But when I venture out for a closer look, it seems their building technique owes more to persistence than proficiency. Whereas other birds might choose fine, pliable sprigs and roots to weave into a base, this pair have opted for finger-thick hazel sticks, which they are attempting to hammer into submission with their bills, losing several over the edge of the nest in the process – to their apparent confusion. It turns out to be more karate than ballet.