Leaving the floodlight on all night isn't helping your security, but it is disrupting a lot of wildlife that was trying to use your yard.
Moths and other pollinators circle artificial lights until they die from exhaustion or get eaten.
Fireflies can't find mates when their species-specific flash patterns are drowned out.
Migrating songbirds get pulled off course by lit buildings, collide with windows, and die by the hundreds of millions every year in the US.
Motion-sensor lights do the security job better. A light that clicks on when something moves is a more effective deterrent than a light that's been on for six hours already. It also uses a fraction of the energy.
Warm-colored bulbs (2700K or lower) are less disruptive to insects and birds than the harsh white bulbs that come stock with most fixtures.
Downward-facing fixtures with proper shields direct light where you need it, not into the sky or your neighbor's bedroom.
Your porch doesn't have to be the enemy.