At the end of January, I heard a northern cardinal sing. Birdy, birdy, birdy. What cheer, cheer, cheer. A crimson-red male sat at the top of the tree and sent out his advertisement to a nearby female.

Thump. Thud. Something was hitting our window! It was a bright red cardinal flying at his reflected image in the glass - which he perceived to be an intruder in his territory. The bird kept it up for ...