April should be, as Chaucer hinted, the sweetest month, bringing warm, settled weather to delight us all after the long, grey winter.
But, from time to time, spring seems to have been put on hold, with temperature that stubbornly stay well below average. When this does happen, it has a profound effect on the timing of natural events – especially the arrival of migrant birds.
Spring 1991 saw birders up and down the country asking one another, “where are all the birds?” Even the common migrants such as swallows, martins and warblers were few and far between, while twitchers – those who chase after rare birds – were at their wits’ end, with virtually no unusual species reported.
The reason for the paucity of birds was a blocking anticyclone: stuck to the northwest of Britain from mid-April onwards, this produced a run of bitter northeasterly winds more like February than April.
For migrant birds, the timing could hardly have been worse; they remained stranded in their millions on the other side of the Channel, waiting for the weather to change.
Things got worse: 29 April saw one of the wettest days ever recorded in parts of southeast England, which meant those migrants that had returned then struggled to find insect food.
And, though May provided some respite, June was dull, wet and unsettled, with temperatures two degrees cooler than average, making this particular spring one to forget – both for Britain’s birds and its birdwatchers.
