Science – Page 3 – David Bradley Science Writer

When the Bittern booms

The call of a cryptic Bittern hidden in a reedbed is one of the most evocative sounds of nature at this time of year. The sound is known as booming, but it’s more like the sound of someone blowing across the top of an empty drinks bottle. Earlier in the season, the frisky males started warming up with some guttural grunts, progressing to the full bottle when they sense the females might be receptive.

If you were out and about in the fens not twenty years ago, chances of hearing a booming Bittern were very low as the bird was all-but extinct in England. Habitat creation and other conservation efforts have led to a resurgence. So, most walks we take at this time of year among our fenland reserves, many of which are essentially repurposed and planted gravel pits, will reward us with a few booms and an occasional flypast.

Bittern in flight

I was walking at RSPB Berry Fen this morning. I’d picked up a whole lot of different warblers – Chiff Chaff, Reed Warbler, Whitethroat, Lesser Whitethroat, Blackcap, and Garden Warbler [What’s a warbler, anyway? Ed.] and a few Great White Egret, Little Egret, and Grey Heron as well as the usual ducks, crows, gulls, and cormorants. I was at the most northerly part of the fen close to one of those repurposed gravel pits known as Barleycroft Lake (part of RSPB Ouse Fen) and just about to head into the lake area when a male Bittern, appeared, flying low from the lake area. You can tell it’s a male from the pale blue marking on the lores. In ornithology, the lore is the patch between eye and bill on the side of a bird’s head. It’s usually featherless and sometimes coloured, as is the case with male Bitterns.

Bittern in flight

There are reeds on the edge of that lake, so presumably that’s this male’s usual patch, but it flew out over the dry edge of Berry Fen, sortied a rather brief reconnaissance flight, turned tail, presumably when it realised there was no reedy cover when it saw me and quickly, flew back into the lake area. Luckily, I had a few seconds of its U-turn to grab a few snapshots as it flew past silently. No sonic boom.

Bittern in flight

The bittern, Botaurus stellaris, is grouped with the herons, storks, and ibises, but obviously most closely resembles a heron than a stork or ibis.

Moth pheromones

I have written about moth pheromones several times over the years, mostly since I started mothing. Specifically, the chemistry of the sex pheromone produced by the female Emperor moth. Pheromones can be used to attract and trap what some people might refer to as pest species, but they can also be used scientifically just as one uses a UV light to attract moths for local monitoring.

I have a range of pheromones in little vials and soaked into various rubber bungs (they come from the supplier like that), which can be hung outside at various times of year to attract specific species, such as the clearwing moths and the Emperor.

The pheromones can be bought from various suppliers, but Anglia Lepidopteral Supplies (ALS) are the company I’ve used. I’ve had great success every year with the EMP lure, and most of the clearwings as well as a couple of other lures for some less well-known micro moths.

The really interesting thing about pheromone lures is that they’re usually mixtures of various chemicals that the moths produce to attract a mate. As such, some of them also attract non-target species, which home in on one of the other chemicals present, or even the target pheromone if they use the same one themselves. ALS gives its customers a list of dozens of moths that might be by-catch when using a moth pheromone for a particular target species. This week, I hung the CUL lure, which targets the clearwing known as Synanthedon culiciformis, the Large Red-belted Clearwing. I am yet to see this moth in the garden, or indeed anywhere. It’s slightly early for it to be flying, but lots of flora and fauna have been appearing earlier than usual this year, so I thought I’d give it a go.

Within seconds of putting out the lure, I saw a couple of micros approaching. Tiny Nemopogon species as it happens. The only one ALS lists as a putative by-catch for the CUL lure is N. clematella, although the lure can draw in quite a few other species:

Synanthedon myopaeformis (Red-belted Clearwing), Phlogophora meticulosa (Angle Shades), Agnathosia mendicella, Alcis repandata (Mottled Beauty), Pammene aurana, Pammene suspectana, Camptogramma bilineata (Yellow Shell), Coleophora amethystinella, Diaphora mendica (Muslin Moth), Endotricha flammealis, Eudonia mercurella, Glyphipterix simpliciella, Nemapogon clematella, Triaxomera fulvimitrella

I’ve had several of those species to the UV lamp over the years and Red-belted to this lure and its own specific lure.

The Nemapogon species I caught this week, looks most like the Grain Moth (N. granella), but as expert moth ID man, Sean Foote, pointed out it’s most likely to be that species, but impossible to know without doing gen det. It could, for instance, be N. variatella or a dull N. cloacella. Neither of those are mentioned by ALS as putative by-catch. Gen det is beyond me, so technically I should report this moth as Nemopogon agg, i.e. as an aggregrated species only identifiable to genus level without additional information. I have mentioned the catch to the team at ALS to see what they think.

Beating British bird crime

The RSPB highlighted its latest UK Bird Crime Report in this month’s magazine and urged members to help spread the word.

The report covers the illegal persecution of birds of prey (raptors) between 2009 and 2023, revealing routine and widespread criminal activity—much of it linked to the gamebird shooting industry. Beyond the ecological damage caused by releasing millions of pheasants and partridges into the countryside each year, we must confront the deeper issue: it’s time to stop killing wildlife for sport.

The report confirms over 1,500 incidents of raptor persecution, though the real number is likely far higher due to underreporting. More than half of the confirmed cases occurred on land used for pheasant, partridge, or grouse shooting. Shockingly, three-quarters of those convicted had ties to the gamebird shooting industry, and more than two-thirds were gamekeepers.

It’s a disgrace.

In the not-so-distant past, raptors were hunted to the brink of extinction. Over the last fifty years, dedicated conservation efforts have brought species like the Red Kite and White-tailed Eagle back from the edge, and have worked to protect Hen Harriers and Goshawks. But these efforts are continually undermined by a profit-driven industry that sees birds of prey as little more than a nuisance.

Hen Harriers, Golden Eagles, Peregrines, Red Kites, and White-tailed Eagles are still routinely shot, trapped, or poisoned. Offenders often go to great lengths to destroy evidence, making successful prosecutions difficult.

Most bird crime takes place in remote areas, often goes unnoticed, and is rarely punished. Current wildlife protection laws are inadequate, and the penalties don’t go far enough to deter offenders. Scotland has taken steps to strengthen its laws. It’s time the rest of the UK followed suit.

Dark Ash Bud Moth – Prays ruficeps

A new moth for the garden last night to the 30W UV U-tube. Having been attracted to the light, it didn’t actually enter the Robinson trap and simply sat on the grubby white sheet hanging behind it. Prays ruficeps is its scientific binomial.

The English vernacular name for this little, black micro moth is the Dark Ash Bud Moth. As the name would suggest, it’s not a brightly coloured moth, although its head is orange. Its larvae feed on Ash (fraxinus). However, there is a complication, until recent DNA testing was carried out this species was simply recorded as a dark, melanic, form of the closely related P. fraxinella, the Ash Bud Moth and wasn’t considered to be a separate species. It ws formally known as Prays fraxinella rustica. This means that the old research on this species was simply lumped together with the original species, according to the UK Moths site, and so little is known about it as a distinct species.

Something I have mentioned before is that often vernacular names for micro moths don’t exist or if they do, there are conflicting names created ad hoc by various lepidopterists and the organisations. When talking science, especially to international colleagues and audiences, it is generally best to refer to the scientific binomial, the name lay people often call the Latin name for an organism. Like that most famous of dinosaurs, Tyrannosaurus rex, it’s perhaps the most well-known scientific binomial, the one used for the king of the terrible lizards. T. rex doesn’t really have a vernacular name. In fact, I’m not sure any of the dinosaurs do. So, use the binomial and we all know what you’re talking about whether terrible lizard or micro moth.

Meanwhile, I checked on the taxonomy of P. ruficeps on iNaturalist and it gave me some interesting names in other languagues – Juodoji Uosine Kandis (Lithuanian), Bruine Essenmot (Dutch), Sysisaarnikoi (Finnish), and Brun Askmal (Swedish), specifically.

Interestingly, when I looked up Sysisaarnikoi, guessing it was Finnish, Google Translate says that word means “carboniferous”. Which given the coal colouring of the moth and the association with ash, is fair enough. However, if you split the word at koi. It translates as Coal Ash Moth. Koi presumably being moth in Finnish. Split out the presumed word for ash, saarni, and it then translates the name as Autumn Ash Moth. That’s intriguing. Saarni seems to mean “coal” and “Autumn” in Finnish, is that right?

The other names seem more obvious, at least bruine and brun are perhaps obviously “brown” and essen and ask are ash, and mot and mal are moth. I can see that Uosine perhaps shares etymology with ash too. Juodoji is black in Lithuanian and Kandis is moth.

Going back to the moth’s scientific name. The species type, ruficeps, translates from Latin as red-throated, according to Google Translate. Now, given, that caput is head in Latin, I suspect it more literally translates as red-headed. Rufus being related to ruber and meaning red. But, of course, as many readers may know from my earlier ramblings, when we say red in many situations, we often mean orange, as English took another century or so after the introduction of the eponymous fruit to these isles to adopt orange as a word for the colour we think of as lying between red and yellow. Hence, Robin Redbreast, Red Admiral, Redshank, redhead, where the colour is so obviously orange, not red.

The Prays genus part of the moth’s name? Well, that’s a little more complicated. Jacob Hübner came up with the genus name in 1825. It could have come from a Greek word, praus, meaning “gentle” or “mild,” possibly alluding to the moths’ delicate nature. Or, it may have been a misinterpretation of some obscure Latin word. Most likely though and common for several of Hübner’s names, it was an arbitrary choice that he simply like the sound of.

Also to the garden trap last night, two male Muslin (Diaphora mendica) and the first Pale Mottled Willow (Caradrina clavipalpis) of the year.

Aves envy and moth matters

Occasional visits to relatives who live in the leafy suburbs of Surrey always make me feel a little envious of the habitat represented by their garden and its surroundings. Lots of old oaks and other tree species beyond their fence but plenty of spots for birds (Aves) and invertebrates in their garden.

I usually get a few moments to survey the life forms in the garden and among those oaks. It doesn’t take long to build a decent garden ticklist of birds. For a recent trip:

Blackbird, Blackcap, Blue Tit, Bullfinch, Buzzard, Carrion Crow, Chaffinch, Chiffchaff, Coal Tit, Collared Dove, Dunnock, Firecrest, Goldcrest, Goldfinch, Great Tit, Greenfinch, Green Woodpecker, House Sparrow, Jackdaw, Jay, Long-tailed Tit, Magpie, Mistle Thrush, Nuthatch, Robin, Song Thrush, Stock Dove, Tawny Owl, Wood Pigeon, Wren.

I only heard and Goldcrest and it was the Merlin app that picked up the Firecrest. The Tawny Owl was a nocturnal caller, of course. Merlin claimed a Willow Warbler, but I didn’t pick that up aurally or visually. Out on a walk up to and along the Wey River added Canada Goose, Greylag Goose, Mallard, Red Kite. Was half expecting to see House Martin and Swallow, and perhaps Kingfisher, but no such luck with those.

Meanwhile, I’d brought my Skinner moth trap with me and put that out for a couple of sessions. Unfortunately, it got very cold (near freezing) during the first couple of nights and there were just a Brindled Pug (NFM) and an Early Grey. Third night was a lot warmer (10 Celsius) albeit rainy, but it brought in a much bigger moth haul. I was very pleased to see a few species I’d not seen before, NFM (new for me) moths. Data for the lighting-up session now with Surrey County Moth Recorder.

Brindled Pug (NFM)
Frosted Green x3 (NFM)
Great Prominent (NFM)
Grey Pine Carpet
Lunar Marbled Brown x3 (NFM)
Muslin
Purple Thorn x2
Red-green Carpet x2
Scarce Tissue x2 (NFM)
The Streamer

Phone photo of Brindled Pug — Brindled Pug

First Streamer of the year for me in Surrey, and also appeared in our Cambridgeshire garden the night we came home.

The Streamer, so-called because of the streamer-like markings on its forewings

The British butterfly ticklist

There are purportedly 59 extant species of butterfly in the UK. Those marked with an asterisk (twenty, as of April 2025) are ones I’ve yet to record here. There is at least one species that may be recolonising, Large Tortoiseshell. There are others that turn up sporadically, vagrants and migrants and don’t breed here.

Adonis Blue
Black Hairstreak
Brimstone
Brown Argus
Brown Hairstreak*
Chalk Hill Blue
Chequered Skipper
Clouded Yellow
Comma
Common Blue
Cryptic Wood White*
Dark Green Fritillary
Dingy Skipper
Duke of Burgundy*
Essex Skipper
Gatekeeper
Glanville Fritillary*
Grayling*
Green Hairstreak
Green-veined White
Grizzled Skipper
Heath Fritillary*
High Brown Fritillary*
Holly Blue
Large Blue*
Large Heath*
Large Skipper
Large White
Lulworth Skipper*
Marbled White
Marsh Fritillary*
Meadow Brown
Mountain Ringlet*
Northern Brown Argus*
Orange-tip
Painted Lady
Peacock
Pearl-boarded Fritillary*
Purple Emperor
Purple Hairstreak
Red Admiral
Ringlet
Scotch Argus*
Silver-spotted Skipper*
Silver-studded Blue*
Silver-washed Fritillary
Small Blue
Small Copper
Small Heath
Small Pearl-boarded Fritillary*
Small Skipper
Small Tortoiseshell
Small White
Speckled Wood
Swallowtail*
Wall
White Admiral
White-letter Hairstreak
Wood White*

Bullfinch in Les King Wood

Went for a brief butterfly walk in our local woodland, Les King Wood. Saw my first Speckled Wood of the year, lots more European Peacock, Whites (Small and Large), and numerous male Orange Tip. No Brimstone nor Comma on this outing.

Male Bullfinch perched on an overhead power cable

Just as I was about to head home, I heard a Bullfinch making its plaintive call. Couldn’t see it, so walked along one of the footpaths to bear round the patch where it seemed to be. Still no sign. And, it sounded like it flew off. So, I did a U-turn and headed back to the gate to leave. As if to taunt me, it seemed to come back, calling closer than ever, so I turned again and slowly walked towards where I imagined it was perched. It flew out, perched on an overhead power cable and looked down disgusted at the togger on the ground below.

Not the most evocative photo. The bird looks fine. But, that cable! So, over to a photo algorithm that claims to be able to replace objects. I selected the cable in the app and prompted it to replace the cable with a branch. I had to edit the claws on the branch to make them look slightly more realistic as the app had generated some weird artefacts that weren’t really claws at all. I’m sure there are other apps that do the same job, but this one will do for now as a demo. It’s called photo.ai, by the way.

Male Bullfinch perched on an overhead power cable, replaced with a branch using AI

There had been a very obliging Linnet and some Long-tailed Tits along the edge of the wood earlier.

Local Peregrine Falcons – Falco peregrinus

Today, we got to a local site about 20 minutes after the pair of Peregrine Falcons that live there had gone off hunting…at least according to one birder who was leaving as we arrived. We trekked on and awaited the raptors’ return and in the meantime watched several Red Kite, some Common Buzzard, and a couple of nesting Kestrels.

The Peregrines turned up about an hour later, preyless. They darted back to their nest site in the chalk cliff. Travelling fast, but not quite at their stooping speed which can be up to 200mph. One of the pair then zoomed off again to look for lunch, leaving the other to stare at us quizzically.

Peregrine on a chalk cliff, angling its head upwards, I suspect it was getting a clearer view o me, rather than looking at anything in the sky

Peregrines often look at you from odd angles…this is perhaps because they have two sharp central focus points in each eye (the fovea centralis), rather than the one we have for each eye. In the Peregrine, one is for long-distance sharp vision that allows it to pinpoint prey from at least a couple of miles away. The second focus point is for shorter distance vision to help it see its prey clearly as it approaches during the stoop.

Peregrine basically means from abroad/foreign. In Latin per is away and egrine from agri meaning field, so “away field” = abroad. Perhaps it is suggestive of the bird somehow being a wanderer, the etymology is unclear.

Peregrine on its nest site staring directly at the photographic intruder some distance away (big zoom lens)

Falcon comes from Latin falcis, meaning curved blade/war sickle, and may allude to the curved beak, the talons, or the wing profile…again, the etymology is somewhat lost in the history of falconry.

Amphibian timeline – Operation PondLife

UPDATE: 25th April 2025 – The tadpoles are pretty much fully grown, but are yet to start sprouting hind legs.

UPDATE: Larval hatchlings by 20th March or thereabouts, and gills and mouth obvious in the tadpoles just under a week later.

Reluctantly, but for safety reasons, I drained and filled our old pond in March 1998 and relocated dozens and dozens of frogs. Luckily, some of the neighbours at the time had ponds. We’d had spawn that year and that was also sent to a friend’s pond elsewhere in the village, hopefully without transferring any problems. It’s generally not advisable to move anything from one pond to another as there are invasive species and pathogens that might be transferred, but I didn’t really know about ponds back in 1998!

2025's first frogspawn — The first frogspawn of 2025, 6th March

In the years after, we’d have an occasional frog in the garden, usually in a wet patch behind the water butts, but sometimes hopping about the garden on sultry summer nights.

I redug the pond in May 2019. Hooray! I made it just half the original water surface area and it was not quite as deep as the old pond. However, I made sure it had terracing within and double lined it. I planted some native aquatic plants. We saw numerous frogs in lockdown year 2020 and the two species of snail present thrived. I did several music sessions live on Facebook as #PondWatch that spring and summer with thousands of listeners at the peak!

The pond attracted and continues to attract several damselflies and dragonflies. The birds seem to use it actively too. Oh, Mrs Sciencebase has witnessed Grey Herons taking frogs from the pond on at least a couple of occasions.

Herpetologist friend tells me that it is possible to have newts and frogs in the same pond. Indeed, this is obvious when it comes to data from another friend’s pond. I had been warned that newts would eat frogspawn, but seemingly it’s more likely that the frogs would predate the newts.

I’ve kept a record of the first appearance of frogspawn each year: 5th March 2021, 21st February 2022, 11th March 2023, 22nd February 2024, 6th March 2025.

Also of note in the summer of 2024 we had our first sighting of a couple of newts in the garden, on the patio on different wet nights, if memory serves.

Voles among us

Voles are rodents related to lemmings and hamsters, but are generally stouter of body and have a longer, hairy tail, smaller ears too. They are sometimes known as meadow mice or field mice. Etymologically speaking, they were generically “field mice”, vole from Old Norse völlr, and related to wold/weald as parts of English place names.

Vole, at the water's edge, Earith car park, RSPB Ouse Fen — Bank Vole, at the water’s edge, Earith car park, RSPB Ouse Fen

Here, we have three species of what we call voles:

Microtus agrestis – the Field, or Short-tailed, Vole, there are an estimated 75 million

Myodes glareolus – the Bank Vole, estimated, 25 million

Arvicola amphibius – European Water Vole, sometimes incorrectly known as the water rat, it is not a rat, despite being called Ratty in The Wind in the Willows. Endangered species. Estimated 100000 individuals.

And, of course, there’s Microtus arvalis – Common Vole, present as a sub-species on Orkney (M. a. orcadensis) and in the Channel Islands, but not in England or Wales.

Distinguishing between the Water Vole and the three meadow voles is relatively easy. Separating Bank from Field is harder unless you can see the tail. The tail of the Field Vole is about 30% the length of its body, whereas that Bank Vole’s tail is much longer, about 50% the length of its body. If you can’t see the tail, there are other indicators, although none seem perfect.

The Bank Vole has a warmer, more rusty, colouration compared to the grey-brown of the Field Vole. The fur of the Field Vole is not quite so smooth and neat as that of the Bank Vole and also largely covers ears and nose, less so in Field Vole. All such indicators can be confused in the field especially when there are variants such as lighter, gingery Field Voles.

Habitat is not a good indicator either, as Field and Bank may well favour similar habitat despite their names. As with many vernacular species names, they can be spurious and based on folklore, pre-scientific observations, and whimsy.

I asked friends on BlueSky to weigh in on the photo above. Terry O’Connor sided with Bank Vole, which was my first thought on seeing it yesterday: “Chestnut with grey underfur looks right and its ears are on the big side for Field Vole.”

One of my biggest missed opportunities photographically speaking was to capture a shot of a Grey Heron gulping down a Water Vole while standing on the roadside verge along a local road bridge over one of our lodes.

I did get photos of a Bank Vole that was swimming across the river in front of the Earith car park at RSPB Ouse Fen. It was my definitely-amateur, but professional-seeming, togger friend Andy who first spotted it. It seemed to disappear at the water’s edge, but I spotted it again, sitting stock still in the water and we both got a few snapshots.