Science – Page 7 – David Bradley

Birders versus Toggers

Broadly speaking, birders are avian enthusiasts, people interesting in seeing birds. Sometimes birders are twitchers, they like to see a bird so they can “tick” that species off a list, often it involves travelling far from their patch to see a species new to them. Twitchers are often not birders, they’re more akin to collectors, but aren’t necessarily interested in the birds per se. Then there are people with cameras who are also birders, twitchers, or both. Birders and twitchers often refer to these birding photographers as toggers, it’s a rather derogatory word.

Now, if a bird of interest shows up on a patch, the Short-eared Owl for instance, several of which we see out on the Cambridgeshire Fens in winter, then birders, twitchers, and toggers, and every permutation thereof, will generally hear about it and head for the patch, to get a look at the bird through their binoculars, and scopes, to tick their list, and to get that perfect photo.

Often the groups overlap, especially on a small patch, or where there’s a good vantage point. There’s often some sneering among the snobbish members of whichever group who see their particular hobby as being the more righteous.

None of these hobbies have any real claim to righteousness, all of us who indulge are impinging in some way on the wild patch that the birds have chosen to inhabit however temporarily. The presence of humans may well be disrupting the birds’ normal behaviour. So, it’s interesting to hear different people complain about the presence of members of the other groups of enthusiasts if they perceive the activity of the others as being more detrimental to the birds and the environment than their own activity. There is an argument to say that people should leave the wild to the wildlife.

One comment I read on a birding group recently was lamenting the number of people who had turned up at one of our local Cambridgeshire Fens to see and photograph the aforementioned Short-eared Owls (Shorties or SEOs). They said, apparently in all seriousness while lugging their scope up and down the Fen, that all these toggers running around were agitating the birds and making the place like a theme park. They asked the question: “How many photos of one bird do they need?”

Well, without getting into the art and craft of bird photography and why you might need to take more than one photograph, I wonder how they perceive their own position in terms of simply looking at the bird…surely the question might be asked of them “How many times do you need to look at one bird?”

Anyway, I personally feel that I’m just a bird enthusiast with a camera. I don’t think of myself as a proper birder, I don’t know enough. I’m not a twitcher, I’ve rarely “twitched” a species (successfully the European Roller that turned up not far from here, the European Bee-eaters in Norfolk when we were visiting, and the Black-browed Albatross that we failed to see at Bempton Cliffs). And, what photographer would call themselves a “togger”?

Enthusiasts and hobbyists of all creeds need to get over themselves, get over their self-righteousness. They need to not start this kind of argument on a public forum for the sake of assuaging what is probably their own guilt about their hobby and whether it is ethical to impinge on the wild in the first place.

We should all take more care to minimise any detrimental impact we have on wildlife and the environment. And, we should all take care to minimise our snarky comments, which can lead to bad feeling between different factions within a wider community that are to all intents and purposes seeking the same positive satisfaction from their interaction with nature.

Invasive species in the UK

Invasive species, a term referring to non-native species introduced to new environments, often establish self-sustaining populations with negative impacts on local ecosystems, economies, or human health.

These invaders, encompassing plants, animals, fungi, or microorganisms (refer to the foot of this article for examples), typically arrive due to human activities such as trade, travel, or intentional release. In rare cases, invasive species might reach the UK through natural avenues, such as animal migration or wind dispersal. Climate change exacerbates the situation, creating new ecological niches due to shifts in temperature and persistent weather changes. Alterations in landscape, urbanization, and habitat loss add pressure to natural ecosystems while simultaneously creating new opportunities for invasive species.

In the context of the United Kingdom, invasive species present significant challenges for various reasons:

Ecological impact: Invasive species can outcompete native species for resources including food, water, and habitat. They may have no natural predators in their new environment, allowing their populations to grow unchecked. This can lead to the decline or extinction of native species, disrupting the balance of the ecosystem.

Biodiversity loss: The displacement of native species by invasive ones can lead to a loss of biodiversity. Native species are often adapted to specific ecological niches, and the introduction of invasive species can disrupt these relationships, leading to a reduction in overall biodiversity.

Human health and safety: Some invasive species can pose risks to human health. For instance, certain plants may be toxic, and some animals may carry diseases that can affect humans. Additionally, invasive species can create safety hazards; for example, certain plants or animals might be harmful if they interfere with buildings, bridges, transportation systems.

Economic consequences: Invasive species can have economic impacts on agriculture, fisheries, and forestry. For example, invasive plants can reduce crop yields, while invasive animals may damage crops or compete with native species for resources. Invasive species can also impact infrastructure, such as clogging waterways or damaging buildings.

Increased management costs: Controlling and managing invasive species can be expensive. Governments, communities, and individuals may need to invest significant resources in efforts to control or eradicate invasive species and mitigate their impacts.

In the UK, various organizations and initiatives actively monitor and address the issue of invasive species. This global concern necessitates efforts to prevent introductions, manage existing populations, and control their impacts, preserving biodiversity, ecosystem health, and human well-being.

It’s crucial to note that some invasive species in the UK have been present for centuries, becoming integrated into local ecosystems. For example, the sycamore, recently in the news having been vandalistically felled at Sycamore Gap on Hadrian’s Wall in Northumberland, had long been part of the landscape but sycamores arrived with the Romans. Distinguishing between long-established non-native species and recent arrivals is crucial for effective management.

Despite confounding factors, certain invasive species contribute to ecosystem services, such as soil stabilization, water filtration, and habitat provision. Invasive crayfish used as food in mainland Europe have established themselves in the lakes of France and Spain and this in turn has allowed ostensibly African and Mediterranean birds such as the Great White Egret and Glossy Ibis to spread further north. It was only a short hop for them across the English Channel to the UK where they are no beginning to establish themselves, without apparent harm to native species or ecosystems it seems.

Indeed, some invasive species may enhance overall biodiversity by providing new habitats or food sources for native species, fostering a more diverse and resilient ecosystem. Additionally, there’s potential for utilizing invasive species in agriculture, forestry, and horticulture.

Examples of invasive species present in the UK

Plants:

American Skunk Cabbage (Lysichiton americanus)
Australian Swamp Stonecrop (Crassula helmsii)
Chilean Rhubarb (Gunnera tinctoria)
Cotoneaster species (Cotoneaster sp.)
Cotula Silverweed (Argentina anserina)
Curly Waterweed (Lagarosiphon major)
Floating Pennywort (Hydrocotyle ranunculoides)
Floating Water Plantain (Luronium natans)
Giant Hogweed (Heracleum mantegazzianum)
Himalayan Balsam (Impatiens glandulifera)
Hottentot Fig (Carpobrotus edulis)
Japanese Knotweed (Fallopia japonica)
Japanese Rose (Rosa rugosa)
Parrot’s Feather (Myriophyllum aquaticum)
Rhododendron (Rhododendron ponticum)
Small-Flowered Water-Weed (Elodea nuttallii)
Spanish Bluebell (Hyacinthoides hispanica)
Water Fern (Azolla filiculoides)
Water Primrose (Ludwigia grandiflora)
Winter Heliotrope (Petasites fragrans)
Yellow Azolla (Azolla caroliniana)

Invertebrates:

Asian Hornet (Vespa velutina nigrithorax)
Asian Tiger Mosquito (Aedes albopictus)
Box-tree Moth (Cydalima perspectalis)
Chinese Mitten Crab (Eriocheir sinensis)
Emerald Ash Borer (Agrilus planipennis)
Harlequin Ladybird (Harmonia axyridis)
Harlequin Shrimp (Hymenocera picta)
Horse Chestnut Leaf Miner (Cameraria ohridella)
New Zealand Flatworm (Arthurdendyus triangulatus)
New Zealand Mud Snail (Potamopyrgus antipodarum)
Oak Pinhole Borer beetle (Platypus cylindrus)
Oak Processionary Moth (Thaumetopea processionea)
Quagga Mussel (Dreissena rostriformis bugensis)
Red Swamp Crayfish (Procambarus clarkii)
Rosemary Beetle (Chrysolina americana)
Signal Crayfish (Pacifastacus leniusculus)
Spanish Slug (Arion vulgaris)
White-Legged Shrimp (Litopenaeus vannamei)
Zebra Mussel (Dreissena polymorpha)

Vertebrates:

American Bullfrog (Lithobates catesbeianus)
American Mink (Neovison vison)
Black Rat (Rattus rattus)
Canada Goose (Branta canadensis)
Chinese Water Deer (Hydropotes inermis)
Egyptian Goose (Alopochen aegyptiaca)
Grey Squirrel (Sciurus carolinensis)
Muntjac Deer (Muntiacus reevesi)
Parakeet sp.
Pumpkinseed Sunfish (Lepomis gibbosus)
Raccoon (Procyon lotor)
Red-Eared Slider (Trachemys scripta elegans)
Ruddy Duck (Oxyura jamaicensis)
Sika Deer (Cervus nippon)
The Red-Eared Slider terrapin (Trachemys scripta elegans)
Topmouth Gudgeon (Pseudorasbora parva)
Wallaby (Macropus sp.)
Yellow-Bellied Slider terrapin (Trachemys scripta scripta)

Fungi/Microbes:

Chalara Ash Dieback (Hymenoscyphus fraxineus)
Dutch Elm Disease (Ophiostoma ulmi)
Horse Chestnut Bleeding Canker (Pseudomonas syringae pv. aesculi)
Phytophthora Ramorum (Phytophthora ramorum)
Sudden Oak Death (Phytophthora sp.)

The Winter Moth – Operophtera brumata

This unassuming little moth has a suitably unassuming little name. It is known as the Winter Moth. It is one of the geometers, or what is referred to as inchworms in North America, because the larvae seem to measure out the earth as they move inch by inch.

The Winter Moth is not to be confused with the November nor the December Moth. It flies at the opposite end of the season to most other moths – October to December and sometimes into January and even February. It is unlikely to ever cross paths with the Spring Usher, the May or July Highflyers although it may well overlap with the Autumnal Moth and perhaps even the Autumnal Rustic, and definitely the aforementioned November and December.

While its common name is rather unassuming and perhaps obvious given the season in which it the males are on the wing (the females are flightless), this belies a resilience and a resistance to the cold that many other creatures do not display. Indeed, while some warm-blooded mammals from hedgehogs to bears will seek out shelter and hide themselves away from the ice and snow during hibernation, this little creature is searching for a mate. Incidentally, the females simply crawl up tree trunks and exude sex pheromones to draw the attention of amorous males.

The females then lay a couple of hundred eggs in crevices in the bark of trees. The larvae don’t emerge until the spring when the daytime temperature reaches about 10 degrees Celsius. Historically, this would have been perfect timing for the larvae to feed on the newly opening leaf buds of their host trees. But, with climate change, that temperature is consistently reached several days before those tasty leaf buds have begun to appear. As such, many larvae that emerge when the temperature rises and the leaf buds have not yet opened simply starve. Evolution, however, has a way. There is evidence that some larvae that incidentally hatch later, when it’s warmer still, can feast on leaf buds. As such, they survive to mate as adults in the winter and so pass on their genes. Among those genes will, of course, be the ones that trigger them to emerge when the temperature is a little higher and so coincide with the opening leaf buds.

The moth’s scientific name is Operophtera brumata, the brumata meaning “short” and alluding to the length of the days at this time of year. I am not 100% certain of the etymology of the first part of the name, the genus Operophtera. Opero could mean I work and the second half could be “to destroy” from the Greek, or it could be a tweak on “wing”, which can be ptera or phtera, I believe. So, it could mean “I work to destroy” or “I work my wings”. Given that the larvae can ravage a small tree’s foliage leading to a halving of the tree’s growth that year, perhaps “I work to destroy” is apt.

I’ve recorded Winter moth since I began nothing, but not every year and only one specimen per season – 2018, then 2021, 2022, and now 2023.

For US readers, the closest relative is the Bruce Spanworm, Operophtera bruceata.

Nudist Snow Buntings

At this time of year, you might spot Snow Buntings pecking about the shingle and driftwood on a remote windswept beach, perhaps in north Norfolk or Dorset. One Studland birder tweeted earlier that this species has now reached their shores.

The birds are apparently on the beach edge just north of the nudist beach…

The twitter birder was at pains to point out to anyone who fancies seeing these birds that the nudist track is a “Wellies only track”.

It’s worth adding that there’s also at least one nudist beach where you might see Snow Bunts in north Norfolk. I have no idea whether Wellies are allowed there or not…but it’s less than 10 degrees Celsius up there and taking wind chill into account, I’m sure the local “club” won’t mind you carrying a muff, just in case it gets too nippy.

Deathcap mushrooms – Amanita phalloides

What makes the death cap fungus (toadstool or mushroom), Amanita phalloides, so poisonous?

Well, the primary toxin present in this fungus is alpha-amanitin. This chemical goes by the following systematic name, although you’re unlikely to see it spelled out in full in the news about the ongoing murder trial that’s in the Australian news at the moment:

2-[(1R,4S,8R,10S,13S,16S,34S)-34-[(2S)-2-Butanyl]-13-[(2R,3R)-3,4-dihydroxy-2-butanyl]-8,22-dihydroxy-27-oxido-2,5,11,14,30,33,36,39-octaoxo-27-thia-3,6,12,15,25,29,32,35,38-nonaazapentacyclo[14.12.11 .0^6,10.0^18,26.0^19,24]nonatriaconta-18(26),19,21,23-tetraen-4-yl]acetamide.

The same toxin is also found in the Destroying Angel fungus, Amanita virosa.

The chemical is essentially a ring of eight amino acids. This structure fits easily into the active site of two enzymes, RNA polymerase II and III and blocks their activity in the body leading to liver and kidney failure. When ingested the toxin ultimately binds to the enzyme and kills liver cells, but symptoms often don’t appear for at least ten hours, sometimes a day. This period of time is way past the point at which stomach pumping to remove the fungus would help.

Diarrhoea and stomach cramps are the first symptoms. These subside after a day or so and gives the poisoned a false remission. By day four or five, the toxin starts to have severe effects on the liver and kidneys, leading to total system failure in both, coma and death ensue within a week.

A November, or a Pale November, or an Autumnal Moth! Who knows?

This is a November Moth…or a Pale November Moth…or maybe an Autumnal Moth…it’s definitely one of the Epirrita species of moth, but I, and almost nobody else could tell you for sure which from this photo.

One of the British Epirrita species of moth — One of three possible moths, so we record it as Epirrita agg (aggregate)

But, it’s is one of those moths that could be any of several different species. You cannot know for sure unless you’ve raised it from larvae and know for sure what species you had, or you’ve done DNA testing but that assumes someone has the genomics for the various species, or you’ve done what lepidopterists call “gen det”.

Gen det, genital determination is where you dissect the male moth’s genitalia. Moth genitalia are markedly different even between otherwise very similar species and so you can identify which species you have from the bits you chopped up.

I am not going there.

So, my records simply say Epirrita agg, meaning an aggregate of all the possible species in the UK and no positive ID for any of them in particular.

There is, however, another British Epirrita species, the Small Autumnal Moth, which as the name would suggest, accurately for once in taxonomy, is actually smaller than the others and its wings markings are stronger. If you have one of those, you can assume you’d be able to distinguish it from the other three Epirrita species.

Moustached Reedlings – Bearded Tits

The Bearded Reedling, Panurus biarmicus, is the only known avian species in its genus. It was originally named the Bearded Tit because of its superficial resemblance to the Long-tailed Tit perhaps, but it is definitely not closely related to that bird nor any other tit.

Female Bearded Reedlings lack the "beard of the males — Female Bearded Reedlings lack the “beard of the males

The odd thing though is that the “bearded” part of its name refers to the facial markings of the males. They have long, droopy-looking black patches either side of their bills, whimsically resembling male facial hair but perhaps sideburns or moustaches rather than a beard. I’ve no idea why it wasn’t originally called the Moustached Tit. Either way, it’s not political correctness that is morphing the tit into the reedling it’s simply that it isn’t a tit, as mentioned.

Male Bearded Reedlings showing his "beard", which looks more like sideburns or a pair of moustaches — Male Bearded Reedlings showing his “beard”, which looks more like sideburns or a pair of moustaches

The species is sexually dimorphic, the “clean-shaven” females lack the sideburns/moustaches/beard as well as differing in size and other aspects of their plumage. They’re often quite shy and tend not to show well when it’s windy. That said, you can commonly catch small groups and sometimes larger flocks darting back and forth making their characteristic “pinging”, or “pew-pewing” contact call as the fly. When they settle on a reed, they often shuffle from a lower portion up to the top of the stem. On other occasions, they will dance about the lower parts of the reeds almost at water level.

Audio birding

During the original covid lockdown in March-April of 2020, you may recall that I mentioned an activity known as noc migging. Essentially, it’s birding at night with a microphone and a sound recording device. You record the sounds of birds passing overhead, many birds migrate at night, and then process the recording to pluck out the sounds of our feathered friends for identification. Oh, by the way, here’s my garden birding tick list.

You can do the ID by ear or you can use software that analyses the sonogram and selects out the bird calls from the background noise of foxes and deer, motorbikes, cars, and other sounds of the night, and then passes it to ID software. Cornell University’s widely available birding app, Merlin, is a very useful introduction to NocMig and Audio Birding, in general.

Of course, there’s an app that can do the recording and the ID all-in-one, and has been for some time: the Merlin app from, Cornell University. Commonly, it’s used by birders and others when they hear a tweet or a chirp when they’re out and about to give them an ID for a sight unseen. The app records and analyses the avian sounds and gives you an ID for the species you’re hearing, usually within a split second. Actually, all that said, you can feed the app bird photos too, for a visual ID.

I’ve used Merlin sporadically for that purpose for quite some time. But, hearing lots of bird activity in the garden a few days ago I set my phone up with the app running, to hear what was around, even though I could ID most of them, hahah!

I wasn’t surprised by the majority of the IDs that popped up as I could hear the likes of Blackbird, Robin, Starling, Chaffinch, Dunnock, Carrion Crow, Goldfinch, Wren, Great Tit, Blue Tit, Long-tailed Tit, Collared Dove, Wood Pigeon, House Sparrow, Rook, Jackdaw, Pied Wagtail, and Magpie and identify them myself.

There were a few more obscure species that it identified that were a little surprising, Goldcrest, for instance. We have had that species in the garden before and I usually recognise their call but hadn’t noticed them toing and froing in our garden lately. The app also picked up a Redwing, one of the winter thrushes, which is likely to be arriving in our area at this time of year and was presumably flying overhead although I didn’t see it. There was an ID that the app labelled as uncertain – Brambling. I didn’t hear it, but it is nice to imagine that this species might be nearby. It also picked up Ringed Plover. Another I didn’t hear, but interesting to note.

Early morning of Sunday 29th October the app had red dots next to two birds it thinks it picked up – Raven and Barn Owl. Ravens are not commonly seen around here and while Barns Owls are not rare 7:30am over our house seems odd, but who knows? Spotted Flycatcher and Wood Warbler here, at the end of October? Almost certainly not.

snettisham ringed plover e1530550793560 — Ringed Plover

I later fired up the app on a walk close to one of our local ponds and picked up a perhaps unsurprising Reed Bunting, confirming that I had indeed heard it. After dark that day I was also able to use the app to confirm a solitary Tawny Owl calling from a tree in a neighbour’s garden. Mrs Sciencebase recorded Greenfinch and Bullfinch as well as some others mentioned above on her expedition with friends. We’ve also now had Grey Wagtail over the house.

The app is yet to suggest an ID for anything that would be very unlikely around here. So, I’m taking it on trust that it’s giving me accurate data. The common birds above are definitely seen and heard in this area. The likes of Redwing and Brambling too. We’ve had Redwing in our garden in past winters, although not yet Brambling, just yet…

You can see my complete garden tick list for birds spotted and heard here.

UPDATE: Morning of 30th October 2023. I set up a studio condenser microphone and directed it to record from my office window. I recorded twenty minutes of sound from the mic, saved the file, and fed it to Merlin. It came back with some spurious IDs like Spotless Starling (Mediterranean bird), Verdin (a new world penduline tit), a laughingthrush (Asian/Indian species), Eastern Towhee, a New World sparrow, reported once or twice only on Shetland . But, there were a couple of species that we are likely to have locally that hadn’t been picked up when I was running Merlin with my phone’s mic on previous sessions: Fieldfare (one of our winter thrush visitors along with Redwing), Blackcap (presumably a wintering arrival from east Europe), Song Thrush (relatively common around here).

UPDATE: 30th October 2023 – RSPB Ouse Fen (Over) app and us picked up Bearded Reedling (formerly known as a Bearded Tit), which we saw a dozen of, Cetti’s Warbler (3-4x), Skylark, Meadow Pipit (half a dozen), Crossbill (possibly, we didn’t hear it though). 11th November: Common Redpoll, Siskin, very unlikely Hawfinch.

My good friend Keith W, a steel industry professional, responded to my social media post about audio birding. He reminisced about how, as a youngster, he used to set up his Pifco cassette recorder on the garage roof at home and head off to school. He would come home to find that the big cylinder batteries were completely run down in the recorder, but he’d have a tape full of bird calls and birdsong. He would then listen to the tape and compare what he heard with the recording on an LP of birdsong.

Mineral Moon

Processing a RAW photo of the moon to enhance the subtle hues of different areas of the surface needs to be done in stages for best effect. The yellows and blues reveal areas on the surface made up of different minerals, which scatter the incident sunlight to different degrees.

A quick glance at the moon in the night sky and you might imagine the surface is fifty shades of grey. But, take a photo, preferably with a telescope or a big zoom lens and you can process the image to bring out the colours in the surface. These colours essentially represent different regions of minerals scattering sunlight in different ways. So with just the right kind of enhancement you can create a geological map of the moon.

I’d heard about this technique some time ago, but hadn’t given it much thought since. But, the moon was lovely and bright last night, waxing gibbous, not full, and I got a quick snap at 600mm on a 2/3 frame mirrorless camera.

The chemicals on the surface of the moon’s seas, the maria (first %), and its highlands (second %)

Silica 45.4%; highlands 45.5%
Alumina 14.9%; 24.0%
Lime 11.8%; 15.9%
Ferrous oxide* 14.1%; 5.9%
Magnesia 9.2% 7.5%
Titanium dioxide 3.9%; 0.6%
Sodium oxide 0.6%; 0.6%

Here’s the RAW shot, unprocessed and loaded into my photo editor. Obviously, I’d messed up, it’s massively underexposed.

So, I re-opened the RAW file out of the camera in DxO PureRaw to apply some initial denoising and let it do some automated camera adjustment based on my lens and camera.

Well, that’s a bit better, but I could perhaps adjust exposure in the photo editor’s own RAW import function and brighten it up properly. The highest exposure compensation is +3.0 in the software and it’s basically done some of the work, but still not enough.

So, I needed to do some basic levels adjustments to get it to this state and you can already see some of those mineral colours showing more than you would see with the naked eye or even through your telescope.

Now, before doing any more, it’s worth applying the photo editor’s automatic colour fix to correct white balance and other potential problems.

Now, to bring out the colours. It would be possible to simply whack up the saturation, but if you do that you get a noisy and solarized (ironically) mess. Although it’s worth trying that, say increasing saturation by 80%, just to see what it looks like. It does show the variations in surface colour that your camera picks up, but like I say it’s an over-the-top result.

So, I reverted that and went to the “layer adjustment window” in my photo editor instead. Ramping up the saturation is possible with multiple adjustment layers so that the effect can be done in a more gradual way to the same level but without losing as much information in one fell swoop as would happen with an 80% saturation boost applied. So, you apply multiple saturation adjustment layers, setting the boost to 20% or so for each, and looking to see how well it works at each step. Alternatively, in my photo editor, I can add a vibrancy adjustment stepwise. That’s what I did for the following image, which had five vibrancy layers of 20% each. Six was too many.

At this point, one might stop. It looks good as it is. But, I next applied a local tone mapping adjustment, which adds a bit more definition to the different coloured regions.

There’s now a need to sharpen and denoise the image again, which I will do by importing into Topaz Denoise AI and choosing some basic settings just to give the final image a bit of a visual bump and tighten things up.

I re-did the whole process using four 20% saturation adjustment layers instead of the more subtle vibrancy to get the following image. I can’t decide which I prefer the previous one or this one.

Mineral Moon – Photo processed to show up the different colours of the surface of the moon that reveal the different mineral present by how they scatter sunlight

To take it to the next level, it is worth doing a burst mode shot of the moon and then using stacking software to overlay them, this is a way to reduce noise. Noise is random in each frame and so overlaying and discarding noise succesively in the software boosts the amount of information you can see in the image and so improves clarity. Applying the above process to such a stacked shot should give you a much better final image.

It’s also worth noting that getting the exposure right in the camera from the off, using a tripod, and live view with either mirror up or in a mirrorless camera will all help improve the images you get.

*More properly known as iron(II) oxide, the lower oxidation state as opposed to ferric, iron(III) oxide more commonly found on earth and as rust.

Is a dog’s life monochrome?

Do dogs live in a black-and-white world?

As a child, I remember my mother telling me something she learned when she was an eye nurse – dogs are colourblind. Now, if I remember rightly, she didn’t mean they could only see in black and white as research in the 1940s had suggested, but that they had limited receptivity to the full colour palate. They were red-green colourblind, like some boys and men. The issue came up after they tested us boys at school for colour blindness with those spotty number colour charts.

The red colour of our lab's collar would've looked grey to her — The red colour of our lab’s collar would’ve looked grey to her

However, proof that the canine world isn’t monochrome didn’t come until 1989, so my mother, as was often the way, was way ahead of her time. Anyway, that proof demonstrated that dogs have dichromatic eyes. They have two types of colour receptor, cones, in the retinas of their eyes based on two pigments. Specifically, they can see various colours just not as many as the average human.

People are generally trichomats, they have three colour receptors, for red, green, and blue and a set of combinations thereof. For most people, there are lots of colours in between the violet, indigo, blue, green, yellow, orange, and red of the rainbow. Although, as I’ve mentioned before while not everyone agrees on the existence of indigo, there really is a much greater gamut of colours in there! Generally, we can discern a million or so colours, hence the seemingly endless parade of options when choosing paint with which to decorate your house.

Dogs have much more limited decorating options, but some women have many more. They are tetrachromats. Some girls and women have four colour receptors in their eyes allowing them to see almost 10 million colours, an order of magnitude more colours than most boys and men and other trichromatic females. Ironically, the fathers and sometimes at least one son of these tetrachromat females with their super-vision are usually colour blind. It’s all about the genes.

The usual colour palate of a photo editor uses the three colours of the monitor to give a million or so hues

Incidentally, we now know that fish, reptiles, and birds are commonly tetrachromats. Some species not only have a greater palate and can distinguish between subtle hues in the visible spectrum, but many can see light beyond the rainbow and into the ultraviolet part of the spectrum. Conversely, many mammals, especially nocturnal and crepuscular species, have through evolution lost two of their colour receptors in favour of greater low-light visual acuity and so, like dogs have a limited colour palate. The ancestors of primates were dichromats, but that third pigment later re-emerged in primates, including humans, and was perhaps a response to fruit eating. The fourth pigment re-emerged in some females.

But, even tetrachromacy is not really super-vision. Some insects, such as the odonata, dragonflies and damselflies, have even more colour pigment receptors in their compound eyes. Research suggests that they have between 15 and 33 genes for visual pigments. The colour palate of their vision could be way, way more detailed than that of even tetrachromat women, they can discern millions and millions of hues.

Dragonflies can probably discern several million more colours than you

The issue of canine vision went viral on social media recently and I suspect at least one person would’ve alluded to dogs seeing just fifty shades of grey…

The question of my blog post title was a QTWTAIN, a question to which the answer is no. No, dogs do not live in a black and white world, they see colours, but just not as many as most men, some women, and definitely not that Emperor dragonfly that was darting about our garden pond in the summer.