Science – David Bradley

One good tern…

Yesterday, I spotted a Sandwich Tern, Thalasseus sandvicensis, colloquially known as a Sarnie, patrolling the open river lock at Brownshill Staunch on the Great River Ouse. It flew back and forth over a stretch of about 200 metres for 20 minutes or so before heading off downstream.

The river cuts through the RSPB Ouse Fen nature reserve (I’d walked in from the Over end rather than Needingworth). The lock is currently open to allow flood water to run to the sea, although it’s not flowing as violently as it was about a month ago.

Anyway, I’ve seen several Common Terns fishing on this reserve and a Black Tern fly through one pre-covid summer. But, a Sandwich seemed unusual so I posted my spot to the local patch’s birding social media group when I first saw it. There was a flurry of interest and one member, Richard Thomas, keen to see the bird, headed to the Staunch. Unfortunately, for him the bird had moved on by the time he arrived, and I hadn’t checked back in on the group after my initial update to let them know. He dipped out. My bad.

Sandwich Tern in flight over Brownshill Staunch

I later spoke to Richard about the presence of the Sandwich Tern. I had assumed it wasn’t a so-called mega rarity, but still its presence was rather unusual. He told me he thinks they’re almost annual in this area despite their being so obviously coastal feeders and breeders.

“Sandwich Terns are just about annual locally – I’ve seen them on six occasions in 20 years and missed them more times than that,” Richard told me. “They are an absolute pain in the neck because they rarely stay more than a few minutes. I’ve been lucky on four occasions with “fly throughs” (including a flock of seven at the Brownshill Staunch).” He added that they’re annual at Grafham Water reservoir, which isn’t far from here either and a nice birding spot, but again, he says, they were almost invariably fly throughs.

There was a subsequent flurry of activity in the social media group, my having alerted the birders to the presence of the species, and it was quickly tracked down to yet another patch of old gravel pits turned nature reserve, RSPB Fen Drayton. Several birders were excited to know it was there and surprised that it had roosted rather than flying through.

The River Great Ouse empties into The Wash on the north Norfolk coast. It’s worth noting that Brownshill Staunch, which lies on the Greenwich Meridian, is the last stretch of the river that still feels the effects of the tide. In recent weeks, my fellow togger friend Andy Hoy saw a seal sunning itself on the riverbank at this point. It had presumably swum upstream from the coast. Seals are not uncommon on the river, although they’re usually seen further downstream. In the summer of 2023, a female dolphin and two offspring were seen on this stretch of river too.

Richard has the last word in adding that one good tern deserves another, he suggests that Caspian Tern or Roseate Tern would be firsts for the patch should they turn up…

Latest intel on the Sarnie is that it’s feeding on the river near Ferry Lagoon at RSPB Fen Drayton 18h00 on the 18th April. On the 17th it roosted on the islands in the Lagoon.

Culling in the name of…

If you have even a passing interest in the natural world, you will have most likely heard the phrase “invasive species”. By definition, a deliberate or accidental release of a species to an area beyond its natural environment where it then multiplies and causes damage to that environment and the native wildlife that relies on it. I discussed the UK issue of invasive species briefly last year and in the context of Muntjac and Black Hairstreak butterfly too.

Reeves' Muntjac Deer

Ecologist and conservationist Hugh Warwick tackles the issue in much more depth in his latest book – Cull of the Wild. Warwick is, as most of us are, not keen on killing in the name of and recognises that the arguments and issues regarding the culling of invasive species where they threaten the very existence of native species and ecosystems are still very complicated.

In Cull of the Wild, he discusses how different approaches to control have been tried worldwide. The grey versus red squirrels, the cane toads in Australia, rats, even Pablo Escobar’s hippos and the Burmese python trade.

Warwick, a former vegan and now a self-confessed meat-eschewing vague-an, points out that millions of animals are killed, or culled, every year in the name of conservation, invasive species, feral populations, domestic animals. Sadly, much of this killing is cruel and essentially unregulated. To quote from Warwick’s introduction:

“We deserve an honest conversation about conservation. To do that we need to establish one very important point. Conservation, wildlife management, and the ecology that underpins them both, is really complicated. Add to this one more variable: people with differing perspectives. Now, it becomes close to impossible to solve the very real problems with which we are confronted. Complicated problems rarely have simple solutions…”

There are, we learn, no absolutes. Each invasive case has nuance where humans have destroyed habitat and the native species that once filled a niche are long gone, an incomer might fill that space and become prevalent. It might be that the new species brings benefits to that environment, perhaps reducing plant overgrowth and opening up biodiversity that resurrects the habitat.

The beautiful Box-tree moth, Cydalima perspectalis, represents an interesting example of the kind of nuance we have to address. It arrived in the UK around 2007, presumably hitching a ride on imported Asian strains of box-tree, Buxus. Unfortunately, it has spread and thrived, ravaging decorative box hedges across southern England.

Box-tree Moth

There is little that can be done to control this invasive species at this point in its history other than grubbing out its larval food plants, Buxus, and planting something else. Insectidal sprays are not the answer as they kill the native species too, pheromone traps are of limited use and while they kill some of the males there will always be another to fertilise the female’s eggs on one’s box hedge, and picking off caterpillars for, ahem, disposal, is not the most pleasant way to spend a lazy Sunday afternoon.

However, to talk of the lack of the nuance and the lack of absolutes, it’s worth noting that Blackbirds are starting to recognise the larvae of this moth as a rich food source. So, whereas the presence of the moth is essentially well-balanced in its native environment, there is hope that this might happen naturally here too.

It is unlikely that many of the problematic invasive species we must cope with will naturalise in that way, so there may well forever be a need to find ways to control them or live with them. Warwick offers much for our consideration of the nuances of invasion.

More Fenland birding

Having spent a couple of evenings watching Starling murmurations with hundreds of thousands of birds, it was time to seek out some Aves in smaller numbers. I had a quick look in at RSPB Ouse Fen (Earith) as it was bright and sunny on Saturday morning. I was hoping to that there would be a chance that the Cranes would be showing. They weren’t but there was a Great White Egret, as ever, and a Chinese Water Deer, I had only fleeting, distant views of a solitary Marsh Harrier. I headed out to Chain Corner to check on the Whooper Swans, a few on the water and one that flew right over me.

Whooper Swan in flight

Next on to a patch of flooded farmland, often used for fen skating historically, it had lots of waterfowl, but no Glossy Ibis there this year, despite their having bred not far from here in 2023. Then on to RSPB Berry Fen, which is just a short hop further up the road. Chiffchaff calling, lots of Widgeon whistling but no Black-tailed Godwit, there were several hundred earlier last week, apparently.

A Wigeon pair in flight, there were many more on the water of the flooded fen

There was also a distant piping Redshank and the Merlin app picked up the sound of a Green-winged Teal (it’s perhaps the same American vagrant we’ve seen here over the last two or three years; previously, there has also been a Blue-winged Teal). There had also been Dunlin and similar species there but I couldn’t see them. There was a Sparrowhawk, known affectionately as a Sprawk to birders, that flew right over me and away with its familiar flap-flap-glide flight pattern.

Sparrowhawk in flight

Further round, the flood, a group of Greylag Geese hanging out with some Russian visitors – three White-fronted Geese. This species, Anser albifrons, might better be known as “white-faced” as you can see from the photos. But as is often the wont of naturalists names sometimes don’t quite match the species description.

The Berry Fen Three - White-fronted Geese — The Berry Fen Three – White-fronted Geese, most likely visitors from Greenland

Anser albifrons flavirostris: The Greenland White-fronted Goose, this subspecies breeds in Greenland and winters in Ireland and Britain, pink colouration at the base of the bill rather than yellowish seen in the Russian race — European White-fronted Goose, a visitor from Russia

According to the BTO website: Two races of White-fronted Goose occur in the UK. A. albifrons (the European WfG) breeds in western Russia and is usually about 1000 to 2000 of them are found in the south and east of England in the winter. A. flavirostris breeds in western Greenland (the Greenland WfG) and about 10000-12000 of this subspecies usually spend the winter in the north and west of Britain and Ireland.

Orange Tip – Anthocharis cardamines

UPDATE: My report of Orange Tip on 2024-03-17 may well have been the first reported nationally this year, according to our County Butterfly Recorder.

I saw my first Orange Tip (Anthocharis cardamines) of 2024 on 17th March in Cottenham patrolling a roadside verge (Broad Lane).

Archive photo of male Orange Tip on Cuckoo Flower

This was the first report for Cambridgeshire and Essex butterflies this year, apparently. I have to admit I’ve not kept a personal record of first sightings of this species, but the Cambs & Essex page does, so I can give you a list of previous years.

4 Apr 23, 24 Mar 22, 30 Mar 21, 26 Mar 20, 28 Mar 19, 17 Apr 18, 28 Mar 17, 8 Apr 16, 8 Apr 15, 24 Mar 14, 25 Apr 13, 26 Mar 12, 24 Mar 11, 11 Apr 10, 5 Apr 09, 21 Apr 08, 12 Apr 07.

So, it looks like my sighting is the earliest Orange Tip of the year in our Butterfly Conservation sector since they started recording public records on those pages. Previous earliest was three years where it appeared on 24 March, i.e. a week later. I posted on Twitter about the sighting and the tweet garnered a lot of interest.

Someone asked if there were wild brassicas, such as Cuckoo Flower (Cardamine pratensis) or Garlic Mustard (Alliaria petiolata) plants in bloom in our area. As far as I know, there aren’t. Indeed, the wildest it gets on that roadside verge is probably with the presence of Common Dandelion (Taraxacum officinale) and Common Daisy (Bellis perennis) unless someone has shaved it to the ground to make it all neat and tidy.

The lack of blooming wildflower brassicas (formerly known as crucifers) species, Cuckoo Flower or Garlic Mustard, could be a problem for early mating Orange Tips as the females are very choosy about the host plants on which they lay their eggs. They need large flowerheads from those wild brassicas and then generally plants that are growing in full sunlight. They don’t even like to fly through shade to find the plants, it seems.

Then there is the issue of egg colour and pheromones. When first laid, Orange Tip eggs are white but change to orange and then brown within days perhaps making their presence obvious to other females arriving at the flower. The female also covers her eggs with a pheromone that dissuades other females from laying eggs in the same bloom. This will benefit the larvae of both females as the original ones will not have competitors for food (the host plant’s seed pods), but also, the more recent eggs, and so younger larvae, will not be cannibalised by the older ones.

The weather patterns have been weird at this time of year for several years now. Think back to the warm days of March during lockdown. I’ve not seen any more Orange Tips yet, so this may have simply been a precocious male who may miss his chance of spreading his seed if no females appear soon. The main emergence may happen at the end of the month and into April, as is more usual.

What a beauty! An Oak Beauty

First Oak Beauty of the year seen in the garden last night (6th March 2024). It’s a quite stunning creature, isn’t it? Sharp-eyed readers will note this is a geometer moth. So-called because their larvae (caterpillars), known as inchworms in the US, move in such a way as to give the appearance that they are measuring the earth, geo-meter, inch by inch.

This is a male Oak Beauty, you can tell from its enormous feathery antennae, which it often folds underneath its body to protect them.

You might also be thinking it looks like a Peppered Moth but with more colourful and more pronounced markings. Well, the Peppered Moth is a kissing cousin of this species, seen a little later in the year than peri-spring. The Oak Beauty is Biston strataria, the Peppered Moth is in the same genus, and is B. betularia. While the shape of the moth is very like the Peppered, the markings resemble those of some of the so-called carpet moths. By the way, they don’t eat carpets, but look decorative, like the luxury item that was a carpet back when the early lepidopterists were giving all these species their names.

This is Planet Earith – Starling murmurations

UPDATE: I mentioned the murmurations to a choir friend, Sara, and bumped into her and her husband on the Fen. I warned them that, because it was very windy, we might not get such good murmurations as I’d mentioned before. But amazingly, as dusk rolled on, even though it wasn’t a bright sunset, we got some wonderful activity from approximately two-hundred thousand Starlings.

The main activity was very much over the reedbeds among which we stood rather than being half a mile away as occurred on my previous two visits. This made it hard to get the full murmuration in the camera frame at the level of zoom I had with me. So, the above video was done on my phone as a record.

The birds would whoosh over out heads at about 50 metres altitude. I warned the people around me not to look up with their mouths open and within a few minutes, my choir friend had undergone a full birding initiation with three deposits from above in quick succession. Amazing that I didn’t get splashed as I was standing only a metre or two away from her.

Anyway, the birds gathered in a very dense flock at about 17h50 and bedded down into the vast reedbed in front of the entrance to the reserve. There were undulations for a good ten minutes as it got darker and darker. At one point, a Merlin was reported to have caught one Starling on the wing. The other 199,999 were fine and had roosted down among the reeds by the time we departed.

At the end of February, I got wind of there being very large numbers of Common Starling murmurating at a local nature reserve – RSPB Ouse Fen (Earith). I got a few photos on an evening visit. There were probably half a million birds, it was quite astonishing. I based my estimate on counts I’ve done of photographs of smaller flocks and extrapolating to the huge patches of sky that were covered with birds on the evening.

I got some nice photos at sunset but my phone video was very smeary and low-res. So, a second visit was essential. Unfortunately, rumour had it that the numbers the next night were smaller, that some of the birds had moved to roosting over the Over side of RSPB Ouse Fen…nevertheless, Mrs Sciencebase and myself headed over to Earith on 3rd March.

Short-eared Owl "chasing" a Chinese Water Deer — Short-eared Owl “chasing” a Chinese Water Deer

It was a much better evening and definitey fewer Starlings, but still many tens of thousands. This time I got some decent video footage of the murmurations.

We also ticked three Short-eared Owls, half a dozen Chinese Water Deer, heard numerous Cetti’s Warbler and saw just one, saw Great White Egret and Grey Heron, heard a couple of Bearded Reedling, and heard one or two booming Bitterns, lots of Geese, Cormorants, Reed Bunting, Widgeon calling, Little Grebe, Water Rail etc. The Cranes that had been displaying south of the car park on the gravel works land flew in to roost about a quarter of a mile in front of us as we watched the starling murmurations. It was a wonderful evening of nature watching.

I played my video to the Merlin app, although we all knew what birds we could hear, but it came back with Coot, Greylag Goose, Canada Goose, Cetti’s Warbler, Ring-necked Pheasant. It didn’t pick up Wigeon, Little Grebe, Reed Bunting, Bearded Reedling, which we had heard.

I opened up one of my stills with a huge flock across it and enlarged it on my laptop screen. I drew a square around a patch that I estimated had 100 birds in it. Double-checked and adjusted the size of the square to make sure it was very close to 100. I measured the square in pixels and then worked out how many such squares would fill the area of the photo filled with birds. It came to about 75000 birds. This assumes average density across the photo. There were probably areas outside the area of the photo that would be around 25000 birds. So, the biggest flock would be around 100000, there were probably about half the same number of birds in the air elsewhere. The previous evening of murmurations I’d have said there were 5-6 such flocks, so guesstimating at least half a million birds going to roost on this patch of the reserve.

Estimate - 75000 Starlings — Estimate – 75000 Starlings

Rinse your recycling

Rinsing food packaging before putting in your recycling bin is critical to making the process as efficient and as effective as possible. Efficient recycling processes can significantly reduce the environmental impact compared to producing new materials from virgin resources.

Rinsing packaging helps reduce contamination in the recycling stream. Contaminated materials can lead to lower-quality recyclables, which may be rejected or require additional processing, thereby increasing costs and energy consumption. Higher-quality recycled materials fetch better prices in the market and have broader applications, contributing to a more sustainable recycling industry.

Rinsing packaging does require additional water usage. However, the amount of water needed for rinsing is generally minimal compared to other household activities. If you can use grey water, or even collected rainwater, for rinsing all the better. The simplest approach is just to add the dirty packaging to the end of your normal washing up. There is no need to put tins, cans, or plastic pots in the dishwasher, of course.

Rinsing also avoids residues that can affect the maintenance requirements and lifespan of recycling equipment. Residue buildup can lead to equipment corrosion, increased wear and tear, and the need for more frequent cleaning and maintenance cycles, all of which contribute to higher operational costs and resource usage.

Encouraging rinsing as a standard practice can also have broader effects on environmental awareness and behaviour. It reinforces the importance of proper waste management and encourages individuals to consider the environmental consequences of their actions.

When it comes to Lepidoptera, plus ça change

An analysis of the genomes of more than 200 butterfly and moth, Lepidoptera, species reveals that genetic framework of what is ostensibly a very diverse group of insects, has remained remarkably stable since they diverged from their last common ancestor over 250 million years ago.

In a study published in the journal Nature Ecology and Evolution, shed new light on the evolutionary history and genetic structure of the Lepidoptera, which could help in conservation efforts for what is an incredibly important group of pollinators, food source for birds, bats, and other creatures, and a vital part of a healthy ecosystem and environment. I’ve discussed the importance of moths and mothing on Sciencebase before.

Despite the wide range of physical appearance and behaviour of the Lepidoptera, of which there are some 160000 extant species around the world, the team has demonstrated that 32 ancient chromosome building blocks, termed “Merian elements,” have changed little in 250 million years and remain consistent across most species. Even the arrangement of genes within these chromosomes has shown consistency over time.

However, some species, notably the Blue butterflies (Lysandra) and the White butterflies (Pieris), exhibited significant chromosome rearrangements, deviating from the typical genome structure. These exceptions offer insights into the mechanisms driving genetic diversity within Lepidoptera.

The study’s implications extend beyond entomology. By understanding the genetic foundations of butterflies and moths, researchers can inform conservation strategies. This knowledge could assist targeted conservation efforts, ecosystem health monitoring, and adaptation to environmental changes, particularly those related to climate change.

Additionally, this research aligns with broader initiatives such as the Darwin Tree of Life Project and the Earth BioGenome Project, aiming to sequence and understand the genetic makeup of all life on Earth. By unravelling the mysteries of Lepidoptera genetics, scientists contribute to a deeper understanding of biodiversity and evolutionary processes.

Understanding butterfly and moth genetics not only provides insights into their past but also lays the groundwork for more effective conservation strategies to protect these important pollinators and herbivores in our ecosystems.

Wright et al. (2024) Nature Ecol Evol – Comparative genomics reveals the dynamics of chromosome evolution in Lepidoptera

Beware the March dagger

In the world of entomology, the naming conventions of moth species often reflect a fascinating interplay between scientific and vernacular language. While some moth species boast evocative common names like Angle Shades or Setaceous Hebrew Character, others, particularly those belonging to the category of micro moths, are identified solely by their scientific nomenclature, lacking universally recognized common names. This situation draws a curious parallel to the realm of dinosaurs, where species like Tyrannosaurus rex are known exclusively by their scientific designations.

However, amidst this taxonomy, there exists a notable exception: Diurnea fagella, a moth species that straddles both worlds of nomenclature. Officially classified by its scientific name, Diurnea fagella, this moth also bears vernacular names, albeit inconsistently. It is sometimes referred to as the March Dagger moth or the March Tubic, though within international and Lepidoptera communities, it is unequivocally recognized as Diurnea fagella.

This dual nomenclatural identity of D. fagella underscores the nuanced complexities of species classification and naming conventions within the field of entomology. While some species remain firmly entrenched in scientific terminology, others manage to acquire colloquial names, reflecting perhaps their significance or visibility.

Beyond the realm of moth identification, this phenomenon prompts broader reflections on the relationship between scientific precision and common language. It highlights the ways in which organisms are categorized, named, and understood by both experts and the general public. Moreover, it invites contemplation on the cultural and linguistic dynamics that shape our interactions with the natural world, illuminating the intricate tapestry of human-animal relationships.

Local White Stork – Ciconia ciconia

I’ve mentioned seeing an unringed White Stork, Ciconia ciconia, in our neighbourhood previously. It is probably a collection escapee and perhaps the same unringed bird that has in previous years been seen in Kent, Essex, and then a couple of years ago in a marina in a village not far from here called Earith and most recently near the flooded farmland on Smithy Fen in Cottenham.

Today, a friend reported that it was on a flood alongside Twentypence Road. Incidentally, it seems unlikely that this bird is a vagrant from continental Europe, but you never know. Some cynical birders would refer to an escapee as a plastic bird.

Zoomed and cropped photo of a White Stork from about 80 metres — Zoomed and cropped photo of a White Stork from about 100 metres

I headed out on my bike to try and catch sight of it, but it was no longer in the reported field. If only I’d checked my messages before I left, as another friend had sent me a photo from the “new” village ponds where he’d seen it and wanted to know what sort of bird it was. Anyway, Mrs Sciencebase having caught me up on Twentypence Road headed back towards home along the Cottenham Lode and spotted the bird in yet another flooded field. She called me to report in and I cycled up to see it. The sun was out for 20 minutes, so got some reasonable views of the bird standing on a mound of earth behind the old stud and stables.

Closer view of a White Stork in the collection at Old Hurst Farm. It's plausible that the Cottenham Stork is an escapee from their flock — Closer view of a White Stork in the collection at Old Hurst Farm

At this point, we messaged some other friends who we thought might be interested and they headed in and got good views too.

Stork in flight over Earith marina, 2022

You may have noticed the White Stork’s scientific binomial uses the same word for genus and species, Ciconia ciconia. The word comes from the Latin for stork, so this bird is a Stork stork, you might say. Such a repeat in a name, a tautonym, indicates that this species is the type, or archetype, of the genus. See also: Cygnus cygnus (Whooper Swan), Bufo bufo (Common Toad), Buteo buteo (Common Buzzard), Carduelis carduelis, (European Goldfinch) and, of course, Gorilla gorilla gorilla (Western Lowland Gorilla).

The White Stork was still in the same field this morning although perhaps 200 metres away, hence the lower-quality photo. But, I’m sharing it to give you a sense of size of the stork relative to the Little Egret.

White Stork and Little Egret, 200m distance and zoomed and cropped heavily hence the distortions