Why is the night vision and adaptation for owls in a desert environment?

All owls have night vision. Since the desert can get so hot, most animals, including owls, come out at evening or night to avoid the heat of day. Since they're active at night, it's good to have nocturnal vision.

Some desert owls are elf owls, pygmy owls, burrowing owls, great horned owls.

It allows them to hunt when it is cooler.