Thought this group might be interested to know that over the past few days
there has been an unprecedented arrival in the south of the UK of some
summer migrants...House Martins, Swallows Sand Martins and also continental
butterfly species.
All these bird species usually winter around the Saharan region though a few
may stay further north, but usually don't start to appear for at least
another month to six weeks time.
Being quite interested in the effects of weather on bird migration I
wondered if any of the experts may be able to point out any possible
meteorological causes of this highly unusual activity?
It is quite common in Spring for a wave of migrants to arrive with a push of
warm air from Europe and Africa, but this early in the year is highly
unusual.
Any thoughts?

J Poyner.

"J.Poyner" wrote in message
...
Thought this group might be interested to know that over the past few
days
there has been an unprecedented arrival in the south of the UK of some
summer migrants...House Martins, Swallows Sand Martins and also
continental
butterfly species.
All these bird species usually winter around the Saharan region though
a few
may stay further north, but usually don't start to appear for at least
another month to six weeks time.
Being quite interested in the effects of weather on bird migration I
wondered if any of the experts may be able to point out any possible
meteorological causes of this highly unusual activity?
It is quite common in Spring for a wave of migrants to arrive with a
push of
warm air from Europe and Africa, but this early in the year is highly
unusual.
Any thoughts?

J Poyner.

.... we had a spell, roughly from the 2nd to 5th (February), when the
airflow in the lowest couple of thousand of feet was from the area of
the Azores (2nd), thereafter from Madiera and the Canaries or further
south - presumably there has been some mechanism to encourage migrants
out of the Saharan interior (see other thread on dust injection), and
they have been encouraged to come north-northeast on the warm, often
brisk flow. Hence the high temperatures noted earlier in the week and
the consistent warmth so far: anomaly +7degC at a conservative estimate
until the last couple of days. Yesterday and today must have been a
shock though - always a problem at this time of year: notably mild
weather cannot be relied upon, and we are about to experience a return
of somewhat more traditional February weather (frost).

Norman Elkins (who I worked with for a brief time at Lossiemouth), wrote
a book on the subject of Weather and Bird Migration - I believe it is
still regarded as a solid reference for the subject: don't know if it is
still available though.

Martin.


--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm

On Sun, 8 Feb 2004 20:32:01 -0000, J.Poyner wrote in

snip
It is quite common in Spring for a wave of migrants to arrive with a push of
warm air from Europe and Africa, but this early in the year is highly
unusual.
Any thoughts?

As Martin has written, the winds for some days early in the month may well
have encouraged them, but I still find this most fascinating. I know next
to nothing about such migration, but would reckon it must be very early
indeed. I imagine the mild conditions further south in recent weeks may be
a another factor in encouraging this early move north.

It does look as if, at least for western areas, there will be a renewed
flow of warm air from the SSW. It will be most interesting to hear if more
arrive and just how far north they get. I don't normally see any of the
swallow family here until well into April. I'll be on the lookout.

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 08/02/2004 21:35:38 UTC

"Mike Tullett" wrote in message
...
On Sun, 8 Feb 2004 20:32:01 -0000, J.Poyner wrote in

snip
It is quite common in Spring for a wave of migrants to arrive with a
push of
warm air from Europe and Africa, but this early in the year is highly
unusual.
Any thoughts?

As Martin has written, the winds for some days early in the month may well
have encouraged them, but I still find this most fascinating. I know next
to nothing about such migration, but would reckon it must be very early
indeed. I imagine the mild conditions further south in recent weeks may
be
a another factor in encouraging this early move north.

It does look as if, at least for western areas, there will be a renewed
flow of warm air from the SSW. It will be most interesting to hear if
more
arrive and just how far north they get. I don't normally see any of the
swallow family here until well into April. I'll be on the lookout.

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 08/02/2004
21:35:38 UTC

Most of these birds wintering in northern Africa would have begun to
gradually push north by now slowly, so does seem that some have been caught
up in these winds and made a very fast track.
It isn't unheard of for the odd one to turn up by February as some may spend
the winter around the Med region. However the influx over this week-end is
pretty unusual with flocks of up to 9 House Martins seen. Reports have come
from Scilly across to Sussex.
It suggests that warm air from the African continent may well be pushing
further north earlier than in the past....taking insects with it and thus
the birds? Insectivorous aerial species such as Swallows being a pretty good
indicator as they rely on quite subtle temperature changes in order for
enough food to be present in the air. In spring their migration is often
"blocked" by cold fronts as happened last March around Spain.
Likewise during April/May arrival waves often occur with warm fronts moving
north from the continent.
One other related point of interest is that this winter has seen record
numbers of "overwintering" insectivorous passerines such as Chiffchaff in
the south. There have obviously been enough frost free days on average for
them to survive so they have not been forced to move further south to France
and Spain as they would have done in the past. As with most animals they
take the easiest option...why waste energy and risk a potentially dangerous
sea crossing when you can stay put.

Thanks for all the very useful contributions.

JP

"Mike Tullett" wrote in message
...
On Sun, 8 Feb 2004 20:32:01 -0000, J.Poyner wrote in

snip
It is quite common in Spring for a wave of migrants to arrive with a
push of
warm air from Europe and Africa, but this early in the year is highly
unusual.
Any thoughts?

As Martin has written, the winds for some days early in the month may well
have encouraged them, but I still find this most fascinating. I know next
to nothing about such migration, but would reckon it must be very early
indeed. I imagine the mild conditions further south in recent weeks may
be
a another factor in encouraging this early move north.

It does look as if, at least for western areas, there will be a renewed
flow of warm air from the SSW. It will be most interesting to hear if
more
arrive and just how far north they get. I don't normally see any of the
swallow family here until well into April. I'll be on the lookout.

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 08/02/2004
21:35:38 UTC

My guess is also, that it has been very warm or even hot in many parts of
Africa in recent days (is nearly 100c above average?) What with the dust
plume that Martin mentioned, this must have had a significant impact on
movement. One other possibility, what if the birds never migrated as far
south as we envisage these days, is there any records of Martins (he, he)
Swallows and migrant butterflies over Spain and Portugal throughout December
and January. Any thoughts on that?

Definitely very intriguing.

Cheers

Tony

"Martin Rowley" wrote here on 08
Feb 2004:

snip
Norman Elkins (who I worked with for a brief time at Lossiemouth),
wrote a book on the subject of Weather and Bird Migration - I
believe it is still regarded as a solid reference for the subject:
don't know if it is still available though.

According to Amazon, the third edition of "Weather and Bird
Behaviour" (if this is the book you mean) will be published next
month:

http://www.amazon.co.uk/exec/obidos/ASIN/0713668253

--
Above address *is* valid - but snip spamtrap to get me to *read*!

Support the world's oldest motorsport venue!
http://www.shelsley-walsh.co.uk/future.html

"tony_powell" wrote in message


My guess is also, that it has been very warm or even hot in many parts of
Africa in recent days (is nearly 100c above average?) What with the dust
plume that Martin mentioned, this must have had a significant impact on
movement.

I've not seen anything of them. I doubt that they would have come here
knowing that the warm wet weather would be provident. It is more likely
that they were forced to move early by the conditions in Africa. However
it appears that they could just have been so well fed by all that
cyclonic stuff they are getting over there, that they were ready early.
http://www.bbc.co.uk/weather/world/a...pressure.shtml

They tend to migrate in flocks made up of similar generations if I
remember correctly. Perhaps these birds are first broods? I presume they
breed in both countries?


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

"Michael McNeil" wrote
Perhaps these birds are first broods? I presume they
breed in both countries?

Strangely most migratory species that come here in summer don't breed in
Africa during our winter, but only breed after northwards migration.

Jack

In uk.sci.weather on Sun, 8 Feb 2004 at 22:36:36, David Buttery wrote :
"Martin Rowley" wrote here on 08
Feb 2004:

snip
Norman Elkins (who I worked with for a brief time at Lossiemouth),
wrote a book on the subject of Weather and Bird Migration - I
believe it is still regarded as a solid reference for the subject:
don't know if it is still available though.

According to Amazon, the third edition of "Weather and Bird
Behaviour" (if this is the book you mean) will be published next
month:

http://www.amazon.co.uk/exec/obidos/ASIN/0713668253

No unusual birds, but I did find a wasp in my room yesterday!
--
Paul Hyett, Cheltenham

Email to pahyett[AT]activist[DOT]demon[DOT]co[DOT]uk

as noted earlier (by David), the title of the book by Elkins is "Weather
and bird behaviour".

The lead article in 'Weather' November 2002 was entitled 'Birds, weather
and climate', and Norman was one of the co-authors. If you can't get
hold of the book (above), this article gives a useful introduction to
the subject.

Martin.


--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm