Observations in the Edgelands

21 July

CONTENTS
A feast for one - a very tiny spider traps a dragonfly
Redpolls finally “relumped”
Edgelands - endangered and unloved land near our cities
The Least Flycatcher
Indistinguishable Greyish Birds

A Feast for One

I was closing up the greenhouse a couple of days ago when, just outside, I almost walked into this scene

You can just see the tiny orb-web spider that spun this web - it will grow a lot bigger than it currently is, no doubt fuelled by the neatly wrapped nutritional resource it has caught. Spider webs capable of trapping dragonflies are vertically oriented, and suspended in midair from non-sticky support lines attached to vegetation or other structures. The capture area is a round, flexible net, made up of sticky strands spun in spiral from a central point or hub. Spider silk is extremely strong and capable of absorbing significant force without breaking, such as the impact of a large dragonfly colliding with the web. Insects become further entangled while struggling to escape. Nevertheless, a dragonfly may still be mobile enough to injure a spider in self-defense - they are strong insects, and much larger than most orb weaver spider species. Conequently , spiders have to be careful in how they go about killing dragonflies snared by their webs.

A trapped dragonfly may die in several different ways, depending on the particular spider species, its size relative to the dragonfly and how hungry the spider is. The spider may rush out, bite the trapped dragonfly, inject its venom, then ingest the liquefied body tissues at its leisure. Spiders that are relatively large compared to the dragonfly prey, who are especially hungry, or who are attacking dragonflies deemed tightly constrained by the web may use this approach, but it is not the only option available … and in this case, although the trapped dragonfly is quite small, the spider is tiny. A spider might, instead, wrap a trapped dragonfly in many strands of strong, thin silk to render it helpless and unable to escape and then wait for the dragonfly to die of exhaustion or dehydration before beginning to feed. Lastly, the spider can simply rely on the strength of its web to prevent the dragonfly’s escape, and wait patiently until the dragonfly eventually dies, at which point the spider can safely feed without risk to itself. I doubt that third scenario applies here, however, as the web is in an area through which I walk several times regularly and I am sure it wasn’t there earlier in the day, the insect being at head height and hard to miss seeing.

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Redpolls Finally Brought to Heel

For years and years there has been back and forth disagreement about the several supposed species distinction of Redpolls - some of which do, there is no doubt, look strikingly different to each other. Now it has been settled. The American Ornithologists Union (AOU) has bitten the proverbial bullet, read the science, and accepted that there is but one, single species. About time too.

Quote:

Re-Lump of Redpoll

All Redpolls are now in one species, Redpoll (Acanthis flammea). This action lumps three former species: Common Redpoll (Acanthis flammea), Hoary Redpoll (Acanthis hornemanni), and Lesser Redpoll (Acanthis cabaret). Genetic work has shown that Redpolls are almost completely undifferentiated except for a single chromosomal inversion that does not prevent interbreeding. The differences in size and melanin-deposition seem to be clinal and a textbook example of Bergmann’s Rule.

Those who are not familiar with the arguments, and those who don’t care but may be mildly curious, will find a simple, and brief explanation in this article:

https://www.allaboutbirds.org/news/from-many-one-how-many-species-of-redpolls-are-there/

Birders defending their life lists who will lose a couple of ticks by this will be less sanguine 😉

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Edgelands - protect the small and scruffy pockets

I still think/hope that the phrase “sixth extinction” remains hyperbole, but undoubtedly it is demonstrable that the world is losing both species, and numbers of individuals within species, at a shockingly rapid rate. In just a few years it only too obvious that we are no longer encountering the number and diversity of plants and animals that we did … almost yesterday it seems.

Back in 2011, when visiting England, I bought a copy of Edgelands: Journey into England's True Wilderness by Michael Symmons Roberts and Paul Farley … utterly fascinating, kept me awake on the plane all the way home. Edgelands are …

… characterised by an anarchic mix of unloved land-use functions … it has been ignored by public and planners alike. However, it has important qualities: it is a refuge for wildlife driven out of an increasingly inhospitable countryside (and) … hidden wildernesses—“topographies we can never really occupy, even as we encroach as closely as we can.” These are places usually referred to as “brownfields” or “dumping grounds,” if they’re called anything at all; “edgelands” doesn’t dismiss their problems but captures their possibilities. (Michelle Nihuis)

Edgelands is a term for the transitional zone that exists between rural and urban areas formed by urbanisation. Developers love these sorts of places which are ignored by most people, deeming them to be scruffy and useless and unattractive. Disposable in other words, not “real” nature, after all and so not worth defending. I am sorry to note that a glaring example of that attitude in the world right now is the newly elected British government (and, for the record, I support them in all other respects) who have already said within a week of being elected, that Edgeland habitat - they call it ‘the grey belt’ - in the hitherto protected greenbelt areas around major cities is going to be handed over to developers. Similar pressures are evident in Canadian cities. Urgent as the housing issue may be in many countries at the moment, just writing off valuable wildlife habitat because it is not pretty enough to be on a postcard by politicians needing a quick fix is unbelievably short-sighted. Once lost they these corners of our world will never be recovered. Oh, and, quite coincidentally, the developers will get very rich by our loss.

Not that this is anything new. Around 1820 during The Enclosures, the poet John Clare -composed “The Lament of Swordy Well”. Here is an extract from the poem ... it is considered to be “one of the first, and still very few, poems to speak for the Earth”. The theme is a lament for useful, productive, biodiverse, species rich common land being exploited for profit.

The bees flye round in feeble rings
And find no blossom bye
Then thrum their almost weary wings
Upon the moss and die
Rabbits that find my hills turned oer
Forsake my poor abode
They dread a workhouse like the poor
And nibble on the road

If with a clover bottle now
Spring dares to lift her head
The next day brings the hasty plough
And makes me miserys bed
The butterflyes may wir to come
I cannot keep em now
Nor can they bear my parish home
That withers on my brow

Edgelands, I contend, comprise not only abandoned and semi-rewilded former gravel pits and the like but also all those overlooked small pockets of abandoned fields and copses that are squeezed in between our buildings. It also includes - bear with me here - the small wildlife reserves that gardens have become by default. Almost everyone has a piece of Edgeland within a short walk.

From parkland to window boxes, wildlife thrives in gardens. These green spaces are a lifeline for wildlife, little havens scattered through the desert of urban sprawl and intensively managed farmland. Trees and shrubs shelter miniature mammals and nesting birds, whilst feeders offer a reliable food source no matter how wild the weather is. Even a single window-ledge plant pot can make a difference, providing pollen and nectar for insects straying into the concrete jungle. Larger parks and gardens can become a wild paradise, home to creatures you would never expect to find so close to home:

When we as a society, wherever we live, shrug and casually allow replacement of an established house and garden by something twice the size, felling a few trees along the way, we lose an important piece of Edgeland habitat. When we cut the trees in that small copse on the corner of the street or stick a suburban shopping mall on the abandoned field between the houses and the bypass we destroy yet more.

There is so much being said right now, today, about the visible and marked reduction in the numbers of birds and insects around our communities. Those birds and bees live in, need, our gardens and parks and segments of the Edgelands. Every time we shrug and say, “well it was only a small piece of land” we are all made poorer by what happens. Birds need a place to nest and the seeds of wild flowers to eat; insects need plants to lay eggs on and flowers to sip nectar from. If we take those features away, bite by nibble by scrape, from our neighbourhoods they cannot be restored. Where is the joy and quality of life in a community that no longer has green space and wild creatures?

The 1001 Species I write about in this newsletter are the creatures and plants that live in the Edgelands. Our neighbours. We are all responsible for their future. And our own.

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Not all is gloom …

A Least Flycatcher - active nearby for a couple of summer months. Least Flycatchers don't spend more time than they have to on the breeding grounds. It takes them about 58 days to find a mate, build a nest, lay eggs, and raise their young from nestlings to independence. They are estimated to spend only some 64 days in their summer territory before heading south again. They nest in clusters so there might be stretches of forest without any Least Flycatchers. But once you come across a cluster, there will likely be several about. They generally catch insects from branches in the middle to upper levels of the forest and frequently change perches, so look up for quick movements.

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UMPTEEN IDENTICAL BIRDS

There is a group of fourteen, visually almost identical flycatchers in the genus Empidonax that usually can only be separated in the field by their distinctive calls … or, if like me you are hard of hearing, not separated at all. These birds are frustrating to say the least. A pair of guides to North American Flycatchers has been published that as a recent review tells me will put me on the path towards the Holy Grail if only I study them with diligence. Or not.

Why not? Well, here’s a paragraph from the book review that refers to some real world experience. Quote:

Now I’ll admit, the joke has been made – by me, if I’m honest – that just for a giggle a field guide to the Empidonax flycatchers could be published using only a single illustration for all species but with text that insisted at great length in each case that there were differences which could be seen in the field if observed with sufficient diligence. As most who have tried to puzzle out these little birds when they are not vocalizing will attest, one of these little grey birds could be perched in the middle of ten illuminated red arrows each one pointing to a particular differentiating field mark and it still wouldn’t make the first bit of difference.

Should you feel mentally up to the challenge, then these are the books you will want. Both are by Prof. Cin-Ty Lee.

• Field Guide to North American Flycatchers: Empidonax and Pewees

• Field Guide to North American Flycatchers: Kingbirds and Myiarchus

Have fun. It’s probably a better mental challenge than crosswords (I can’t do those either).