Science – Page 33 – David Bradley

Weave your antiviral facemask from cotton and silk

If you’re wondering what materials to use to stitch together your antiviral mask, it seems it could be that you need a couple of different fabrics for it to work best – woven cotton and a piece of silk or chiffon…

Tightly woven cotton acts as a physical barrier to viral particles and droplets carrying the virus. Silk and chiffon can both build up quite a static charge and this will help trap viral particles electrostatically.

Screengrab from OnlineKyne's facemask howto video linked below

Together the materials will reduce the risk of the wearer shedding virus from nose or mouth into the environment and on to other people or surfaces that others might touch. Conversely, the mask will, to some extent reduce the risk of you inhaling viral particles from the air. The researchers say that substituting chiffon or silk for flannel or using a cotton quilt with cotton-polyester backing could be just as effective. But, Sciencebase would add that it’s not so strong a fashion statement

There is also the added benefit of wearing a facemask in that it will reduce how often you touch your nose and mouth with your filthy, disease-ridden hands. Now go and wash them thoroughly with plenty of soap and warm water for at least 20 seconds!

https://www.acs.org/content/acs/en/pressroom/newsreleases/2020/april/the-best-material-for-homemade-face-masks-may-be-a-combination-of-two-fabrics.html

The research paper is in ACS Nano here. OnlineKyne howto video here

Purple Thorn – Selenia tetralunaria

Mrs Sciencebase spotted this fellow roosting in the garden last night…it was the moth that was roosting, not Mrs Sb. It’s a Purple Thorn. So-called because the larva (caterpillar), which is stick-like in appearance has a spiky projection and the adult has a purple hue to its wings.

Its scientific name (binomial) is Selenia tetralunaria. It has four white crescent moon shapes on its wings, hence the tetralunaria of its binomial. Selenia is the genus and there are a couple of dozen of this type of moth around the world, a fraction of the 180,000 different known moths (and butterflies, same thing)

Birds to listen out for during your exercise allowance

While we’re still allowed out of our homes for a period of exercise each day, have a listen out for some of the birds that are singing and calling right now, various migrants and others you may not have noticed above traffic noise even in the countryside previously:

Swallow

Whitethroat

Buzzard

Reed Bunting

Yellowhammer

Kingfisher

Listen to the birds in an English country garden

People often tell me they don’t know what that bird is they can hear singing or calling but cannot see. There’s an international crowd-sourced project called Xeno Canto that has the calls and songs of almost every bird around the world. But, for local friends and family who might want to know what they can hear in the gardens, here’s a small selection of some of the more likely in England:

Chaffinch

Greenfinch

Robin

Blackbird

Great Tit

Blue Tit

Dunnock

Wood Pigeon

Collared Dove

Starling

House Sparrow

Most of these birds will have a song and a call, some of them seem to improvise or do abbreviated versions of their songs and calls. The sound files you can listen to above are just a starting point for learning how to identify birds you might hear in your garden and then associate them with a visual ID.

Adela reaumurella – Green Long-horn Moth

Day-flying moths among the tops of the sycamores today

Adela reaumurella, the Green Long-horn Moth, is a species of moth belonging to the family Adelidae. It is a small moth with a wingspan of around 12-15 mm. The forewings are metallic green, the hindwings slightly darker. The most distinctive feature of this moth is the long antennae that can be twice as long as the wingspan. The Green Long-horn Moth is widely distributed throughout Europe and parts of Asia. It can be found in a variety of habitats, including woodlands, heathlands, and grasslands.

The species typically has two generations per year. The first generation emerges in May or June, and the second generation emerges in August or September. The larvae feed on leaf litter.

The species is not considered to be a threatened species. However, like many moth species, it is under-recorded and little is known about its population status. As with many Lepidoptera, it plays an important role in the ecosystem as a pollinator of flowers. It is also a valuable indicator species for monitoring the health of woodland habitats.

The Emperor returns

I have a pheromone lure to attract the male of the lepidopteral species Saturnia pavonia, also known as the Emperor moth. It’s a beautiful creature. The male flies during the day drawn to the sex attractant exuded by the night-flying and less brightly coloured female. I’ve photographed them on the wing in the garden previously and also on a stage with a macro lens, as regular Sciencebase readers will know.

I only put the lure out for a few moments once a week or so, but it never fails. A couple of males turned up today within 20 minutes of the pheromones being released. One of them ended up in the conservatory, frantically flapping on a curtain for a few moments, so I got some fast shutterspeed (1/4000s) shots of him before giving the curtain a bit of a gentle flick to send him on his way and putting the lure back in the freezer until next week. It’s wonderful to know that these beautiful creatures are going about their lives with no care for our human woes.

Wren – Troglodytes troglodytes

As regular Sciencebase readers will be well aware, I often work from my laptop in the garden in the summer time, when the weather is fine…I reach right up and grab a camera sometimes…

Showing well today, a rather bold Wren, Troglodytes troglodytes, munching on grubs and caterpillars from various bushes and not worrying too much about my presence. I’ve been making efforts to let the garden go a bit wild, without it simply turning into a couch grass, thistle, and nestle patch. Lots of wildflower seeds are in, the pond is buzzing. Red Valerian and Green Alkanet are thriving, foxgloves are about to burst into bloom (hopefully). There are bird seed (mixed, sunflower, nyjer) and fat (suet) feeders aplenty.

Kingfishers at Dawn

Kingfishers at dawn…well…it wasn’t quite dawn. We awoke at about 7am had a cuppa and then headed out to a very local patch of waterway we know to see if we could spot the Kingfishers going about their business, all part of our once-daily exercise allowance under Covid-19 lockdown, social distancing, self-isolation rules.

We avoided touching any styles or fences, there were no other people around to avoid, apart from a farmer, just as we had finished our exercise. Anyway, combining photos from first thing last Sunday morning and today in this post

Nest Watch

Fans of the Facebook page may have seen the various Live broadcasts I’ve done in the “Watch” series, all very tongue in cheek and an excuse for me to broadcast some of my music or offer some relaxing video – there’s been PondWatch, LawnWatch, FeederWatch, and the fascinating ShedWatch.

Today, I once more put my phone on a tripod and pointed it at a feeder hanging in our apple tree for SuetWatch. Robins, Erithacus rubecula, have been pecking at this all week. I hoped to catch them on video. I don’t think I did, but when I went to terminate the video I noticed for the first time a nest in an old homemade nest box hanging on the shed. I wondered whether it was the Robins, so pointed the phone camera there and stepped back so as not to disturb the birds.

A quick scan through the video revealed a Dunnock, Prunella modularis, sitting on top of it at one point, so perhaps most likely that bird’s nest rather than that of the Robin.

The footage is awful and the bird activity so brief I won’t bother posting it. But, do take a look at my Facebook as there will most likely be more in the Watch series coming soon…

Dave Bradley on Facebook here.

Noc migging- Night flight call recording

I mentioned noc migging at the end of last year as something I planned to do in the spring of 2020. “Nocmig” or Night flight call (NFC) recording as the Americans know it, is basically making an audio (or indeed video) recording of the sky above you at night with the aim of plucking from the audio the calls of birds flying overhead as they migrate.

We’re coming into the main migratory season in the UK with a few of our summer visitors already here, many more heading this way and crossing the Iberian Peninsula and other parts of the continent lying between their winter holiday homes further south and The British Isles. Of course, the wintering birds are also returning to their summer roosts and mating grounds further north, in the far reaches of Scotland, Scandinavia, Siberia, and The Arctic.

So…I just need to waterproof a microphone to stick out of the window and setup some audio recording software to run overnight. I’ll use my music software as it has lots of options for cleaning up the sound. With a “tape” in hand it can either be scrolled manually looking for bursts of sound in the waveform and these sampled out to be analysed spectrally or it fed into a second bit of software such as a spectrogram to filter out barking dogs and vehicles and other non-avian noises. Cornell University then has an app – Raven – that can take the cropped analysis and identify the birds from their calls in your recording.

I’ll keep you posted…