Never mind the appearance of the first robins of the season; our permanently resident northwestern crows have begun to display their early pre-spring assertiveness, heralding the lead-in to the mating and nesting cycle. Rather than a short flight away on approach, they hop and skip into their comfort zone, casting a baleful eye towards the intruders. In particular, groups who are feasting on chafer beetle larvae are reluctant to move more than a couple of meters away. Even when not engaged in eating, there is more squabbling and bickering interspersed with short frantic chases which may be preliminary stages of mating behaviour.
With crows, one may wonder what criteria are involved in making a choice. In many bird species colour and conspicuous plumage can be an attractant or maybe a sweet song warbled in the treetops. Since all crows seem to be blessed with the identical set of feathers, beauty must be in the eye of the beholder. And any of the varied utterances issuing from their beaks could hardly be mistaken for a romantic, melodious come hither invitation. In spite of this, they obviously begin to hang out in pairs and begin their nest building in anticipation of egg laying after the nine week gestation period.
During this time, the skies become quieter during the morning and evening, since they are far fewer crows heading to and from the communal roosts; in addition, they are less likely to congregate in midday, suffering everyone with their cacophonous assault on the eardrums. However, once nesting is established the pairs become highly territorial and extremely defensive against any and all intruders. So walking or running, especially under or close to coniferous trees, the sought after nesting sites, can be an invitation to an open air dive bombing attack across the top of your head. Shrieking close enough to make you aware of the air movement can cause an immediate ducking reaction, in fear of having a two inch sharp beak protruding into your skull. While I have never heard confirmation of a direct hit, one can imagine an older, vision challenged bird making direct contact instead of a fly-by. And occasionally, one of the more demented defenders will maintain an ongoing assault far past the nesting site before finally giving up and glaring from a tree branch or electrical wire. Maybe just a momentary lack of control due to onset of avian air rage.