Science – Page 45 – David Bradley

The Brood Parasite

The Brood Parasite…sounds like a schlock horror video nasty from the 1980s only available under the counter from your video shop on a dodgy, copied VHS (no Betamax). Of course, it’s a biological term to describe certain species that allow another species to raise their young as their own. For the duped species, this is a real-life horror story.

On the 18th May, 2019, Mrs Sciencebase and I once more visited RSPB Ouse Washes, near Manea, Cambridgeshire, and witnessed one such brood parasite, the European Cuckoo (Cuculus canorus), as it emerged from a reedbed where there were lots of Reed Warblers, Sedge Warblers, and Reed Buntings chattering and calling.

We can only assume this was a female, recently mated having arrived with the male cuckoos from Southern Africa in the last couple of weeks. As every schoolchild knows, the Cuckoo builds no nest, instead, it lays its eggs in the nests of other birds and then abandons them, leaving the hapless warblers to incubate the Cuckoo’s egg alongside their own. When the Cuckoo hatches it will commonly nudge out any warbler eggs in the nest and leave its tiny surrogate parents to run themselves ragged feeding it and raising it as their own.

Neither the surrogates, parasitised in the truest sense of that word nor the imprinted Cuckoo chick is aware that anything is wrong with this scenario…but we do…and it is horrific. I say the adult cuckoos are unaware…but if so, why do they look so guilty?

Two weeks later – #Pondlife Part the Fifth

UPDATE: 22 May 2019 – After another water feature rebuild, I think we have settled on how it shall now stay. The pump in the middle of the pond at its deepest point and I’ve encased the wiring in a piece of hosepipe and peeled back the turf to bury it. It forms an almost invisible seam in the lawn. That edge will in time become overgrown as I’m leaving the grassed area to the side and behind the pond to go wild and hopefully accumulate wildflowers with a little seed assistance.

The water is relatively clear, albeit with a green hue, but no layer of floating pond weeds nor algae, just a few mosquitoes and some of their larvae. I’ve not seen the frog for a day or two.

UPDATE: 19 May 2019 – We rebuilt the water feature and used a longer length of hosepipe to get the pump deeper and into the middle of the pond. During the work, we must have disturbed a new, amphibious resident, Mrs Sciencebase spotted it first, a large-looking Common Frog, Rana temporaria, seemed to have an almost pinkish hue in the greenish water. It’s a good sign of a healthy wildlife pond, we believe.

Well, we’re two weeks into PondLife, no sign of the frogs yet, but plenty of green matter forming a blanket in the bottom of the pond, and some algae on the top. The plants have survived so far, but maybe there are not enough to keep the algae down. A pump is now in situ and a few extra rocks installed to create a nano-Niagara.

The aerating, circulating effect of the pump and, probably more to the point, a bit of skimming of the surface with a sieve seemed to clear the algae, which hadn’t taken too much of a hold.

You can read about the initial work, the redesign, and the plants here:

Beginning – Part 1 – Operation Sciencebase Pond

Lining – Part 2 – PondLife moves on

Restructuring – Part 3 – A new landscape

Planting – Part 4 – Oxygenators and filters

Puss Moth, Cerura vinula

Last night was a very different nightÂ of mothing. It had been up to 20 degrees Celsius during the day but got down as low as 7 degrees Celsius in the night, it was still and dry, with a waxing gibbous moon. The haul one gets to an actinic light moth trap can never be predicted, but numbers were the highest they had been since the warm patch in April 2019, it’s now mid-May 2019.

I was very pleased to see one of the larger British moths sitting on the outside of the trap this morning, the very furry Puss Moth, Cerura vinula. This specimen was an impressive 4.5 centimetres long from front leg to wingtip and has the most striking patterning.

As you can see from my photos it is very furry, has broad white wings. The forewings have very dark concentric lines that look like indentations, there are dark cross veins on the wings and bronze lines radiating down the thorax. This specimen also has a greenish hue to its heads and black spots. Gently coaxing it from the trap into an examination pot was quite an eerie feeling, the large size and furriness make you think you’re handling a small, alien-looking mammal, rather than an insect.

Also new for me, potted as it approached the trap last night was a Coxcomb Prominent, Ptilodon capucina, a species common from Ireland to Japan in the Palearctic ecological zone.

It was the busiest night for moths in the garden last night for a month or so, also ticked this morning and last night, 12 species, 20 specimens:

Puss Moth, Red Twin-spot Carpet, Hebrew Character, male Muslin (2x), Shuttle-shaped Dart (6x), Turnip Moth (2x), The Streamer, Double-striped Pug, Common Pug, Heart & Dart (2x), Light-brown Apple Moth.

Incidentally, I remember seeing photos of the Puss Moth caterpillar in books when I was a child, it was often the cover star of a wildlife book, for instance. You may recognise it too. Incidentally, don’t annoy this larva, it can spray formic acid at you…

Hobbies at RSPB Ouse Fen

The Eurasian Hobby is back over RSPB Ouse Fen (May 2019), one of 6 or 7 seen hunting on the wing. The bird’s scientific name is Falco subbuteo means “falcon below the buzzard”. But, yes, that’s where the name of the football game – Subbuteo – comes from, the inventor wanted to call it “Hobby”, but the company said that couldn’t be trademarked, so he went all cod Latin.

As you can probably tell, they fit into a sequence of falcons found in the British Isles, from largest to smallest: Peregrine > Hobby > Kestrel > Merlin. Hobbies mainly eat dragonflies on the wing and you can see them clipping off the wings and discarding everything but the insects’ bodies as the bird flies over you. I have also seen them take swifts out of the air on a couple of occasions, both midsummer above our garden with the hobby flying out of the sun towards the screaming, circling swifts high above.

Taking photos of birds on the wing is difficult at the best of times, but photographic quality is also compromised at this time of year by atmospheric disturbance (you cannot filter out the heat haze, unfortunately).

Heart & Dart, Agrotis exclamationis

Just added another new moth species to the mothematical list, the Heart & Dart (Agrotis exclamationis). Here’s a focus-stacked shot looking down on the moth so you can see its “darts” and its “hearts”.

Here’s a face-on closeup, also focus stacked using digiCamControl to capture a sequence of six photos at different focus positions, front to back, and then aligning and stacking together with CombineZP. The stacking has not worked brilliantly in this shot, the antennae have artefacts, but at least you can see this species’ distinctive black band visible only when looking at the front of the thorax head-on.

Apparently, the Heart & Dart is one of the most common of the so-called owlets, the Noctuid moths, common in Europe and widespread in the UK, attracted to light and its larvae (known as cutworms in this genus of moths). The larvae eat all sorts of garden and wild plants, turnip, potatoes, maize, spinach, strawberries, lettuce, beetroot, as well as oak leaves and brambles.

The moth’s common name is perhaps obvious, but so too, in some sense, is the scientific binomial: Agrotis from the Greek for farmer, exclamationis meaning an exclamation! A farmer’s exclamation. Not a species to be encouraged in one’s new #AllotmentLife.

Of course, some cultures get their own back on the plant-eating moths, by eating the moths themselves. The related Bogong moth (Agrotis infusa) is an icon of Australian wildlife due to its historical role as a food source for Aboriginal people of Southeastern Australia, Its gathering led to inter-tribal feasting. The moths are roasted to remove wings and scales and often made into moth meat paste, which apparently has a nice, nutty taste.

Light Emerald, Campaea margaritaria

Another one of those insects almost everyone else thinks of as grey or brown…just look at that pure greeeen.

Light Emerald (Campaea margaritaria). This is a geometer moth, which means its larvae “measure the earth”, they’re inchworms, in other words. Although I think it’s time they went metric AND they’re not worms…they’re larvae (moth caterpillars).

Although this moth is pretty much flat, I took three photos of it at different focus depths and then aligned and stacked them together (using digiCamControl and CombineZP, mentioned as my current free tools of choice for focus stacking some time ago on the blog.)

If you look closely you can see why moths and butterflies (essentially the same thing) are called Lepidoptera. (Lepis means scale, pteron means wing in ancient Greek, so – scaly wings)

Barred horsetail and more – Part 4 #PondLife

UPDATE: Part 4b Night of 6 MAY 2019, spotted what I think is the first inhabitant of the new pond, a surface-swimming beetle of some kind, perhaps a “diving beetle”.

Having redesigned, realised that the internal shelving of the pond isn’t quite what it should’ve been for the best views…

Anyway, a few plants are in now as is the weird double-handed milk jug we cadged off the blokes at the dump 20 years ago. Plants: barred horsetail, Equisetum japonicum. A tall marginal pond plant, with banded vertical stems. Hydrocotyle var. A pennywort oxygenator. Grows in the muddy margins and shallows of the pond. Scirpus cernuus, more colloquially known as bristle reed is in there too now as is Phragmites variegata, Norfolk reed.

Also in the shallows, an intriguing plant called Juncus effusus, the corkscrew rush. Iris pseudacorus, the yellow water iris, and Primula rosea.

That’s it for now. Full to capacity loaded with a few filtering and oxygenating plants. Needs some more landscaping although that patch at the back is going to be set aside as a micro-meadow, the repotted yucca will probably be relocated, although I’ve also taken 3-4 cuttings from the parent plant the main stem of which was dead.

Oh, we also need to deal with the gravel and mud from the hole…but there’s stuff to do on the allotment before then! None of this is really about aesthetics anyway it’s about creating a nano-ecosystem in our garden for insecta, amphibia, aves, and possibly some mammalia.

Pond Life – Part 3 #PondLife

UPDATE: Another iteration…I think the embankment will go in the morning and the doubled-up liner will be folded beneath the stones rather than cut…for now.

Like I said in the earlier blog about re-digging our old pond, I hadn’t really mapped out the site and how I was going to manage it. We have now decided to use the spare acreage of Butyl liner to double line it…and we are now filling with water. If someone tells me now that that’s not the right thing to do then I’ll just tip the gravel back in the hole and stick the old garden lamp we inherited from previous owners of Pelham Towers on the resulting mound. It’ll be that or the moth trap.

Anyway, while it’s filling, we’re “pondering” what plants to buy to stock it and what rocks to use to edge it. Mrs Sciencebase would like a nano-waterfall of some sort and maybe lights…by the way, the breezeblocks and bricks are history.

An interesting tip from a US site walking you through creating a wildlife pond suggests sampling a few pints of water from a local, established pond and adding that to your own pond water to kickstart an ecosystem. It sounds as pointless as those active, bio yoghurt drinks, to be honest. And, worse, you could introduce parasites and pathogens as well as weeds from another site int your own.

I reckon once you add plants to the pond and a few birds have released copious amounts of uric acid waste into it, it will establish its own system quite quickly. We’ve also got rainwater in butts that might suffice, it’s not stagnant but definitely has some eco going on, Mrs Sciencebase having had the same thought has just checked. So, I reckon a bucket from there would be useful. Indeed, some recommend not using tapwater, but really, it’s going to take quite some time if you let just rainwater fill a pond, and the only chemicals (other than water itself) in tapwater are chlorine products which, soon get used up and the byproducts evaporate.

Meanwhile, as it’s still filling and in between chilling showers, here’s a snapshot from under our Wisteria, seven years, I think since it first blossomed.

Garden Pond Project – Part 2 #PondLife

Having decided to reinstate our garden pond after twenty years, I dug out and shaped the hole, built a mole-size mountain range and then headed to the garden centre to get some Butyl* sheeting and some sharp sand.

The sharp sand was to bed the base of the pond and hopefully reduce the risk of stones piercing the liner. The liner…calculation suggested that I needed about five square metres. Garden centre had a 6m roll, so 5x6m it would have to be and I could trim off the excess. Turned out that even with squashing the sheet down into the hole I pretty much had the same area spare. So, that’s left over. Don’t rely on an online garden centre’s calculator to work out how much you need! Lesson learned…too late.

Any, two bags of sand was just about enough, I’d recommend adding 50% to your estimate for how much you think you’d need. The mole mountain range is now backed by some breeze blocks and bricks and infilled with the gravel. I plan to get some more attractive flat stones to create a dry stone wall on this and the other bricks around the edge.

The sheeting will be cut to a better shape once the pond has water in it…next few days. And, then the edge of the lawn will be trimmed to this shame and the excess sheeting covered with some of the pea shingle that had originally covered our garden when we moved in and was used to backfill the old pond.

Aquatic soil and some aquatic plants to stock the pond as well as the aforementioned drystone wall materials will be purchased soon. Watch this space for further updates.

Butyl, or more formally butyl rubber is a synthetic rubber, a copolymer of isobutylene with isoprene, commonly used for inflatable dinghies and the like as well as pond liners.

Operation Sciencebase Pond – Part 1 #PondLife

Back in the day, we had an enormous garden pond. Dozens and dozens of frogs. Something of an accident waiting to happen with a baby and a toddler in the house. I drained it, relocated the frogspawn to friends and neighbours with ponds and donated the frogs. Fill it in with gravel and hardcore and turfed over it.

Regretted it ever since.

So, now that we have no toddlers in the house, I thought it was time to get back to aquatic nature. The original pond was kidney-shaped (classic), about 6m by 3m, you could always see where it had been as the grass was sunken and it was the patch that dried out the soonest whenever we had a prolonged dry spell. I didn’t even need to mark out the area to dig it was so obvious where that would be…although I have opted for something slightly smaller than the original an ovoid about 3×2.6m. It’s about 0.6m at its deepest with a built-up surround to one end and some “shelving”.

I started digging at 14h48 today and stopped at 16h14 (same day!). Now, I just need to buy a liner, some underlay and sand to make a firm base, get some aquatic soil to assist the plants, and, of course, some aquatic plants. I can then send out invitations to the local amphibia.

We have not decided whether to add a trickling water feature…it isn’t essential as the plants will do the requisite oxygenating of the water and will suffice unless we decide we want to keep fish…and that’s another decision that is being deferred.