No rookies in art of nestbuilding

ROOKS, known as ‘crows’ in Ireland, are impatient birds; they can’t wait to begin nesting.

Some start renovating old nests as early as December and, from now on, black balls in bare trees will be a familiar sight. Building begins in earnest in February. Rooks’ are not great architects but constructing big bulky nests on thin windswept branches is quite an engineering feat. How they manage to do it is something of a mystery. There have no drawings to guide them; the blueprints are in their heads. The design is inherited and construction is by trial and error. Practice makes perfect.

Rooks tend to choose the same trees year after year. Mature fat-cat pairs build on the tattered remains of a previous nest. Young Johnny-come-latelys must find a virgin site. Crows form strong pair-bonds; some even remain together for life. But these are quarrelsome birds with big egos; partners can disagree over where to build. To spite each other, males and females have been known to embark on rival structures. Eventually, they compromise and only one nest is completed. A spinster female may build a nest on her own, presumably hoping that some Prince Charming will happen along.