The sun is losing its heat and the nights come sooner: the leaves are turning and the swallows have already gone.
Every year the bird migration is different. This autumn the swallows, swifts and house martins have left earlier than usual for Africa. Maybe the dry late summer meant there were fewer insects on the wing and there was little to tempt them to stay; maybe fewer actually arrived this year; maybe they know a cold winter is coming.
Sitting on the front porch of our house is a great place to watch migrants arrive and leave. Birds coming south sweep down the Rhine valley, but when they hit the first folds of the Jura mountains they are funneled together and we see great wheeling flocks of hirundines feeding briefly over the garden before pushing on south.
Some migration patterns are surprisingly similar. Last year we were amazed to see a flock of bee- eaters burbling and tumbling over the hill, unmistakable in bright blue with a silhouette of a stocky starling. Other people saw them on the same day as they left the Kaiserstuhl in Germany ( where they breed) returning to Africa. This year we were on the lookout for them and sure enough a flock of 50+ birds flew over to our great delight. We checked our records and were astonished to see that this flock went over on exactly the same day and at exactly the same hour, last year.
Seems like some birds keep to the timetable!