December 2015

This is the last Nature Notes for 2015, and soon the television will be full of those dreadful ‘review of the year’ shows.  But there’s no need to worry, this won’t be a review of the natural year.  Nature is very much a ‘happening now’ subject and there’s usually too much going on right now to worry about what happened last month.  Besides, I have enough trouble remembering what happened last week anyway.  One thing that happened this week, however, was very memorable – I saw a badger!  Nothing remarkable about that you may say, but running across the lawn in the middle of the day, hours away from dusk?  It made me wonder why it was out in daylight and what had disturbed it.  Perhaps it was confused by this long drawn out autumn we are having – we’ve had the warmest October, and November also looks like setting records with a high of 22 deg. C in Wales on November the 1^st and two weeks of warm humid weather since then.  As I write this in mid-November there are still plenty of leaves left on the trees and we have Verbena, Fuchsia and ‘Bowles Mauve’ still in flower in the garden.  We even have a confused apple tree that put out a tentative bit of blossom a couple of weeks ago.

Eyed Hawkmoth

Hopefully, it will get colder soon and we’ll get some frost to slow down the garlic and ensure a good crop for next year.  Cold weather isn’t good for everything though, but most of the animals in your garden won’t experience that as they will have died weeks or even months ago.  Perhaps I should qualify that – by most, I mean numbers, and the largest number of visible animals in your garden are probably insects.  Most solitary insects like flies, midges, solitary bees and wasps, dragonflies and butterflies, have a very short life as an adult and may last only a few days or a few weeks at most.  These insects will have invested their future in eggs or larvae that will hopefully be in a safe place until spring warms enough to accelerate their growth process to become adults.  Not all insects do this though and there are some notable exceptions, especially larger insects like the winter damselfly and Peacock and Brimstone butterflies.  You would expect some of our larger moths like the hawkmoths to overwinter as well, but mostly this does not happen.  For many, like the convolvulus hawkmoth and pine hawkmoth, which are immigrant species, the UK moth book gives the stark message – unable to overwinter.  (For some, like the lime hawkmoth, the message is even more stark – does not feed.)  Most overwinter as a chrysalis – the privet hawkmoth sometimes twice.  The only hawkmoth I could find that overwinters as an adult is one of the smaller ones – the delightful humming-bird hawkmoth, which can cope with mild winters in the south west.

Convolvulus Hawkmoth

The social insects like bumblebees and wasps all die out in winter with the exception of mated queens that will carry the next generation as a packet of sperm in their abdomens.  Exceptions to this are the remarkable honey bee, that stores honey to keep the workers going over winter, and ants that are just basically tough and resourceful (and carnivorous) and stay underground.

One thing that prompted me to write about overwintering animals was curiosity about spiders and what happens to them at this time of year.   Sadly the answer is fairly boring – some overwinter as adults, and some don’t.  But while I was looking I found a very remarkable fact about spiders – they can fly!  And these are not just some exotic species shown to us by David Attenbrough from some jungle in South America, but things like our own British money spiders.  The spiderlings squirt enough silk from their spinnerets to form a sort of kite which is directed into the air in the hope of catching an up draught.  If successful, they let go of their perch and drift to wherever the wind takes them.  This is, of course, a risky strategy – they may end up in another spider’s web, or as a snack for swallows, or frozen at 30,000 feet, or even in the sea.  So why adopt such a strategy?  Well simply because staying around hundreds of other cannibalistic spiderlings is even more risky.

Humming-bird Hawkmoth

This picture of the humming-bird hawkmoth is a bit of a cheat in that I took the photo in Sicily.  In my defence I can confirm that I saw several this year from the kitchen window feeding on the verbena, but they had always gone by the time I got out with the camera.

Tree Bumblebee

November 2015

You may have seen in last month’s magazine, that a red squirrel was seen bounding along the sea wall at Pett Level.  The immediate question that comes to mind is ‘Are you sure?’  Well, at least two people saw the squirrel, and one even went so far as to describe the white front, which only the red squirrel has.  The front of a grey squirrel is pale but not as distinctively marked as the red.  So assuming that both witnesses saw the same animal, then it is very unlikely that both mistook a reddish grey squirrel (which does happen) for a red squirrel, then we have to ask what it was doing there.

The nearest natural colony of red squirrels is probably on the Isle of Wight and even though red squirrels can swim, it is unlikely that they would manage to swim across the Solent, and then take on the 100 miles or so between there and Pett.  One of the reasons that red squirrels are still living on the Isle of Wight is that the Solent provides a natural barrier against grey squirrels.  There are of course nearer red squirrels in France, where they are much more common than here in the UK, but again it would have needed to have travelled here as a stowaway. 

The obvious difference between the red and grey squirrels is in their colouring, but it is by no means clear cut.  When red squirrels go through their pre-winter moult, they temporarily have a grey coat.  They also lose the ear tufts that can normally be used to distinguish reds from greys.  Also, continental red squirrels have a much greyer coat than the UK population.  Add to this the fact that some grey squirrels have a reddish tinge to the fur on their back and legs.  The only reliable colour difference is in the tail.  The fur of a red squirrel’s tail is always a single colour – grey or red, but the tail of a grey squirrel has three different shades – a base of reddish brown surrounded by black hairs with a halo of white ends.  Another way of telling greys from reds is size – red squirrels are quite a bit smaller than grey squirrels, but of course young greys could easily be the same size as a fully grown red.  Despite these confusions there is little chance of mistaking one for the other in the UK in September if you get a good look.

Aside from physical differences, there are differences in their habits.  Though both species eat the same diet of seeds and nuts – and also therefore compete for food, red squirrels live at much lower densities than greys – about 1 red per hectare compared to up to 10 greys per hectare.  They manage this largely because greys can digest the tannins in acorns.  Reds will eat a few acorns but they can’t cope with many.  One of the most interesting wildlife spectacles is to watch grey squirrels burying acorns. At this time of year they spend hours running back and forth from tree to stash, and even though they only bury one in each place, research has shown that they manage to remember where a high proportion of them were buried.  The ones they don’t remember or need also have a fair chance of producing a crop for future generations.

It is interesting to note that though red squirrel numbers have been declining since the 1880’s when grey squirrels were introduced from North America, their numbers are currently rising.  This is due in a large part to conservation efforts that reduce grey squirrel populations.  This allows red squirrels to expand into their former territories.  Grey squirrels not only out-compete the reds for food, but they carry a squirrel-pox virus which is deadly to reds, and has no impact on the greys.  There are many projects in place to protect red squirrels – greys have been eradicated from Anglesey, are being excluded from the Isle of Wight, and are even being culled in Cornwall.  Perhaps sadly though, it is not always being done for the best reasons – a population of red squirrels is a sure guarantee of an increase in tourism!  And I can understand that – I’ve seen red squirrels in Scotland and at Formby in Lancashire, and they never fail to enchant.  I only wish I’d seen the one at Pett Level and I hope that however it got here; it manages to find a safe place for the winter.

Here are the only other pictures of squirrels that I have.  Both taken in Canada where they also compete with the North American grey squirrel, apparently successfully.

Black Squirrel

Douglas Squirrel