Tuesday, September 29, 2015

Tandem dragonflies



We spent a fascinating afternoon recently watching dragonfly behaviour at Ashes quarry at Stanhope in Weardale.
















The most numerous dragonflies in the shallow, moss-edged pools there are common darters, Sympetrum striolatum. We watched them on their egg-laying flights, where the male tows the female around, attached by the tip of his abdomen to a point just behind her head.

























Coupling up like this is the male's way of defending the female he has inseminated, preventing rival males from mating with her and displacing his sperm.

























It's an unwieldy arrangement. At frequent intervals the male lowers his abdomen, forcing the female down to the water surface where she drops fertilised eggs from the tip of her abdomen.

























That's an awkward manoeuvre, when the male momentarily hovers in this vertical position.




















The males are fiercely defensive of their territory, often perching on a favourite stone or ....

















... plant stem, ready to drive off rivals and pursue any passing female.




















The second commonest dragonflies at this site are black darters Sympetrum danae. There seemed to be quite a lot of interspecific aggro - we watched several aerial battles between the two species.


















These dragonflies land with their wings outstretched but ....
























... finally come to rest with them in this swept-forward configuration.


Sunday, September 27, 2015

Crow v. Sparrowhawk

A couple of days ago we watched this aerial dogfight between a crow and a sparrowhawk near Wolsingham in Weardale.


The sparrowhawk was just cruising along, minding its own business, when the crow dived down on it, missed, soared upward ...


... turned sharply and then had another go.


The hawk veered away ....


... then the crow tried again, this time from below, while ....




... the sparrowhawk looked down to keep an eye on its pursuer ....


... before diving down on the crow as it overshot its target ...






After that the crow kept a respectful distance before ....





















... they both went their separate ways

Friday, September 25, 2015

Wildlife viewed through beer goggles: 6. Is this the world's first moss-themed beer?



Still in pursuit of wildlife-themed beers (click here for earlier examples), here's a complete novelty. I suspect that this must be the world's first moss-themed beer.

























Old Sphagnum has been brewed by the Allendale Brewery to celebrate the tenth anniversary of the Peatland Restoration Scheme by the North Pennines Area of Outstanding Natural Beauty Partnership.



This is Sphagnum, the wonderful moss that grows from the top, dies from below and produced deep peat deposits that - amongst other attributes - lock away atmospheric carbon.



And here, high in the North Pennines in Weardale, is a peaty pool, partially full of Sphagnum, that is a superb habitat for all sorts of wildlife.



Sphagnum absorbs water like a sponge, thanks to these highly specialised leaves that are formed by a network of living cells separated by dead, empty cells that hold water.



Here they are under the microscope, showing that network of living cells (green) and the hollow dead cells in between that hold water.

The Peatlands Restoration project aims to reverse past damage from moorland drainage, that has killed the Sphagnum and led to rapid peat erosion. 






































This is the only moss-themed beer that I've ever encountered and has instantly become an indispensable addition to any bryological field trip.