Blenheim Farm Nature Reserve
Porters Pond marks 20 years as a BBOWT nature reserve
Porters Pond was created at Blenheim Farm Nature Reserve in October 2008 to mark the 20th anniversary of the site as a BBOWT nature reserve. Don and Pamela Porter generously donated the field to BBOWT in 1987 when they moved from Blenheim Farmhouse in The Slade to their house in the Enstone Road; they wanted the site to be preserved for posterity and safe from being developed for housing. Don died in January 2007 and Pamela in April 2009 and the new pond is a fitting memorial to their love and enthusiasm for the natural environment.
If you want to create a pond in your own garden then look at the Freshwater Habitats Trust website which has lots of good advice. If you'd like to find out more about your local Wildlife Trust then look at the BBOWT website.
Looking back at photos over the past 27 years shows how beneficial it is to plant native trees and shrubs such as hawthorn, guelder rose, hazel, spindle, wayfaring tree, and field maple. These native species grow really quickly and can be bought bare-rooted very cheaply. They now provide a substantial protective boundary to the site which is a woodland edge type of habitat providing homes for a wide diversity of wildlife.
Photos on the left are from 1987 compared with 2006 on the right
Listen out for the first Chiffchaff which are the first warblers to return to the UK to breed, they overwinter in northern Africa so their journey is shorter than Willow Warblers which overwinter south of the Sahara. Chiffchaff and Willow Warblers look virtually identical but their songs are totally different, the Willow Warbler sings with a lovely falling cadence. They both build nests close to the ground so are very vulnerable to attack by dogs and by predation from stoats, weasels, and cats. You are also likely to hear Blackcap and Garden Warblers which sound very, very similar but look totally different.
VIDEO: BBC Nature - Ground nesting Willow Warblers feeding their young 50 times an hour.
Unfortunately a dead Woodcock was found here in December 2009. Woodcock are nocturnal, they have a very stout long bill for probing the ground for worms and cryptic plumage for spending the day perfectly camouflaged in the undergrowth. Their big black eyes near the top of their head help them see in the dark when they fly at dusk to fields to feed. They fly very fast and unfortunately this one hit the low voltage electricity cable that goes across the reserve. Although Woodcock are resident in the UK, many thousands come over from Scandinavia & Western Russia during the winter to escape frozen ground which prevents them feeding. In spring the males carry out a characteristic roding display flight and make a strange croaking call to attract a mate - the tips of their tails are a bright white which the female on the ground then flashes to the male flying overhead.
Local volunteers have worked on the grassland for the past 20 years to reduce the strength of the grass and increase the range of wildflowers growing there. We’ve done this by cutting the grass twice a year and raking it off so it doesn’t re-fertilise the soil as it rots down. We’ve also sown (4) yellow rattle and red bartsia, both of which are annual parasites that feed on grass and weaken its growth so it doesn’t swamp the flowers. We’ve created bare patches (in places removing the topsoil) into which we’ve directly sown local wild flower seeds. Our efforts have been rewarded by a colourful display throughout the summer, which attract a host of butterflies feeding on the nectar.
- Yellow flowers include cowslips, yellow rattle, (2) lady's bedstraw, agrimony, perforate St John's wort, meadow buttercup, and bird's foot trefoil.
- Pink flowers include ragged robin, wild marjoram, wild basil, musk mallow, sainfoin, red bartsia , and teasel.
- Blue/purple flowers include (3) meadow cranesbill "blue geranium", spear thistle, woolly thistle, black knapweed "hardheads", tufted vetch, and scabious .
- White flowers include cow parsley, hogweed, angelica, (1) wild carrot "Queen Ann's Lace", ribwort plantain, and ox-eye daisy.
In 2013 we started cutting the grass with scythes, and volunteers are relearning the country skill of scything, a skill lost just a few generations ago with the introduction of tractors. Please contact Christine (01608 811057) if you want to learn how to scythe. Apart from scything being rather enjoyable, the grassland and flowers also benefit because the grass can be cut right down near the ground and bare patches of soil are exposed providing the right conditions for the flower seeds to germinate. In 2014 we started cutting grassy areas without flowers in June to make hay and sprinkled yellow rattle and other seeds collected on site to flower next year.
Look out in particular for Marbled White (5) from June to August, shown below feeding on scabious and lesser knapweed. Painted Lady (6) butterflies are annual migrants arriving from Africa/Arabia, they lay eggs on thistles which develop into butterflies in late summer, however, they cannot survive our winters and those that don't fly back south will die out. 2009 was a "Painted Lady" year - following heavy rain in the Atlas Mountains in Morocco, millions of these fast flying butterflies migrated north and arrived here at the end of May. Surprisingly, two Small Tortoiseshells (7) were seen on a pile of dog poo in June 2014 - the dog poo of course is a real nuisance when you're scything the grass and has to be removed by hand! Small Skipper and (8) Large Skipper are often seen during June/July, they never close their wings flat so are very easy to recognise, the photo shows a male Large Skipper with black scent bands on the forewing.
We’ve also had White-Letter Hairstreak butterflies - as caterpillars these feed on Elm leaves and as butterflies they feed on nectar from the thistles and brambles - this butterfly dramatically declined in the 1970s at the time of the devastation of the elms by Dutch Elm Disease. We do have a lot of elm suckers growing on the reserve on the northern boundary which do regularly die off and the dead branches become colonised by bright yellow lichen.
April: Brimstone, Orange Tip, Speckled Wood
May: Brimstone, Orange Tip, Speckled Wood
June: Large Skipper, Small Skipper, Speckled Wood, Ringlet, Orange Tip, Marbled White,
July: Painted Lady, Large White, Wall Brown, Meadow Brown, Comma, Marbled White, Speckled Wood
August: Brimstone, Small Copper, Red Admiral, Common Blue, Peacock, Brimstone, Speckled Wood, Marbled White,
September: Speckled Wood
The shallow pond is fed by rainwater running off the grassland and the water level has proved to be remarkably stable - not drying out in summer nor flooding in wet winters. Generally, the water level in ponds does fluctuate and pond life has evolved to cope with it, e.g. by burrowing into damp mud (it is better to let the water level drop in your garden pond than to fill it up with tap water). The pond has been fenced off to protect its edges which were planted up with native plants and seeds. The surface of the pond freezes over in winter but the pond is deep enough for the wildlife to survive in the unfrozen water below and in the mud at the bottom of the pond. There is no need to break the ice up.
Robins were the first birds seen enjoying the pond – these bold birds turned up immediately just like when you’re digging in the garden. This damp habitat will increase the biodiversity of the reserve and the number and range of dragonflies and damselflies will increase. Almost straight away water boatmen and pond skaters (below) were seen - these are always early colonisers of new ponds. Please don't let your dog into the pond, this disturbs the crust of soil at the bottom of the pond, stirs up the mud and makes the water cloudy and this adversely affects the insect and plant life in the pond. It takes a couple of hours for the silt to settle from a single incident so just a few dogs throughout the day can stop daylight reaching into the water for the whole day.
The large Southern Hawker dragonfly is regularly seen, the photo shows a female laying eggs in one of the rotten logs by the edge of the pond. The eggs overwinter and hatch into larva the following spring and these grow over a period of 3 years eating tadpoles and other invertebrates, before finally emerging as an adult dragonfly with wings during early summer. Ruddy Darter dragonfly, Broad-bodied chaser dragonfly and Azure damselfly have also been seen.
Amphibians live on dry land but return to the water to breed and the young live in water until they become adults. Spend a few moments looking into the pond during the summer and you are likely to see loads of black tadpoles and also newts coming up to the surface to breathe. The small black tadpoles are toad tadpoles unlike the larger brown frog tadpoles. Tadpoles are popular food for dragonflies and newts but toad tadpoles, like the adult toads have inbuilt protection - they taste nasty and are slightly poisonous.
We were surprised to find that the newts are mostly palmate newts, 50 males were seen one day in 2013 - easily identified by their black webbed back feet. In April 2014, we found a pregnant palmate newt - she doesn't have webbed feet but is identifiable by her translucent throat which unlike the smooth newt doesn't have any spots. We also found lots of baby newts (efts) - these still had their orange gills to take oxygen out of the water like fish and maybe the late cold spring in 2013 meant they hadn't have enough time in 2013 to grow into adults in a single summer. Amphibian Identification Guide
A few minutes pond dipping at the end of July 2009 found several tiny creatures: water boatman larva (9), cranefly larva (10), and the larva of the broad-bodied chaser dragonfly (11) which had been seen flying near the pond during June. Also ramshorn snails (12) and water slaters (water hoglouse) (13) which are related to woodlice. In April 2014 we found more water hoglouse , lots of transparent phantom midge larva which have two air sacs one at each end of the body so they can float and eat water fleas, leeches which are carnivores and feed on small invertebrates like snails, dragonfly nymphs which are voracious carnivores, and swimming mayfly nymphs (14) which breathe through the gills along the sides of their body.
Plants growing around the pond include Water Figwort (15) which has a browny-orange flower which is pollinated by wasps and the bright mauve Corncockle (16) which is an annual and historically a common arable weed prior to modern farming practices, it was sown the first year to give immediate cover to the bare soil and each year fewer and fewer germinate in the closed sward around the pond.
Pond opening 2009
About 60 people came to the opening of Porters Pond on Sunday afternoon 16 August 2009. Dr Gaby Porter opened the pond in memory of her parents Don and Pamela Porter and then BBOWT provided refreshments and a lovely pond cake beautifully decorated with frogs and hedgehogs. The pond designer, Rod d'Ayala talked inspiringly about how important ponds are as a habitat for a wide range of wildlife and then did some pond dipping. Three different sorts of water beetles were found, together with pond skaters, leeches, wandering snails, and larvae of water boatmen and dragonflies. During the afternoon lots of Southern Hawker dragonflies kept flying low over the pond. This was a BBC Breathing Places event.
Sightings within the first year
20/08/09 - female (green) Southern Hawker dragonfly laying eggs on rotten wood
17/08/09 - male Yellowhammer drinking from the pond
10/08/09 - Great Diving Beetle
09/08/09 - 3 red (male) Ruddy Darter dragonflies
30/07/09 - green and blue (male) Southern Hawker dragonfly
30/07/09 - Bat at midday over the pond
04/07/09 - green and blue (male) Southern Hawker dragonfly
04/07/09 - pale blue (male) Broad-bodied chaser dragonfly
04/07/09 - blue (male) Azure damselfly
03/06/09 - 2 blue (male) Broad-bodied Chaser dragonflies
09/12/09 - dead Woodcock found below electric cable crossing reserve
Please contact me if you see anything interesting on the reserve.
Christine Elliott, Reserve Warden, 01608-811057
Please don't transfer anything into the pond from your own garden pond or elsewhere - the pond has already been populated with a wide range of plants from known sources and we want to observe what turns up naturally in the pond. It is also important to avoid diseases and alien plants and animals being introduced.