Current view: Text account
Site description (2006 baseline):
Site location and context
Hummock Island is the largest island in the group,
stretching to nearly 2.5 miles (4 km) long and running in a
north-west to south-east direction. The highest point is a
very distinctive peak of 190 m looming like a gigantic
breaking wave towards the north-east. Much of the
coastline is cliffs, often reaching over 60 m in height. In the
mid-20th century, it was used as an extension of the New
Island sheep farm and a high level of grazing has led to
much of the coastal Tussac being eaten out and replaced by
bare ‘black ground’. Considerable Boxwood Hebe elliptica
grows on the cliffs and there is a varied flora across the
central oceanic heathland.
Rabbit Island is 2.8 miles (4.5 km) north-west of Hummock
Island and about 3.5 miles (5.5 km) west of Roy Cove. It is
roughly rectangular, about 0.77 miles (2 km) square with a
long promontory extending south-eastwards. The island
slopes gently to the east and has very steep slopes up to
61 m facing north and west, with highest points of about
91 m. It has been heavily grazed by sheep in the past,
though probably not since about 1986. An old shanty in a
valley is in bad condition. The presence of rats was
confirmed in 2000/01.
Middle Island is a small, conical island reaching to around
120 m in height, with dense, thick coastal Tussac. There is
no beach as such, but flat stone slabs and low cliffs form
the shoreline. It is believed to have been grazed for a short
period prior to 1930, however since then the island has
been ungrazed. It is also free of introduced predators. The
Tussac thins out and is replaced by short spongy grasses
further inland. The island was struck by lightning and
badly burnt in the late 1960s and again in the 1980s. It was
declared a wild animal and bird sanctuary by the Falkland
Islands Government, with the consent of the owner, in July
1966 and was retained by the Government when the estate
was sold in the 1980s.
Green Island is the smallest of the group, only 0.6 miles
(1 km) offshore and extending to just 4 ha. The vegetation
is apparently limited to dense Tussac. Little information
exists about the birds present, although 10 species were
recorded during a short offshore observation period in
November 1997, including Tussacbirds.
Gid’s Island is almost round and reaches approximately
60 m towards the north-western coast. Tall and healthy
Tussac grass extends from the coastal fringe almost to the
top of the slopes, although there are patches of black and
eroded ground present. The island is thought to be free of
introduced predators and has been grazed only
intermittently in the past. No livestock are currently present.
These
islands were visited during the Striated Caracara Survey in
1997; Hummock was revisited in 2001. Canary-winged/
Black-throated Finches, Falkland Steamer Ducks and
Tussacbirds are present, but numbers are not known and
therefore do not qualify the site. On Hummock Island, 28
bird species were found, including all native passerines
except Falkland Pipits, but the visit was short and a
thorough examination of the island was not possible. A
total of 14 species were recorded on Middle Island, of
which probably 12 were breeding. On Rabbit Island, there
was a 32% increase in Rockhopper Penguins’ nests from
1995 to 2000. A total of 20 species was recorded in
November 1997; 18 were breeding or probably breeding;
only two individual Tussacbirds were seen and no Cobb’s
Wrens, Canary-winged/Black-throated Finches nor Ruddyheaded
Geese. Magellanic Penguins were breeding but
counts are required. Gid’s Island held 17 species and 15
were probably breeding. At Green Island, in a very brief
landing and circumnavigation, only 10 species were seen,
of which nine were probably breeding. Thin-billed Prions
and Common Diving Petrels may be present on some of
these islands, but no surveys have been possible.
Non-bird biodiversity: More than 50 Southern Sea Lion pups were born on Gid’s
Island in an earlier season and 29 were found in the 2003
census. The other islands are used as haul-out sites for a
few non-breeding seals. In two visits, 53 flowering plant
species were recorded on Hummock Island, including the
largest known population of an unidentified purslane
(Calandrinia), possibly a new endemic plant. These plants
were growing on the north-west-facing slopes below the
peak at a height of about 46 m. Five endemic species were
found: Lady’s Slipper Calceolaria fothergillii, Woolly Ragwort
Senecio littoralis, Coastal Nassauvia Nassauvia gaudichaudii,
Falkland Rock Cress Phlebolobium maclovianum and Vanilla
Daisy Leucheria suaveolens. One interesting and rare
introduced species, Jersey Cudweed Gnaphalium luteoalbum,
was found in very small numbers. On Rabbit Island, 45
species were identified, of which four were endemic and
six introduced.
Pressure/threats to key biodiversity
The entire group is worthy of further study and there are
many populations that require close examination as a matter
of priority. The present owner of Hummock Island has
declared his intention not to put sheep on the island, but to
allow the vegetation to recover and view it as a private
reserve. Hummock, Green and Gid’s Islands could therefore
be considered for National Nature Reserve status. Hummock,
Middle and Gid’s Islands are free of rats and mice. All
visitors should be informed about the dangers of accidentally
introducing alien species to these islands. Rats are present on
Rabbit Island and Green Island. It is important that the
Falkland Islands Countryside Code is followed, particularly to guard
against the risk of fire.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Hummock Island Group (Falkland Islands (Malvinas)). Downloaded from
https://datazone.birdlife.org/site/factsheet/hummock-island-group-iba-falkland-islands-(malvinas) on 22/11/2024.
