© Andy Rouse

We work with a huge number of different people to make sure that nature conservation and wildlife are integrated into the current and future development of the Cotswold Water Park.

We work towards creating new nature reserves and at the same time making sure we get the best deal for wildlife from built development, mineral extraction and the provision of sports and recreation.

The Cotswold Water Park Biodiversity Action Plan is a key tool to guide this work and realise these aims.

© Dave Kilbey

Why the Cotswold Water Park wildlife is special

Lying at the head of the Thames Valley, the mosaic of habitats in the Cotswold Water Park has created one of the biodiversity hotspots of the South-West, and an important wetland corridor.  Over the next 50 years this area and its nature conservation value are set to dramatically increase.

The Cotswold Water Park Trust is working with a range of partners to integrate nature conservation and wildlife into the current and future development of the Cotswold Water Park, creating new reserves whilst maximising the contribution to nature conservation from built development, mineral extraction and the provision of sports and recreation.

The Cotswold Water Park hosts internationally important numbers (20,000+) of wintering water birds and nationally important winter populations of Pochard, Gadwall, Coot and Great Crested Grebe. Ten of the lakes are designated as SSSI because of the important aquatic plants that thrive in the clear lime-rich waters. The lakes support a nationally important breeding population of Great Crested Grebe and 20 species of dragonfly.

Between the gravel workings and established lakes there are numerous unimproved wildflower meadows of which two are Special Areas of Conservation (SACs) and a further 6 are designated SSSIs. There are several limestone rivers and streams (including the Churn, Coln and Leach) running through the Water Park into the River Thames. These rivers and streams support healthy fish populations, as well as Otter, Water Vole and Kingfisher.

Alongside the constant demand in the Water Park for more mineral extraction, there has always been tremendous commercial pressure for business developments – including water sports, recreational developments, second homes, hotels and holiday complexes. Partly in response to this pressure, the Cotswold Water Park Biodiversity Action Plan was developed.  This is a working document, and helps steer habitat improvements in response to local and national targets.

Key Facts

  • Internationally and nationally important for wintering wildfowl
  • Nationally important for breeding birds such as Great Crested Grebe and Little Ringed Plover
  • Many species that are declining nationally are either stable or increasing in the Water Park including Nightingale, Reed Bunting and Tree Sparrow
  • Up to 200 species of bird visit the Cotswold Water Park each year
  • A thriving Otter population and expanding Water Vole numbers
  • Regionally important dragonfly numbers
  • Home to 14 out of the 18 UK species of bat
  • Ten lakes are designated as Sites of Special Scientific Interest (SSSIs)
  • Six wildflower meadows are also designated SSSIs
  • A large population of Great Crested Newts
  • Several species of rare stonewort thrive in the freshwater lakes

CWP Species Check List

The Cotswold Water Park Trust has published an updated species checklist for the birds, mammals, butterflies and dragonflies of the Cotswold Water Park.  The first such checklists to be produced since 2000, they have been updated and added to. For the first time, a mammal checklist has been produced, which includes all bat species recorded in the CWP to date.  These have been produced in response to requests from the public as part of the ongoing efforts of the Trust to encourage and support local and visiting naturalists.

Download the  CWPT Species Checklist and use it as a general guide to what can be seen in the Cotswold Water Park throughout the year, or as a recording sheet for species sighted – please do send in any sightings as we would love to hear from you!

© Dave Soons


The Cotswold Water Park provides excellent habitat for a diverse range of bird species throughout the year.  Its central location within the UK, combined with its vast area of wetland, ensures that there is always something of interest here among the 151 lakes.

From over 20,000 wintering waterbirds and 21,000 wintering gulls, to large numbers of breeding warblers, Nightingale, Little Ringer Plover and Common Tern, the CWP holds a plethora of opportunities for either the amateur birdwatcher or the seasoned twitcher.

Regular monitoring of breeding and wintering waterbirds on important sites in the Water Park is carried out by a mixture of professional ecologists, CWP Trust volunteers and partner organisations.  These studies highlight the importance of the area for breeding as well as its role as a key stop-over for migrating species in the spring and autumn.


  • Early Spring, April and May for the early arriving warblers and hirundines as well as the Nightingales of Swillbrook Lakes (Lakes 46/48). The Hobbies arrive back, often in large numbers and often with a Red Footed Falcon in tow.
  • The Summer for breeding waders such as Little Ringed Plover, Oystercatcher and Lapwing and for large numbers of breeding ducks such as Tufted Duck and Gadwall. Also breeding Hobby, Barn Owl and Little Owl.
  • The Autumn for the sheer number and variety of passage birds migrating through this inland site; recent passage birds have included Pied Flycatcher, Wood Warbler, Yellow Wagtail, Whimbrel, Temminck’s Stint, Grey Plover, Black Tailed Godwit and Bar Tailed Godwit, Mediterranean Gull and Black Tern.
  • The Winter yields large numbers of wintering waterbirds and gulls; look out for Pochard, Gadwall, Goosander, Smew, Caspian Gull, Yellow Legged Gull, Iceland Gull, Little Egret, Red Throated Diver, Green Sandpiper, and Yellow Browed Warbler; plus large flocks of Lapwing and Golden Plover. Also worth keeping an eye out for Cetti’s Warbler, Peregrine Falcon, Merlin, Snipe and Kingfisher.

Check the CWP Bird Blog for details of what is currently being spotted.

© G Harris


With its rich array of rivers, lakes, fields, hedgerows and trees, the Cotswold Water Park provides ideal habitat and foraging opportunity for many species of bats.  So far, 14 out of the 18 UK bat species have been recorded here, and monitoring studies are carried out regularly to try and gain a better understanding of their use of this unique landscape.  The Trust’s conservation work focuses heavily on providing habitat enhancements for these highly specialised mammals.

CWP Bat Project

In spring 2005, the meeting of several interested parties from Gloucestershire and Wiltshire Bat Groups and the Cotswold Water Park Society (now The Trust) lead to the launch of the Cotswold Water Park Bat Initiative, part of the Cotswold Water Park Biodiversity Action Plan (CWP BAP). Since 2005 an enormous quantity of bat survey and monitoring was undertaken across the CWP, by a large number of volunteers. Over 250 bat boxes of various designs are monitored several times per year each year; numerous bat roosts are monitored annually through emergence surveys, with several new roosts being found each year. Mist netting surveys (undertaken under the appropriate Natural England licence) are frequently employed to gain further information on the bats using specific sites, whilst radio-tracking studies commenced in 2010. Working with local landowners, lake-owners, developers and mineral companies, numerous surveys have been undertaken and opportunities for bats on specific sites maximised, through for example, creation of bat houses, habitat creation and enhancement of commuting routes. Local communities have supported the project by supporting surveys of farmland, churches, bridge structures etc.  This is a true community project. The CWP Bat Initiative has a series of long term aims:

  • Continue to find and study new bat roosts each year in the CWP.
  • Maintain a database of records and data and share annually with the county records centres (WSBRC & GCER).
  • Provision of training for future potential bat workers.
  • Education and co-operation with the local community and other interested parties.
  • Establish a flagship study for the CWP on a species characteristic of the area, for example Daubenton’s Bats.

CWP Bat Atlas – download CWP Bat Atlas (PDF 5mb). Read the full story here

© Dave Soons


The Cotswold Water Park is home to many of the UK’s mammal species, including Roe Deer, Badger, Polecat, Brown Hare and Harvest Mouse.  In addition, the CWP’s unique landscape lends itself rather well to supporting thriving colonies of aquatic specialists such as Otter, Water Vole, Water Shrew and more recently the Beaver!

Water Vole

The Water Vole has recently been cited as the UK’s fastest declining mammal species, with numbers down by 90% in the last 25 years.  This has largely been due to habitat degradation and predation by the non-native American Mink.  The Cotswold Water Park Water Vole Recovery Project has been running since 2002, and focuses on surveying the extent of Water Vole populations in the CWP, and eradicating the American Mink.  Numbers of mink have been on the decline since the project’s inception, and 2011 saw the first mink-free year.  However, we remain vigilant, and during the flooding of 2012/13, we began to see individuals keen to escape swollen rivers and set up territory in the Water Park.  These have been successfully removed as in previous years, and as a result of the efforts of Trust staff and volunteers, Water Vole numbers have stabilised and are increasing on some stretches of river.


After reaching near extinction in the 1960s/70s, otters have recently been making a comeback on the UK’s rivers.  The Cotswold Water Park supports healthy numbers of this keystone species, partly due to the ease with which they can navigate between watercourses by utilising lakes.  A healthy Otter population is also an indication that our rivers are in recovery, with fish numbers on the increase.


Native to Britain, the Beaver became extinct by the 17th century due to over hunting.  Their fur was highly prized, along with their “medicinal” catoreum glands.  These glands actually store Salicylic acid (Aspirin) which the Beaver accumulates from all the willow bark that it consumes.

In October 2005, 6 Beavers were released into an enclosed lake at Lower Mill Estate in the Cotswold Water Park.  They have thrived in this environment and continue to be studied closely to monitor their effects on their surroundings.

© Dave Kilbey


The Cotswold Water Park supports a diverse range of Dragonfly and Damselfly species, reflecting the variety of wetland habitats found here. To date more than 20 species have been recorded, ranging from tiny damselflies and demoiselles to the larger hawkers and emperors. Large numbers of Banded Demoiselle may be seen fluttering along many sections of the River Thames, demonstrating the high water quality and excellent habitat.  Many of the deeper lakes support vast swarms of several thousand Common Blue Damselflies, a species suited to deep water habitats.  The warm shallow waters of lake margins and recent mineral workings can support huge swarms of Black-Tailed Skimmer and Blue-Tailed Damselfly.  The rare, Scarce Blue-tailed Damselfly has been recorded in some mineral workings in the Cotswold Water Park, utilising the warm, shallow pools in the earliest stages of vegetation.  Key sites such as the diverse wetlands of Swillbrook Lakes support a superb dragonfly assemblage of 16 breeding species, a result of the variety of water depths and pool sizes seen here. The Cotswold Water Park Dragonfly Atlas Project 2008-2012 was launched in spring 2008 to survey, record and map the distribution of dragonflies and damselflies across the CWP.  Surveys have now concluded with publication hopefully due in the very near future.


Trees and plants

Wildflower meadows, woodland, hedgerows and aquatic plants make the Cotswold Water Park one of the more diverse botanical landscapes in the UK.  10 of the lakes in the CWP have been designated as Sites of Special Scientific Interest (SSSI) for their aquatic plant assemblage, with delicate stoneworts thriving in the gravel lined waters.  Lowland meadows such as North Meadow have been afforded National Nature Reserve (NNR) status, as well as being protected as a Special Area of Conservation (SAC) and a SSSI.  North Meadow supports the UK’s largest population of Snake’s Head Fritillary and visitors come from miles around to see them in full spring bloom.

Black Poplar

Our native Black Poplar is the UK’s rarest timber tree, partly due to it falling out of favour in comparison to the fast growing hybrid varieties.  Added to this, the conditions required for reproduction from seed, are specific and uncommon, leaving the Black Poplar largely reliant upon planting from cuttings.  The UK Black Poplar population estimates fewer than 500 females which represent less than 1% of the total, so the sexual imbalance is obvious!  Conversely, of the 350 individuals so far identified in the CWP, 60% are female, indicating that the Water Park could be home to the most important population of this water-loving tree.  DNA studies are ongoing as part of the Trust’s Black Poplar Project, so that we can propagate the most diverse variety of cuttings and further the conservation of the species.