Who would swallow a moth?

This pile of large yellow underwing moths was found the other day in the doorway of one of our old farm buildings. All that remains of the moths are the wings, the legs and the head – the juicy body parts have been eaten!

So, what made this pile of yellow underwing body parts? At first I put it down to swallows, as the remains lie near where the birds nest. It looked like the birds had taken a liking for these juicy creatures, and had fed their young on exclusively on this moth species. However, this did not seem to make a huge amount of sense, as yellow underwings are night flying moths, and it would mean that the swallows would be hunting throughout the night.

On further investigation, I found out that the pile of moths was not the handy work of hungry swallows, but of something altogether different... what creature would hunt for night flying insects? A bat of course!

Accumulations of moth remains, especially the remains of yellow underwings, are a very common sign of brown long-eared bats. These bats take their prey to be eaten on perches, often in porches or barns, and they usually have a favourite spot, meaning that the insect remains start to pile up over time.

As well as catching insects in free flight, brown long-eared bats are gleaners, often flying slowly amongst foliage, picking insects off leaves and bark. Their broad wings and tail allow a slow, highly manoeuvrable, hovering flight. Sometimes they land on the ground to take insects, and can even take them from lighted windows. Their ears are nearly as long as their body, but are not always obvious as they often tuck them away under their wings while they are roosting.

So, if you ever come across a mysterious pile of moth remains, maybe you too will have found a brown long-eared bat eating perch