This not only negatively affected the songbird population, it also increased hunting time for the hawks, which in turn affected the survival rate of their nestlings. Cats can be trained to enjoy supervised outside time on a leash if you start them when young. Here you see Mikie enjoying his garden time in a cat harness with his owners. Often, the female is taken while she is sitting on the nest, and the babies starve to death if they are not killed along with her. Young birds just learning to fly are also at risk.
All birds are at risk at night, regardless of the time of year.
Most birds are night blind, and have little hope of escaping an attack by a cat at night. Birds eating at feeders or bathing in birdbaths are also at risk if there is low vegetation around where cats can hide. Keep this in mind when you are putting up your feeders and baths. Keep the ground clear around the feeders so there is no place for the cats to hide and stalk the birds. Provide bushes and thorny shrubbery nearby for them to hide in case of an attack.