Wednesday, 30 September 2015

Knot much room

I paid another visit to RSPB Snettisham earlier this month to see the spectacular flight of waders as an extra high tide drives them off the mudflats.  The highlight is the sight of tens of thousands of knot which fly together and crowd into the lagoons.

Monday, 28 September 2015

The butterfly of doom

In 1881 red admirals appeared in Russia in very large numbers, an event that was thought to presage the assassination of Tsar Alexander II that year.  The Russians could see the numbers 1881 on the butterfly's underwings. Here is a red admiral upside down on my buddleia.  It does appear to have the number 18 on its hind wing and I suppose that would read 1881 from underneath with its wings outstretched.

The red admiral gets its name from a corruption of "red admirable".  Its scientific name Vanessa atalanta was chosen by Linnaeus in 1758.  The name Vanessa was made up by Jonathan Swift in a poem Cadenus and Vanessa written in 1712 and first published in 1726.  You don't meet many admirals called Vanessa!

Saturday, 26 September 2015

Bird of the week - Pheasant

I am sorry about this.  It wasn't my idea but he's been going on about it for weeks.  "How come you have all those pigeons and sparrows as Bird of the Week and you've never had a pheasant?"  I tried to explain that some people don't regard the pheasant as a proper British bird because it is often raised for shooting.  "Nonsense." he said.  "My family came over with the Romans and we've been here ever since.  We're more British than you are."  Calling him a common pheasant didn't go down well either.  Like most people he believes he is distantly related to aristocracy, in his case Lady Amherst's pheasant, although it probably isn't true (see below).  Anyway, for what it is worth, this week's Bird of the Week is the (common) pheasant.

This is "my" pheasant keeping an eye on me in the kitchen garden this week.  He probably thinks of me as "his" human.

He still comes to the door almost every day to ask for food, preferring peanuts to sunflower hearts.

The common pheasant (Phasianus colchicus) is a widespread game bird now found in many parts of the world.  It was introduced to the UK by the Normans, and perhaps by the Romans, but has only been extensively reared for shooting since the 1830s.  Around 35-40 million birds are released each year for the four month shooting season (October to January).  Just over a third of those are shot and another third or so are predated by foxes.  Perhaps 5-13% are killed on the roads and a smaller number, perhaps up to 5%, are killed by buzzards.  Some survive to live wild and breed and they are common sight in the countryside all year round.  This map is from the BTO Bird Atlas.

Common pheasants are becoming more common!

Common pheasants are native to Asia and exist as several subspecies.  Most of the birds in this country are hybrids, mainly of the Caucasus type and the Mongolian type.  "My" bird is mainly of the former, with no neck ring, while these ring-necked birds probably have more Mongolian ancestry.

Rare types of pheasant in the UK are the golden pheasant, which I have not seen, and Lady Amherst's pheasant, shown below.

Listen to the BBC Radio 4 Tweet of the Day on the common pheasant here.  Watch several short BBC Nature videos on common pheasants here.  Read a selection of BBC Food pheasant recipes here.

Friday, 25 September 2015

Flying in tandem

There are still some ruddy darters around.  These two presented a photographic challenge as they were flying through the grasses.  It is interesting to see how they fly with their legs folded.

Thursday, 24 September 2015

Brimstones on purple loosestrife

The brimstone is the original butter-fly.  Purple loosestrife is a favourite nectar source for the adults while the larvae feed on buckthorn and alder buckthorn.  These were on the Somerset Levels last month.

Wednesday, 23 September 2015

Dragon quest

For two years I have been trying without success to take a photo of a brown hawker dragonfly.  I have seen plenty but they seem to fly constantly when in view and then suddenly disappear.   Finally I struck lucky last week.

Brown hawkers typically rest low down in grass and vegetation and this is how this one was when we first saw it.

Fortunately the sun had gone in and the dragonfly seemed happy to rest while I took a few (dozen!) photos.  This is a male with blue eyes, a waisted abdomen and extra blue markings on S2. 

The next target now is a female brown hawker!

Monday, 21 September 2015

Ghost bees

At the end of the summer we see a lot of white bees around, a sure sign that they have been collecting nectar from Himalayan balsam.  Here is a honey bee emerging from a balsam flower covered in white pollen.

The bees seem to find the pollen a nuisance or an irritant and spend a lot of time scraping it off.

One place they cannot reach is the back of the thorax so they end up with a very characteristic white mark when they get back to the hive.  I don't know where balsam grows close to my home but the bees have certainly found it.

Honey bees seem to collect very little of this pollen.  This bee has a small amount in its pollen baskets but nearly all the pollen being brought in is from other flowers (and is of other colours).  The bees are very fond of the balsam nectar but the pollen is presumably not of the quality they are after.

Bumblebees are also very keen on the nectar.  This bee has its tongue out even before getting into the flower.

Bumblebees seem also to dislike the pollen.  I haven't seen a bumblebee with white pollen in its baskets.  This common carder bee had been collecting brown pollen before stopping by for the nectar.

The bumblebees also spend a lot of time grooming to get rid of the pollen.  These two show how they can't quite reach the small of their backs with their middle legs.

This is a solitary bee emerging from a balsam flower but it has so much pollen on it that it is difficult to tell what species it is.

Wasps are enthusiastic visitors for the nectar as well.

The Himalayan balsam flower is beautifully designed.  It has a landing platform at the front but the nectary is right at the back.  Here there is a small drop of overflowing nectar.

The bees pass through the flower and under the anthers in the roof of the flower, getting covered in pollen as they do so.

The flower is in two parts so they sometimes emerge through the side but almost always seem to go in the front.

The fertilised flower produces a seed pod which distributes its seeds with explosive force and ends up with the spring sprung like this.  A single plant produces up to 800 seeds.  The seeds can end up up to 4m away but as the plant commonly grows at the waterside the seeds can obviously travel much farther.

Himalayan balsam (Impatiens glandulifera) was introduced to the UK as a garden plant in 1839 but soon escaped into the wild.  It is a non-native invasive plant listed on schedule 9 of the Wildlife and Countryside Act in England and Wales.  It grows very tall and out-competes native plants thus promoting riverbank erosion.  It is widespread throughout the UK.  This photo shows how it has spread along the banks of the river Nene in Northamptonshire.

There is another non-native balsam found on our riverbanks - orange balsam, Impatiens capensis.  Also known as orange jewelweed, it is a native of North America but seems much less invasive than Himalayan balsam over here.

It seem that we are stuck with Himalayan balsam.  It is much more widespread than other alien invaders such as Japanese knotweed and giant hogweed and will be impossible to eradicate.  The bees won't be complaining though as it is their favourite source of nectar at this time of year.