In Shakespeare's Twelfth Night Feste the clown is cajoled by Sir Andrew Aguecheek and Sir Toby Belch. "Come on, there is sixpence for you; let's have a song," Sir Toby says, thereby providing what is believed to be the first written reference to the well-known nursery rhyme. You remember it, of course:
Sing a song of sixpence, a pocketful of rye,
Four and twenty blackbirds baked in a pie;
When the pie was opened, the birds began to sing;
Now wasn't that a dainty dish to set before the king?
The rhyme itself is thought by some to be a veiled reference to Henry VIII's dissolution of the monasteries. The blackbirds, the theory goes, are monks, and the narrative recalls the abbot of Glastonbury sending a present to appease the king, a pie in which were hidden the title deeds of 24 manorial estates.
But then the allegory grows obscure:
The king was in his counting house, counting out his money;
The queen was in the parlour, eating bread and honey;
The maid was in the garden, hanging out the clothes;
Along came a blackbird and pecked off her nose!
The only reasonable deduction is that weather at the time must have seemed suitable for drying clothes.
The problem facing the maid, before the blackbird came, was to arrange for water to change from the liquid into the vapour state through the process of evaporation. Evaporation is an energy-intensive process, and she would have known intuitively that it increases when abundant energy reaches the drying object from the sun, when there is bright sunshine.
Temperature is also important. The higher the temperature of the ambient air, the more moisture it can absorb from wet clothes. And another factor is humidity; dry air has the spare capacity to collect additional moisture; damp air can accommodate only a little extra water before becoming saturated, at which point no more can be absorbed.
Moreover, when water evaporates in calm conditions, the still air adjacent to the evaporating surface gradually becomes more humid until finally it reaches saturation. But with moving air, the rate of evaporation is increased by the constant arrival of a fresh supply of drier air. Wind, therefore, improves evaporation and makes for better drying.
Assuming, therefore, that this maid knew her business, we can surmise that at the time these events took place the weather was warm and sunny, there was a fresh breeze, and the relative humidity was low. But as to whether these conditions prompted in any way the aggressive behaviour of the blackbird, we can only speculate.