During spring migration the number of birds at your feeders and in your yard will increase, as well the danger of them accidentally striking your windows. Glass windows can be invisible to birds, especially when they reflect trees or look through to another set of windows. One simple way to make your windows visible is to pull down the shades, but there are other actions you can take to prevent window strikes (see https://abcbirds.org/get-involved/bird-smart-glass/). Up to a billion birds are killed each year due to hitting windows and other structures. Don’t contribute to their mortality; help them make it to where they are going.