I am writing this blog post on a very wet Sunday afternoon. I have been lacking inspiration to post for a while now. No special creature has appeared no profound thought of ecological theory has struck. I have very much been struck in the rut of the change of seasons, the summer visitors have gone, and the winter ones seem not to be bothering to come at all this year. Last week the temperature did take somewhat of a dive, and this resulted in the return of the Marsh Tits to my patch, a small flock of Teal, a nice view of some Goosander, and a very fleeting view of an accidentally flushed Woodcock.
This past week the cold has
evaporated to be replaced by rain, torrential downpours. Facebook happily reminded
me that 6 years ago today we were under 6 inches of snow what a difference. I
did see my first Redwings of the year, just three not the hundreds one would
expect. From this introduction, you may assume that I am going to wax lyrical
about climate change and the shifting of the season, but I feel I have done a
lot of that already and I would imagine that most of my readers are not climate
deniers. Instead, what piqued my interest were a few still shots from my main
camera trap.
This particular camera trap has
been situated in the same hedgerow recording 24/7 since 2015. This is my magnum
opus, my long-term contribution to wildlife, and in particular mammal
recording. My usual focus is on the Badgers, the local clan is seen less and
less (I am very worried about them at present), but more recently the Roe Deer
family and Otters have drawn my focus more. What has intrigued me most this
week however is the ubiquitous Grey Squirrel.
Laying aside the obvious debate
concerning its status as an invasive species, the demonic species that has devastated
the native Red Squirrel, even though it is just doing its thing…survival, what
drew my attention was some interesting behaviour.
It is easy to watch wildlife and become
focused on the individual, websites, and books are filled with portraitures of
birds and animals, and whilst delightful, I think I find the behaviour to be extra
interesting. We are now into December and like I said we have had a cold snap
now followed by rain. On the trail camera, I caught a few stills of a Grey
Squirrel collecting leaves, it was noteworthy enough to add it… well to the notes
section of my records.
Consistently for approximately an hour on the 28th of November in the early afternoon, a squirrel could be seen collecting beech leaves and taking them up the tree. This continued across the 7th, 8th and 9th of December despite the rain. This is obviously evidence that the individual is either building or remodelling its drey.
Squirrels live in dreys, collections
of leaves and twigs sometimes lined with grass and moss. They are not a species
that hibernate, and, in the winter, it provides, a warm refuge to retreat to
between foraging expeditions. Dreys are built in the crook or v of branches in trees
2-20 metres off the ground, they appear roundish and nest-like, in fact, they can
be confused with magpie nests although magpies are much messier.
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| Photo care of Rosser1954 on Wikimedia Commons CC-3.0 Grey Squirrel Drey.jpg |
What interested me however was the timing of this event. I understand building it now, the weather has turned and the squirrel needs to shore up its existing drey or repair its old one if conditions are likely to worsen but this squirrel seems to be in quite a hurry often working in the night!
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Squirrels are pretty much diurnal perhaps more active at dawn and dusk. Previous analysis of activity has indicated a rather broad daytime activity pattern on my patch. An aggregated count from 2015-2019 indicates activity occurring between 7 am and just past 5 pm so it surprised me to record the squirrel actively collecting leaves at 2.18 am, 5.40 am, 9.40 pm and 10.29 pm.
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| 2.19 am and still collecting leaves! |
A quick internet search suggests that squirrels are not nocturnal however I am one who on the whole eschews the internet as the font of all knowledge and so have fallen back on my books. My go-to bible in these situations is Harris and Yalden’s Mammals of the British Isles: Handbook, 4th Edition.
The Grey Squirrel account is
written by J. Gurnell, R.E. Kenward, H. Pepper and P.W.W. Lurz and only has a
paragraph on activity in which it states that they are less arboreal than Red Squirrels.
Of note is a section on communication and senses. Seeing the squirrel in the
dark I was concerned for its safety. It is predated by stoats, buzzards, and
foxes. I have seen a vixen carrying a squirrel back to its litter, given that
its usual life strategy is based on daytime activity just how vulnerable was
this squirrel? The answer it appears is very, the book details the structure of
the eye drawing the conclusion that the species can see in up to dim-light so
fully nocturnal activity is very risky. Admittedly they have excellent hearing
but their agility on the ground and up trees is based very much on vision.
I then considered the effect of the moon; a full moon could give enough light for the squirrel however from the 7th-9th of December the moon was a waning crescent with only 24% illumination on the 7th falling to just 10% on the 9th.
I will not get a definitive
answer to this conundrum, nature does what nature does and most certainly does
not follow the rules of the textbook. I considered that the individual could be
pregnant and was forced to build/improve the drey for that, and births have
been recorded right up until the end of November. Perhaps the mild spell
allowed for a late pregnancy, but this is very much on the edge.
Animal behaviour is very much a
cost/benefit game, and this squirrel obviously felt the need to put itself at
risk and it would not do this if not for gain, unless this is one of those
individuals that shape evolution, either making a mistake that inevitably leads
to its predation and the end of its gene line or the pioneer that stakes out a
new niche for all its kind.
It are these puzzles that make
ecology such a fascinating topic to study.
