In a few months, the town of Bath, England, will likely get something it already has in surplus—another seagull.

While visiting the vacation town in early May with his wife, aspiring wildlife filmmaker Matthew Spivack caught two of the town's seagulls mating on top of a train station. Spivack believed he was initially photographing two birds grooming each other until the male jumped onto the back of the female.

As it happens, males will often stand on the backs of females to signal that they are ready to mate. With the exception of a few species, most male birds don't have penises. Instead, they store their sperm in an internal chamber of their cloaca. Male and female birds typically have a cloaca,