Science – Page 28 – David Bradley

Local starling murmurations

Back in September, the number of starlings on farmland around the village seemed to build. It seemed early for the European winter influx, maybe it was just wishful thinking. I was hoping for large numbers that would begin to murmurate over the Broad Lane balancing pond before diving into their nocturnal roost in the reed bed there. (This particular video of mine was from November 2018)

Other concerns took over my thought processes, as they are, in October and early November, and I’d all but forgotten about the starlings by the time the local birders started pinging me about rising numbers 30 to 20 minutes before sunset over the pond. When I finally got the opportunity to check out the swooping and swirling of these maestros of social distancing, the murmurations were occurring most evenings and the numbers, I and birding friend Neil (watching at two-metres distance) estimated there were about 6000 there. Quite an amazing sight and the whooshing as they soar close overhead before diving into the reeds is astonishing. The next evening, the numbers had grown, perhaps to around 7000.

That was the peak for Cottenham’s murmuration. Over subsequent nights and having shared video on social media and mentioned to a few friends, the numbers began to decline as the number of observers rose. At the human peak, I think there were about 20 people, adults and children and a few pet dogs, waiting patiently for Dave’s Spectacular. It hadn’t happened in Cottenham again as far as I know. Another friend, Liz, reported that their daughter suggested 12 starlings wasn’t quite what you’d expect from Sir David…

Meanwhile, the Cottenham birder list alerted me to a large number at RSPB Fen Drayton, some 7000 birds were murmurating there over Elney Lake. It could easily be the same flock that apparently had departed Cottenham. There was also a peregrine falcon there hunting through the flock. Indeed, murmurating is flocking behaviour to reduce the risk to the individual bird being predated by such raptors ahead of bedding down for the night. I got a little distant video footage of those birds.

Also to be seen at Fen Drayton, four cattle egrets, birds that until recently were rarely seen in the British Isles, but whose numbers like those of the Little Egret and Great White Egret, ostensibly “foreign” birds have been growing over the last couple of decades. Climate change may well be playing a part in how such species are extending their range.

The story doesn’t end there. We visited RSPB Ouse Fen (Reedbed Trail side, accesses from the car park at the Over edge) one morning in mid-November. The RSPB warden – Hannah Bernie – was still there with her team hacking back reeds with a view to increasing plant, and thence animal, diversity on the reserve. She told us that they had spotted another rare visitor, a glossy ibis. The bird had been spotted at Fen Drayton a couple of nights before, but had flown, and this was presumably the same bed making Ouse Fen its temporary home. One birder I spoke to on the day I saw the GI told me he’d seen five or six on the reserve during the last decade or so.

The warden also mentioned in passing that they had a large starling murmuration of about 10000 birds. I felt obliged to return that evening to witness the spectacle. That night I would estimate that there were at least twice as many birds as there had been at Cottenham’s peak, so perhaps 14000.

Of course, such numbers are minuscule compared to other murmurations such as the knot (a wader, or shorebird) that one sees at this time of year, hopping the tide at RSPB Snettisham in North Norfolk. We saw 68000 of those birds there in September and the numbers had doubled by late October. And those numbers are dwarfed by the multi-million strong murmurations one might see in the original sub-Saharan homes of some of those “foreign” birds I mentioned. Where vast, entrancing murmurations swoop and swirl above the cattle egrets pecking at the feet of herds of majestic wildebeest. Still, we must enjoy the nature to which we have relatively easy access, especially in times of covid.

Sir David Attenbradley

Please send unusual bird and nature sightings to [email protected]

Glossy Ibis – Plegadis falcinellus

UPDATE: As of 2020-12-08 there have been sightings of about seven Glossy Ibis around the area at RSPB Fen Drayton, Ouse Fen, Ouse Washes, at Earith Sluice, and elsewhere. This is almost an irruption!

You don’t expect to turn up at a Cambridgeshire wildlife reserve to be told by the warden (Hannah Bernie) that there’s an African bird species hanging around. But, in early November, that’s what we heard at RSPB Ouse Fen. Actually, I’d heard that this species was at RSPB Fen Drayton, but I’m not a real twitcher so hadn’t gone out of my way to see it there. We were actually there on a fairly calm day to see if we could sight the Bearded Reedlings.

Warden Hannah told us there was a Glossy Ibis, Plegadis falcinellus, present and it had been seen but it was lurking behind the reeds at the time. She also mentioned a 10000-starling murmuration the night before. I visited the same sight later that day and reckon there are 14000 starlings murmurating there.

Anyway, back to the GI, we didn’t see it and we only heard Beardies. So I headed back again today, I usually visit once a week. Parked up and within 200m of the car, there it was, on the edge of the reeds. Apparently, a birder had predicted one might turn up, the RSPB having cleared a lot of old reeds from these former gravel pits. I got a few record shots, nothing clear nor sharp.

Fellow walker – name of Richard – with a birding ‘scope, stopped 2-3 metres away from me as I was snapping the bird on my return pass. He mentioned that they are not as rare as one might imagine in the British Isles these days. He said he’d seen them five or six times over a decade of visiting this reserve. Given that other African birds – Little, Great White, and Cattle Egret are also rising in numbers here we mused on how even the most casual birders are no longer as impressed as they once were at the sight of such species. Indeed, the presence of a Whinchat or a Pied Flycatcher might be more exciting than any Egret or even the GI, amazingly.

Climate change will definitely be driving the northwards flights of these birds which originate in sub-Saharan Africa but are spreading their range. But, Richard also mentioned that the accidental introduction of Red Swamp Crayfish (Procambarus clarkii) to lakes in northern France had provided a lot of food for such species and they are thus much further north partly because of that. It is only a matter of time, perhaps, before that invasive crustacean finds a niche in the former gravel pits of East Anglia and we begin to see even greater numbers of these African birds settling in this part of the world.

First time I saw a wild Glossy Ibis was in Botswana in the early 1990s, if memory serves. Most recent sighting was on the edge of a former gravel pit in a windswept patch of South Cambridgeshire.

Noc Mig Redux

Months ago, at the beginning of lockdown 1.0 I think I mentioned nocmigging. It’s the nocturnal audio recording and analysis of overnight sounds that might include the calls of migrant birds flying overhead. In April, I set up a microphone and recording software and poked it out of my office window and left it running overnight. In the morning I checked to see what had recorded and sadly it seemed at the time that the software had failed and all I had was the first 20 minutes from when I set things running.

NocMig recording in Audacity Spectrogram view showing the rise of the dawn chorus, 2020-04-07

I had tried a few more times and had managed to record the dawn chorus once or twice, but I didn’t think I had captured a long period of nocturnal noises until I was scanning my hard drive with the aim of deleting unwanted large files to clear some space. I found a 6h45m 4.5 gigabyte audio file. Exciting stuff.

So, now processing with Audacity in spectrogram view with the aim of feeding the output into the nocmig software. Here’s how to configure audacity for a nocmig recording.

Turns out there’s very little to hear other than occasional motorbikes and cars, at least until the first Blackbird of the dawn chorus, followed by Robins, Dunnocks, Wrens, and Wood Pigeons. Nothing was apparent and high-pitched in the spectrogram during the preceding hours. And, an audio scan didn’t even give me muntjac, foxes, nor even cats in the night, possibly one very distant dog barking. It was all very quiet, sadly. Still, there’s always next year.

60-year laser theory overturned

Quantum theorists have overturned a 60-year old theory about how lasers work that could fundamentally remove the Heisenberg Limit on coherence in these important and ubiquitous devices.

The coherence of a laser beam is essentially the number of photons that are emitted consecutively into the beam with the same phase. It determines how well a laser performs in various precision tasks, such as controlling all the components of a quantum computer.

However, researchers from Griffith University and Macquarie University in Australia writing in the journal Nature Physics have now shown that new quantum technologies open the possibility of making this coherence vastly larger than was thought possible.

‘The conventional wisdom dates back to a famous 1958 paper by American physicists Arthur Schawlow and Charles Townes,’ explains Howard Wiseman. ‘They showed theoretically that the coherence of the beam cannot be greater than the square of the number of photons stored in the laser. But they made assumptions about how energy is added to the laser and how it is released to form the beam,’ adds Wiseman. ‘The assumptions made sense at the time, and still apply to most lasers today, but they are not required by quantum mechanics.’

The new work shows that the true limit imposed by quantum mechanics is that the coherence cannot be greater than the fourth power of the number of photons stored in the laser. The researchers have now demonstrated through numerical simulation how this might be achieved, which could lead us to a “super laser”.

‘Our work raises many interesting questions,’ said Wiseman, ‘such as whether it could allow more energy-efficient lasers. That would also be a great benefit, so we hope to able to investigate that in the future.’

Catocala Underwings

UPDATE: Greece, June 2024 – Added Catocala nymphaea to my list of photographed Erebid “underwings”.

Catocala nymphaea moth with its orange and black marked hindwings

UPDATE: New Forest, 25 Aug 2022 – I finally trapped the Light Crimson Underwing (Catocala promissa) at our holiday house in North Poulner, Hampshire, which completes the British set for me, I believe. There’s a short video clip of the LCUW on the Sciencebase Instagram, with Going to the Chapel as the background music for good reason.* In the summer of 2023, Adrian Matthews caught an LCUW in Chesterton, a first for Cambs.

The Catocala moths are a group of relatively large moths in the family Erebidae. They are often known as “underwing moths” because of the intriguing colours and patterns of their hindwings, which are usually hidden from view under the forewings while the moths are at rest and only revealed either in flight or when the insect is startled.

Clifden Nonpareil, Catocala fraxini, the Blue Underwing

Not to be confused with dozens of others species in the Noctuidae that have the word underwing as part of their common name (e.g. Yellow Underwing, Straw Underwing, etc) and Geometridae (Orange Underwing).

Clifden Nonpareil, Catocala fraxini, the Blue Underwing

These large Catocala underwings are not common in The British Isles and where they are known are often localised to particular niches. In my time mothing since late July 2018, I have trapped, photographed and released three of the group: Red Underwing, Dark Crimson Underwing, and the (once extinct here) Clifden Nonpareil (the Blue Underwing). Actually, I had the Red in the garden in 2019 and then saw it a few days later on a camping trip to the eastern coast of Norfolk.

I am yet to see the Oak Yellow Underwing, the Rosy Underwing, the Minsmere Red Underwing, or the French Red Underwing. There are 30 Catocala species in Europe and 250 globally.

*Interesting to note that they all have scientific names alluding to nuptials and wedding nights. The naturalists who named them, whimsically imagining that the brightly coloured hindwings were like a bride’s brightly coloured bloomers! So we have C. sponsa, C. nuptia, and C. promissa. The Clifden Nonpareil is the exception, its scientific name, C. fraxini, alluding to the ash tree, wholly inappropriately as its food plant is the aspen.

More moths, birds, and other nature shots via the Sciencebase Instagram, please join me there.

Clifden Nonpareil, Catocala fraxini (Linnaeus, 1758)

Clifden Nonpareil – For the incomparable moth from Clivedon House, blue is the colour!

Blue is not a common colour in British moths

The UK Moths website described Catocala fraxini as the Victorian collector’s classic all-time favourite”. It also goes by the name of the Blue Underwing because of the shock of blue on the hindwings, which are usually covered by the forewings when the moth is at rest and are exposed when it reacts to a threat.

C fraxini feeds on aspen rather than ash (the frax of its name)

The moth was well known in the British Isles in Kent and Norfolk until the middle part of the the 20th century, the site explains, but it ultimately became extinct in terms of being a breeding resident on these shores and was seen only occasionally by lepidopterists as a vagrant immigrant from the continental mainland.

Thankfully, the species has been gaining new traction in the South of England and in East Anglia. It is now thoughtto be recolonising and is almost certainly breeding in the south. As an amateur moth-er, I hoped to draw this species beyond compare to the actinic lure I light up some nights in our Cambridgeshire garden. I didn’t hold out much hope until I heard on the mothing grapevine that there had been one or two sighted in neighbouring counties.

Blue Underwing with my secondhand copy of Manley behind

Then, in the middle of August, a fellow moth-er at the other end of our village here, reported a sighting of a Clifden in his garden. At the time, the closest I came to the fabled Blue, was another Catocala species, the Dark Crimson Underwing, that came to the actinic lure (it’s just a UV lamp, by the way). The Dark Crimson is usually confined to the New Forest, I was happy to see it.

A couple of weeks later my village friend reported a second Blue and his own NFG (new for the garden) Dark Crimson. I had my fingers crossed as tightly as they can be, but no luck. The autumn kicked, in then a mini-heatwave or two. There were endless Large Yellow Underwings (which are unrelated to the Catocala species, being Noctuidae rather than Eribidae. There were also lots of Lunar Underwings, yet another noctuid with veiny forewings and a moon-like crescent on each hindwing. Lots of Square-spot Rustics too and the Black Rustics of autumn. But no Blue.

Finally, on the night of 28th September at about 22h50, I let the dog into the garden for her late-night ablutions and checked the actinic lure, immediately spotting lots of craneflies on the adjacent wall, a Lunar Underwing on the box itself and…oh…there…an enormous speckled, patterned, grey moth with its shimmering band of blue on each hindwing exposed when the moth is disturbed. It truly is beyond compare, nonpareil.

This specimen was a little battered by the time it reached my lure. It is about 48 mm from palps to the tip of its folded forewings. The books describe it by wingspan which can be 80 to 90 mm. For a British species, it is truly enormous and impressive, not quite as big as our largest resident the Privet Hawk-moth which can be up to 120mm when its wings are fully expressed.

Why do accelerating electrons emit photons?

TL:DR – Discussion explain why an accelerating electron emits photons.

My friend Alice Sheppard, known on Twitter and elsewhere as @PenguinGalaxy, asked her physics pals to explain why it is that an electron emits photons when it is accelerating/change direction?

There were several replies that suggested this has been thought about a lot but nobody could come up with a simple, solid explanation. There was a bit of hand-waving and a lot of obscure words that I only vaguely rememberd the meanings of. As I understand it, even the great Dick Feynman got it wrong in one of his famous lectures.

Now, I am a lowly chemist, with aspirations, as you all know, to being some kind of award-winning photographer by day and a rockstar by night, and the farthest I got with physics was to successfully pass the first year undergraduate university course after two fails. But, I did try hard, did a lot of background reading and as you also know I have now spent more than thirty years writing about all kinds of science, including a lot of physics and quantum mechanics. So, I had a go at an explanation. Please feel free to pick holes in it and explain its fatal flaws as an answer to Alice’s question.

Electrons have an electric field. If they're moving they have a magnetic field too. If you give an electron a flick you add energy, like flicking a rope, this produces a wave in the electric and magnetic fields together, a wave in an electromagnetic field is a photon. The electron cannot hold on to this photon, so it is emitted.

I asked a Prof of Physics if my lay explanation passed muster and thankfully he said yes it does ;-)

Knots taking off and knots landing

As winter encroaches (it’s mid-September and we’re in the middle of an Indian Summer here in East Anglia, ahem), the (Red) Knot, Calidris canutus, start to flock on The Wash and their tidal activity can be seen as the waves break repeatedly and these waders take to to the air in their thousands, if not tens of thousands.

We were treated to a wader wonder on 17th September 2020, at Snettisham Beach on the North Norfolk coast. Patiently we watched the tide rise and the birds feeding and occasionally flocking. At the point there was essentially no visible mud flat remaining, the birds flock and make like a murmuration of starlings, whirling and cavorting in a seemingly coordinated way. Sometimes they head further out to sea, but occasionally a flock will fly overhead and head for the lagoons behind us. It is quite incredible, the sight and the sound.

Difficult to time it just right. It has to be the perfect tide, the right conditions, and you have to be lucky to be there.

The new garden moths of 2020

With Covid-19 lockdown hitting some people very hard, it seems churlish to complain about its effects on me. It felt hard – no pub visits with friends, no limited time outdoors and so not much chance for nature photography and long walks with the dog, no rehearsing with C5 The Band nor the TyrannoChorus choir, no panto to plan for etc, like I say, relatively easy, but still hard.

As such, I was really hoping for an exciting moth year to keep me sane, and I have had some crackers, but numbers and diversity seem to have been low…all I’ve really seen for the last couple of weeks are quite a few Large Yellow Underwings and Square Spot Rustics and little else.. They’re of interest in their own right, of course, but once you’ve seen a few dozen, you’ve seen them all.

I am yet to see the so-called Blue Underwing, the Clifden Nonpareil, a beautiful and fascinating European species that seems to be spreading northwards (I hear they’ve been ticked in Shropshire now). It’s odd a fellow moth-er in this village had two of these a couple of weeks ago. I did see its relative the Dark Crimson Underwing a month before he did. That species is usually only seen in the New Forest but is also spreading its wings so to speak.

UPDATE: Clifden Nonpareil actually turned up at the end of September.

Anyway, without going into all the statistical detail of 250 or so species I’ve noted this year so far more than 30 of them were new for the garden (NFG), new to me (NTM), in fact, I’d not seen them live before. Where a name has “agg” that means aggregate and it is to mark those species that look superficially identical to others and cannot be separated into distinct species without dissection or DNA analysis.

Agonopterix heracliana-ciliella agg
Beauty, Brindled (Lycia hirtaria, Clerck, 1759)
Bell, Two-coloured (Eucosma obumbratana, Lienig & Zeller, 1846)
Brindle, Clouded (Apamea epomidion, Haworth, 1809)
Campion, The (Sideridis rivularis, Fabricius, 1775)
Case-bearer, Coast Green (Coleophora amethystinella, Ragonot, 1885)
Clifden Nonopareil (Catocala fraxini, Linnaeus 1758)
Emerald, Common (Hemithea aestivaria, HÃ¼bner, 1789)
Figure of Eighty (Tethea ocularis, Linnaeus, 1767)
Footman, Orange (Eilema sororcula, Hufnagel, 1766)
Hawk-moth, Pine (Sphinx pinastri, Linnaeus, 1758)
Highflyer, May (Hydriomena impluviata, Denis & SchiffermÃ¼ller], 1775)
Knot Grass (Acronicta rumicis, Linnaeus, 1758)
Knot-horn, Twin-barred (Homoeosoma sinuella, Fabricius, 1794)
Knot-horn, Warted (Acrobasis repandana, Fabricius, 1798)
Lackey, The (Malacosoma neustria, Linnaeus, 1758)
Lozotaenia forsterana (Fabricius, 1781)
Marble, Diamond-back (Eudemis profundana, Denis & SchiffermÃ¼ller, 1775)
Nutmeg, The (Anarta trifolii)
Oegoconia agg. (Haworth, 1828)
Pearl, Lesser (Sitochroa verticalis, Linnaeus, 1758)
Pearl, Rusty Dot (Udea ferrugalis, HÃ¼bner, 1796)
Pearl, Straw-barred (Pyrausta despicata, Scopoli, 1763)
Pseudoswammerdamia combinella
Ptycholoma lecheana
Rustic, Brown (Rusina ferruginea, Esper, 1785)
Rustic, Clancy’s (Caradrina kadenii, Freyer, 1836)
Shears, Tawny (Hadena perplexa, Denis & SchiffermÃ¼ller], 1775)
Straw, Scarce Bordered (Helicoverpa armigera, HÃ¼bner, 1808)
Tortrix, Red-barred (Ditula angustiorana, Haworth, 1811)
Underwing, Dark Crimson (Catocala sponsa, Linnaeus, 1767)
Webber, Juniper (Dichomeris marginella, Fabricius, 1781)

Green Carpet moth

There is a whole group of moths called “carpets”. Despite (un)popular opinion about moths they do not eat carpets. Indeed, there are only one or two British moths (out of 11000 species!) that feed on wool and other textiles.

No, these moths are called carpets because when they were identified and scientifically named carpets were luxury items and the naturalists wanted to honour the beauty of these little creatures by naming them after something luxurious. This Green Carpet, Colostygia pectinataria, was drawn to the actinic light in our back garden last night and photographed this morning.