Monthly Archives: October 2011

Autumnal Anisopterans

Posted on October 28, 2011 | 1 comment

Yesterday, 28th October, was one of those glorious sunny autumnal days where the air was fresh but the temperature was raised by bright sunshine, and I’d heard that the winter migrants were arriving on the lakes at Milton Country Park on the northern edge of Cambridge. So I took my camera to work and headed there for a stroll at lunchtime in the hope of snapping a teal or wigeon or perhaps a more unusual visitor. Several waterbirds were on parade including these cormorants:

Several migrant duck species were there too, including wigeon (Anas penelope, Dansk: pibeand), the duck with the chestnut head in the background of the cormorant picture is a male wigeon, tufted duck (Aythya fuligula, Dansk: troldand):

A male tufted duck resplendent in his pied plumage and bright yellow eye

…and gadwall (Anas strepera, Dansk: knarand).

What I didn’t expect to see though, certainly not in the kind of numbers present, were dragonflies. It’s nearly November and the weather has started to get more autumnal but the warm weather up to now must have suited these airborne predators. In particular common darters (Sympetrium striolatum) were conspicuous, six at one time including two mating pairs. It’s always a treat to watch dragonflies but especially on a sunny day at the end of October, living uo to their name and darting about making a loud low frequency buzzzing noise .

Stunning symmetry of a pair of mating common darters

The darters were sunning themselves on the fence lining a viewing jetty on the edge of a lake and while they were busy warming and copulating a migrant hawker (Aeshna mixta) was patrolling the adjacent reedbeds. All the dragons were pretty much oblivious to my presence unless I ventured too close then they would rise into the air, the copulating couple in tandem, only to return to pretty much the same spot with 30 seconds or so.

Migrant hawker

Every so often one or more of the common darters would chase the hawker away until it lived to its name and plucked one of them out of the air and butchered it whilst flying around our heads, scattering the inedible parts around us. After its aerial snack it headed up into the treetops and disappeared.

The hawker missed a trick. It went to alot of effort catching its darter on the wing when it could have had twice as much protein if it had spotted this pair. But I’m glad it didn’t!

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Posted in Anisoptera, Birds, Darter dragonflies, Dragonflies, Insects, Milton Country Park, water birds

Tagged Aeshna mixta, Anas penelope, Anas strepera, Anisoptera, Autumn, Aythya fuligula, Cambridge, Common darter, cormorant, dragonflies, gadwall, knarand, Migrant hawker, milton country park, Phalacrocorax carbo, pibeand, skarv, Sympetrum striolatum, troldand, tufted duck, wigeon

Colourful Corvids

Posted on October 24, 2011 | Leave a comment

Rooks, crows and jackdaws are the most commonly seen and easily identified ‘crows’. They’re all black and they are widespread across the UK. But they’re not the only members of the crow or ‘Corvid‘ family. Ravens and choughs are also black members of the crow family, although the chough has bright red beak and legs, but both these species are fairly uncommon and seen mostly at or near the coast. There are two common and more colourful crows, the magpie (Pica pica, Dansk: husskade) and the jay (Garrulus glandarius, Dansk: skovskade).

Magpies can be seen everywhere, this one was in a tree opposite my garden

Magpies have an unfortunate reputation on two counts. They are considered to be inveterate thieves, having a particular fondness for shiny objects and they are generally reviled for their feeding habits during nesting of raiding other birds nests and predating the chicks. Of which more in another post. It seems to me they are handsome birds which are much maligned, they simply do what all wild creatures do, i.e. whatever is required to survive and propagate the species. While I watched this one I could hear several green woodpeckers (Picus viridis, Dansk: grønspætte) yaffling around the field and eventually one chased this magpie away from the top of the tree:

The woodpecker, bottom left, was extremely unhappy with the presence of the magpie and voiced it’s discontent with lots of shrieking as it flew aggressively into the tree

Jays are less frequently observed than magpies, predominantly dwelling in wooded areas in the countryside, but they are also seen in towns and villages where there are wooded areas. I’ve seen them along the Backs in Cambridge, and my friend who lives in a less wooded part of Cambridge has photographed them in his back garden. I encounter the occasional jay brightening up the day when I’m out walking around Histon, but last Sunday I had eight sightings, which is completely unprecedented. There were at least five individuals, one pair appeared together in the fields followed by a separate one a few seconds later, and another pair were busy burying acorns in the orchard opposite my garden. And they are spectacularly colourful, not at all what one might expect from a crow:

The splendid plumage of the jay!

Several jays and magpies came and went from this spot at the top of the tree in the space of a few minutes.

And when in flight the electric blue flash on the wing-bend opens up into a fan

As well as having an eye for sparkly trinkets jays are accomplished stashers and hoarders, and I’ve heard that a single jay can stash as many as 5000 acorns. They also show higher levels of intelligence whilst stashing, if they become aware they are being watched they will pretend to stash and then move away and hide their acorn somewhere else. I think that’s remarkable behaviour; moving away and hiding food elsewhere is one thing, but awareness of what another creatures intentions may be, and reacting to that by subterfuge suggests a level of underdstanding and reasoning not commonly associated with creatures other than humans.

On the ground with an acorn in its beak looking for a suitable burial site, and checking its handywork :

As I watched this pair of jays at work, one of them put it’s acorn down and picked up a short stick, probably around 10cm long, and used it to make holes to bury the acorns in. So as well as the other tricks this jay used a tool to make bigger holes in the ground than it could manage with it’s beak in order to secrete its winter food supplies.

They’re remarkable birds, the Corvid family, and half an hour spent watching any crow species is entertaining and more than a little thought provoking.

Unseasonal Lepidoptera

Posted on October 15, 2011 | 5 comments

I was walking in the countryside last Saturday morning around 8am and the weather was bright and sunny. It was also freezing and the grass was glistening with the first frost of the Autumn. Despite the temperature it was a beautiful morning, enhanced by a deep blue, cloudless, sky and a three quarter moon, and as I wandered along a hedgerow a red admiral butterfly fluttered past.

Red admiral – not the one that fluttered by on Saturday, this one is from earlier in the year.

The colours of the red admiral are gorgeous. It was only when I studied a photograph of one that I really noticed the electric blue spots at the back of the wings and lining the tip of the forewings, and I wonder if the red circle is meant to resemble a fearsome Cyclopean eye to deter potential predators. Whatever the biological rationale they look stunning against the green foliage.

The appearance of the red admiral surprised me for two reasons, firstly because it was so cold, and secondly because in my part of the world all butterfly numbers seem to have been massively reduced compared to last year.

Last year was a really good year for butterflies and in early August, on a hot summer day, myself and my daughter went to a close-by fallow field and did the Big Butterfly Count organised by Butterfly Conservation (http://butterfly-conservation.org). We counted 9 species in our 15 minute survey window, including painted ladies which migrate to the UK for the summer from as far afield as Africa.

Painted lady

I think intercontinental migration is an astonishing feat of endurance for any creature, but for one as delicate and ephemeral as a butterfly it’s totally awe-inspiring. The odds stacked against any individual surviving such a journey must be mightily slim!

Conversely, it was very noticeable that the weather in 2011 was alot colder (it was the coldest summer since 1993 apparently) and butterfly numbers were significantly down compared to last year, in particular the common blue:

The aptly and, this year, inaptly named common blue. This one, with his wings wide open, is a male…

…and with his wings closed

Bizarrely, the female common blue is actually brown

She is looking ragged after a hard summer of mating and egg laying necessary to secure next years population. Common blues and brown argus butterflies can commonly be seen together, they are closely related and the brown argus and female common blue can be tricky to tell apart. She is distinguishable from the brown argus by her overall shape which is very similar to the male above, the white around the orange spots on the hindwing, the blue along the wingroots and the lack of a black cell spot on the forewing, all of which are not observed on the brown argus:

Brown argus sipping nectar from ragwort flowers above. And below revealing the slight differences in the spot pattern compared to the common blue female:

The brown argus can have a blue irridescent sheen when it catches sunlight at the right angle and the wing veins extend through the white wing border, which they don’t in the female common blue.

During a walk through our field at the start of August last year I would see tens of common blue, both male and female, but on the same walk at the same time this year I was lucky to see more than 2 or 3. The results from this years Big Butterfly Count corroborated my unscientific observations and it reports that common blue numbers were down by 61% in this years survey. I’m hoping we get a milder winter this year and a warmer summer next year so the numbers of these beautiful creatures can recover.

I took lots of cool butterfly pictures last year, but as it was before I started writing the Naturephile I was hoping to post them this year. But it didn’t quite come to pass so I’ll try to sneak some of them out under spurious pretexts to brighten up this winter!

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Posted in Butterflies, Buxhall Farm Histon, Countryside walks, Insects

Tagged Aricia agestis, Big Butterfly Count, brown argus, butterflies, Butterfly Conservation, butterfly migration, Cambridgeshire, common blue, histon, Lepidoptera, painted lady, ployommatus icarus, red admiral, survival, Vanessa atalanta, Vanessa cardui

Cragside

Posted on October 7, 2011 | 2 comments

Whilst exploring Northumberland in August we ventured into Bamburgh Castle which is well worth a visit not least because it houses a museum dedicated to the Victorian engineering genius and arms manufacturer, William Armstrong. Armstrong used a portion of his colossal wealth to build a remarkable house at Cragside near Rothbury, which is also well worth a visit because it is set in some pretty amazing countryside which is teeming with wildlife. It’s also remarkable because it’s the first house on the planet to be lit by hydroelectricity. So the man who amassed wealth beyond belief by producing arms which were responsible for the deaths of an awful lot of people also set the stage for renewable energy. And that’s a dichotomy which, in my book, makes him a very interesting man.

So… on the way home from Northumberland we decided to avoid the A1 as far as we could which involved going close to Rothbury, and when, completely serendipitously, we passed a road sign for Cragside (and having joined the National Trust whilst on the Farne Islands) we rapidly decided a visit there was on the days agenda.

And that was a good decision. The house itself would take a long time to explore so we stuck our heads in the front door and decided to explore the surroundings instead. It was a cold and windy day threatening rain, but despite that the gardens were full of flowers attracting bumble bees and butterflies, particularly red admirals. The wooded slopes were full of birds, particularly tits, and most particularly coal tits (Periparus ater, Dansk: sortmejse).

My son spotted a baby toad in the long grass but I didn’t want to disturb it too much so I didn’t get a photograph, but I was rewarded shortly after when I found this little chap walking along the woodwork of a bridge over a stream:

This nascent toad, Bufo bufo, was smaller than a 50p piece and slipped into the water whilst crossing the bridge, but he sat still for just long enough

And as we were chasing toads a handsome cock pheasant appeared in the adjacent field,

Pheasant male, Phasianus colchicus (Dansk: fasan) showing off his magnificent plumage

The pheasant was introduced to the UK from Asia, where it’s native range extends from the Caucasus to China, around 1000 years ago. It is extensively hunted, which probably explains why it has been introduced to so many countries!

But the ornithological highlight of the visit to Cragside was the dipper (Cinclus cinclus, Dansk: vandstær). It flew past me at high speed low over the stream before landing on a rock which it used as a springboard to hunt insects underwater. I thought it is called a ‘dipper’ because of it’s diving prowess, but while it was perched on terra firma it flexed its legs resulting in a dipping motion of it’s head – so maybe it’s this action that gives it its name. I was wondering why it did the dipping and thought it may enable it to see small prey items underwater more easily.

Dipper perched on a rock contemplating a snack…

Hunting in the stream…

And with a catch – I think it has landed a damselfly

Dippers are unique in that they can swim underwater and even walk on the bottom as a result of having solid bones.

Photographically the dipper posed some interesting problems. It’s mostly a dark coloured bird and was in a dark coloured stream under tall trees on a cloudy morning so there was very little spare light, and it didn’t stay still for very long. Consequently I had to use ISO 800, f5.6 and 160th sec exposure and cross my fingers! Fortunately I was able to focus on the white breast and managed to get a few good shots. It’s a charming little bird and I was very pleased to be able to share some pictures with you.