It's the beginning of January, the shortest day has passed by just over a week. The suns movement towards the northern hemisphere is now triggering a physiological reaction in birds. From now they know its time to follow the suns track north and reap the benefit of life created by its energy. This life will be a plentiful food source enough to feed one or more broods of young.
March
High tides at the beginning of the month fueled the jet stream bringing strong winds at the start of the month but little was blown in suggesting a non-existant pasasge. The first suitable passage came when light southerly winds across the bay of biscay brought a fall migrants on the 14th/15th March. Many Sand Martins, Chiffchaffs, Wheatears and White Wagtails were brought in. Shortly after, the UK was hit with cold northerly winds putting a halt to any significant passage.
Fall conditions on 14th leading to a fall on 15th March.

Crown copyright 2008 Published by the Met Office
April
High pressure over the bay of biscay brought cross winds over the north spain coast but suitable conditions for passage from france. Litlle Crake, Black-winged Stilt, Purple Heron, Bluethroats and a Little Bittern were recorded as new arrivals. Portland and Hengistbury recorded good numbers of willow warblers until cold northerlies bringing snow eventually dried up anything new coming in.