Hypnotic Orbits.

As I was making breakfast, I watched a large flock of pigeons circling Persevere House - a particulate mass, undulating and changing shape not unlike a murmuration of starlings.

After a couple of minutes the flight split up, circled Citadel House, collided with a flock of gulls, scattering then reforming before making two more circuits of each block of flats before roosting below the nearby rooftops.