Squirrelling Away……

23 Sunday Oct 2022

Posted by theresagreen in Nature of Wales

Tags

acorns, autumn, berries, caching, grey squirrel, horse chestnuts, mast year, October

Here in our corner of North Wales we are enjoying a gloriously colourful and particularly bountiful autumn. This year is another ‘mast year’; a natural phenomenon, still not completely understood, where some tree species produce very large crops of seeds in some years, compared to very few seeds in others. In the UK the last mast year was as recent as 2020, when oak trees across the whole country produced thousands of acorns. This year it’s an unusually big one; you might have noticed exceptional amounts of hawthorn, holly, rowan berries and sloes too, I certainly have, but more about that in my next post.

Over a few recent days, from my front windows, I’ve noticed a lot of grey squirrel activity taking place on the lawn in the grounds of the flats where I live. Now to put it politely, I’m not generally known to be a fan of grey squirrels, for many reasons and in our locality, it often seems we have more than our fair share. Having said that, at this time of year it would take someone with a much harder heart than mine to not enjoy watching the annual ritual of them scurrying around, nose to the ground, teeth clenched around precious treasure, searching for a spot in which to bury it. Here, where sessile oak trees abound, it’s most often an acorn, but unusually at the moment, I’ve spotted them with much meatier horse chestnuts. This is interesting as there are very few horse chestnut trees nearby, and those I know of rarely produce more than a few fruits each year. The nearest one I can just see the top of from my window is probably about 30 metres away behind other trees. Perhaps this year it too has produced more chestnuts than usual.

A moment of indecision – where to go to bury this acorn?

Grey squirrels are well-renowned for their intelligence and resourcefulness and are notorious as opportunistic and resourceful garden bird-feeder raiders, so perhaps it’s not surprising to learn that when it comes to finding and then burying nuts, an apparently simple process, there is much more to it than first meets the eye. When it comes to selecting food for their larders, squirrels are picky; each and every nut making it to their larder will have undergone rigorous quality control. When a potentially good one is found, it is picked up and held in a paw to be scrupulously examined and assessed on its potential for long-term storage. Before burying the appearance is scrutinised carefully – there must be no visible signs of damage or infection. The weight is also crucial, a well-chosen nut will feel firm and heavy, a lighter one may be under-developed or occupied and partially eaten by a boring insect. Only those nuts passing all tests will be buried to keep fresh for future consumption.

A grey squirrel giving a horse chestnut the once-over before placing it in the ground

Once a burial spot has been chosen, the squirrel uses its front paws to dig a hole 2.5-5cm deep, then drops in the nut, ramming it in with its mouth.

When it’s satisfied the nut is firmly in place it replaces the soil, patting it down to firm it. A final check to make sure no-one is spying is made, then leaves are placed on top to disguise signs of recent digging.

The nut is covered with soil and firmed in

A nut buried is by no means guaranteed to stay there. In the wake of an interment, all kinds of subterfuge and blatant piracy is likely to ensue.

An interloper about to dig up a recently buried chestnut

If an individual suspects it has been watched by another squirrel, it may wait until it feels safer, retrieve its own treasure and re-inter it in another spot. And there are always those that have no scruples (or perhaps less experience) that will enter a territory to steal from one more conscientious and industrious. Sometimes they will make off with their stolen booty and re-bury it as their own, and sometimes they have even less scruples and will simply sit and eat it right out in the open.

One piece at a time the squirrels build up a supply of food when times are good to save them from hunger when there is less available during the winter months, bearing in mind that grey squirrels in particular only hibernate during extremely cold weather. They work extremely hard to conceal a huge number of items in a scattered pattern (called scatter-caching) as a degree of insurance against discovery by other squirrels, mice or birds. But using this apparently random method of hoarding, how do they remember where they have buried their treasure?

A lucky grey squirrel can expect to enjoy a long life and it seems their brains get bigger the older they get. Not only that, but researchers have also discovered each autumn their brains get bigger again, and it’s this added capacity that enables them to create a huge mental map of where their treasure is buried. So, when they get hungry, it’s thought that memory guides the squirrel to the general area and then scent guides it to the specific location of a cache over the final few centimetres.

No matter our personal feelings towards these often-contentious little animals, one redeeming feature may be that many of their caches will remain untouched. Here in the UK, it has to be acknowledged that this behaviour practised by both red and grey squirrels contributes to tree dispersal, and therefore plays a part in regenerating our native woodlands; (and equally important, in the case of reds in particular, they also aid fungi dispersal). It’s such a shame they are so destructive; they are fascinating to learn about and entertaining to watch.

Sloe Picking down a Memory Lane

19 Saturday Oct 2019

Posted by theresagreen in Nature, Northamptonshire

≈ 9 Comments

Tags

common centaury, flowering in October, October, Polebrook Airfield Nature Reserve, robin's pincushion, sites reclaimed by nature, spotted crane-fly

Polebrook Airfield Then

Memories of childhood wanderings were brought back vividly the weekend before last as my sisters, niece and little great-niece headed out on a sloe-and-blackberry foraging foray around the old Polebrook Airfield in east Northamptonshire. Once a flat, open site used for agriculture, the site was commissioned for use by the RAF and then used by the US Airforce as a base for bomber aircraft during World War II. After the war ended it was decommissioned by the Air Ministry and sold back to the adjacent Ashton Estate. Most of the buildings were removed from the site’s surface, but below ground many concrete shelters and chambers remained, rendering it unfeasible to restore it back to use as agricultural land. The woodland of Ashton Wold was already a Private Nature Reserve and separated from the old Airfield only by a narrow country road, so their owner took the opportunity to leave it alone as a protective buffer zone between the Nature Reserve and the surrounding farmed land, interested to see what happened when nature was allowed to venture back in.

1960s

Way back in the mid to late 60s we lived at Ashton Wold and in my early double-figure days, I spent hours wandering around the woods and fields and sometimes ventured over to the Airfield. Then it was unfenced, easily accessed and without the warning signs that might pepper such a place nowadays. It was doubtless a potentially hazardous place for people, strewn with all kinds of crumbling, part-demolished buildings and underground shelters half-hidden by long grass and brambles. There was always the sense that you shouldn’t really be there, which of course added to its appeal. At that time I had no real idea about the site’s history or plans for its future. But I did know that in the Spring I could find Great-Crested Newts swimming in what I thought of as water-filled ‘tanks’, probably old concrete foundations or something similar, then later Lapwings (or Peewits as we knew them) nested here; hunting for their hidden ground-level nests is how I learned that the parent bird would sometimes feign an injury to try to draw you away from a nest. There were wildflowers too and I’m sure a great deal that passed me by in this burgeoning sanctuary.

AND NOW

The site now is almost, but to us, never completely unrecognisable. Part of the site is used by a Warehousing Company, part is once more farmed and most importantly the Northern edge of the site is now also designated as a Private Nature Reserve. A Bioblitz there, carried out by the Northamptonshire Biodiversity Records Centre in August 2015, resulted in an impressive species count that included 40 species that have a notable or protected status at National level, including 17 birds, 2 bats, 7 moths, 3 butterflies, 1 amphibian, 9 lichens and 1 moss species.

Today we were there to gather sloes and blackberries, but needless to say, even now on a cool, damp and intermittently sunny Autumn day, there was so much more to see it was impossible to keep focussed.

Blackberries and red berries of Black Bryony

Wide mown grass paths now crisscross areas of Hawthorn and Blackthorn scrub bound up with tangles of brambles and wild rose briars that are interspersed with rough grassland.

There were always Teasels here and it’s good to see them thriving still. It’s a native plant and an important source of summer nectar and pollen for insects – Bumblebees love the flowers and then in the autumn the distinctive prickly dried heads hold seed that is sought by birds, particularly Goldfinches.

Amongst the large patches of rough scrubby grass there were still a few flowers to be found, a sprinkle of purple thistles and a few plants of Common Centaury. The latter plant only fully opens its flowers in the sun, which was only intermittently shining on us, so I didn’t get to see them out unfortunately.

Common Centaury-Centaurium erythraea

There are lengths of old concrete aircraft runways or service roads still in place, but now colonised by moss enriched by decomposed fallen leaves, they are concealed beneath a growing medium sufficiently deep for plants adapted to dry conditions to establish. In one such place we came across a spreading colony of Great Mullein, whose thick silver-grey felted leaves are perfectly adapted to potentially dry conditions.

Great Mullein-Verbascum thapsus

One plant stood out from the crowd as it had produced the most enormous leaves I’ve ever seen on this species. it was amazing and must have sprung from a seed that had fallen in an especially fertile spot.

It’s downy leaves, additionally warmed by sunshine were attracting insects too and must have made a cosy place for these Spotted Craneflies to couple-up.

Mating Spotted Craneflies

Flies paused to rest there too; I managed to catch a bright shiny Bluebottle and a golden-brown, or officially Orange Muscid Fly basking in a spell of warm sunshine.

Muscid Fly – Phaonia palida

Bluebottle

Some Blackthorn looks old, and has grown into small spreading trees. Their brittle branches and tangles of twigs are mostly leafless and bear sparse fruits, but they are encrusted beautifully with lichen.

We wandered through the maturing woodland where the trees are mainly Ash and Oak with some Silver Birch. The ground beneath the trees is strewn only with fallen branches; it may be kept clear as there are numerous deep rectangular holes, their covers moved to the side and covered with moss. Quite hazardous if you don’t watch where you’re going. There are still intact brick and concrete-built shelters here too, their roofs are now camouflaged by vegetation, but the entrances are clear and accessible and it would seem watertight.

On a moss-covered fallen log, tiny mushrooms with pretty mauve caps were growing. I tried to persuade my 3 year old great-niece that they were stools for fairies or pixies, but she didn’t believe me! She just wanted to walk along the log! I don’t know the name, but have been advised it’s probably a species of Marasmius, commonly known as ‘parachute mushrooms’ because of the ribbed and domed shape of their caps.

We headed out of the woods and back onto safer ground to resume our berry hunt. Many were tantalising beyond our reach, like these that hung high above a twining rope of heavily-berried Black Bryony.

Beyond us, but all the better for small birds like this Blue Tit – one of a party that were travelling around, keeping up a companionable dialogue of contact as they foraged.

We passed by a huge spread of Knapweed, entirely gone to seed now, but it must have been a lovely sight back in the late summer.

Clusters of ‘keys’ dangle from Ash trees

Intriguingly a small iron-framed wooden bench seat has been set beneath an oak tree.

A rather beautiful yellow-green spider was finding the sun-warmed metal much to its liking. My picture isn’t great, but I think it may be a Green Huntsman Spider.

We reached the high dense Blackthorn hedge that forms an effective boundary with the road. There were sloes to be found here, but there distribution was a bit erratic; some bushes had a lot, many had few or even none at all.

A wild rose using the hedge for support is decorated with ferny-mossy Robin’s Pincushions, also known as the Bedeguar Gall. The familiar fibrous growths are the plant’s reaction to being chosen to host the larvae of a tiny gall wasp, Dipoloepis rosae.

Heading back I found clumps of aromatic Wild Basil in the long grass; this plant is a member of the Deadnettle family

Wild Basil-Clinopodium vulgare

and a little later I came across a close relative, a nice patch of White Deadnettle, whose leaves remind me of stinging nettles.

A lovely family wander which brought back happy memories for my sisters and me that I hope may be recalled and even better, relived by our children and grandchildren in another fifty years!