Autumn passage of Swallows through our area of Lancashire in September 2001 was a most unusual and thought provoking event, posing many questions as to their movements around the British Isles prior to their departure south.

Swallow passage usually peaks around mid-September, locally, tailing off well into October. In fact, last year, Swallows were still feeding young at Waring's farm, Back Lane, Heath Charnock on October 8^th. On this same day at 7.40am, our winter visitors were seen arriving as a skein of 65 Pink-footed Geese made south-east over Grey Heights, presumably bound for the Norfolk grain and sugar beet fields, which they have found so inviting over the last couple of years.

A major factor in stimulating Swallow movement is the wind direction. Throughout the period from 1^st - 24^th September 2001 (which covers the peak passage season locally), apart from a notable exception on the 12^th, the wind blew from a north-west to a north-east quarter. The reason for this was that a blocking Atlantic high pressure system, normally centred on the Azores, took up a position more to the north, bringing persistent northerly winds down over Britain for almost the whole of September. On the 12^th, however, in a light south-westerly, a heavy passage of Swallows was observed moving south along the west flanks of Grey Heights. In the 15 minutes from 7.00am to 7.15am, 700 Swallows were counted passing low in groups of 30+ birds, possibly leaving some local or Ribblesdale roost. From first light to 10.00am, a minimum of 3,000 Swallows, with an occasional House Martin, passed south. After 10.00am, they continued to move through at around 50 per hour up to noon or even later. This date (12^th September) was the only day between 1^st & 24^th September when any notable Swallow passage was observed moving in the 'right' autumn direction.

Passage over the rest of that period was mainly to the north-west, especially on the 18^th, 19^th and 20^th. On these three days, Swallows and House Martins were moving north west along both west and east flanks of Grey Heights at up to 200 birds per hour. Passage was heaviest between first light and noon but continued in smaller numbers up to 5.00pm. This movement north-west coincided with two days of heavy rain in southern England.

It is known that Swifts move hundreds of miles to avoid low pressure systems, and one wonders whether the hirundine movement in question was in response to just such conditions in the south, with the birds moving towards the fine weather, which prevailed at the time in North West Britain and Ireland.

After 24^th September, winds returned to a southerly quarter, and a much lighter passage of Swallows with a few House Martins was noted moving south. Interestingly, numbers of Swallows on passage at Spurn bird observatory for September 2001 are well down on the previous two years:-

• September 2001 6,854
• September 2000 21,672
• September 1999 33,726

Whilst it is generally accepted that Swallow numbers are well down this year, due to a poor breeding season, it does lead one to wonder whether they moved out of the country on some other route, possibly through Ireland.

Further studies may reveal the answer.