Summer (June – late August)
Insects
There are seven species of dragonfly / damselfly that are confirmed residents on the islands and one or two more that have been recorded but their current status is uncertain. This makes the islands an excellent place to start learning this group of fascinating insects. They may be encountered almost anywhere where there are bog pools although the 10 km squares encompassing Druidibeg National Nature Reserve and the north-west corner of North Uist have recorded the most resident species. The first to fly is the Large Red Damselfly from early May, followed by a peak in July when all the rest (Common Blue Damselfly, Blue-tailed Damselfly, Common Hawker, Four-spotted Chaser, Common Darter) are flying although the last to emerge, the Black Darter, does not peak until August.
There have been 16 species of butterflies recorded in the Outer Hebrides with the scarcest species nationally being Large Heath. This butterfly has been classed as threatened in the U.K. due to destruction of the wet heaths that it inhabits, especially in the south of the U.K. On warm, calm days in June this butterfly is common throughout the main islands in the Western Isles (undoubtedly due to the boggy habitat that it prefers is widespread here). Other species you may encounter are Red Admiral, Small Tortoiseshell, Green-veined White, Small White, Large White, Small Heath, Dark-green Fritillary, Common Blue and Meadow Brown. The Grayling also occurs but appears to be scarce and Speckled Wood recently established a colony in the Castle Grounds in Stornoway.
(Dark Green Fritillary, Eriskay 2006)
July and August
are also the months for the greatest variety of moths and on warm, still nights anyone running a moth trap may
find it heaving with the beasties in the morning. Many species that are
struggling in England due to the widespread use of chemicals, global
warming, agricultural intensification and the loss of hedgerows
etc. are doing well in the Outer Hebrides. The
Garden Tiger has declined by a massive 80% over the last 25
years, nationally but is still very common here
on the Outer Hebrides. Out of 15 species that are now classed as
Endangered in the UK due to huge declines in the last 25 years, 6 of
these can be found in the Outer Hebrides and 3 of these are common.
(Six-spot Burnet; John Love)
There are
six species of bumblebee and two species of mining bee to
be found in the Outer Hebrides. Colletes floralis is a mining bee that
makes its home in bare sand dunes along the west coast from Barra to
North Uist. It has a very restricted distribution in the U.K. and is a very rare species throughout its range. Formerly it
was recorded on the Baltic coast and in the mountains of the European
Alps, the Pyrenees, the Caucasus and the Urals. It is also known from
mountains in Central Asia as well as other Hebridean islands, the west
coast of Scotland, north-west England and coastal Ireland. The U.K.
probably holds as much as half the world population. It may be found on
warm, sunny days in July but is easily over looked. The very similar
Colletes succinctus also occurs but is active in August (after
C floralis) and found away from the coast.
(Colletes floralis, Jamie Boyle 2005)
Two
species of bumble bee are worth a special mention. The
Great Yellow bumblebee was once
widespread throughout many parts of the U.K. but is now largely
restricted to the Uists and Orkney due to agricultural intensification
in other areas. The flower rich meadows and fallow machair help support
this and the following species. The Moss Carder Bee is common
throughout the islands and may be confused with the Great Yellow
Bumblebee later in the summer when worn. The Moss Carder Bee is
widespread throughout the U.K. although it is now suspected that the variety in
the Outer Hebrides may be a unique subspecies as the one in Shetland has
proven to be.
(Bombus muscorum - Moss Carder Bee)
( More on insects of the Western Isles here)
Flora
The summer is
also the time to visit to make the most of the wild flowers. Throughout
the summer months the machair is in bloom with dominant yellows of early
summer turning to the reds and purples later on. The machair is rich in
flowers with different assemblages depending on whether you're looking
in the crops growing at the time or in the fallow of one or two years of
age. The traditional, less intensive crofting
techniques have allowed many species of agricultural “weed” to survive
which in turn support a variety of insects that have become rare or
indeed extinct in many other parts of the U.K. Each machair has its own
unique feel with some species being more prevalent than others in each
area. The mosaic of crop and fallow as well as the variety between each
machair is fascinating and little understood.
(photo: Johanne Ferguson)
It’s not just the coastal plain that holds fascinating plants and many of the orchids are found in the Blacklands and more acidic areas. Grazing obviously plays an important role for certain of these orchids. Lesser Butterfly Orchid are abundant in some areas of the Uists especially where there is light cattle grazing or seasonal cattle grazing. Other species to be found in the Summer months are Common Spotted Orchid (Hebridensis), Common Twayblade, Lesser Twayblade, Frog Orchid, Northern Marsh Orchid, Lapland Orchid (Harris) and Bog Orchid for those who are very lucky. There are also a handful of sites in Barra and Benbecula for the rare Irish Lady’s Tresses orchid.
Irish
Lady's Tresses
is a common species on the other side of the Atlantic but here it only
occurs in a few scattered locations in western Scotland and Ireland.
Nobody knows how it got here although there are one or two theories such
as the tiny spores produced by the orchids were picked on the feet of
migrant geese in Greenland and then transported across the Atlantic.
Others believe that spores find their way into the Jet Stream and are
propelled across the Atlantic Ocean by these powerful winds. We’ll
probably never know how it came to be here but it is here, although there
are no confirmed records of this plant reproducing sexually which leaves
it in a vulnerable position with a small gene pool.
(Irish Lady's Tresses - Aird, Benbecula August 2006)
The hills are largely acidic although some areas do have base rich flushes that support a different set of plants. Many plants struggle to survive on the peats as much of the mineral content is locked away and not accessible to the plants. This has driven some adaptations such as supplementing their essential mineral intake with insects. There are three species of sundew on the hills two species of butterwort and then there are bladderworts in the lochans all ensnaring unsuspecting insects in their own way, which is a very pleasing thought to those that might find themselves on the hill on a warm, calm day in the summer.