Why They Peck
A male bird pecking at the window isn't chasing a tasty meal or trying to get indoors. It's actually pecking at itself -- its reflection, that is. Male birds, particularly during mating season, see that reflection as a threat that must be dealt with. The same bird may even peck at several windows on your home, or even at windows and mirrors on the car. Even shiny hubcaps may be targets.
Breeds Bound to Peck
Only a handful of bird species exhibit window-pecking behavior. Robins, cardinals, blue jays chickadees and some mockingbirds are more likely to peck at their own reflections than males of other species.
Continual pecking at the windows may not only seem annoying -- it could be distracting the bird from predators or other dangers nearby. To stop the pecking. close the curtain or install a screen on the outside of the glass to cut down on the reflective properties of the window. Decals of predatory birds such as falcons also help prevent window pecking; stores that sell bird feeders carry such supplies. Other stick-on materials such as window clings or even, temporarily, a strip of painters tape, will keep those bird beaks away. Pecking behavior generally happens during mating season, so later in the summer, feel free to remove the preventive measure.