Nature 2008 June

Black is the new grey for the shadow-tailed one

I’m not sure if it is just me or have others noticed all our seasons seem mixed up these days? I guess it could be to do with a climate influenced by global warming but then again just as easily the English obsession with the weather. Last year, our summer was much wetter than in recent years (as wet as 1914; a very wet year). This year, although a repeat is not expected, the Met Office tell us we are liable to have some unsettled spells with cool wet springlike days as late as June or July.

The name ‘squirrel’ comes originally from a Greek word meaning ‘that which makes a shade with its tail’. Squirrels are back in the news again for two reasons. Firstly grey squirrels have established themselves in Scotland, territory of the ‘reds’, for the first time and secondly, black squirrels are displacing greys in England. In mainland Europe black and albino variants of red squirrels are quite common but are unusual in Britain, meanwhile albino variants of grey squirrels have been regularly reported, mainly in Essex, Kent, Surrey and Sussex. Between 1876 and 1929, around 30 introductions of American grey squirrels were made into England and Wales although the ones introduced to Woburn Park (Bedfordshire) at the end of the 19th Century are attributed with their subsequent naturalisation in England. ‘Black’ examples of ‘greys’ have until now been limited in number but the situation is changing rapidly in seems. Surveys indicate there are about two million grey squirrels in the UK and between 125 and 150 thousand ‘reds’ the majority of which are in Scotland. However it has been estimated there are at also at least 25,000 black squirrels distributed across the eastern side of England. The ‘black’ is a variant of the common American invader the ‘grey’. When I say black, some are ruddy/brown/black while others are a sleek jet black, the latter offspring of two ruddy adults, two black or combination of both.

But why? Where blacks occur they appear to be dominant over their grey cousin. Genetically they are missing a sequence of DNA. As originally described by Darwin in his theory of Natural Selection for such a mutation to persist it must be giving the black variety an advantage: in this case providing the black with a better immune system or higher levels of testosterone in its blood, which in turn influences the animal’s behaviour. In short they are thought to display more aggressive behaviour than the more placid grey – tell that to a red squirrel at the time the greys were introduced!

The first sighting of the black mutant was in 1912 in Letchworth Hertfordshire, which now has a black squirrel as its town mascot. Since then they have spread out to other parts of Herts and Cambridgeshire where in some villages (e.g. Girton) they represent 50% of all the squirrels present and it is anticipated to move into parts of East Anglia. So are they coming this way? Maybe. The sightings nearest to us have been in Whipsnade and nearby Studham, which is, but a squirrel leap from Ashridge forest. So it is quite possible the odd black shadow-tail is lurking in a beechwood around here. Keep an eye open.

There are around 260 species of bee in the UK. Each year, regular as clockwork, our outhouse plays host to a small but growing colony of wild social bees. The queen that hatched at the end of summer last year and hibernated over winter is first seen in late March/early April, seeking out a suitable venue to lay its eggs. In this case the space behind some pine lap, accessed via a discrete knot-hole. May sees the first activity of this year’s brood of workers. As I write this they are streaming back and forth, decked in the yellow pollen gathered in the rape fields about a mile or so away. By June the hive is at its height of activity as the queen will be in full-swing egg-laying, supported by the drones, which according to a local (female) apiarist, are “just typical of males, hanging around the nest just in case the queen needs servicing!” These small bees are almost silent; there is just a slight hum as you listen close to the entrance. The peace is disturbed though by the low-frequency drone of a larger very black and hairless bumble bee ferreting (can a bee ferret?) back and forth aside the pine boards until it alights, switches off the power and then silently enters via the hive entrance. This methinks may be a cuckoo bumble-bee, one of six varieties we have here. Their life is one of solitude and their habit is parasitic and brutal. They carry no excess baggage so are honed for speed and attack. The mission of these all female agents ‘women in black’, is to enter the hive undetected, kill the queen, lay their own eggs and exit unscathed mimicking the behaviour of the social bees and so avoiding discovery. Meanwhile the ‘midwived-cuckoos’ are looked after by the mesmerised host drones. Not this time though as this cuckoo has been rumbled and makes a speedy retreat from the nest.

Hedgerows are at their very best this time of year. My suggestion this time is to make a bee-line for one near you and dally a little to take the vista in. Hedges are just blooming alive with animals on the make at the moment. The creamywhite of elderflower takes over the baton from hawthorn. Clumps of yellow archangel point to a hedge-line that is all that remains of scrubbed out woodland. A typical hedgerow herb is the pinky-white cuckoo flower (lady’s smock), which is out between May and June in these parts. It’s just one of many given an alternative name by poets or herbalists of old associating them with the arrival, call or departure of the eponymous bird. Others include cuckoo buttons (burdock), cuckoo’s bread and cheese (wood sorrel), cuckoo boots and stockings (bluebell), cuckoo rose (wild daffodil) and cuckoo buds (buttercup) used by Shakespeare in Loves Labours Lost.

Cuckoo, bring your song here!
Warrant, Act and Summons, please,
For Spring to pass along here!
Cuckoo Song – Rudyard Kipling

And finally, I will have to be more careful in the future when asking as I did last time for reports of the first cuckoo as it seems I may be causing a bit of a frenzy around these parts. This year I had both emails and calls over the 12 hours between 15-16 April (a day earlier than last year) announcing arrival of at least one very busy male bird in Hawridge and St Leonards. The males arrive first and fly around calling a lot to try and maintain as large a territory as possible ahead of the females. Interestingly enough, cuckoos are not the only ones on the hunt for bird nests this time of year. Despite having strict vegetarian habits for eleven months of the year, the shadow-tailed one is also partial to a bird’s egg or two about now.