Siskin photographed at Saumarez Park [SAU] on 18/2/2013 Photo: © Cindy Carre (visit site)

Siskins were unknown to Smith although he writes 'The Siskin can only be looked upon as an occasional accidental visitant - indeed, I only know of one instance of its occurrence, and that is recorded by Mr. Couch on p. 4296 of the 'Zoologist' for 1875 in the following words:- "I have the first recognised specimen of the Siskin; a boy knocked it down with a stone at the Vrangue in September." This communication is dated November, 1874.' He goes on to say that he has no reason to doubt it as the Siskin is migratory and reaches Spain, the Mediterranean coast and north-west Africa and that 'the Channel Islands would seem to lie directly in its way.'

The species remained very scarce after this record and Dobson lists only one record. Up until the early 1970s Siskins were still rare birds in the Bailiwick and merited a mention in the annual report in the Transactions. In 1971, after a series of winter records in Saumarez Park, Bisson wrote that they were 'probably a regular winter visitor to this locality' and small numbers were seen in autumn and winter throughout the 1970s. In February 1976, 674 birds were reportedly ringed at the Dell Nursery (GBN) [this needs to be checked as they don't appear in annual ringing totals - see doubling below) but it was not until 1980 that large numbers started to regularly pass through the islands. In the autumn of 1980, the Guernsey ringing total was doubled when 135 birds were caught at the Dell Nursery. The following year a flock of 300 was present at the Dell Nursery throughout October and into November and these numbers were noted in the Transactions as 'unprecendented' and 'appeared to have reached an all time high'. In 1985, a massive autumn movements took place and over 1,600 birds were ringed at the Dell Nursery in that autumn.

There are no confirmed breeding records but a female Siskin was trapped with a large brood patch at La Fougeraie on 6 June 1977. There was no other evidence of successful breeding but the date is incredibly early for a returning migrant and it is possible that a breeding attempt was made.

Since the first irruption in 1980, Siskins have been a regular but somewhat erratic autumn passage migrant and winter visitor. The first birds usually pass through the islands during the first week of October and numbers peak in the following two weeks. In good Siskin years, flocks of 50+ birds are regularly reported from coastal headlands throughout October. By the end of October, few birds remain on the islands and smaller numbers can be found wintering. These winter flocks tend to be smaller, generally in the region of 1-10 birds but parties of up to 100 birds have occasionally been recorded.

Siskins are an irruptive visitor. In some years many will be seen whereas in others less than 50 birds are recorded. In 1993, large numbers passed through the islands and 17 records, totalling 2,700 birds, were received by La Société. Between 5-8 October in that autumn, flocks of 50-250 were recorded across Guernsey, on 16 October many hundreds were seen passing through Herm and an impressive 2,000 were estimated to pass over Pleinmont on 16 October. These numbers have not been repeated since and in 1995 and 1996, only 4 and 8 records totalling <50 and <100 birds were received. This irruptive behaviour is well known in the UK and is dependent in available food supplies and breeding success.

The pattern of occurrence has shifted since the first arrival of large number of birds. During the 1980s, records in Guernsey almost exclusively came from the Dell Nursery and other wooded areas, such as the Silbe Nature Reserve, where birds were attracted to alder trees. These have been widely planted since the eradication of the Guernsey Elm through the introduction of Dutch Elm Disease. In the 1990s, the Siskin has become more widespread and now occurs in other wooded areas such as the Talbot and Quanteraine valleys and small numbers also winter in gardens where they can often be found on bird feeders. Most records, however, now come from coastal headlands and involve birds on active migration.