Science – Page 47 – David Bradley

Well-stacked Muslin Moth

UPDATE: 9th April 2020: First Muslin to the lure, conventionally photographed from three angles on stone.

The male Muslin Moth (Diaphora mendica [Clerck, 1759]) that I saw in the trap these last couple of mornings was there again today. I know, because he has a little snick out of the end of his left antenna. I was hoping a female might turn up, their wings are muslin-white, but the only other moth in the trap was a solitary Hebrew Character.

Anyway, the Muslin’s arrival gave me the opportunity to try out some more focus stacking. This time I used a couple of free tools. The first a controller for my Canon dSLR, digiCam Control. This software lets you control you dSLR via a USB cable from your computer and has builtin focus stacking (and many other functions).

I used its simple focus stacking to take a focus-bracketed set of four photos of the moth illuminated with an LED ring flash and natural light from my “studio” window (it’s just our back bedroom, which I use as an office). Anyway, each of the four photographs has its focus from near to far away from the camera. So the moth is pin sharp in each photo but only in a certain plane parallel to the camera’s sensor. The depth-of-field is very short with a macro lens at close quarters even with a small-ish aperture of f/9.5.

I then combined (automated process) the four shots using another piece of free software, CombineZP. I used what seemed to be the simplest option “Do Stack” and the resulting composite image was generated in a couple of minutes.

All very quick and easy. I am sure with practice and more attention to the details of optimising each piece of software and perhaps the lighting for the subject, I reckon it would be possible to get even better sharper shots, without having to spend hundreds of pounds on new hardware.

I also did a sequence of face-on portrait shots with the moth, automatically aligned them in CombineZP and then applied the “Do Stack” command, great result.

Simplified seeding with Seedball

The manufacturers of Seedball sent me a couple of tins of their product to try out and review. It’s an ingenious idea, little pellets of clay and soil packed with lots of different wildflower seeds in each and a little chilli powder to keep the ants away. You scatter a few over your putative seedbeds and wait for the rains…or as I did grab the watering can and sprinkle a few drops of pre-stored rainwater from the waterbutts.

These seem like the perfect answer for the wannabe gardener who doesn’t want all the hassle of seed trees and seedlings and pricking out and thinning out and all that malarkey. I’m not averse to a bit of proper gardening as long-time readers will remember and also more recent readers will be aware that Mrs Sciencebase and I have taken to #AllotmentLife recently. Nevertheless, I thought I’d set up a couple of tubs with Seedballs from the bat and the butterfly tins. Each ball contains 30-150 seeds and there were a couple of dozen Seedballs in each tin. I’ve used half from each tin in my tubs, and we’ll give it a couple of weeks to see how germination goes (it can take 2-6 weeks depending on water exposure, apparently). There’s nothing to show you just yet, I have great expectations, however.

Meanwhile, the sciencey bit. The clay acts as a protective casing keeping birds away from the seeds. Once sufficient water has permeated the clay, however, the seeds will hopefully begin to germinate, with a little help from the nutrients and minerals in the ball. There are several natural pesticides and invertebrate-repellant compounds in chillis, so this additive deters ants and slugs while the seedlings grow.

The butterfly mix will hopefully draw the lepidopteral crowds assuming germination happens before what naturalists call the June gap, which happens between spring butterflies and the summer butterflies. I’m in two minds about the bat mix, I love bats. We have 2-3 pipistrelles that frequent our garden catching myriad moths on the wing. But, therein lies the rub, as most readers will know I’ve got a bit of a fixation with moths at the moment. Circle of life.

Also in the Seedball range mixes of seeds for birds, shade, “Cloud Meadow”, beetles, bees, poppies, and the aforementioned butterflies and bats mixes.

Thinking about it, I might take the bat mix tub up to the allotment. Not much call for moths on the vegetable patch, to be honest…

Focus stacking an Angle Shades moth

Yesterday, I had a Muslin moth to photograph. Today, I had another go at focus stacking a macro shot, with an Angle Shades (Phlogophora meticulosa).

Focus stacked moth, note how from nose to tail the image is largely in focus

Focus stacking involves taking essentially the same photo several times but focusing first on the foreground, then the mid, then the farthest point on the subject. You can take as many shots as you like to “bracket” the image and get a sequence of shots that have the whole of the object in focus at some point in each photo. As you can see in the photo above.

It works best if you set the camera up on a tripod and take the series of photos using magnified LiveView and manually focusing on different parts of the subject. There are automated systems (software and hardware) and some cameras have focus bracketing built in (think of it as the focusing analogue of exposure bracketing, which lets you create high dynamic range (HDR) photos.

Once you have your set of focus-bracketed photos, you can then use a photo editor to blend them into a single composite image where pretty much all of the shot is in focus. The technique overcomes the very shallow depth-of-field you have with a small aperture when shooting taking close-ups. That said, the technique works to extend DoF for any type of photo.

Today’s subject is the beautifully patterned Angle Shades moth (who said moths were dull and grey?). I had it sat in a pot and perched that on an old patterned chair. If I could have persuaded it out of the pot without it flying away, you could have seen better just how well camouflaged this moth is against such William Morris style arts and crafts prints. In the wild, of course, it finds itself beautifully camouflaged among multicoloured and dappled foliage.

Focus stacking a Muslin moth

It has been a bit quiet on the new-to-the-garden moths, basically because it’s still quite cold and the night-flyers aren’t out in great numbers yet. Nevertheless, a male Muslin moth (Diaphora mendica) turned up last night. Hashtag #floof. Here he is “focus stacked” using half a dozen macro close-ups and Zerene Stacker. The aerial view is a single shot.

Photo stacked Muslin moth

The females don’t have the big pheromone antennae and are white with the black spots.

Overhead view male Muslin moth

The other moths that are around and that have turned up in varying numbers in the last month or so include: Common Quaker, Small Quaker, Twin-spotted Quaker, Hebrew Character, Clouded Drab, Early Grey, Twenty Plume, Common Plume, Early Thorn, Garden Carpet, Nut-tree Tussock, Agonopterix yeatiana, March Moth, The Chestnut, Double-striped Pug, March Dagger, Dotted Border, Pale Pinion, Oak Beauty, Pale Brindled Beauty, Acleris cristana.

Photos of all these updated with the new entries can be found in my Mothematics gallery on Imaging Storm, also includes butterflies, but they’re really just a type of moth, anyway.

The Phantom of the North

This blog post isn’t about some supernatural Geordie, rather a species of owl that haunts the northern parts of the Americas and Eurasia- the Great Grey Owl (Strix nebulosa). It’s the largest species of owl we have, by length, although ignore the feathers and it isn’t quite so impressive looking, but then which bird is? Also known as the cinereous owl, spectral owl, Lapland owl, spruce owl, bearded owl, and sooty owl.

The sub-species S. n. nebulosa flies from central Alaska eastward across Canada to south-western Quebec, and south to northern California, northern Idaho, western Montana, Wyoming and north-eastern Minnesota. S. n. lapponica can be found in Fennoscandia through Siberia to Sakhalin and Kamchatka Krai to Lithuania, Lake Baikal, Kazakhstan, Mongolia, Manchuria and north-eastern China.

Your twitter friends’ Aussie ancestor

There are more than 11,000 extant species of bird around the world, they all evolved from the theropod dinosaurs of which Tyrannosaurus rex is perhgaps the most famous. They are a seemingly diverse bunch of animals from the tiny Firecrest and the Hummingbirds to the Emu and Ostrich by way of the Vultures and the Cockatoo.

There are 137 families of perching birds, the so-called passerine birds, which have three toes pointing forward and one pointing back. The Passeriformes account for almost two-thirds of all bird species and are found across the globe. The term passerine comes from the Latin word for that archetypal perching bird, the House Sparrow (Passer domesticus). Passero or passera is Italian for Sparrow.

Anyway, a new DNA analysis reveals that all of those thousands of species of Passeriformes have a common ancestor that lived 47 million years ago in Australia. Discussed in more detail by Eleanor Imster in EarthSky.

Meanwhile, a genetic analysis in Science this week, explains why that Australian resident, the Emu, and indeed Ostriches and other ratite birds cannot fly.

What birds might I see in an English country garden?

I seem to have inadvertently duplicated this article and then edited it. The original with my garden “list” can be found here.

Reader John S asked me to put together a report on the topic of what birds we are likely to see in our gardens here in the village of Cottenham a few miles north of Cambridge. I suspect there are a few of you who will have spent an hour back in January counting species for the RSPB’s Big Garden Birdwatch and so hopefully there are others would be interested to know what they might see.

Of course, which of our feathered friends turns up in your garden is down to many different factors, the size and layout of your garden, tree and other plant species, the presence of cats, whereabouts you are relative to patches of woodland, farmland, and whether or not the visitors find a useful supply of food in the form of berries on your bushes, seed feeders and bird tables, coconut shells full of suet, and whatever else you might put out to attract them.

Some birds will arrive in great numbers to feast on fatballs for instance. Most of us have been perplexed to see expensive fatballs disappear in a matter of minutes when a flock of starlings turn up. Other food, such as nyjer seeds in a specialist feeder will draw in Goldfinches and occasionally for some Redpolls. Sunflowers seeds with the husk intact, sometimes referred to as black sunflower hearts, will keep Greenfinches, Blue Tits, Great Tits, Coal Tits, and Long-tailed Tits busy, and if the nyjer seeds run out the Goldfinches too.

Robins, Blackbirds, Wood Pigeons, Collared Doves, Dunnocks, will spend much of their time pecking around under the feeders, although the Blackbirds will join Mistle and Song Thrushes plucking insects from the lawn. And, Thrushes will famously grab snail shells and smash them on the ground to get at the occupant. If it’s very cold out on the farmland, the winter thrushes – the Fieldfares and Redwings – will come into the warmer more urban areas and attempt to snaffle berries from your bushes and trees much to the consternation of the Blackbirds who will attempt to make them flee.

You might also spot Bramblings during the winter. They are another finch resembling the Chaffinch but brighter and more orange colours. I have heard from people on Broad Lane who see them in their gardens occasionally, but they are more likely to be elsewhere.

Unusual but increasingly common in the winter are Blackcaps, a type of warbler normally considered a summer visitor, but turning up in our gardens from Germany and Eastern Europe rather than heading to the Iberian Peninsula and North Africa. Speaking of summer, by the time you read this birds that you might see above your garden or heading into your eaves may have started to arrive: House Martins first, then the Swallows that don’t necessarily a summer make, and finally the Swifts. Listen out for Cuckoos too. Certainly houses on The Green backing onto farmland have regular cuckoos visiting for the breeding season.

If you have ants among your plants, you might see Green Woodpeckers, also known as Yaffles for their scoffing call in flight. Ants are the Yaffle’s staple diet, so hold off the powder if you want to see them pecking at the ground in your garden. And, speaking of woodpeckers, there are quite a few Great Spotted Woodpeckers around, which will often come to garden feeders. Of course, if you’re attracting lots of small songbirds to your garden you might also attract predators including Sparrowhawks and less obviously egg-eating Magpies, and chick-chomping Jays. Great Spotted Woodpeckers will also peck into birdboxes to eat baby Blue Tits and the like.

Another reader, Diana S, also pointed out that she’d had Reed Buntings in her garden and had seen Little Grebe and Teal on the reedy pond at the back of her housing estate.

Toad of Lode Hall

Well, actually Toads of Anglesey Abbey. Common Toad (Bufo bufo) spawning in the bird-hide pond on the National Trust site in Lode, Cambridgeshire. Note, the toad spawn looks like a necklace of black beads on a string, whereas frogspawn forms in clumps. That said, there’s no real distinction between toads and frogs. Toads are just a type of frog (Bufonidae), just as butterflies are a type of moth.

These photos were taken at NT Anglesey Abbey on 21st March 2019. The spawning may well be over by now. There was also a Water Rail present on the opposite side of the pond.

Moths, dull, grey, night-flying insects?

Ask anyone who isn’t a moth-er to describe a moth and usually terms such as dull, grey, brown, night-flying, drab, dingy, useless are the ones that arise. Someone might go so far as to describe them as the boring relatives of butterflies. Well semantics aside, butterflies are just a sub-group of the moths, they’re all Lepidoptera, but they’re anything but useless and many of them fly during the day and are incredibly vivid and bright.

Perhaps the most vivid and bright of the British species is a moth I’d not seen until today, only in books. It is the Emperor Moth, Saturnia pavonia, the only member of the Saturniidae, the silk moths, found in the British Isles.

The males are very brightly coloured, the females a version where the colours look as if they have been desaturated. The male flies during the day, the female at night. Both male and female have a vivid spot on each fore- and hind-wing that give them the appearance of having two pairs of eyes looking back at a predator. The species is actually fairly common across the British Isles although it favours heathery heathland and open country, but that does include Fenland, of which we have plenty hereabouts.

Female Emperors [should that be Empress moths? Ed.*] exude a pheromone to alert the day-flying males to their presence and their urge to mate. The males can detect picograms of sex pheromone on the wing with their feathery antennae. Purportedly, they can sniff out a female from up to ten miles.

Other Saturniidae moths in Japan and the Americas seem to use hexadecadienals and esters of those compounds as their sex pheromones. I’m yet to find a paper that isolated and characterised the sex pheromone of S pavonia. Nevertheless, you can buy a little lure impregnated with the sex pheromone. A moth-er might hang such a lure in the garden on a sunny and breezy day in the hope of attracting an Emperor, which is what I did.

First sighting was today. He wouldn’t settleÂ and I couldn’t safely net him, so I snapped away 100+ shots and maybe got 4 where the moth is in focus and in the frame.

*There is no “Ed.” it’s just me.

NWT Weeting Heath

We headed to Lakenheath, had a quick stop off to watch a load of F15, Strike Eagles, take off from the RAF base before bypassing RSPB Lakenheath and heading further out to a reserve we had not visited previously – the Norfolk Wildlife Trust’s Weeting Heath site.

Weeting Heath (Grid ref: TL 758 884) is right in the middle of The Brecks and one of the lookout hides looks out over arable land while the other has a small pond and lots of well-stocked feeders frequented by woodland birds including the usual array of Goldfinches, Chaffinches, Robins, Dunnocks, Collared Doves, Wrens etc as well Bramblings and Yellowhammers.

Cross the speedy road and there is a larger woodland patch with a circular walking route through the pines (although Forestry Commission and NWT were felling trees during our visit so some paths were closed off. Anyway, saw the usual array of woodland birds here but also heard Woodlark, which staff had mentioned as having been showing well that week. Back at the main site, I snapped the last of the Bramblings, several Yellowhammers, a Wren eating a caterpillar, and numerous Goldfinches.

There had been reports of Stone Curlew (Burhinus oedicnemus), and I caught sight of one of the five or so that had been showing. There was also a Kestrel in a lone tree and a solitary Lapwing on the same patch as the Stone Curlew.

Stone Curlew, not a great shot, but first time seen one of these.

Then, I dashed back to the main road when Mrs Sciencebase alerted me to a sighting of a winter buzzard that was in the area, a Rough-legged Buzzard, specifically. Unlike the more common Common Buzzard, the Rough-leg only over-winters occasionally in the UK. Second time she’s spotted one of these ahead of the crowd and we had seen one at Cley in North Norfolk in November 2018. I wasn’t back from the hide quickly enough to get a view of it low down but managed to snap it just before it disappeared into low cloud. Other birders arrived minutes later and never caught a glimpse.