It's been a bit slow in the south-west lately. A small pulse of migrants came through yesterday giving cause for analysis. Again it was a repeat of last months mini fall. Two days of southerly winds with the fall coming on the second day. Recorded new migrants on my patch on the 6th were 20 Willow Warbler, 3 Wheatear, 5 Chiffchaff, 1 White Wagtail, 6 Swallow and a Tree Pipit.
Forecast: High pressure is due to pass through over northern Europe. The forecast high pressure will bring light winds and clear skies ideal for birds but not birders. Sure, a few migrants will be seen but most will be passing overhead un-noticed. From past experience, dawn and dusk will be best to seek out new migrants unless you have the patience to stake out known hot spots as the birds that do stop off will be very short stayers.

6th April 2010 chart shows perfectly how the birds took advantage of the weather. The dotted line showing the highs' path of travel.

My fall predictions were correct but the timing was wrong. I was expecting to see some birds yesterday afternoon but there was no sign. It nearly all went pear shaped but a text from a fellow birder just up the road saying his patch was "dripping with Chiffchaffs" made me realise my mistake. I went straight out a recorded 15 Chiffchaff, 10 Sand Martin, 2 Swallow and a Wheatear. 30 Meadow Pipits looked to have made the journey also. From this last mini fall I can see that there are 600 miles as the crow flies from the Spanish coast to the Severn Estuary. Multiply this by an average 25mph and you get 2 days before they reach the estuary.

22nd March 2010 showing calm clear conditions over northern Spain. The birds would have hit the fronts to the left the next day.

Finding out where the birds are coming from helps making predictions much easier. In my mind we are getting in the south-west more birds from Spain than France and if you bear this in mind the pressure chart analysis makes sence. I've summarised the recent events below with the relevant charts.

High pressure over France providing clear skies and light winds over the north coast of Spain.

Occluded fronts coming in off the atlantic dropping yesterdays Spanish departures in the UK

Just as a little comparison. Below is the weather chart of 23rd March 2002 which brougt Woodchat Shrike, Hoopoe, Little Bustard, Black-eared Wheatear, Scops Owl and Night Heron. There were plenty of commn migrants too.

Many saw this one and it was a nice easy one to predict. The high pressure sat over us a week ago eventually moved into France but the clear skies and light winds meant many of the migrants would have been passing over too high to see. There was however an increase in spring migrants but no falls. Low pressure with occluded fronts moved in today. Right on cue the migrants started appearing. Good numbers of Wheatear, Sand Martin and Chiffchaff arrived in the south. Meadow Pipits were also recorded in good numbers.

Wheatear Sand Point 17th March 2010

Since my last post we have seen the previously mentioned high pressure sitting over the UK. Today it has finally moved west out into the atlantic. Although bright and sunny, these conditions bring cold weather by clearing out the cloud and producing colder easterly or northerly winds across the southern half of the UK. The ground will have conducted a lot of this cold and will take a bit of time to recover. The changing weather will undoubtedly have an effect on migrant birds but I don't see any significant patterns yet. Despite anticyclonic conditions forecast to spread into northern France, the temperatures seem a little too low still to coax much further north. Whilst our atlantic lows continue to hit southern europe, it means a slow start to spring in my estimation.

High pressure over the UK drawing in the first spring migrants.

February along with July are perhaps the quieter months of the year. Despite this, a mild spell in the last week of February did trigger some early signs of spring. Hazel catkins started appearing on trees, birds started singing and moths started emerging. During this short mild period I saw Lesser Black-back Gulls starting to trickle overhead whilst duck numbers on the local pools starting to drop. Meadow Pipits, Golden Plover and Siskin were moving east along the Severn Estuary into a headwind. During the end of February, Low pressure hit France bringing strong winds causing much devastation. As it passed, high pressure started building and the first spring migrants appeared. Common Crane, Little-ringed Plover, Garganey, Sand Martin and Wheatear turned up.

January 2010 started off rather quietly and looked to be a year beginning like any other but all that changed as low pressure sitting over Scandinavia brought fronts from the Norweigan Sea on cold northerly winds beginning on 5th January. Heavy snow swept south throughout the whole of the country forcing many birds to move. Many counties saw temperatures as low as -8 and as a result the reservoirs began to freeze.

5th January 2010 surface Pressure chart showing the cold front that brought snow to the whole of the country. Crown Copyright 2010 Published by the Met Office.

The most notable species were thrushes with big numbers of Fieldfares, Redwings, Song Thrushes and Blackbirds feeding on any berry laden trees even in town gardens. Skylarks (along with small numbers of Woodlark) were also seen in their 1,000's.

The cold weather stayed with us until the 14th when warmer air off the atlantic finally came into the UK bringing a slight thaw. The following day temperatures were almost in double figures bringing rapid melting and assissted by rain overnight on 16th. It was quite a surprise to see on 16th and 17th a great deal of coastal migration as birds headed back north. Waders, wildfowl as well as Skylarks moved through in good numbers which markedly dropped off in the ensuing days. A good example in Weston were 1,000 Teal on 17th, 480 on 18th and 150 on 19th.

16th January 2010 surface pressure chart showing warmer weather fronts. Crown copyright 2010 published by the Met Office.

Much of the UK remains quiet now.

Three days of clear sky and no movements. Today the cloud came with just the threat of snow. The reality was hardly a sprinkling. More significant changes today with the most notable being 1,050 Woodpigeon and 23 Stock Dove flying west along the River Axe. This count was made in just half an hour. Clearly the cloud has caused the birds to move but it remains my biggest question in bird migration. Does the cloud drop them to visible height or are they moving at all in clear conditions. If they are, presumably movements are taking place overnight too. These Woodpigeons will be part of the british population that have come down from the north of England.

Snow hits the UK becoming widespread across the country by the 6th January. Today the snow has cleared leaving blue skies and temperatures as low as -17.7 degrees in one part of the country. I couldn't see any movement during the period of snowfall but following the clearout of cloud and drop in temperature it's been all go again. Berrow Dunes, Somerset saw 2,500 Lapwing, 100 Golden Plover, 370 Skylark, 350 Woodpigeon 3 Snipe and 100 Redwing. Christchurch Harbour yesterday recorded an impressive 3,000 Skylark, 42 Woodlark, 33,000 Fieldfare and 12,000 Redwing all heading east.

The first cold snap of the year began on 1st January with cold northerly winds clearing the cloud. Temperatures in the south-west have been -5 degrees today. The cold weather has forced many birds to move. Skylarks have been moving in the north-east of england plus the Netherlands and France had good counts heading south. Thrushes have also been turning up with many fields and hedgerows containing new fieldfares, redwings, blackbirds and song thrushes. Waders have been passing through. In 3/4 hour I saw 750 Dunlin flying down channel in the Severn Estuary on 2nd January along with 113 Woodpigeon. Wildfowl have also been cropping up with Cheddar Reservoir, somerset turning up new birds daily. Today Red-crested Pochard numbers have increased. Black-necked Grebes, a Slavonian Grebe and a Smew have all come in with the recent northerlies. Surprisingly Chew Valley Lake and Blagdon haven't mirrored these new arrivals so far, so these birds may have come from the east.
I read a report from a ringer who had ringed 80 different Robins in her garden in 2009. On new years day 2010 she ringed 4 new Robins so it seems there must be Robins passing through also. I have heard some making the same unusual high pitched alarm call which I imagine are made from continental migrants.