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season opens in early March with the first Chiffchaffs, Goldcrests and
Wheatears passing north, harbingers of the busy spring migration period.
Visitors assist the daily censusing of birds and the full scale ringing
programme begins. Up to 8,000 birds of 97 species have been ringed in a
year, caught mostly in mist nets or Heligoland
traps. Instruction is given to those who wish to see ringing in progress,
whilst for the trainee or experienced ringer, a visit to the Observatory is
a valuable opportunity for increasing knowledge.
As spring advances, Sedge Warblers, Willow
Warblers, Whitethroats and Spotted Flycatchers become abundant passage
migrants. Chances of a rarity are high in May and early June:
Collared Flycatcher, Pine Bunting, Snowy Owl,
Red-throated Pipit, Subalpine Warbler and
Black-headed Bunting are some recent examples |
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By late July the autumn
migration has started, and August to October sees the busiest period. Common
species appear in large numbers, together with some unusual species such as
Melodious Warbler, Icterine Warbler and Greenish Warbler. In September the
warblers are followed by chats, crests and flycatchers. This is also a good
time for watching seabirds on migration.
As well as large numbers of the more common species, Great Skua, Sooty
Shearwater and Leach’s Petrel are regular in their appearance. There are
sea-watching hides on the north-west corner and southern tip of the island. |
| It is October which has the
most to offer anyone wishing to see the full strength of autumn migration.
It is a vibrant month with continual passage of restless migrants.
Spectacular overnight arrivals of Redwings and Blackbirds are matched on
occasion by massive diurnal movements of Chaffinches, Skylarks and
Starlings; over 25,000 have been counted flying over in a single morning.
Mist netting and ringing take place whenever possible and it is probably
true to say that this is the best month for uncommon vagrants, whether from
North America, Europe or Asia. Rose-coloured Starling, Isabelline Shrike,
Ortolan Bunting, Radde’s, Pallas’s and Lanceolated Warbler are recent
October records, whilst Firecrest, Red-breasted Flycatcher and Yellow-browed
Warbler are seen almost every year. Common Yellowthroat in 1996 was a fifth
record for Britain and the island list now stands at just over 300 species. |
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Bardsey is well known as one
of the few sites where night migration can actually be watched taking place.
Under certain weather conditions following the new moon, migrating birds are
attracted to the revolving beams of the lighthouse, sometimes in thousands,
and the night is noisy with the flight calls of divers species. Since 1978
the Observatory, in co-operation with Trinity House, has had a unique “false
lighthouse” - powerful lamps near the lighthouse proper. The lamps draw some
bird species safely away from the lighthouse to the gorse bushes, so that as
many as 40,000 migrants have roosted there on one night alone. Visitors may
watch these ‘attractions’ and help under the supervision of the wardens. |