By a willow tree

A wasp feeding on the pollen of a grey willow.
I spent some of Sunday sitting by the bank of one of the streams that feeds into the Nire river in the Comeragh mountains. In front of me was a willow tree and, in the distance, I could just about hear the faint call of a cuckoo, my first for this year. The willow was blooming, and I could see dozens of bumblebees, wasps and hoverflies crawling over the buds. And where there are insects [and willow], there is usually a willow warbler. This one moved quickly from branch to branch, scooping up anything crawling about. Both cuckoos and willow warblers fly to Africa for the winter, and return to Ireland in early summer to breed. Of course, the cuckoo lets other birds do most of the hard work. However, the willow warbler is likely to be fooled by cuckoo chicanery than other species. In the evolutionary arms-race of deception and detection, willow warblers have become adept at spotting cuckoo eggs in their nests [just as the cuckoo has evolved to lay eggs that look like the host eggs ]. Willow warblers will mob any cuckoos that they spot in their vicinity – this one may well be tested in the next few weeks.

Willow warbler.