January 2013

[Jack Harrison]

Well I wouldn't mind my fist sighting of ANY butterfly.

Mind you, I did see an ENORMOUS Buzzard* (aka Golden Eagle) on Friday and also had a pretty good view of an Otter on land. They almost made up for the lack of butterflies.

*I was given a good tip about raptors on Mull. If you see an "Eagle" then it's most likely just a Common Buzzard. If you see a raptor and say: "Wow, that is HUGE" then it might just be an Eagle.

Jack

[jenks]

[quote="Jack Harrison"]I was given a good tip about raptors on Mull. If you see an "Eagle" then it's most likely just a Common Buzzard. If you see a raptor and say: "Wow, that is HUGE" then it might just be an Eagle.

And if you see something that looks like a flying barn door, that`s a White tailed Sea Eagle; they make Golden Eagles look small !.


Jenks

[MikeOxon]

Some genuine spelling mistakes can be hilarious

My all-time favourite was in a note I had written about how to lay outdoor sensor cables. My typist put: "Laying in single beds is recommended by the Home Office" The word should have been 'shingle'.

[David M]

Some genuine spelling mistakes can be hilarious

My all-time favourite was in a note I had written about how to lay outdoor sensor cables. My typist put: "Laying in single beds is recommended by the Home Office" The word should have been 'shingle'.

It's amazing how the presence/absence of a single letter can afford a sentence a completely different meaning.

[Padfield]

On his father's death, my former Sanskrit tutor acquired a notebook of exam howlers lovingly copied down in the course of years as an English teacher and examiner for UCLES. He posted the contents here:

http://bombay.indology.info/howlers.html

I've always though being an examiner must be thoroughly tedious but the monotony is surely relieved when students come out with things like, 'The octopus wrapped his testicles round the diver & strangled him.'.

Guy

(Apologies for continuing the digression, but I hope there won't be too many January sightings - it's not a good thing for the butterflies)

[Jack Harrison]

I made a lovely typo on ukb a couple of years ago. I had been looking for Wall Browns in the Fens and referred to a nearby pubic car park.

"Short and curly cars only then Jack?" came a follow-up post.

I was puzzled for a moment or two until I realised I had omitted a vital letter L.

Spell checkers but not sense checkers. Software must surely exist that does the job properly.

Jack

[nomad]

I have never heard of the Painted Lady being able to over- winter in the U. K. before, just amazing.

Nomad

[Jack Harrison]

Nomad:

I have never heard of the Painted Lady being able to over- winter in the U. K. before, just amazing.

I wrote on 1st Jan as soon as I heard that report:

I would surmise that it is not an over-wintering adult as such, but a newly emerged individual from a slowly developing autumn larva/pupa.

Nobody so far has commented on, or objected to, that idea.

Jack

[David M]

Nobody so far has commented on, or objected to, that idea.

It's hard to say, Jack, and you may well be right. However, surely at some point in recent history Painted Ladies have made it through British winters in the most sheltered parts of the country. Same too goes for Clouded Yellows. These insects have often been observed in late winter/very early spring, so they can't have migrated over a cold and windswept English Channel.

Perhaps your theory regarding Red Admirals has some value here - that the array of winter-flowering plants people increasingly seem to be growing these days provides some kind of sustenance to them that helps them get by without the option of proper diapause.

[Mikhail]

I suspect that the Bonchurch Painted Lady was a migrant, rather than an overwinterer. There have been a number of sightings recently. One at Worth Matravers, Dorset on 27th December, and one each at Studland, Nr Corfe Castle and Keyhaven, Hants, all on the 1st Jan. In addition, there have been migrant moths at the Portland bird observatory over the same period. This recalls the much larger winter influx of Painted Ladies and migrant moths in February 2004. That year I saw Painted Ladies on 14 days from 4th February to 7th March, on two occasions as many as 5 in a day. They were most often nectaring on Hebe, but also Aubrieta and Rosemary, and once on Laurustinus. During this period there were frosts on at least 8 nights. The most extraordinary sighting was one I saw on 27th Feb. flying in the sunshine over lying snow following a light fall overnight. According to my diary the night minimum was minus 5, but that temperature may have been recorded at Bournemouth airport, which is a noted frost spot.

M.

[Neil Hulme]

I agree with Mikhail - these look like migrants to me. We had a faded Painted Lady in Sussex on 1st January, sunning itself on boulders at the base of the chalk cliffs near Beachy Head. The simultaneous appearance of Ladies along the coast points to them being new arrivals. Winter influxes of PL (and Red Admiral) are nothing new.
Neil

[Jack Harrison]

I bow to Kipper and his thoughts that these Painted Ladies are immigrants. But from where? The great 2009 invasion was, as far as I understand, not direct from North Africa to Britain. I had understood that the initial wave left North Africa (circa) February, these then bred in southern Europe and it was the offspring of those that arrived in such numbers in May.

So is the suggestion now that the January 2013 arrivals have flown direct from Africa? In 2009, were there any overshoots (from southern Europe) that arrived in Britain in February or did we have to wait until the next generation in May?

Jack

[Neil Hulme]

Hi Jack,
Descriptions of e.g. migratory behaviour in butterflies such as the Painted Lady should be seen for what they are - generalised summaries. These are accounts of large scale behavioural patterns and trends, not blueprints to which every individual in a population necessarily conforms to. For entire populations to simultaneously behave in an identical manner increases the risk of extinction. During the great 2009 Painted Lady invasion we saw waves of different age groups passing through the UK, sometimes together. These included ragged and battered individuals which had probably originated from North Africa, together with freshly-emerged butterflies which would have been the progeny of advance party voyagers, hatched somewhere along the way. But not every individual butterfly will conform to the behaviour pattern of the masses. A few Painted Ladies will be 'dropped' at all points along the way (travelling both north and south), and continue the constant breeding cycle wherever they may be, with varying degrees of success at any given location or time of year. Individuals and small groups will always be pushing the boundaries and pushing the limits, and that includes minor forays at surprising times of the year. So the recent arrivals could have come from any point south of a line where conditions have allowed the Painted Lady to continue its life-cycle. If the Painted Lady wishes to achieve world domination, which it does, it must behave with some flexibility.
BWs, Neil

[Jack Harrison]

Makes good sense.

Jack

[David M]

Winter influxes of PL (and Red Admiral) are nothing new.

How are butterflies able to cross 30+ miles of ocean in December & January when temperatures are in single figures (without even factoring in wind chill)?

[Jack Harrison]

DavidM:

(without even factoring in wind chill)

This is where I put on my (retired) pilot's hat. Wind chill in the commonly understood sense does not exist for an object that is moving with the air (but see below). Perhaps the simplest example is a hot air balloon. It is drifting with the wind, ie its speed over the ground is that of the wind. Occupants in the basket do not sense the wind (apart from transient gusts) from any particular direction even though they might be moving with respect to the ground.

So now think Painted Lady. Let's say it cruises through the air at 15 km/hour (15 kph). It would of course feel 15 kph on its head! That might be perceived as a wind chill. What many people think is that if the butterfly flew into a headwind of 10 kph, it would feel a more severe wind chill as if it were actually cruising at 25 kph. That is not so. It would perceive the same 15 kph wind chill as if it were flying on a flat calm day.

However, it wouldn't make much progress. Its airspeed (speed through the air) is 15 kph. The headwind of 10 kph would mean that its groundspeed (speed at which it covers the ground or sea) would be a mere 5 kph. Birds certainly know all about the slowing effect of a headwind and are often smart enough to avoid those days if possible (or fly at a different height if the wind is mover favourable/less adverse there). Some birds actually have other tricks such as flying different airspeeds according to the conditions (as do pilots) but we needn't go into that here.

Just as an aside. Does sticking a thermometer out the window of a car makes it read low because of a perceived cooling effect? No. If anything (trivial at car speeds) it over-reads (frictional heating - sort of!) At Concorde speeds, the over-reading amounted to some 40 deg C (Yes, I know, despite their huge salaries, Concorde pilots didn't have to hold their hands out the window!)

Jack

[Neil Hulme]

Hi David,
Firstly, the later part of December was quite mild - indeed a maximum temperature of 15.0 °C was recorded in Somerset on the 22nd. Some butterflies, particularly the over-wintering nymphalids, are able to operate at quite low temperatures, hence we occasionally see Red Admirals flying over snow. Mikhail gave some examples he has witnessed himself (in Painted Lady) in his posting above. One of the factors which allows for this, is the heat generated by the act of flight. Moths are even more efficient at raising their own core temperature, by vibrating their wings very rapidly prior to flight. Butterflies are doing the same when they appear to be shivering on cold days. Friends of mine have actually measured this effect in moths. Under an ambient 14 deg. a Privet Hawkmoth raised its thoracic temperature from 17 deg. to 28 deg. in a matter of minutes.
Neil

[David M]

As far as I know, wind chill merely makes it feel colder than it actually is. It doesn't make the actual air temperature any lower. If a Painted Lady flew out from northern France on a December afternoon when the air temperature was just 9c, wouldn't the insect 'feel' colder if there was a 20kph easterly breeze constantly buffeting it?

[David M]

Hi David,
Firstly, the later part of December was quite mild - indeed a maximum temperature of 15.0 °C was recorded in Somerset on the 22nd. Some butterflies, particularly the over-wintering nymphalids, are able to operate at quite low temperatures, hence we occasionally see Red Admirals flying over snow. Mikhail gave some examples he has witnessed himself (in Painted Lady) in his posting above. One of the factors which allows for this, is the heat generated by the act of flight. Moths are even more efficient at raising their own core temperature, by vibrating their wings very rapidly prior to flight. Butterflies are doing the same when they appear to be shivering on cold days. Friends of mine have actually measured this effect in moths. Under an ambient 14 deg. a Privet Hawkmoth raised its thoracic temperature from 17 deg. to 28 deg. in a matter of minutes.
Neil

Thanks, Neil. So, what you are suggesting is that Painted Ladies seen in deepest winter will not be the same ones here in numbers during August, but more recent immigrants, having crossed the Channel opportunistically when conditions were unusually benign?

[Padfield]

I have nothing learned to add, but can illustrate this pre-take-off warming up in a chequered skipper:

http://www.youtube.com/watch?v=j1RbYCEEAQs[/video]

The day had rather suddenly cooled when I took this.

Guy