Biology – Page 13 – David Bradley

Navigating the Blackcap’s changing migratory patterns

TL:DR – There is no evidence that Blackcaps that overwinter in the UK are “demigrating”, they all tend to leave by mid-April. That said, much of their migratory behaviour remains a mystery.

I’ve written about a warbler species we see here in the summer known as the Blackcap, Sylvia atricapilla, several times on Sciencebase. Commonly, for many, many years, thousands in fact, Blackcaps that migrate to the UK in the summer have spent the northern winter in Iberia or North Africa. They migrate north to south and back again, year in, year out.

There is, however, a number of Blackcaps that tend to spend the northern summer in mainland continental Europe, Southern Germany and Austria, for instance. Those in the western part of that region then head somewhat west for the winter to spend the colder months on the Iberian peninsula or in the northern parts of Africa. Those in the eastern part head South East presumably to Serbia, Croatia, Greece etc.

In the last 20-30 years or so there has been a shift in behaviour among these German Blackcaps, ast least the ones in the west. Some of them seem to have lost their internal compass calibration and have been turning up in the UK for the winter instead of the slightly balmier climes of Spain and Portugal. Their internal compass is genetically programmed into these short-lived migratory birds though and so this “mistake” has proven beneficial as it has proliferated in a sub-population of the birds that find well-stocked garden feeders in British gardens. They have thus taken to over-wintering here and then find their way back to the continent for the summer come late March or early April.

Over the last few years, we usually have a male in our Cambridgeshire garden, and one year recently we had both a male and a female. They seem to join in the stripping of mistletoe berries from the trees as well as partaking of the fat balls we hang in the garden. Previously, they have departed in the spring not to be seen again until the winter. We never see Blackcaps in our gardens in the summer, but we do see them in local woodland and these would’ve been birds that overwintered in Iberia and North Africa.

blackcap fan 768px — Blackcap visiting for the summer

There is now some intriguing evidence that the UK overwintering Blackcaps are not mixing so well with their Iberian counterparts and that we might begin to see speciation taking place. In this, they might ultimately stop interacting and mating and begin to diverge genetically into two sub-species. If the evolutionary pressure is sustained they might one day split into two distinct species.

Now, the male that has been in our garden through the whole of the winter of 2022-2023 has recently been singing rather vigourously from our rowan tree. It was as if he was attempting to establish breeding territory although given his shyness at the feeders compared to the sparrows and even the tits, maybe he was just singing with frustration. Of course, the males do start to sing, or at least partially sing, in March under normal circumstances, perhaps rehearsing for their leading role once they get back to their summer breeding grounds.

I asked Greg Conway of the British Trust for Ornithology (BTO), who has undertaken a lot of research on Blackcap migration about the misinformation that seems to be circulating that claims some overwintering Blackcaps are becoming resident. You can read about work on Blackcap migration in a paper from van Doren et al. on which he is co-author here: https://doi.org/doi/10.1111/gcb.15597

“Virtually all the wintering birds do migrate in the spring and head across the Channel,” he told me. “Currently, there are just a handful of British-bred birds that have remained here to winter, amongst the more than 1000 of ringing recoveries.” He adds that “The winter tracking work did not reveal any resident individuals.”

The bottom line then is that demigration is not happening in Blackcaps. Conway expanded on what I suspected about the behaviour of my own overwintering Blackcap:

“Typically, the wintering birds depart between mid-March and mid-April.,” he explains. “And, just before they go, they gorge themselves at the garden feeders to build fat stores for their long journey. So you might see a bit more feeding activity this week.” He added that I should expect my Blackcap to depart in the next spell of fine weather. Indeed, by the 9th April our overwintering Blackcap had departed.

We know a lot about bird migration and movement but much remains a mystery. I’ve previously discussed the cases of Little, Great White, and Cattle Egrets, Spoonbill, and Glossy Ibis. All of those species have extended their range into the UK over the last few decades. Of course, many migratory patterns have been altered by the ice ages, shifts and changes in environment and food supply, and in the modern age climate change.

“There is still so much we don’t know about Blackcaps and their migratory behaviour,” adds Conway. Licensed ringing and citizen science observations and reporting from birders, of course, are helping build up a picture of what happens. Hopefully, one day we can expect to get a clear understanding of this little bird’s comings and goings. Conway adds that there is also an initiative for reporting ringed Blackcap sightings. If you see any ringed individuals you can send date and place details and whether male (black cap) or female (brown cap, also juveniles have a brown cap) to [email protected]

UPDATE: 24th March 2024 – Having not seen any Blackcaps in our garden this winter, sudden sighting of a male feeding on our mistletoe. So, maybe he’s been around but just not visible. The Merlin app has certainly heard him a couple of times in the last few days when I stick my phone next to our open bedroom window some mornings at 7am-ish. (Our overwintering male Blackcap had departed our garden by the end of the first week of April 2023).

Attracting birds to your garden

TL:DR – Advice on how to improve your chances of attracting birds to your garden.

Sciencebase reader Michelle messaged to ask how she might attract more birds to her garden. There are plenty of things she can try to see more of our feathered friends on her patch. Some things will have an almost immediate effect others might take a little longer. The rewards are always worth the effort to see the variety and numbers of birds that can appear. I have an article about the birds you might see in an English country garden. Here’s my garden tick list.

What to do

The most obvious thing to do is to ask what the birds need and then try to fulfill those needs: water, food, shelter/cover, somewhere to nest.

So, you could put out a couple of shallow, but wide, bowls and fill them with water. One could be at ground level another on a stand. Of course, there are plenty of birdbaths of different kinds to be bought at garden centres or online. A more ambitious approach might be to dig a wildlife pond, stock it with a few native pond plants and let it thrive (avoid using a pump, don’t add fish). Birds need water to drink and to bathe and it’s always a treat to see them doing so. It’s a good idea to clean birdbaths and bowls and to refresh the water often. Birds are not particularly hygienic and will often leave poop in the water, which can spread disease to other birds.

Brambling Titchwell feeder — Brambling on a feeder

Bird food is the next easy way to attract birds. There is a massive variety of feeders and food available for garden birds. I’ve found that it can take a week or more for birds to find a new feeder, but other people tell me birds are drawn immediately as soon as they hang one out even if they have never done so before.

Feeders designed for particular foods are usually needed. Suet and seed balls (great for Blackbirds, Blue Tits, Great Tits, Cole Tits, Robins, Starlings, overwintering Blackcaps). Nyjer seeds and a feeder that mimics a plant seed head will be a draw for Goldfinch and perhaps even Redpoll.

Black sunflower seeds (husk still on) need a strong bill and will tend to be eaten by Greenfinch and Goldfinch but sunflower hearts (dehusked) can be eaten by a wide range of additional species. Peanuts also need a special feeder that forces Blue Tits and others to break off tiny pieces of nut rather than grabbing a whole nut that might choke them or a chick. It’s important to use good quality peanuts sold for birds to avoid feeding them peanuts with toxic and cancer-causing black moulds.

Dried mealworms are tasty and attract different species. You can put them in a hanging feeder or on a ground feeder (use a refuge if there are cats that visit your garden or you have a dog). Products such as “Flutter Butter” come with special wall- or post-mounted dispensers and encourage birds to stay at the feeding station as they cannot easily grab a morsel and fly off to a tree to eat it.

Longer-term plans might involve that pond or if you haven’t already got native bushes and trees in your garden think about planting some. I’d be keen to plant bushes that produce lots of berries to provide a winter food supply for Blackbirds, Mistle Thrushes and visiting Fieldfares and Redwings. Also, let any ivy go to flower (attracts lots of insects) and produce berries (again, feeds those birds in the winter). The bushes and trees in your garden provide shelter and potential nest sites for a wide variety of species as well as hosting insects.

Adding a couple of strategically placed bird boxes also gives the birds another reason to visit your garden. They need to be placed fairly high up on a post or tree in a relatively small garden and generally have a line of sight from a post or tree opposite and several metres away if possible. If you have large windows, consider adding some decals, perhaps bird-shaped stickers, to the windows to help flying birds see that there is an obstacle and so avoid collisions with the glass. I wrote about Wood Pigeons leaving behind a powder down imprint on our windows back in 2017. Look into installing swift boxes or swift bricks too and perhaps adding a squealer to attract the birds arriving in the spring.

What NOT to do

A couple of things not to do. Don’t hang or install shiny, moving ornaments that glint and shimmer in the sun, these might shock easily startled birds and discourage them from enjoying your garden.

Also, don’t trim and prune too hard, in fact, don’t tidy your garden too well. If you leave the bushes and trees to grow a little wild and allow wildflowers (weeds!) to show through, you will encourage insects and that means an additional food source for the birds in terms of the adults and their larvae and caterpillars.

I’d also avoid pesticides and herbicides, these are generally easily avoidable in a small garden. Also, don’t put down ant powder or ant traps in the garden, ants are the staple food of Green Woodpeckers (yaffles). If there are no ants in your garden, you’re unlikely to see that bird visit.

I don’t recommend scattering bread or other cooked products for birds in your garden and no bacon rind. These are generally too high in sugar and salt for birds to cope and can also attract rats.

If you notice birds looking ill or with lumps on their heads or bodies, it’s a good idea to remove all feeders, discard uneaten contents, wash thoroughly in soapy hot water and leave them to dry. Don’t put the feeders out again for a couple of weeks so that the diseased birds might disperse.

Don’t use Astroturf and don’t pave over or gravel too much of your patch.

More on ponds

Your garden wildlife pond can be as ambitious as you like, but you can also create a great micro ecosystem using a half barrel or a Belfast sink. You might need to line them, you can sink them into the ground or leave them free standing. Let them fill with rainwater and then get some native pond plants (it’s best not to acquire materials from other garden ponds to avoid sharing disease).

Put some pots or stones within strategically placed to allow any frogs that turn up to easily get in and out and to avoid trapping hedgehogs that wander in. Terracing and shelving is essential for a full-size pond in this regard too.

An additional thought about ponds is to create a spillover area behind your point that will provide a permanently muddy patch, this will provide habitat for plants and organisms that favour something in between dry land and deep water. Again, increased natural diversity for the sake of the wildlife and for your own interest is the aim.

A smelly boost for your mothing life

TL:DR – Recent research has demonstrated that adding the volatile organic compound amyl acetate to a scientific moth-trap can boost the number of moths attracted to the UV light by almost a third.

A social media discussion about UV light sources for scientific moth-trapping, the type of vanes on the trap, and the environment in which one traps brought up some interesting thoughts. Several moth-ers use double sources to give them a better chance of enticing numbers and diversity to their traps. Although moths have been shown almost always to simply opt for the most energetic (higher frequency, shorter wavelength) when given a choice. There is evidence that black lights (UV bulbs painted black) are not so effective for attracting those species that are drawn more to visible light.

Also, it seems that white plastic vanes seem to work better than other types of vane and certainly better than rain-shield supporting rods on the commonly used Robinson and Heath moth traps. It also seems that the specific terrain and vegetation can affect numbers and diversity in some ways more than light source or other factors. There was also some recent work on how low-wattage UV light sources have a very limited range of attraction, but also the range varies among macro moth families, some attracted from 30 metres others from just 10 metres.

Anyway, in the discussion, fellow moth-er Stephen Roughley mentioned a paper by Chris Tyler-Smith and Yali Xue in the journal Ent Rec, “Amyl acetate increases macromoth catches in light traps” 2021, 134(6), 315-321, that looked at how lepidopterists might boost their haul for scientific and citizen scientific purposes. They suggest the use of a simple organic molecule that smells of fruit, called amyl acetate, amyl is an alternative name for the five-carbon alkyl chemical group pentyl, to augment one’s trapping. They demonstrated that amyl acetate boosted the number of macro moths drawn to the UV trap by up to about a third. Strictly speaking, the product contains 3-methylbutyl acetate, so five-carbon group but not in a straight chain.

Chemical structure of the ester amyl acetate — The ester amyl acetate smells fruity

The molecule, sometimes known as pear oil, is used as a flavouring agent, as a paint solvent, and in the preparation of penicillin. It is also the fuel for Hefner lamps. But, it is also found naturally in the volatile organic compounds exuded by ripe pears and presumably other fruit and fermenting or decaying vegetable matter.

I asked author Xue about the work. “We only tried amyl acetate from Etsy, but suspect that moths would not care about the grade, and any that smells like pear drops to a human would be fine, they told me. “We used enough to moisten a cotton wool pad and placed this beside the trap in a metal bowl as the solvent dissolves plastics.”

Many species of moths are known to be attracted to the odours given off by ripe fruits and flowers. There is a suggestion that some female moths may well be particularly attracted to such odours, including amyl acetate, as they seek out ripe fruit in which to lay their eggs. Indeed, it’s worth noting that a lot of moths that are not necessarily interested in light can be drawn to a strong-smelling sugary solution made from molasses boiled with beer or wine and various other concoctions. Most moths use their olfactory senses to locate food, mates, and suitable habitats, so this is perhaps not surprising. It was the technique of sugaring to attract moths that inspired the team. (See also wine roping). Amyl acetate mimics fruit odours and so should attract moths. Indeed it has been used in the past as a sugaring ingredient.

The team suggest, however, that the chemical simply applied could substitute for sugaring concoctions and might boost moth trapping where scented flowers are not present at a site. It all adds to the useful data that might be gathered to feed back to moth recorders for scientific purposes and to show where and when various species appear around the country. I have previously discussed the pros and cons of moth-trapping on Sciencebase.

Overwintering

TL:DR – I wrote about bird migration and so I thought I’d write a poem about it too.

I have a post in which I discuss the intriguing and changing migratory behaviour of the Blackcap, Sylvia atricapilla. For several years, we have seen this species spend the winter in our garden. One year we had a male and a female.

The likelihood is that these birds flew from their summer breeding grounds in southern Germany and instead of reaching Iberia or North West Africa they got slightly lost and ended up in Old Blighty…England. It’s been happening like this for a couple of decades at least.

The male that overwintered with us 22/23 has departed and soon the Blackcaps that migrate from sub-Saharan Africa will arrive in our woodlands to breed in the summer.

Anyway, I wrote a poem for Sylvia.

An overwintering poem for Sylvia, the Blackcap

Overwintering

She came in from the East. Her compass quite askew
Should’ve spent the winter in Iberia, but Old Blighty will have to do
Her chestnut cap is fluffed up. And her buff breast is scruffy too
Those chilly winds chill the feast, there’s nothing else that she can do

but peck at firethorn berries behind sparrows in the queue
And sulk among the mistletoe. Till Christmas takes its due
This land beyond the floodlands, with a date she’ll take in lieu
No nest, no mate. No direction yet, a Blackcap looking blue

When seasons change, they’ll send her back to the place where once she flew
And with the spring and high on life, she’ll bid us all adieu
Then find a mate, and build a nest for now she takes her cue
She’ll live her life and raise her brood with not a thought for you

But the world will turn and the winds will change as always they will do
Bring her back to Old Blighty. Yet, with no different a point of view
She’ll sulk and peck at mistletoe. The winter she’ll see through
And bravely hide from Easterlies, there’s nothing else that she can do

–David Bradley

Why do some moths have eyes on their wings?

TL:DR – A few examples of plants and animals that use disguises.

Lots of animals and even plants have evolved to have a visual resemblance to other organisms. The flowers of the Bee Orchid as the name would suggest look like female bees and as such attract roving male bees who alight on the “female” hoping that they’ve found a mate. In so doing, they inadvertently pick up pollen from the male part of the flower and this is transferred to female parts of the next “mate”, thus pollinating the plants.

Bee Orchid closeup — Bee Orchid complete with fur and pollen sacks

There is a bird that has evolved to look like a snake and so ward off predators. Indeed, not only does it look like a snake when it postures defensively, but it writhes around so that its head really does look like a snake about to pounce.

Among the lepidoptera, the moths and butterflies, there are so many disguises it is hard to know where to start. The Bufftip moth resembles a piece of snapped of birch twig while the unrelated Buff Arches resembles a piece of flint on a stony woodland floor.

Buff Arches moth resembles a chunk of flint

There are so many examples of this faking it camouflage among the Lepidoptera. Perhaps the most obvious examples of this pareidolia are among the species that have “eyes” (ocelli, singular ocellus) on their wings. The European Peacock, for example, roosts with wings closed. The dark undersides are sufficient disguise in the dingy nook of a tree during hibernation but if disturbed it flashes its eyes, which to a bird or other predator look shockingly like a big face staring back, the face of an animal that might fight back rather than a gentle butterfly.

Dark undersides of Peacock butterfly wings

The Emperor moth also has four eyes but does not have the advantage of being able to fold its wings flat against each other. When disturbed or agitated it opens out its wings to reveal four scary eyes staring back at a predator.

The staring "face" of an Emperor moth at rest — The staring “face” of an Emperor moth at rest

However, even at rest with its forewings covering its hindwings the Emperor is always watchful. Indeed, if one imagines a predator flying into to check out tasty morsels on the heather, it will be shocked to see something resembling a predator staring back at it!

Mothing really matters, anyone can see

TL:DR – Reasons to be a citizen scientist lepidopterist.

I’ve been mothing since July 2018. By which I mean I have used lures (ultraviolet light sources, pheromones, and occasionally sugar mixtures) and a trap to allow me to monitor, count, photograph, and release the moths that pass through my garden at night. It has apparently since become an even more popular hobby, particularly among wildlife enthusiasts during the time when we were all in covid lockdown and had limited opportunity to be out and about exploring nature in situ, birdwatching, gulling, seeking out wildflowers, etc.

Convolvulus Hawk-moth, a rare migrant to the UK that sometimes breeds in Spring, but is generally unable to overwinter here.

There is an argument that mothing might be detrimental to the already heavily threatened populations of moths, but I think the benefits in terms of scientific insight and education far outweigh the negligible impact on moth populations.

The stunning Clifden Nonpareil was once relatively common in the UK but disappeared. It is seeing a renaissance and spreading northwards

Indeed, there was a scurrilous article in The Guardian in 2019 that had lots of reasons why we shouldn’t moth, largely invalid and easily debunked by anyone with an announce of conservation savvy. So, here’s a list of ten good reason why mothing matters:

Moth trapping and recording is a valuable citizen science activity that allows non-scientists to contribute to scientific research and conservation efforts. The overall scale of scientific moth trapping on reserves and at research centres is far greater than amateur garden mothing.
Moths play important roles in ecosystems as pollinators, food sources for other animals, and indicators of environmental health and so understanding their behaviour and distribution can help in deciding on conservation initiatives.
Moths are often overlooked compared to butterflies (which are actually just a grouping within the Lepidoptera like any grouping of moths), but there are around 160,000 species of moths worldwide (2500 in the UK), making them an incredibly diverse and fascinating group of insects. The more we know about such diversity, the better.
Moths are also important bioindicators, as they can be used to monitor changes in habitat quality and climate.
Moth trapping and recording can help identify new species, expand knowledge of distribution and range, and range extension and reduction, as well as migration, and provide important data for conservation efforts.
Moths are often nocturnal and elusive, making them difficult to study through traditional observation methods. Moth trapping provides an opportunity to observe and study these insects in greater detail.
Moth trapping can also provide a unique opportunity to engage with the natural world and inspire curiosity and interest in science and conservation in young and old alike.
Moth trapping can be done in a non-invasive and ethical manner, with moths typically released unharmed after being recorded and identified.
Moth trapping can provide valuable data on population trends and species diversity, which can help inform conservation decisions and management strategies.
Moth trapping is a relatively low-cost and accessible activity that can be done by people of all ages and backgrounds in their own gardens or even from the balcony of a tower block, making it an ideal way to engage a wide range of people in science and conservation. Lots of nature reserves running mothing events open to the public.

Funnily enough, even trapping every evening makes very little difference to the moths overall. In fact, there is an added benefit to regular moth trapping: it most likely increases biodiversity at the specific site or garden as more species passing in the night are being lured in. If you’ve created good habitat, this can only benefit the moths. But, it’s also good for the bats in your garden, good for the garden frogs too, and good for the birds who can feast on adults and larvae.

Nocturnal pollination #MothsMatter

TL:DR – Many species of moth are important nocturnal pollinators.

2018 was the year I took a serious interest in studying moths in my garden having been loaned a scientific mothtrap by a friend in the village. It was late July that year that I fell in love with the “nocturnal” Lepidoptera.

By the September, I’d recorded about 120 species of animal I’d never noticed, seen, nor observed ever before. In subsequent years I added yet more species. There are about 1600 moth species in the UK and I have ticked 464 (as of 1 April 2023). That same month there was some research demonstrating once again why moths matter and why we should not dismiss these remarkable creatures. The paper:

Construction, validation, and application of nocturnal pollen transport networks in an agro-ecosystem: a comparison using light microscopy and DNA metabarcoding

Callum J. Macgregor, James J. N. Kitson, Richard Fox, Christoph Hahn, David H. Lunt, Michael J. O. Pocock, Darren M. Evans First published: 17 September 2018 https://doi.org/10.1111/een.12674

The study compared two methods, light microscopy and DNA metabarcoding, for constructing pollen-transport networks of nocturnal moths, with a focus on their feeding mouthparts. The researchers found that DNA metabarcoding detected more pollen on individual moths and more interactions per moth species compared to microscopy.

The results also showed that the pollen-transport network metrics differed between the two methods due to their varying abilities to detect multiple pollen types per moth and to separate morphologically similar or related pollen. The team also demonstrated some unexpected moth-plant interactions using metabarcoding, revealing new insights into nocturnal pollination systems.

The authors suggest that while the two methods revealed similar yet distinct networks, the potential applications of metabarcoding for studying plant-pollinator interaction networks, especially for understudied pollinators like moths, are encouraging.

Trip to Teesdale

TL:DR – Brief spot of garden birding with friends in Teesdale and some sightseeing.

We spent a lovely couple of days with wonderful friends at their place in Teesdale…unfortunately I’ve been struggling to walk with an ankle injury so the usual long country walks and sightseeing were off the agenda, but we did get to toddle around the fabulous Bowes Museum in Barnard Castle and to sample some local ale at the local pub for local people (and their friends).

Through-window shot of male Great Spotted Woodpecker

Our friends had also arranged a fabulous selection of birds to use their garden bird feeders while we were there: Brambling, Nuthatch, Coal Tit, Great Spotted Woodpecker (M+F), Redpoll, Goldfinch, Long-tailed Tit, Great Tit, Blue Tit, Dunnock, Robin, Chaffinch, Jackdaw, Rook (either or both of which repeatedly knocked the feeders on to the lawn), Blackbird, House Sparrow, Starling (mainly in the trees not on the feeders); also Chiff Chaff calling from one of their trees. Didn’t see Tawny Owl on this visit.

Typical Teesdale — Teesdale village view

The Tees at Barnard Castle was too rough and high within my walking range to catch sight of Dippers or wagtails fishing this time, but there were Mallard ducklings on the foamy banks and a solitary Whooper Swan looking rather out of place below the castle ruins.

One of very few authentic French Art Deco pieces in a public British collection. This by Jacques Gruber — Art Deco stained glass window by Jacques Gruber held at The Bowes Museum

The pseudo chateau of The Bowes Museum, Barnard Castle — The Bowes Museum, Barnard Castle

The Butterbur, Petasites hybridus — Butterbur on the banks of The Tees

Yellow mallard/hybrid duckling on the Tees — Yellow hybrid Mallard duckling on the Tees

Solitary Whooper Swan, Cygnus cygnus, on the Tees at Barnard Castle — Solitary Whooper Swan, Barnard Castle

Common Redpoll photographed through a kitchen window — Redpoll photographed through the kitchen window

Teesdale chicken — Gallus gallus domesticus

Red-green Carpet

TL:DR – It’s spring and at least one hibernating moth, the Red-green Carpet, has arrived in our garden so far this year

Lit up with my Heath trap again last night and despite the rain, but perhaps because it didn’t drop below 9 Celsius there was a small clutch of moths to ID and record this morning. Specifically, 2x Clouded Drab (new for the year), Common Quaker, Early Grey, 2x Hebrew Character, and a Red-green Carpet, also NFY.

Red-green Carpet (Chloroclysta siterata) — Red-green Carpet, Chloroclysta siterata

The Red-green Carpet is usually on the wing in the Autumn, the males die, but the females can hibernate to lay eggs in the spring. To my eye, they generally look green with some spots and patches at this time of year, but the autumnal ones are more obviously green and red…ish.

The “carpet” part of its name refers not to the notion that its larvae eat carpets, rather than in the 1700s when species were first being classified and named, the early entomologists and indeed the Lepidopterists perceived the beauty of these creatures and equated their colourful patterns and markings as being like the luxury items carpets were at the time.

The Red-green Carpet moth is a beautiful and fascinating species of moth that belongs to the family Geometridae, which includes many other species commonly known as “carpet moths”. This moth is found throughout Europe, including the United Kingdom, where it is one of the most common species of carpet moth.

Like all Lepidoptera, the species undergoes a complete metamorphosis, with four distinct life stages: egg, larva, pupa, and adult. The eggs are laid on the leaves of the host plant, which can include a wide variety of deciduous trees, most commonly oak and rowan. The larvae, which are often called “inchworms” (US usage) because of their distinctive way of moving, measuring the earth…hence geometers undergo several moults before pupating. The pupa is a non-feeding, transformative stage in which the larva transforms into the adult moth. Finally, the adult emerges from the pupa and begins the cycle anew by finding a mate and the females laying eggs.

Early Oak Piercer just for FUN

TL:DR – Pheromones are a useful tool for discovering what day-flying moths are in your neighbourhood.

As regular readers know, I do a bit of mothing…I have had a FUN lure, a pheromone lure aimed at attracting Grapholita funebrana. It’s been sighted in the garden for a couple of weeks with nothing appearing until 21st March 2023 at which point I was lucky enough to catch a couple of micro moths, Pammene giganteana (known to some unofficially as the Early Oak Piercer) not the target species but nice to see, nevertheless.

The micro moth Pammene giganteana (Early Oak Piercer) — The micro moth *Pammene giganteana* (Early Oak Piercer)

The larvae of the Early Oak Piercer feed inside oak-apple galls, which are themselves formed by parasitic wasps.

According to Anglian Lepidopterist Supplies from whom I bought this and other pheromone lures, the FUN lure has a long list of non-target species that might be drawn to it at different times of year, there may be others yet to be reported:

Glyphipterix fuscoviridella , Phyllonorycter quercifoliella, Grapholita janthinana , Cnephasia stephensiana , Ochsenheimeria vacculella, Epiblema costipunctana, Grapholita tenebrosana, Pseudargyrotoza conwagana, Dichrorampha aeratana, Acentria ephemerella, Argyresthia curvella, Endothenia gentianaeana, Hadena confusa (Marbled Coronet), Lymantria dispar (Gypsy Moth), Agrotis segetum (Turnip Moth), Tinea semifulvella, Pammene argyrana, Pammene aurana, Pammene giganteana, Pammene albuginana, Pammene obscurana, Pammene suspectana, Pammene fasciana, Amblyptilia punctidactyla

Pheromone moth trap — A simple pheromone moth trap. The lure is held in a receptacle above an funnelled opening, a moth attracted to the lure will commonly fall into the funnel and be unable to escape, ready for identification, logging, and release back into the wild unharmed.