Interesting art - NOT amateur radio

I was sent this by Steve G1KQH. Turn it 180 degrees and take a look. I have no idea where it came from originally.

House Martins - NOT amateur radio

This year, we seem to have had plenty of swifts (now gone south) but fewer swallows and house martins. Mind you, we saw lots of house martins (100+ ?) at Castle Acre yesterday. A few more weeks and these will be off too.

The house martins were in the air and resting on the roof on the left. I hope you can make them out in the photo. You may have to click the photo.

See https://www.rspb.org.uk/birds-and-wildlife/bird-and-wildlife-guides/bird-a-z/h/housemartin/