14. December 2009

55 Tiree, Strathclyde Region

Site map
History: It is said that in 1892, Greenland White-fronted Geese were only exceptionally seen on Tiree, yet by 1898 they were reported as numerous between mid October and mid April, with numbers reaching 4-500 by 1913 (A-W 1963).   A-W (1963) was unable to report full island counts, but doubted that the numbers reached half of that figure in his time and suggested that the combined numbers for Coll and Tiree together normally numbered between 50 and 150.  R&O provided counts from 3 winters on Tiree, but very few details indeed about relative abundance or distribution.

Status: International importance (part of R&O 49). Despite recent declines on Tiree overall, the island remains of outstanding importance for the population and has suffered less than many resorts in the magnitude of the declines since the peak numbers in the late 1990s.  Numbers at peak reached 1464 on Tiree in April 1998 but have since fallen back slightly.  Since 1982, efforts have been made to standardise the counting to avoid double counting whilst ensuring total coverage of all potential sites.  Very major changes between years in these counts suggest that there is dynamic movement to and from Tiree, probably most often exchanges with Coll, but potentially with other resorts further afield.

Maximum winter counts:

Breeding success: A long run of production data from this site showed highly variable proportions (but generally high) of young during the period of increase, but consistently low output since 2000 (see first diagram below).  The annual proportions of young birds closely track those on nearby Islay (see second diagram below).

55tiree   55tiree2

Feeding sites and habitat: Geese are mainly concentrated on The Reef, an extensive open expanse of base-rich marshland, wet pasture and machair, situated in the middle of the island.  However, smaller groups are associated with other habitats, including the many of the small pockets of wetlands and peatland that exist on Tiree, often mixed in amongst quite extensive areas of intensive agriculture and crafting lands.  Small groups have also been seen on Gunna (e.g. 24 in March 2005, Bowler & Hunter 2007) There are also extensive tracts of reseeded ley used both by the White-fronted Geese but also by the expanding numbers of Greylag Geese which breed and winter on the island.  Although there have been resightings of individually marked birds on the island these are not sufficient to assist in deliminating the feeding ranges of discrete sub units on Tiree.  The geese seem to range widely, but there seems some evidence for defining seven different feeding areas as discussed below.

1. Hough (NL9545) is area an area of rough pasture with some Molinia and Juncus in the north-west corner of Tiree, with most use of a few fields 500 m southeast of the road through Hough.  Geese have been seen feeding in the boggy pools and hollows with rough pasture and mire at NL964454.

2. Loch Bassapol (NL9747) supports an area of machair and free draining reseed and pasture which is less frequently used by geese.  The flock is more often reported from the shallows and peripheral wetland areas or on the nearby croftlands of Kilmoluaig and Cornaigmore (NL9746).

3. Balephetrish/Gott/Vaul (NM0147-0448) The northern coast of Tiree is rugged, inaccessible and undisturbed, making it difficult to census.  A series of rocky outcrops with numerous small dubh-lochain, basin mires, patches of rough grazing and occasional in-bye and improved pasture offers a wealth of relatively undisturbed habitat.   Geese seem to break up into small groups throughout this area making complete census difficult, although totals can be quite high.  At Balephetrish (NM0147) and Vaul (NM0448) the birds feed on improved pasture, but they also exploit Eriphorum angustifolium in the bogs such as those behind Gott Farm (NM0347). Geese from all these widespread areas seem to converge on Loch Riaghain which seems to be the regular roost for these areas, where roost counts may offer the best chance of accurately assessing the numbers of birds using this area.

4. Beinn Gott (NL0345) also supports numbers of geese that feed on the improved grass behind Scarinish (NL0444) and along to Baugh in the south (NL0244).  These birds could potentially be the same birds as use The Reef ( to the west) or the Balephetrish birds which extend to Gott to the north.  They have not been watched to roost.

5. The Hynish/Balemartin  area in southern Tiree also supports White-fronted Geese that feed on the croftlands in the two townships.  Here they occur  amongst increasing numbers of Greylag Geese, feeding on the grass fields of the areas.

6. The area around Moss, Heylipol and Barrapol supports the most regular wintering group away from The Reef on Tiree, feeding most consistently on the old improved pasture at Heylipol (NL717433), wet Juncus dominated fields near Barrapol (NL947432) and above there (NL947435) and long improved fields at Moss (NL962452), sometime feeding in the Heylipol valley mire at NL966437.

7. The Reef is a very extensive open area of windblown sand machair traditionally used for summer grazing.  The site is of considerable overall conservation importance and is highly attractive to White-fronted Geese where grassland and extensive base-rich wetlands exist in close mosaics.  The most popular areas with the geese lie in the north west corner behind Balephetrish (NM0046) and along the eastern fringe below Orisgal (NM0145).  Several hundred birds regularly feed scattered all over this area, albeit often at low densities over large areas, making it by far the most important resort on the island and underlining its international importance as a feeding site in its own right.

Roosting sites: Fortunately, Scottish Natural Heritage funded a major investigation of the roost sites used by Greenland White-fronted Geese on Tiree (Young 1996), with the result that we know relatively much about the sites and the feeding sites from which they draw.

1. The Moss flock have been watched flying to roost at Bhiraeapol Bog (NL968444) but the flock will also use Loch a’ Phuill (NL960424) and Loch a’ Chlair (NL984445).

2., 3. and 6. The north shore of Loch Riaghain (NM035474), Loch Dubh Bog (NM036485), Loch Ghrianal (NM039479), Loch nan Ob (NM027484) all seem between them to represent the roost for most of the geese using the northern part of the island.

5. The Hynish/Balemartin birds probably all roost at Loch Garradh nan Capull (NL968418).

4. and 7. The roost for the Beinn Gott birds is not known with certainty, but is likely this complex.  The roost sites for the birds using the Reef and Gott are not well known, geese will stay on The Reef on moonlit nights, but intensive study by Young (1996) found the geese using roosts at An Fhaordhail Marsh (NM015451), Cnoc Ibrig Bog (NM027452), Loch a’ Chapuill/Loc a’ Bhleoghainn (NM023456), Loch na Buaile (NM035447), Loch Leana na Moine (NM027445), as well pools on The Reef itself (NM010460) and North An Fhaodhail (NM017464).

Habitat change: There was considerable drainage on Tiree in the 1980s.  Although the geese have benefited from reseeding, they often seem to prefer more rushy fields and still rely upon the peatlands for supplementary feeding.  Much earlier drainage on The Reef may have been detrimental to the White-fronted Geese, but the site is now protected and hopefully sympathetic management now prevails.

Aircraft disturbance: The civil airport near The Reef precludes low flying military activity in the vicinity without causing excessive disturbance itself, so the geese are very little disturbed despite the vicinity of the airport to this important concentration.

Hunting disturbance: Hunting of the geese has been a major problem in the past, including some illegal shooting post protection.  There is still much hunting on the island but it seems much reduced compared to the 1970s and 1980s, so apart from duck hunting on some of the roosts, this source of disturbance is not considered to be highly disruptive to the geese on Tiree.

Agricultural disturbance: Not known

Site safeguard: Parts of the feeding and roosting areas of the geese lie within the An Fhaodhail and the Reef SSSI and the Crossapol and Gunna SSSI.  Both are NCR sites and are components, with other areas used by the geese, of the Sleibhtean agus Cladach Thiriodh (Tiree Wetlands and Coast) SPA and Ramsar site.

SNH Natural Heritage Zones/Area: Coll, Tiree and the Western Isles.

Threats:   Not known

Linkages with other sites:
There have been 190 resightings of 46 different marked Greenland White-fronted Geese on Tiree over the years.  One of these was ringed on Islay, 14 on the moulting grounds in Isungua, in west Greenland and the remainder at Wexford.  Most of the Greenland ringed birds were clearly regular wintering birds on Tiree, but the circumstances relating to the Wexford birds varied considerably.  The majority were seen on Tiree taking a year out from wintering at Wexford.  Others staged briefly on Tiree in spring after wintering at Wexford (e.g. D0F and C4X in spring 1995, F5C, CZ and DF in spring 1996 and N1P, N2S, N7S, N8S and N9T in spring 2005) or Islay (7UE spring 1994).  Others, like 3KT, visited Tiree in one winter after visiting many different sites throughout the wintering range in its life.  However, some emigrated permanently from Wexford to winter regularly on Tiree for a number of years, including C0N and C0S (2 and 3 years respectively) and F4N and F9S (7 and 6 years respectively).  7CJ was unusual in that it moved to Islay after several years at Wexford after it was caught there, but shifted to Tiree midway through winter 1999/2000.  Such changes of wintering site are unusual, but it obviously liked Tiree because it was seen there many winters afterwards from 2000/01 to 2004/05.  These diverse movements suggest that the geese are generally site loyal to Tiree, that migrants en route northwards in spring towards the breeding grounds may stage on Tiree, and there is some interchange with other resorts, most notably Islay and Wexford.

References

Bowler, J. & Hunter, J. (2007)  Birds of Tiree and Coll. Paircwood Publishing, Balphuill.

Fox, A.D., Francis, I.S. & Stroud, D.A. (1989)  Greenland White-fronted Geese in Coll and Tiree.  pp.129-142. In: Stroud, D.A. (ed.) The Birds of Coll and Tiree: status, habitats and conservation.  NCC/SOC, Edinburgh.

Young, J. (1996) Greenland White-fronted and Barnacle Goose Roost Survey, Isle of Tiree, Argyll.  Report to Scottish Natural Heritage.