14. December 2009

68 Machrihanish, Kintyre, Strathclyde Region

History: Berry (1939) reported White-fronted Geese from Kintyre, but the implication from an article in The Field from 1923 was that “of the large number of geese migrating through Kintyre, the bulk was certainly Whitefronted”.  Unlike the more recently established Rhunahaorine flock, the Greenland White-fronted Geese that frequent the area around Machrihanish were known to ornithologists for some time.  Even at the time of A-W (1963) this group was estimated to number 400 individuals and although there was considerable annual fluctuations in the annual maxima presented in R&O (1979), these authors noted that there had been relatively little change over the last 17 years preceding their review.

Status: International importance (R&O 54).  Despite these annual fluctuations in number, the overall pattern for this flock has been that of an impressive increase.  Numbers seemed to have been more or less stable during the period up to R&O (1979), but this was followed by a very dramatic increase in numbers, which uniquely has tended to increase to the present day (see figure), peaking at 1716 in 2006.  Some inter-annual fluctuations in the late 1990s suggests missed birds, perhaps using unknown feeding areas, or perhaps exchange of birds with other flocks.  Nevertheless, there is no clear evidence of the recent downturn in numbers that is so apparent from around 1999 amongst most of the other flocks, which makes this group of some interest.

Maximum winter counts:

Breeding success: As at Rhunahaorine, the assessment of breeding success has fortunately been regular and of long duration carried out by Malcolm Ogilvie over a long period years.  The pattern in annual production has almost exactly tracked that on Islay throughout the period since 1982 (first diagram below).  There has been lower production since 2000, but conspicuously this group produced good numbers of young in 2006, which may help explain why this flock has buffered the decline seen elsewhere amongst other flocks (second diagram below).

68macrihanish   68macrihanish2

Feeding sites and habitat: Stubble feeding in autumn, but an array of grassland types are used throughout the winter, including reseeds. The main feeding grounds of this flock consist of intensively managed agricultural lands around the southern part of Machrihanish airfield, to a lesser extent the grassland on the airfield itself and occasionally in amongst the dune grasslands of the sand dunes at the western end bordering the sea. Feeding also takes place along the valley along the route up to the roost but to what extent this has been used in recent years is obscure. Sites on Kintyre were the subject of detailed surveys in 1986/87 (Bignal 1987), 1987/88 (Batty 1988) and by the RSPB in 1993/94 (Thompson & Harding 1994).

Roosting sites: The principal roost for this flock is Tangy Loch (NR6927) in the hills about 7 km from the feeding areas.  In former times before protection, sporadic hunting at this site displaced the geese to neighbouring Lussa Loch which may still offer an alternative site.

Habitat change: None known to affect the geese.

Aircraft disturbance: The geese feed in and around a former military airbase, and although there is no air traffic these days, the geese formerly seemed to habituate to the level that existed at that time.

Hunting disturbance:  There was a problem with hunting in and around this site in the past, and it may be that hunting pressure on the Greylag Geese with which the White-fronted Geese associate had an effect both on the distribution of the geese and their abundance.  The present extent of this issue is not known, but is not thought to be a problem.

Agricultural disturbance: Not known, but although there will undoubtedly be some; this flock has many alternative feeding areas that any disturbance is not thought to constitute a significant problem.

Site safeguard: Tangy Loch, the roost for the geese, has SSSI status and falls within the Kintyre Goose Roosts SPA and Ramsar site.  The feeding areas used by the flock are currently unprotected.

SNH Natural Heritage Zones/Area: Argyll West and Islands.

Threats: Some local hunting of Greylags offer potential difficulties of disturbance, wounding and accidental killing of White-fronted Geese at this site.  There have been several instances of illegal killing of birds at this site in the 1980s, some of which have led to successful prosecutions.

Linkages with other sites:
As of June 2006, there had been almost 600 resightings of 91 different marked birds on Kintyre, involving 46 different individuals, of which 6 have also been seen at Rhunahaorine.  These include 22 geese caught originally at Wexford, 21 from Greenland birds caught during moult and 3 caught in Hvanneyri in western Iceland, remarkably similar to the break down of capture sites amongst the Rhunahaorine flock!  Of those caught at Wexford, 9 were seen once briefly in autumn staging before continuing to Wexford for the remainder of the winter and one was seen briefly in April on spring migration having spent the winter at Wexford.  The rest included 4 birds that remained at Machrihanish for one year before wintering elsewhere (including some that returned to Wexford), one that wintered at Machrihanish for two years then returned to Wexford, whilst the rest either settled on Kintyre or continued to move winter quarters between years.  Again, as at Rhunahaorine, the presence of so many Greenland marked birds caught in the southern part of the breeding range in Isungua and Eqalungmiut confirms the leapfrog migration pattern found amongst ringing recovery and resighting information from elsewhere.  The very low incidence of occurrence of birds marked at Hvanneyri in west Iceland also conforms to the pattern that most birds breeding in the southern part of the breeding range stage in the southern (rather than western) parts of Iceland during passage there.  Hence, it would appear that this flock derives mostly from breeding stock nesting in the southern part of the range, but there has been some interchange with Wexford and Islay and other resorts, but relatively little with the adjacent flock at Rhunahaorine.

References

Batty, P. (1988) Counts of Grey Geese in Kintyre and Knapsdale.  Unpublished report to Nature Conservancy Council, South West Region. 25pp.

Bignal, S. (1987) Counts of Grey Geese in Kintyre, Argyll 1986-1987.  Rhunahaorine and Machrihanish.  Unpublished report to Nature Conservancy Council, South West Region. 18pp.

Thompson, K. & Harding, N.J. (1994) Winter bird surveys on proposed Special Protection Areas in Scotland.  Report 3: Winter Goose Surveys in Kintyre, Wigtownshire and Flanders Moss.  Report by RSPB to Scottish Natural Heritage.