It's getting to be what the locals around here refer to as a little back-endish—by which they mean summer is on its way out, and autumn approaches.
Returning to my house today, I spotted several swallows congregating on the nearby telephone wires. At this time of year, this is a clear sign that they are preparing to migrate south for the winter. As they appeared to be fairly settled, I grabbed my camera and walked back down the hill to fire off a few photographs. It turned out that the swallows on the telephone wires were recently fledged juveniles, who were waiting to be fed. I watched for ten minutes or so as their parents gathered flies over the adjacent fields and returned to feed their young.
By coincidence, I am currently reading Richard Mabey's biography of the famous Eighteenth Century naturalist, Gilbert White (Amazon UK), who was an early influence on Darwin. White was fascinated by swallows. Their annual appearance in spring and disappearance again in late summer was still a mystery during his lifetime. In February, 1769, he wrote to his friend, Thomas Pennant:
When I used to rise in the morning last autumn, and see the swallows and martins clustering on the chimnies and thatch of the neighbouring cottages, I could not help being touched by a secret delight, mixed with some degree of mortification: with delight to observe with how much ardour and punctuality those poor little birds obeyed the strong impulse to migration, or hiding, imprinted on their minds by their great Creator; and with some degree of mortification, when I reflected that, after all our pains and inquiries, we are yet not quite certain to what regions they do migrate; and are still farther embarrassed to find that some do not actually migrate at all.
To his dying day, White never did find out for certain whether swallows migrated or hid (by which he meant hibernated). We now know that swallows migrate from Britain to South Africa during our winter: a phenomenal journey for such a small bird. And we now know that this impulse to migration is not imprinted on their minds by a creator, but by evolution.
Darwin was right: there is grandeur in his view of life.