Sunday, 22 November 2020

Carrion Crow, Regurgitated.

This morning there was a lone carrion crow in the garden. Nothing unusual about that, though to be truthful although carrion crows are common around here, as elsewhere, rarely does one come into the garden and perch on the fence. 

Julie my wife alerted me to its presence surveying the garden.  It was one of those autumnal days when everything is sodden. Not quite freezing overnight but a heavy dew covered every available surface as the mist began dispersing with the strengthening sun. Earlier I'd seen the flash of a male sparrowhawk over the garden, though I was preoccupied in other things to concentrate on garden activity. The carrion crow however grabbed my attention, crows being an interest to me. I readily forget how large these corvids are when seen close too. Much like herring gulls when in the garden, who seem to fill it with their wingspan, this crow dominated the fence. That heavy black bill directing the observant deep set eyes to survey the scene, a crow seemingly at rest. 

Though highly intelligent carrion crows (Corvus corone) are the most wary of the corvids in my experience, never letting me get close to them. This year a pair successfully raised two (possibly three, but I'm unsure) young in the trees about 100m away. Squabbling magpies mobbing the crows each time they flew into the tree alerted me to the nest back in the spring. That squabbling was to continue all summer and well into September. The adult crows used the large fir tree in our garden as respite from this bickering it seemed, but they never came into the garden. Either one or both would sit on the top most branches preening and generally observing the world, before suffering the magpies wrath as they returned to the nest. Interestingly a pair of magpies had a nest in the fir tree this year, tit for tat maybe?

Whether the bird I observed preening its wing was one of the same adults I'm unsure, though logic decrees it would be and in its territory.  After a few minutes watching this crow it hopped off the fence and down onto the gravel. There on the path it flicked over a few stones before flying up onto the shed roof. Slipping and sliding down the shed roof, the crow then hopped onto the back wall and stood for a while. A perfect poised motionless corvid. I was tempted to get my camera but knew it would have disappeared before I returned. I therefore watched. 

It was while simply observing I saw the crow open it's bill and almost as if silently craa-ing, shook it's head while keeping its bill wide open. Again the bill opened, this time turning its head in the opposite direction. It then hopped slightly to the left and opened its bill once more, this time a pellet fell out of the crow onto the wall. I've known for years that crows regurgitate pellets but I've never seen this actually happen (nor have I been absolutely sure I've found one in the countryside). It is well known that birds of prey, especially owls regurgitate indigestible food remains, but a number of other bird species regurgitate too including herons, and dabbling ducks. And also crows; thanks to the work a century ago by Sven August Heintz a Swedish biologist. Post pellet regurgitating I read a paper reviewing his work [Green et al 2019].

In this recent article by Green et al they review the work of Heintz in the context of contemporary science and ornithology. A century ago Heintz suggested at least eleven corvid species were key seed dispersal species both through cache, hoarding, faecal droppings and pellet regurgitations. One of the species confirmed as doing this was the hooded crow (Corvus cornix), which in 1917 was then considered the same species as the carrion crow, with the former just more plentiful in numbers in Sweden.   

Heintz stated that "It is well-known that some members of the crow family (Corvidae) are important for seed dispersal either via frugivory (e.g., when feeding on berries) or by scatter hoarding (e.g., of nuts).....corvids are partly granivorous and have long had a reputation for causing damage to cereal crops"

[Heintz] "... carried out germination experiments of the contents of regurgitated pellets and excrements from Magpie and Hooded Crow. Most germination trials were carried out in early spring, of seeds that had been collected the preceding autumn or winter. Although many seeds germinated within a few weeks, trials were run throughout summer and autumn..... in total Heintze identified 157 plant taxa from 42 families which were dispersed by corvids by endozoochory (dispersal via ingestion)

Heintz concluded It appears that within these zoogeographic areas [the Holarctic and the Neoboreal] corvids are the most important seed dispersers among all landbirds.” 

All of the above I gleaned from reading Green et al after watching the crow on my garden wall. Which after regurgitating its pellet flew off, allowing me to collect it (image above).

At the time of writing I have not dissected the pellet though on external examination it is packed with what will be indigestible seed husks and what look like acorn remains. Which was interesting in itself, as the literature suggests most regurgitations occur when crows feed on beetles and other invertebrates with tough carapace or wings. A quick search on the internet drew a blank for grain derived pellets. Could it be that seed based pellets are less obvious as they fall apart and are dispersed by wind more readily?  More investigation needed I feel, although given corvids are very granivorous during harvests and in autumn, it is not surprising really what this pellet contains.

That simple act of watching a carrion crow in the morning opened me up to the work of Heintz which until today I'd not known about. I'm not alone it seems. A quick scan through indexes in various books I have on crows fail to mention Heintz, seemingly Green et al are correct in their own conclusion that the work of that Swedish scientist a century ago has largely been forgotten, but it stands the test of time and is as pertinent today as in 1917. 

Reference :

Green, Andy J, Elmberg, Johan and Lovas-Kiss, Ádám (2019). Beyond Scatter-Hoarding and Frugivory: European Corvids as Overlooked Vectors for a Broad Range of Plants. Front. Ecol. Evol. | https://doi.org/10.3389/fevo.2019.00133

Sunday, 15 November 2020

November has a sound; silence

Is there a sound to November? Or do I mean the month of November has its own sounds? I'm not sure as for me the dominant sound in November is silence. The dominant feeling stillness. On reflection November has a sound that no other month has. It is hard to explain but then on one day I realise that November has arrived. 

In his book The Quiet Fields, the writer BB describes this beautifully in his entry for November 2nd. He begins: [page 175] 

"The sudden arrival of true winter has taken me unawares. It seems only yesterday that the sun shone with warmth enough to tempt a late tortoiseshell to the fading Michaelmas daisies...." 

 He continues [p177] 

" Standing on the lawn this early evening - watching the last sad yellow leaves of the birches drift down to the dark sepia brown of the pond, I had a sudden surge of excitement that winter is almost here again - maybe it was an almost animal awareness hard to explain.... "

This still silent sound of the eleventh month appears as if by osmosis. A time when autumn has almost forgotten why it exists. Is winter here yet? Not quite, but I've lost interest and need to slow down. The sound of silence is accompanied by stillness which provides the release of an emotional connection in me at this time of the year. It's an emotion I love so much. 

Even in late October, although the days are short, the sun may still shine strong and warm, the last of the summer migrant birds are heading south, too soon yet for their winter replacements. In October the remnants of summer bounty cling on in the hedgerow larder, keeping harsh winter at bay much as lichen does on the lee of an exposed mountain wall. Then, on a single day, a day no official diary will note, the feeling changes. November is still autumn yet it cloaks this season of mellow fruitfulness with a quiet veil of wintertide.

As BB himself did 40 years ago I found myself, just a few days ago, standing in the garden at dusk. The silence alerted me to the suggestion of stillness. In reality it was already there, it waited patiently for me to notice it. The countryside felt suddenly expanded, opened out, my hearing became distant, as if the ambiance of silence was coming from somewhere unseen in the far distance. Of course partly this is a lack of foliage in November. October storms have laid bare many trees, the air has less to resit its passing than in high summer when the rustle of leaves dominates. But there was not a breath in the air, not a bird song, nothing, just November's presence. 

Moments earlier a weak yellow sun falling towards the horizon shone beneath steel grey clouds which had dominated the sky all day. For a minute or so, just beyond the garden, the yellow leaves of a field maple were illuminated into a fire-glow of colour. But what a colour! As only witnessed in November pale buttermilk hues, with the intensity of a watercolour wash, lit every branch, before, as if by the flick of a switch, the sun fell to earth. The sky itself now took centre stage, creating its own emulsion of orange and indigo; the countryside equivalent of following the harmonious suggestions of an artists colour wheel. Larger trees were now silhouetted, contrasting with the vibrancy beyond. Slowly that hue faded as dusk advanced, indigo deepened and I observed all was quiet, all was still, all was very November. 

A few days later, a number of starlings are chattering on the roof. Not the urgent banter of spring when all efforts focus towards raising a successful brood or two. In November their toil is over, simply the relaxed contact calls of adults and offspring,  like a gaggle of gossiping farmers in the auction mart weighing up cattle. Wheezes, shwees, sqwarks, high pitched rapid fire rattling chat, responding replies, all cascade from the rooftop. They nest and roost in the eves of the house and though I can't see them, there may be half a dozen birds. Starlings chatter and bicker all year of course, but in November their constant communication throws me back to winters in Newcastle, a time when thousands of starlings would come in to roost high above the Christmas shoppers below in Northumberland Street. As a child I would listen to this deafening chorus in amazement, a sound way  higher than the passing traffic, not knowing I was witnessing something which no longer occurs. Today town roosts are a thing of the past as health and safety took over the cleansing of the streets via the netting of the rooves.

Winter has always been my birdwatching season. Maybe that is it, my November moment, my own animal awareness triggered possibly with the first seep seep of redwing flying unseen overhead in a starlit sky, their calls heralding the glory days of winter wildlife watching to come. 

A few days ago with the bedroom window open I listened to a pair of tawny owls somewhere beyond the garden. It was 1.30am, pitch black of course except for the bright moonshine of a waning moon. These two males were twoo-hooting their resolve to claim and hold a territory. Possibly two young males eager to stake their claim (tawny owls can lay their first eggs in February).  One was much closer, maybe they had negotiated their patch and delighted in confirming their prize. Whatever the reason this went on for a good half an hour, in-between times absolute silence in the still and surprisingly mild night air. In spring a little owl calls in the same field, summer too, but I have never heard them in autumn. Whereas tawny owls only tend to be heard in autumn and winter - owl dynamics at play.  While listening to their contact chat minutes passed and I was lulled off to sleep, only later to be woken before daybreak by a robin.

There's nothing unusual in that, robins are early singers, well before dawn, often starting in July, so by November they've got into their stride and most mornings perform their duty as dawn-herald. This particular morning was different. Maybe the moonlight, maybe the mildness of the dawn,  or maybe just because I'd not noticed before, a hesitant dawn chorus seemed to briefly occur. As I listened to the robin, the tik tik of a blackbird, maybe two could also be heard, a tuneless mallard flew somewhere in the night sky, a wren erupted into song in the hedge boundary. Herring gulls and lesser black back gulls flew noisily from their roost in the Bristol Channel islands. Inevitably a carrion crow barked its morning command and was replied to by a grey heron. I often hear grey herons at night as they move about the landscape, avoiding potential predators, sometimes I think it is a vixen if I'm half asleep.

It was by now a half light which in turn disturbed a dunnock whose contact calling somewhere beyond the garden added to this false dawn chorus. It was a mild morning, there was a stillness, sound travels farther in the leafless countryside. 

By the time the sparrows in the eves began chattering it was almost light. They are lazy in my book, nearly always the last to emerge to feed, like teenagers after a late night. I looked at my watch, 06.50am, and as I did so a redwing overshot the house. In twenty minutes ten birds could be heard calling at different times. As dawn choruses go it was paltry, obviously, but the sound of awakening avian species, chatting and communicating before the foraging day ahead was a pleasing start to a November day. 

As it became lighter, the daily flotilla of around 100 jackdaws passed over, noisily jak-a-jak-ing in their pairs or trios as they flew by. It amazes me how regular those jackdaws are, I can almost set my watch to their passing each day, heading south in the morning, and returning north in the evening at roughly 5 minutes earlier or later than the week before. Some days they fly so low over the garden, I'm above them if looking out of an upstairs window, today though they were high, noisily keeping the young birds in line. 

That hesitant dawn chorus is not the true November sound. What is are the myriad of contact calls as late afternoon merges into dusk. That is a favourite time of mine, to sit quietly and reflect on what is happening. Go for a walk across any farmland, ramble through a deciduous woodland, or sit on a hill at dusk and I can guarantee pheasants will call somewhere. There is something primeval in that pheasant call, especially if heard from a great distance. In the right habitat, blackbirds set up a continuous tik tik, or sep sep as they jostle and fidget before sleep. Robins of course who never seem able to sleep add to the melee, and wrens too. I recently watched the silhouette of a wren at dusk. Its diminutive plumpness shook with the effort of its song. Against a sunset sky this sound which has permeated down the centuries, spoke more to me of November stillness than I could imagine. But then it was off, into the hedge across the lane and out of sight, though not out of earshot.

I could suggest the November silence is also about corvids, rooks, carrion crow and increasingly ravens calling in the distant soundscape, their caws and chatter from an unseen stubble field, is of the season. If you are lucky on that wander, jays cackle alongside fieldfares high in the trees. It may be just here in Somerset, but I feel the once wary jay is becoming bold. I now see them flying over motorways with crops stuffed with acorns or in Bristol streets where they have always been a familiar sight and of course in the silent woods as they noisily fly away from you.  

It is the lack of other ambient sounds which heightens these and all bird calls. By November most insects have done their best, the woods and farmlands fall silent of their buzzing and stridulating. Summer migrants have left, taking with them their chattering and exotic song. Trees have mostly lost their leaves, hushing the gentle rustle of air through their branches. The ground is soft, footfall across grassland is mostly silent, the dry rustle of early autumn a faded echo. Sounds travel far, scent too in the all too still landscape.

At dusk there is that scent of November which is not replicated at other times of the year. Air inversions move moist aroma upwards from the still warm soil with the lightness of touches. It's a rich mix of earth-bound mycorrhizal, associations with dampness and the thousands of microorganisms decomposing the plentiful biomass of summer in readiness for the growth year ahead. There is nothing like it, especially if mixed with wood smoke from an unseen dwelling. That for me is November. To sit outdoors on a calm late autumn evening simply absorbing nature's bounty. Not every evening will have a robin sing, but I know it is there. Likewise the starling, sparrow and tawny owl. They'll be watching me, I am blind to them, and I simply watch the mist from my mug of tea, evaporating, spiraling upwards to oblivion, ever so quietly.

I began with a quote from The Quiet Fields by BB. At the end of his entry for November 2nd he references two giants of nature writing, W.H.Hudson and Richard Jefferies within the context and reflections on the changing seasons. 

[p178] "Certainly Richard Jefferies felt it, and Hudson also who was less of a dreamer than Jefferies, but with the same keen perception and with more literary skill"

BB's view is that to connect with this primitive 'outdoor' feeling, sudden and swiftly passing can only be felt by your true countryman - your sportsman - naturalist. That is the nub of all connection with nature, that connection, that primitive outdoor feeling none of us who feel it can really explain, it is simply primeval. Jefferies, Hudson and BB all came from that era of shooting game to becoming naturalists. It is a lost world to modern naturalists. Yet for centuries, longer maybe, people have listened to November's silence, watched the sun set and connected with the landscape and wildlife around them. It is thanks to BB and all those writers throughout history, who captured those long forgotten moments in November, that we the future reader can connect across time. As ever their writing stirs the soul into stillness, reflection and November.


BB (1981) The Quiet Fields, illustrated by D.J Watkins-Pitchford. Michael Joseph. London