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Monday, 28 September 2015

Testing the Water 27 Sept 2015

A sunny September Sunday, and a chance for visitors to Riverside Valley Park to give thoughts and suggestions for the future of two of the valley parks in Exeter and the new flood relief works. For information about 'Testing the Water' see https://twitter.com/hashtag/TestingTheWater?src=hash.

(To find out more, there is to be a guided walk 'The Joy of Exe', looking at the River Exe flood works and their wildlife enhancements in a couple of weekend's time on  Sunday 11 October).
 
Activities yesterday included planting seed bombs, carrying out bug hunts, and, chiming with another of those putative 'things which really work' (we hope), a bug hotel, designed and built mostly by industrious youngsters throughout the morning and afternoon. 4 old pallets, 10m+ of old piping, a small roof's worth of old broken tiles and slates, air bricks, branches, hessian rags and a forest of old tree guards were recycled as insect and bug homes, furnished with bamboo canes, grass and soil, and topped off with a turf green roof.
A premier inn for bugs. Pic (c) Testing the Water twitter

Bug of the day would be Great green bush-cricket Tettigonia viridissima, the largest bush-cricket we have and quite rare, a Devon Biodiversity Action Plan target species. In the UK it has a southern distribution, including the south west, where the Devon coast provides a national hotspot. It might be an unusual find in the middle of Exeter, though there has been a previous record from the edge of Exwick. Both male and female were found on the day during John Walters' bug hunts.

Great & green. Pic (c) Testing the Water twitter

The loud call can seem to come from everywhere, said to sound like a machine gun, or a shrill computer printer, or a sewing machine. Yesterday it was putting up a good contest, or possibly might have been interacting with, the generator. Perhaps someone who has drunk a very strong coffee, sewing together a very long trouser leg.

More on GGBCs:
Tom Williams has recorded the call at Dawlish Warren
www.pterodaktyl.co.uk/2009/08/11/great-green-bush-crickets/

GGBC info at:
www.devon.gov.uk/dbap-insect-cricket.pdf
www.devonwildlifetrust.org/species/Cricket'2C+Great+green+bush+cricket/
www.orthoptera.org.uk/species/account.aspx?ID=10

Testing the Water poster

Life after concrete 1-3: streetwise ferns

Some more examples of urban plant survivors around Exeter (see 18 June below). Let me know if you see any other good candidates.

1. Poundland* polypody, with gull, Sidwell street
(* other pound shops are available).

There must be a nest up there on the flat roof. I waited a while for the gull to walk into view.

2. Parliament St polypody, on the 'narrowest street in Britain'.
 

3. Tudor house polypody (Tudor St, near Renslade House), more at home as an epiphyte on the ancient wooden timbers, maybe.


Monday, 14 September 2015

Night of the Wear bats

Wednesday 9 Sept 2015

South of the city centre alongside Riverside Valley Park is the old paper mill at Countess Wear.
Mill buildings have probably been present here since Mediaeval times. Originally for grinding corn, the mill  was thought to switch to paper manufacturing in 1638, making paper from linen rags. In C18 and C19, high quality paper was made there for newpaper and banknotes. The present building is the result of reconstruction after a fire in 1816. The mill at its height employed some 200 people around the 1850s, closing in 1885.

Since Grade II listed, the roof and wall tops were restored in 2008 to protect the remaining structure.... And as part of that project, a large bat loft was installed, along with three woodcrete bat boxes in the unroofed section. As well as these bat bespoke features, there are many nooks, crannies and cavities around the old walls and surrounding woodland, all ideal for roosting bats.
Inside the Mill for 2013 check - the bat loft is the large structure in the rafters
That's in theory anyway, but would anyone be at home? To find out requires a long ladder, a head for heights, a torch, and a bat licence. We last checked the site on 23 Sept 2013: a Brown long-eared bat was in the special loft, and a white-tummied Natterer's bat was roosting in a cavity in the wall, the tips of its pointy ears characteristically folded over at rest. Bat detecting later on recorded many pipistrelles and occasional fleeting horseshoe bats flying by.

This time there was a scatter of bat droppings in the bat loft, sign of some use. In the unroofed section were a number of holes in the brickwork also with bat droppings, and in the Natterer's cavity from 2013, a Daubenton's bat. There was also evidence that the woodcrete bat boxes had been adopted - by a Soprano pipistrelle.

It's now more widely known that only fairly recently in the 1990s was the pipistrelle bat discovered to be two separate species, based in part on their echo location calls: common or 'bandit' pipistrelles at 45 kHz, and 'soprano' pipestrelles higher at 55 kHz. This is straightforward with a bat detector, but seriously much less so in the hand: they look very similar indeed.

A diagnostic feature is that a particular wing vein in the soprano pip has a simple 'Y' shape, whereas this is more branched and complicated in the common pipistrelle. Also, males, like the one we found, have gingery fur around their male bits. This was one of this year's young, with pale translucent ends to finger bones where these join but are not yet fully calcified. At 4.5g, it had a little fattening up to do for hibernation, but with a forearm of 30.5mm was adult size. For the time of year, it was also in fine breeding condition; let's just say one could tell.
Paper Mill pip, 9 Sept 2015

Safely returned to the batbox, next on to the woodland to check the bat boxes there. The woodland seems old and well established, but this was once an intensively industrialised mill area extending over 2 hectares, with riverside berths for the import of linen  from Holland, troughs for fermenting rags, and coal stores from when the mill converted to using steam power and woodpulp. The remains of brick structures are still dotted about the hazel coppice stools and mature trees that have grown up since.
Greg checking bat boxes, from 2013 check
This is where we stopped for the evening. We'll return to take an inventory of the boxes and make some box repairs. A remote bat detector with a month's battery power was also left in the bat loft to record any batty visitors. There are likely to be further bat surveys and bat projects at the site in the future; anyone interested can find out more by joining Exeter City Bats, link below.
Many thanks to Jo and Ruth for bat-licensed supervision and Chris from Exeter City Council.

Info about Exeter City Bats and the Exeter Big Bat Survey 2014-15
https://www.facebook.com/Exeter-City-Bats-223297294481957/timeline/ 
http://bigexeterbatsurvey.edublogs.org/ 

Info about UK bats, including Soprano and common pipistrelle, Daubenton's, Natterer's & horseshoe bats
www.bats.org.uk/pages/uk_bats.html

Info about Countess Wear Mill
www.britishlistedbuildings.co.uk/en-481015-countess-weir-paper-mill-devon#.VfWBqM6sN3U


Friday, 11 September 2015

Stoke Woods strangeness

A Bank Holiday visit to the woods, under the overcast sky. It wasn't raining (yet), but there was a soft and steady pattering sound emanating from the tree canopy overhead. Venturing closer, this was revealed to be a regular green rain of many fragments of knopper galls, tumbling down from above. Knopper galls are misshapen acorns, stimulated to modified growth by a tiny gall wasp. I'm guessing these were being nibbled open for the wasp grubs inside (by squirrels? I couldn't hear any nuthatch hammering noises).

For more info about knopper galls, see https://en.wikipedia.org/wiki/Andricus_quercuscalicis

At home, a hitchiker emerged from my backpack: a strange invertebrate, flattened like a flea and with flea-like clicking, jerking jumps, but, at 1cm ish long, far too big and with far too many legs; a sort of flea-woodlouse.

No hints in any of the books. Some quick Googling of 'terrestrial amphipod' suggested it was a 'Woodhopper' or 'Lawn shrimp' Arcitalitrus dorrieni, an introduced species from Australia, now widespread in the south west among leaf litter and damp detritus in woods and gardens:  
http://www.bmig.org.uk/species/arcitalitrus-dorrieni

Monday, 7 September 2015

Mincinglake re-match

After wash out on 5 July, an impromptu re-visit.

Mincinglake Valley Park, looking south towards the Exe Estuary

There was lots of hogweed and patches of fleabane, tansy, knapweed, ragwort, all worth checking out for insects. I have to say, watch your footing for dog pooh and pooh bags.

While watching where feet were going, this Mining bee was spotted at the path edge (Halictus rubicundus?)
 



Tuesday, 1 September 2015

Pollinators in the park events


Mincinglake Valley Park 5 July 2015

Rain stopped play, via a forceful shower in the hour before the event was due to start, and for half an hour afterwards. When this eventually subsided, it was one of those days when the sunshine surged strongly through the dispersing clouds, making the tarmac steam.

There was a post-shower fresh stillness, then a kind of natural reawakening. First up was a strident blackcap, the song magnified and reflecting off the wet surfaces (just as Bernie Krause describes in his book The Great Animal Orchestra); then some bumblebees droned into view, foraging among bramble flowers; finally a pair of mating ringlet butterflies, bombarded by competing males, in a sunlit spot.
A mini-nature fix to be enjoyed that day, after all.




Duryard, Belvidere Meadows, 2 Aug 2015

Much more sympathetic in terms of weather and mini-beast activity was the Duryard follow up event. The idea was to show some of the agents of the 2/3 of pollination services we rely upon, but which are not honey bees.

Belvidere Meadows, looking NW towards Exe Valley
Honey bees are important pollinators and receive a lot of attention. But by numbers and diversity, hoverflies are estimated to be the largest and busiest pollinator group by far [1], and there are numerous others: other flies, bumblebees, solitary bees, butterflies and moths, beetles, wasps.

At the start of the walk, peeking into a convolvulus flower along the boundary hedge to the site, we found a tiny flower beetle, well-dusted with pollen. From another convolvulus flower emerged a red-tailed bumblebee. Making our way to the pasture area itself, several other plant-pollinator associations were on show. Very conspicuous were other bees: common carder bumblebee monopolising red bartsia, other red-tailed bumblebees, plus an individual of their cuckoo bumblebee Bombus rupestris, on black knapweed, and a ball of  mating small metallic green solitary bees (probably Lasioglossum morio) on creeping thistle. Marbled whites, skippers, holly blue, ringlets, gatekeepers, meadow browns, and burnet moths flitted through the scene at grasstop height. Checking hogweed and other platformed flower heads revealed the common red beetle Rhagonycha fulva, and Oedemera nobilis the 'thick kneed beetle', or the 'fat-thighed beetle', though be sure to note only the males have fat thighs. 

Further down the slope, at the boggier and wooded edges we found a wasp beetle Strangalia maculata, a tree wasp Dolichovespula sylvestris (check the dots on the thorax and face), and, on its favoured angelica, Eristalis pertinax hoverflies. Towards the end of the walk, a Silver-washed fritillary butterfly patrolled the woodland hedge margins, and our final pollinator was a Coronet moth Craniophora ligustri, pretending to be lichen or bird dropping.  A range of representative insect pollinator types, in the course of our brief survey-stroll.
Coronet moth - bit ragged


[1] This taken from various sources. A useful summary is http://gardenchampions.leeds.ac.uk/wp-content/uploads/2012/05/19885_UoL_Pollinator-Story.pdf but this link doesn't seem to be available any more. For some more info, try this University of Reading paper, http://centaur.reading.ac.uk/25072/2/Insect_pollination_in_UK_agriculture_Final.pdf, a Bristol & Cardiff Universities study http://rspb.royalsocietypublishing.org/content/282/1805/20142934, and the Urban Pollinators blog http://urbanpollinators.blogspot.co.uk/2013/08/identification-of-common-garden.html. In case it comes up on QI sometime, pollination vectors were once categorised into different groups, each with a different technical name: https://en.wikipedia.org/wiki/Pollination_syndrome