I cover the birds' cages at night, both for the extra "darkness" it provides and, in the winter, because it might keep the inside of the cage warmer (we have heating, but it is generally set a little lower at night). This has always worked really well until a few weeks ago for one bird, and only one bird.
She has figured out how to remove the clips holding her cage cover up so that lately, every time we enter the bird room for the first time in the morning, we see a partially covered Léa (she apparently only removes the one clip). This morning, when I went in to get Piper, Shade and Zuri for their out of cage time, I was greeted by a very proud Léa; she was bobbing her head and moving her whole body so I was sure to see her. It was rather funny, but we'll have to figure out a better way to attach the cage cover to her cage. Maybe it'll be time to get a custom made cover; I've only been using bed sheets and clips up until this point.