Kamakaze Magpie

Over the last three of four weeks we have had a young Magpie dive bombing into one of the kitchen windows. He doesn't do it every day, it has happened about half a dozen times. He hits the glass hard and makes it vibrate. This happened last year, but the maggie was an adult male, and it was nesting time. I guess he could see his reflection in the glass, and thought it was a rival, and he was just 'seeing him off'. He also stripped one of the fiberous fillings in my hanging pot to line his nest.
If the present one is a male, and he has ideas of pinching my new fibre fillings, I might get a bit savage! It will soon be Spring, so I will need to be alert.