Friday, 18 December 2015

Mostly Pollarding with some added Cranes

As the festive season draws nearer and everyone at Wicken is getting into the Christmas spirit, the Fen outside is feeling unseasonably warm.We had to mow the grass around the picnic tables near the cafe last week, a job we're normally finished with at the end of October. The odd queen wasp has been spotted, very sleepy and confused having been woken up by the warm weather. We have even spotted a snowdrop in bloom, which doesn't normally happen until late January to February time.

The warmer weather does mean that we Rangers have no excuse to not head out to work on the Fen. We have been working at getting a small area of scruby woodland back into a four year pollarding rotation. Pollarding is when you cut the branches off the a tree, normally at around shoulder height, which will stop livestock or deer eating the new shoots as they grow. By cutting one section every year, we are hoping to create structural diversity within the wooded area, the more diversity in the structure, the more habitats we create and the more species that can live there. By implementing this management scheme there should always be a variety of tree ages within the wood, which will be used by different species. When the section has just been pollarded, the canopy will be opened up to let more light in, helping flowering plants to grow in the glades and along the rides. By having plants such ox eye daisies, birds-foot trefoil and white clover there's lots of food plants for insects, bees and butterflies including Common Blues (Polyommatus icarus). There's also plenty of butterflies that will enjoy the long grasses in these areas, such as Gate Keepers (Pyronia tithonus), Small Skippers (Thymelicus sylvestris) and Speckled Woods (Pararge aegeria) whose catterpillars all feed on grasses such as Yorkshire Fog and False Brome. Brimstones ( Gonepteryx rhamni) will then use the Buckthorn  trees for their caterpillars. Once the trees have grown again from the stumps they form a canopy again, which provides lots of places for birds to nest. It also makes lots of aerial runways for small mammals to travel along, particularly when bramble has also grown up as this also provides a good food source for the mammals and birds.

There was great excitement around the fen on Wednesday morning when 16 cranes flew over the visitor's centre. There are estimated to be around 75 cranes (Grus grus) resident in the UK, with 9-14 breeding pairs and then a few more visiting from the continent in the winter. Breeding cranes are thought to have become extinct in this country around 400 years ago, with some still visiting over the winter since. In the 70s some of these visitors decided to stay and breed one summer in the Norfolk Broads. The population has been growing slowly since then, and the cranes have been spreading their territories, including two breeding pairs fledging young at Lakenheath Fen this year. There is also a breeding program in Somerset called the Great Crane Project, that has been very successful at releasing hand reared birds to create a stable population in the South West. All our native cranes are watched and monitored closely, and they can all be individually identified by the colour and size of their bustles (the long feathers that look like a tail, but are actually the tertial feathers on the wings). The Cambridge Bird Group website ( has lots of interesting info about which birds have been seen where, and where they think they've come from.
John managed to get a quick video of the 16 cranes flying over which can be seen here:

I hope you all have a lovely Christmas and a fabulous New Year!