Natural History of Anglesey

Anglesey abounds with areas where interesting birds, plants and other wildlife can be seen and enjoyed. Being an island it has over 100 miles of coastline with varied habitats, such as sea cliffs, dunes and beaches, salt marshes and mud flats. These provide homes for a wide variety of animals and also harbour a varied flora. Inland much of the island is low lying agricultural land. Numerous areas are flooded and marshy, providing for a whole other set of plants and animals.

Anglesey is also a geologist's heaven, with a wide range of often complex rock formations, ranging from the Precambrian to the Carboniferous. This is topped off with some excellent displays of the effects of Quaternary glaciations.

The rest of this section describes some of the more notable areas where visitors can appreciate Anglesey wildlife. Those wanting to explore the natural history further will want to get the book A New Natural History of Anglesey, edited by W. Eifion Jones and published by the Anglesey Antiquarian Society, Llangefni, 1990; you can purchase a copy through our books page.

For those not familiar with Welsh words, here are translations of some of the more common elements of the Welsh place names used below: ynys - island, afon - river, llyn - lake.

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PuffinSouth Stack

Towering over Ynys Lawd and its lighthouse, the cliffs at South Stack annually provide thousands of seabirds nooks and crannies on which to raise their young. The greatest number of the birds are guillemots, with razorbills and kittiwakes also being numerous. A small colony of puffins also nest in their burrows above the cliffs. The rare chough, a member of the crow family, is commonly spotted at South Stack. There are estimated to be only 100 pairs of choughs in all of Wales, but there are usually six or so pairs here; more pairs nest elsewhere on Anglesey. Peregrine falcons also nest here.

The vegetation on the wind-swept cliff top is mainly heather. A beautiful display of maritime wildflowers colour the area in the summer. Species common here include thrift (Armeria maritima), sea campion (Silene maritima), bird's-foot trefoil (Lotus corniculatus) and kidney vetch (Anthyllis vulneraria).

The cliffs themselves are composed of the folded Precambrian greywackes of the South Stack Formation. Stairs descend the cliffs to the bridge leading to the lighthouse; from here the structure of the cliffs can be appreciated fully.

On top of the cliffs stands Elin's Tower, the information centre for the Royal Society for the Protection of Birds (RSPB), who manage South Stack. Here you can pick up literature and chat to the warden and volunteers. It is also a good place for observing the birds while staying warm; a number of spotting scopes and binoculars are available at the top of the tower and a video screen linked to a camera and microphone on the cliffs lets you get a closer look at some of the nests.

You can find South Stack with this map. You can also read more about South Stack lighthouse.

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RabbitNewborough Warren

In the thirteenth century the Newborough area was a region of rich farmlands and a prosperous town. Newborough was populated by the townspeople who were evicted from Llanfaes, in the north of the island, by Edward I. However, in the fourteenth century a series of extremely violent storms buried a large portion of this area under sand dunes. The fears of the residents that the dunes would completely swallow the town prompted Queen Elizabeth I to enact a law protecting the marram grass, the roots of which help to stabilize the dunes. This stopped the advance of the dunes and also provided raw material for a new industry in the town, the weaving of the marram grass leaves to form mats.

Rabbits soon colonized the dunes, giving the area the name Newborough Warren. This provided the residents with another valuable resource, as over 100,000 rabbits a year were taken from the warren. The reduction of the rabbit population through forestry plantation and the myxomytosis epidemic of the 1950's allowed the vegetation on the dunes to spread.

Today, besides the marram grass (Ammophila arenaria), the warren is vegetated by a wide range of interesting plants. On the dunes themselves, plants such as dune pansies (Viola curtisii), sea spurge (Euphorbia paralias and E. portlandica), and sand cat's-tail (Phleum arenarium) grow alongside the marram grass. Between the dunes, in the marshy hollows called the slacks, a rich flora can be found composed of creeping willow (Salix repens) and a variety of orchids including the marsh orchid (Dactylorhiza purpurella), along with butterwort (Pinguicula vulgaris), grass of parnassus (Parnassia palustris) and yellow bird's-nest (Monotropa hypopitys).

Birds common to the dunes include herring gulls, oystercatchers, lapwings, curlew, skylarks and meadow pipits. The dunes are also home to an abundance of toads and lizards as well as insects.

Newborough Warren is part of a National Nature Reserve, which also includes Llanddwyn Island. You can find Newborough Warren with this map.

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Cat-tailsMalltraeth Marsh

Just north along the coast from Newborough is an estuary formed by the Afon Cefni, which flows across the island from a point north of Llangefni. Much of the river flows through a low-lying valley, forming the Malltraeth Marsh. The river once meandered freely through this area, but in 1810 an embankment was erected to exclude the tidal influences of the sea. The river was subsequently canalized to reclaim much of the area for agriculture. Despite this, many parts of the valley still have wet meadow environments that are now protected as Sites of Special Scientific Interest (SSSI).

Ditches, formed from the old meanders of the river, occur throughout this area and contain an interesting collection of plants. These are dominated by reed canary-grass (Phalaris arundinacea), water plantain (Alisma plantago-aquatica) and branched bur-reed (Sparganium erectum). Other interesting species are horned pondweed (Zanichellia palustris), flowering rush (Butomus umbellatus) and mare's tail (Hippuris vulgaris). The rare species pillwort (Pilularia globulifera) and autumnal starwort (Callitriche hermaphroditica) occur here as well.

Birds that occur in the marshy areas include mute swan, shelduck, shoveler, lapwing, curlew, redshank, snipe, grasshopper warbler, sedge warbler and reed bunting. Buzzard, kestrel, marsh harrier, reed warbler and tufted duck can also be found there. Bittern are occasionally heard. A section of the SSSI has recently been purchased by the RSPB. They are redeveloping the marshland environments and reedbeds to encourage bird life.

Pools next to the aforementioned embankment (called the Cob) also contain abundant birdlife, including dusky and spotted redshanks, black-tailed godwit and grey plovers. For three decades this area was the home of the renowned wildlife artist Charles F. Tunnicliffe. An exhibit about his life and work is on display at the Oriel Ynys Mon.

You can find Malltraeth Marsh with this map.

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GooseLlyn Alaw

Llyn Alaw is the primary water reservoir for the island, created in 1966, and is also the largest body of freshwater. In developing the reservoir one end was set aside as a bird sanctuary. The permanent bird hide built there by Welsh Water is a popular place to view waterfowl.

The lake hosts a wide variety of ducks, including wigeons, mallards, teal, tufted ducks, pochards and goldeneyes. They are accompanied by Canada and greylag geese, as well as whooper and Bewick's swans. During breeding season common tern, black-headed gulls and tufted ducks nest on the islands in the lake.

When water levels are low a number of waders can be spotted on the exposed lake bed. Here you can see lapwings, curlews, dunlins, and golden plovers, as well as the rarer pectoral and wood sandpipers. The abundance of smaller birds in turn attracts raptors such as peregrines, Merlin, hen harriers and kestrels, along with short-eared owls and barn owls.

You can find Llyn Alaw with this map.

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WaderRed Wharf Bay

Along the north-east coast of Anglesey is a large bay called Red Wharf Bay. Its Welsh name is Traeth Coch (Red Beach). The bay is very shallow and at low tide almost 25 square kilometres (10 sq. mi.) of sand is uncovered. As a result the area attracts a large number of waterfowl and wading birds, including shelduck, grey plover, purple sandpipers, curlew, oystercatchers and dunlin. The bay is bordered by salt marshes and sand dunes. Some of these dunes are rich in shell fragments and support a flora common to lime-rich areas, including the pyramidal orchid (Anacamptis pyramidalis).

The western side of the bay (in the centre of the photo above) has some excellent exposures of Lower Carboniferous limestone deposits. Of particular interest here is a cyclothem sequence topped by a palaeokarst surface. Potholes in this surface, filled with sandstone, are exposed in a couple of places. Fossil corals can be found along here as well.

To see a 360° panorama of the bay, plus a video and photos of the bay in icy conditions, click here. You can find Red Wharf Bay with this map.

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LobsterMenai Strait

Anglesey is separated from the mainland by the fifteen mile long Menai Strait. The strait was carved out of an existing valley by glaciation during the recent Ice Ages. Much of it is bordered by steep wooded banks, with sand and mud flats at either end.

The strait is subject to fierce tidal currents, which can reach up to 8 knots (or 15 km/h) in the narrow region between the two bridges known as the Swellies. These currents have led to many unfortunate ferry accidents during the island's history. The direction of water flow changes during the course of the day, due to the differing times of highest and lowest tides at either end. This leads to the common (but untrue) folk legend that the same water remains in the strait, simply being shuttled back and forth.

The sheltered waters of the Menai Strait provide excellent conditions for growth of marine algae such as Laminaria saccharina and L. digitata, both of which achieve unusually large sizes in these waters. Species of Fucus, Pelvetia and Ascophyllum also occur here. Sheltered rocky areas provide homes for various barnacles, marine snails, and other molluscs, while mussel beds occur in some of the flatter areas.

A variety of fish occur in the waters of the straits, including bass, cod, whiting, conger eels and plaice. Lobsters also occur, as do sponges and sea anemones. The visitor to the island can get a closer look of some of these creatures at the Anglesey Sea Zoo, located on the shores of the strait near Brynsiencyn.

You can find the Menai Strait with this map. A web cam showing the tidal zone at Menai Bridge is here.

You can find more information about natural history of Anglesey at the Anglesey Nature : Natur Môn site.

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About Anglesey History

This is a web site developed by Dr Warren Kovach to celebrate the history of the Isle of Anglesey, North Wales.


Copyright © 1995- Warren Kovach, Anglesey, Wales. All Rights Reserved. The photographs and text on these pages may be downloaded and viewed for your own interest, but you MAY NOT distribute them, reproduce them on other web sites, or use them in any form for any commercial purpose without the express permission of the copyright holder.

Last modified 1 September, 2023