coast in recent years, after first being recorded in the years 1980 and 1996. Migrant moths arrive in small numbers every year, for example the annual arrival of Hummingbird Hawkmoths in the autumn; rarer immigrants in the past have included Death’s Head Hawkmoths, Vestals, Crimson Speckled and Red-necked Footman.

In recent years, a greater emphasis has been placed on recording and identifying the so-called ‘micro-moths’, which has resulted in the finding of 41 new species for Bardsey since 2011. In 2012, the coastal subspecies of Eana penziana (E.p.colquhounana) was re-found on the island, which was the first time that this Nationally Scarce species had been recorded on Bardsey since 1966. Apotomis semifasciana is also amongst the scarcer species of micro-moths to inhibit the island (also Nationally Scarce).

Butterflies are present on the island in small numbers, with species such as Common Blue, Small Copper and Small Tortoise-shell being the most common. A scarcer breeding species is the Grayling, which can be found in small numbers on the top of the mountain. Migrant butterflies such as Painted Lady can arrive in their hundreds, although other migrants such as Clouded Yellow and Dark-green Fritillary are quite rare.

Bardsey's Wildlife

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Thursday, 3 April 2014

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