These small and grey forest birdsare often quite difficult to spot. But the trilling warble is a dead giveaway as to their presence.
A bird who prefers the high canopy in our forest we hear them more often than see them on Ulva Island, but around the Village where the trees and bushes are mostly re-growth and so relatively low we see them much more often. Grey Warblers will nest twice in a reasonable season, with the first clutch generally fledging undisturbed. But by the time the second clutch arrives the Long Tailed Cuckoohave arrived from their Pacific wintering home, and our Grey Warblers are vulnerable to these parasitical nesters.
Grey warbler nests have a very small opening and it was once thought impossible for a cuckoo, which is relatively quite large to have actually laid an egg into the small entrance hole. Until that is an observer noticed the female lay the egg on the ground, and transfer the egg to the nest in its beak.