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Thursday, 27 October 2016

Back to back bulbs and bats

Ludwell Life woodland action morning Sunday 23 Oct
Wild About Gardens bat event Monday 24 Oct 

Rain. Downpours over the last couple of days will be good for the wildflower bulbs Ludwell Life planted on Sunday, but were not so welcome for our Wild About Gardens bat talk & walk on Monday evening. The silver lining had more than its quota of accompanying cloud.

Ludwell Life's October practical task saw a dozen of us enhance the woodland area alongside the Panny watercourse. When originally planted over 20 years ago, it wasn’t foreseen how the Norway maple would self-seed so prolifically, blocking out the understorey for most other species and the underlying ground flora.
Sweet sweet bulbs: clearing patches for planting

The first step was to remove Norway maple seedlings, leaving space for the field maple, holly, and surviving elms to grow. Underneath these we planted clumps of wildflower bulbs for next and future springs: wood anemone, wild daffodil, snowdrops and native bluebells, at their various spacings and depths. These flower early in the season, before the overhead leaf canopy casts dense shade. Some hopefully will put on a flowering display next spring and attract all sorts of early butterflies, bees and other insects; others may take some years to establish.

We ran out of water by the end, but the Sunday evening weather took care of that. 

Future monthly activities at Ludwell are to continue: November’s will include tree planting. All volunteers are very welcome at these friendly events; details will be posted on the Ludwell Life website in due course.

On to Monday evening, and Wild About Gardens Week's theme this year was bats: how to encourage them with garden planting schemes, ponds and logpiles, which support invertebrates, aka bat food. Also through providing roosting sites around the home, via the various different sorts of bat box, bat tiles, tubes, soffit boxes and bat bricks. And finally understanding, on the larger scale, how hedges, watercourses, lines of trees, and darker areas free from artificial light enable bats to find their way around the urban landscape.   
Half a dozen hardy souls braved the misty gloom, armed with bat detectors. What might have been detected was our thoughts on whether October was a good time of year for a bat event. But in the damp and drizzle, we were able to see how some of these ideas have been put into practice in DWT’s Cricklepit Mill wildlife garden.

Street and leat bat detecting    Photo: S Butcher
Night-scented plants, such as soapwort, bladder campion, catchflies, night-scented stock, tobacco plant, evening primrose, jasmine and different honeysuckles, which will flower in sequence through the year, are good for attracting moths, a key food item. Alongside midges, gnats and flies, of which bats can consume some 3000 a night, there are also some perhaps surprising non-flying, aquatic and diurnal invertebrates on the menu, such as spiders and the odd millipede and earwig, according to a Mammal Review paper (N Vaughan 1997 The diets of British Bats, vol 27 (2), pages 77-94).
It reflects a diverse range of foraging techniques, not just in flight, but also gleaning from leaf and water surfaces, and would explain why generic wildlife gardening features, such as ponds and logpiles, as well as providing habitats for insects and other wildlife, also benefit bats at the same time.   
Just after dusk, despite the unpromising drizzly weather, we were joined by 5-6 soprano pipistrelles, flitting around the edge of the tree canopies on Cricklepit street and leat in characteristic flight pattern. At the this time of year bats will be needing to feed at every opportunity, evidently tolerating some light rain and lower temperatures in the run up to hibernation. We can do a bit to help in our gardens and open spaces, and maybe a damp October evening was not such a bad time to think about our local bats after all.    
Some more information

Friday, 14 October 2016

German cousins

The striking firebug Pyrrhocoris apterus is very rare in the UK, known since at least 1865 from one Devon offshore islet site only, near Torquay, a Devon speciality. But it's common on the continent, here hitching a ride on my wrist at the Olympic stadium in Munich, where I was visiting last week.

Bug o'clock (photo: C. Kurz)

It feeds on tree mallow, especially the seeds, and on lime trees. 'apterus' means without wings, and is the distinguishing feature from other red and black bugs; it perhaps suggests why it hasn't been able to colonise the mainland yet, or since 1865.

For more information about Devon bugs, see Keith Alexander's excellent mini-article, from which some of the details above have been taken (link here - uploads Word document directly).

Monday, 3 October 2016

Outside the whale

A visitor from the deep washed up at Red Rock Beach near Dawlish at about 6am on Thursday, not a customary thing to see from the train window.

UK Strandings Investigation Team took samples and confirmed identity as a Fin whale Balaenoptera physalus, the second largest in the world. This is a pelagic, temperate and cool water ocean species, long and slender, built for speed, with two sub-species, one each in the northern and southern hemisphere. The global population is estimated at around 100,000 - 120,000, recovering from 38,000 in 1997*, perhaps less than 10% of its pre-whaling level.  

Fin: final resting place on Dawlish beach

This was the third Fin whale washed up in the UK in 2016; typically 2-3 such incidents occur annually out of around 600 stranding reports each year**. Another Fin whale was stranded two weeks ago on Shetland

At 16-17m, this one was as big as a lorry, but still not fully grown (largest can reach 26m) and was thought to be a sub-adult, weaned and maybe relatively recently independent, about 3-4 years old. Turned slightly on its back, the fin was not visible though the black and white baleen plates, and a white patch on the right side of the lower jaw, are distinctive feature of the species***. 

This month's BBC Wildlife magazine says that from July onwards fin whales regularly turn up along Cork and Waterford coasts in south east Ireland, sometimes also seen around Scotland and the south west of England, peaking in October - November as the whales venture closer to shore in pursuit of shoals of sprat and herring.

A fin whale had been observed in the English Channel over the last few months, which may have been this same, now deceased, individual. Coastguards had been tracking the carcass for the last few days, in case it may have been an upturned boat. It is thought to have died about 2 weeks ago, and been drifting on tides since.

The baleen plate of brushes - instead of teeth - meant this clearly wasn't a sperm whale, one of the toothed whales, as in some early reports. The baleen is what filters out the zooplankton and small fish from the huge mouthfuls of water the whale takes as it feeds, filling up the expanding mouth pouch and forcing the water out through the brushes, trapping the food inside.

Interestingly there seemed to be a couple of bite marks in the jaw blubber. Apart from a puncture wound in the side, which may have
occurred after death, there were no signs of obvious injury, such as from a collision. The results of the sample analysis may provide more information in due course.

Although still fairly intact on the outside, the carcass was too decomposed internally, hastened beneath the thick cushion of insulating blubber, for a post-mortem. Any approach from downwind, from as far away as Dawlish Warren, suggested as much.  

The leaking from the wound congealed with the sand, which stuck well to footwear, so that a reminder of this encounter was carried around for some hours afterwards.

Teignbridge council are responsible for Dawlish beach, and now also the large and unusual clean up operation of what could swiftly become a health hazard.

Whale meat again: advised to clean footwear thoroughly if don't want them to remind you of dead whale for the next couple of days

Over the weekend the carcass is likely to be rendered and removed piece by piece. Next time from the train window there won't be a trace, except for the lingering memories prompted by faintly smelly shoes.

* from figures on Wikipedia for Fin whales taken in the Southern hempisphere between 1905-76
** Rob Deauville of UK Cetacean Strandings Investigation Programme, quoted in Daily Mail online
*** David MacDonald & Priscilla Barrett 1993 Collins Field Guide Mammals of Britain and Europe