Almonds are a good source of vitamin E which is also the breeding vitamin so you need to be careful how many you feed your bird during the cold weather months. And do get the ones in the shell, almonds are soft and can be cracked open by even smaller species but, if the bird has trouble at the beginning, just hit it with a hammer once to open it up a bit and let the bird do the rest of the work. They need to forage and opening nuts is part of that.