Map Ref: SO630127
This study will show the variety of birds that frequent Woorgreen Lake and Marsh; the data was gathered by the use of a point census (Sutherland 2006) over three months. The following descriptive will show the variety of birds that now use the lake and surrounding habitats, the site is relatively young having been used as a mine up until 1981. This will show the importance of the site for water birds, both resident birds and those that visit the area, as the lake and marsh are featured in the ‘Nature Reserves of the Gloucestershire Wildlife Trust’ (Gloucester Wildlife Trust, 2002) is will useful to have data for each reserve in the guide.
Woorgreen Lake is found in the heart of the Forest of Dean and is on land that was once used for open cast mining, this mining finished in 1981. The lake and surrounding area having quickly been inhabited by wildlife, now there is an abundance of flora and fauna to be found, being one of the best sites for dragonflies in the Forest of Dean. (Nature Reserves GWT 2002)
Figure 2: Showing the location of Woorgreen Lake in relation to the surrounding countryside.
The reserve has been held under agreement with the Forestry Commission and the Gloucestershire Trust for Nature Conservation since 1984, working together they have allowed the natural development of the site, although this has been complemented by conservation work to manage the Bulrush (Typha latifolia ) that grow around the lake and the planting of Alder (Alnus glutinosa) and Willow (Saxix triandra) to screen the lake (Blamey et al 2003).
Woorgreen Lake is fed via Foxes Bridge Bog, with the water levels being managed by a sluice. There are different habitats in the area, woodland, heath land, marsh and open mud areas; these support a variety of wildlife and plant species.
The various habitats are situated around the lake, with coniferous woodland lying to the North grading into marshland to the East. The South is where a mud scrape has been created, this area has coniferous woodland on the Easterly side and to the West there is Willow and Alder grading into Gorse (Ulex europaeus) and Bell Heather (Erica cinerea), this is quite an open area, on this side of the lake there is a swathe of reeds in the lake giving good cover for the more wary wildlife. (Blamey et al 2003)
The method for this survey is a point count (Sutherland 2006), visiting the site once a week at nine o’clock in the morning over three months, starting on the 4th November 2007 and ending on 27th January 2008.
In this point count there are four stations at each different habitat around the lake, at each station a wait of five minutes to allow the birds to settle after the disturbance of the arrival, followed by a ten minute observation. A viewing radius of approximately 100 feet at each station, logging down each birds either flying through or settling in that area. (Sutherland 2006)
At the first station the habitat is Alder and Willow, with dead hedges on either side of a small mud scrape. There is a small tree growing at the bank of the lake to the left that hangs over the lake, several small areas of reeds protrude into the lake at this point. There is cover from the dead hedges giving hiding places for birds and other wildlife. This station looks out to the island that lies in the centre of the lake, on this side of the island there is a large rock that protrudes from the water. The island itself has deciduous woodland growing; several large nesting boxes have been placed on trees on the island, one of which is visible from this station. (Figure 2)
The second station is located in heath land, with Gorse and Hawthorn (Crataegus monogyna) on the left side of the track, to the right is the lake. The Gorse area is interspersed with Hawthorn, Alder and small Birch (Betula pendula); the ground is of a wet nature in this area. The lake in this area has a large expanse of reeds from the bank to about 25 feet across the water; the island from this station has a steep bank with mature trees growing almost from the waters edge. (Figure 2)
Station three is an area of mud scrape on the edge of the coniferous woodland; there are two small islets that can be seen from this station, although this is dependent on water level. There is a concrete lined outlet at this station; a small concrete bridge spans this of about four foot across. There are two nest boxes that can be seen on the island, another expanse of reeds can be seen on the left. At this station the viewing radius is slightly less at seventy to eighty feet, because of the island obscuring the viewing radius.(Figure 2)
This station is found in amongst the coniferous woodland, there is also some Gorse in this area. The coniferous woodland in this area grades into marshland, there are clumps of grasses and reeds extending into the lake, water enters the lake via the marshland at this station. Although there are other brooks and streams that feed into the lake at other places around the lake. (Figure 2)
Figure 2: Os map of Woorgreen Lake and surrounding area. (Map ref: SO630127 Scale: 1:25,000)
Many woodland birds were found a few in large densities, for example the Greenfinch (Carduelis chloris) was the most frequent of all the species being observed in large groups on several occasions, over the whole survey an average of 26.75 (Table 1). Large flocks of these birds were seen amongst coniferous woodland feeding both on the ground and in the trees, these were at times accompanied by Blue tits (Parus caeruleus) and Coal tits (Parus ater). This shows the surrounding area is able to support these woodland birds and water fowl, although Greenfinches were sighted during the latter stages of the survey (see table 2). The maximum number seen on just one of the twelve surveys was forty nine, spread between three stations. (Table 1)
Another species that frequented Woorgreen Lake and the surrounding area were the Dunnock (Prunella modularis) a small bird of the sparrow family, on just one survey fifteen were seen (Table 1). This is far less territorial than other woodland species that were observed on the site, a resident Robin (Erithacus rubecula) was observed on every survey therefore giving it an average density of 2.75. (Table 1)
The waterfowl species that were observed on the lake were diverse and at times in relatively large numbers (Table 2), with the Goosander (Mergus merganser) being observed towards the latter month of the survey. The Goosander is resident all year around, but gathers in large flocks during the winter months, the Goosander is one of the few waterfowl that nest in holes in trees (Fitter 1976).
The Greenshank (Tringa nebularia) a notable visitor to England, mainly an Irish migrant, two were seen once during the whole survey. The Greenshank is a wading bird feeding in marsh pools on water insects, worms and small fish, on this occasion a passing through species. (Fitter 1976)
Whereas the Greylag goose (Anser anser) is present all year in Scotland, but over-wintering species in England, although some pairs have been introduced. A large goose that feeds on land not in the water, these birds were ringed but the observer was unable to identify the ring numbers.
A resident Heron (Ardea cinerea) was seen on almost every survey, giving an average of 2.25 (see table 1), although it was seen on the island fishing from various sides. It was well camouflaged against the back ground, a majestic species that has a large range of about 12miles. (Fitter 1976)
Another often spotted bird for Woorgreen Lake was the Kingfisher (Alcedo atthis), often seen on a tree protruding from the shallow area of the lake at point one. This is unusual as they are predominantly a river species, although they feed on lake shores in harder winters, feeding on Gudgeon (Gobio gobio), Minnows (Phoxinus phoxinus) and Sticklebacks (Gasterosteus aculeatus). (Arlott 1992)
The Pochard (Aythya farina) is winter visitor to England, although there are about 200 pairs breeding in Kent and Essex, the rest migrate to Eastern Europe. They often frequent inland lakes where they dive for food and occasionally dabble; they very rarely are seen on land due to the position of their legs. (Fitter 1976) As seen in table 2 the Pochard was seen early in the survey, a short break and then weekly for three weeks, it then was not seen for the latter of the survey.
The Mute Swans (Cygnus olor) were sighted in the early part of the survey and not sighted again, although they do breed on the site, the swans seen were juveniles, probably last years cygnets.
The results from this survey show that Woorgreen Lake and the surrounding habitats support a variety of birds, giving feeding, breeding and migratory sites to not only local species but to more unusual species as well, for an area that is relatively young (twenty-fours years old) it already supports twenty-eight species of birds.