‘Lesser’ Golden Plover Pluvialis dominica / fulva – a review of 20th century records, March 2016.

Following the occurrence of the first ‘Lesser’ Golden Plover Pluvialis dominica in Mayo in 1894 (Ussher & Warren 1900) it became clear that, in addition to European Golden Plover Pluvialis apricaria and Grey Plover Pluvialis squatarola, there was an additional vagrant species of Pluvialis to contend with in Ireland. Once it was established that a candidate was smaller, slimmer, with greyish underwings and longer legs, the acceptance as ‘Lesser’ Golden Plover was straightforward. Only three individuals occurred prior to 1966 (Mayo, 1894; Meath, 1952; Kerry, 1963), but from that year onwards the species was recorded more or less annually, in small numbers, and its occurrence soon became an expected part of the birding year. Prior to 1986, the species was considered to comprise two subspecies, nominate dominica in North America and fulva mainly in east Asia. In general, no real attempt was made to identify birds seen here or in most European countries to subspecific level, although a few older specimen records, both in Ireland and in Britain, were assigned to subspecies.

However, in 1986 this was to change when the British Ornithologists' Union Records Committee (BOURC) adopted a proposal (Connors 1983) to raise both races of ‘Lesser’ Golden Plover to full species status, i.e. American Golden Plover Pluvialis dominica and Pacific Golden Plover Pluvialis fulva (Ibis 128: 601-603). Two papers were published (Pym 1982, 1984) in advance of the split alerting birdwatchers to the field characters of both, and identification criteria were also dealt with (Hayman et al. 1986). Armed with new knowledge and improved optics, birdwatchers soon began to confidently identify 'lesser golden plovers' seen well to species level. In the case of adult birds, it became accepted that birds with long primary projections, dark flanks and dark undertailcoverts were American Golden Plover, whereas Pacific Golden Plover differed in having, among other features, a shorter primary projection, a whitish line along the flanks, paler undertail-coverts and perhaps yellower-spangled upperparts with feet that projected beyond the tail in flight. Juvenile American Golden Plovers were grey-buff birds with long primary projections, and juvenile Pacific Golden Plovers had shorter primary projections and were more similar in colouration to European Golden Plovers of the same age.

Hot on the heels of the split, Ireland’s first Pacific Golden Plover, an adult, was found at Tacumshin Lake (Wexford) on 17th August 1986 (Irish Birds 3: 622). Just 13 individuals have occurred to date (the most recent in 2012; Irish Birds 9: 589-590), making it a far greater rarity than American Golden Plover. Since the split, American Golden Plover has occurred annually, with 275 individuals recorded in total to 2014 (Irish Birds 10: 244). In some rare cases, the evidence available to the Irish Rare Birds Committee (IRBC) has been insufficient to allow for a confident specific identification, and these birds have been published as ‘indeterminate’ and could be either American or Pacific Golden Plovers. However, records published as ‘Lesser’ Golden Plover prior to the split were never formally reassessed to determine if they could be identified to one or other taxon, which prompted the IRBC to undertake a review of these historic records.

Results of Review

Unfortunately, written documentation for only 16 records was available and these were circulated among the committee for review. The challenge of separating American and Pacific Golden Plovers is more complex than had been previously understood and some recent records have generated considerable debate. For instance, a bird at Kinsale Marsh (Cork) in 1991 generated lively discussion, before being accepted as a Pacific Golden Plover (Irish Birds 5: 88). More recently, a bird at Tacumshin, Wexford in 2002 was, for a time, believed to be a Pacific Golden Plover before being correctly identified as an American Golden Plover (Irish Birds 7: 394). These tricky individuals have shown there is overlap in some features formerly believed diagnostic. These include projection of the feet beyond the tail, formerly considered diagnostic of Pacific Golden Plover. However, it is now realised that some Pacific Golden Plovers can look long-winged and that some adult Pacific Golden Plovers can show black undertail-coverts. In addition, much of the documentation available was compiled at a time when the importance of accurately recording a bird's primary projection was not fully appreciated. With these difficulties it is hardly surprising that most (11 of the 16 records reviewed) individuals were considered unsafe to assign to either species with confidence, and remain as indeterminate American or Pacific Golden Plovers. The remaining five individuals were considered acceptable as American Golden Plover. It should be noted that a bird seen at Ballycotton on 22nd and 23rd July 1983 (Irish Birds 2: 557), showed some characters suggestive of Pacific Golden Plover, but regrettably, did not meet the necessary criteria for acceptance as one by the committee. Had it been, it would have represented the first Irish record.

The following records are now considered acceptable as American Golden Plover:

• Adult, Ballyheigue Strand and Akeragh Lough (Kerry), 15th to 22nd September 1963 (Irish Bird Report 11: 17)
• Juvenile, Keenagh Turlough, near Mount Talbot (Roscommon), 15th to 16th October 1966 (Irish Bird Report 14: 29)
• Adult, Akeragh Lough (Kerry), 25th May 1971 (Irish Bird Report 19: 34-35)
• Adult, Ballycotton (Cork), 10th to 18th September 1971 (Irish Bird Report 19: 34-35)
• Adult, Termoncarragh Lake, Mullet Peninsula (Mayo), 24th September 1978 (Irish Birds 1: 426)

The following remain as indeterminate American / Pacific Golden Plover:

• Adult, Lissagriffin (Cork), 7th to 21st September 1966 (Irish Bird Report 14: 29)
• One, Shanagarry (Cork), 18th September 1966 (Irish Bird Report 14: 29)
• Adult, Douglas Estuary (Cork), 30th September to 8th October 1966 (Irish Bird Report 14: 29)
• Adult, Ballinrannig Marsh, near Ballyferriter (Kerry), 25th June 1969 (Irish Bird Report 17: 34)
• One, Akeragh Lough and Carrahane Strand (Kerry), 13th to 27th September 1969 (Irish Bird Report 17: 34)
• One, Barley Cove (Cork), 19th to 21st August 1970 (Irish Bird Report 18: 29-30)
• Adult, North Bull Island (Dublin), 10th October 1971 (Irish Bird Report 19: 34-35)
• Adult, Tacumshin (Wexford), 25th to 27th September 1978 (Irish Birds 1: 426)
• Adult, Ballycotton (Cork), 22nd to 23rd July 1983 (Irish Birds 2: 557)
• Adult, Rahasane Turlough (Galway), 23rd August to 7th September 1983 (Irish Birds 3: 111), and presumed same, 15th to 29th September 1983 (Irish Birds 2: 557) (see also Irish Birds 10: 244)
• Juvenile, Rahasane Turlough (Galway), 7th September 1983 (see Irish Birds 10: 244)

No documentation was available for the following records and they will continue to be treated as indeterminate American / Pacific Golden Plover:

• One, Ballycotton (Cork), 20th October to 6th November 1979 (Irish Birds 1: 564)
• One, Ballycotton (Cork), 29th October to 4th November 1979 (Irish Birds 1: 564)
• One, Lissagriffin (Cork), 14th to 21st September 1980 (Irish Birds 2: 99)
• One, Ballycotton (Cork), 16th September 1980 (Irish Birds 2: 99)
• Juvenile, Ballycotton (Cork), 28th August 1982 (Irish Birds 2: 386)
• Adult, Ballycotton (Cork), 27th September to 5th October 1982 (Irish Birds 2: 386)
• One, Rahasane Turlough (Galway), 15th to 17th October 1984 (Irish Birds 3: 111)

Summary

These results do not drastically change the status of these two species. Only five records were acceptable as American Golden Plover, and, of the 11 indeterminate records, most suggest American Golden Plover but just fall short of being sufficiently well documented to allow a confident identification. As previously noted, the bird at Ballycotton (Cork) on 22nd and 23rd July 1983, was more suggestive of Pacific Golden Plover in many respects. It should be noted that the only two individuals of ‘Lesser’ Golden Plover relating to the period before this review (i.e. 1963) are of specimens of the American Golden Plover obtained in Mayo (1894) (Ussher & Warren 1900) and in Meath (1952) (Kennedy et al. 1954), and both reside in the National Museum (Natural History Division), Dublin.

References

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