Summer migrants

The sky was full of them. Their wings and sound danced over us as we walked, and as it seeped into my consciousness I noticed there were hundreds, no thousands, filling the air with their play and what felt like rising excitement. How many thousands, or millions of years has this ritual been played out? They have been flying this way since before this island was an island, and tundra joined our shifting geology to the continent. The birds' migrations map the tectonics of our planet... By now, following the river south, drawn by the magnetite in their brains, by sunlight or star patterns, many of them must be far away from this green jewel of a place. Away from our folding valleys and hills, past the choppy brown strip of the English channel, flying somewhere over the Sahara. Swallows. I'd never seen so many - at least not recently. I remember there being more a few years ago. These days I usually only catch sight of five or six of them, their sky-borne streams of song straying out of the air, marking the turning season. They're like sparks of concentrated energy, they fill my mind with questions: are those two a pair, or are they fighting over the traced path of a single insect as it swerves to dodge the mica-sharp beaks? I go back to watch as day after day more and more gather and depart. What can they be saying to one another? What are they feeling? I notice the trees that line the river are full of the weave of their intricate twittering, and the sound echoes all around and deepens into the reeds. Days later they have all gone, replaced by heart-rending chants of geese in the cool September air.