"Lookout" or "look out"

Here is our hawkish friend who sits behind the studio everyday on the lookout for a dinner to pass below his perch. Apparently, we're part of his hunting territory. We have plenty of mighty meaty mice in the woods that we would much rather he snag for family takeout--his family, that is--than catch in my traps before they get into the house. It's just one of those great balances in nature and it's also a good reason not to have an outdoor cat.