Here in Southern Australia (? New Zealand too) you have to be careful about feeding nectar-eating birds - honey-eaters, with honey or sugar water all year round. They need vitamin B which they get from insects. (They also need the insects as nestlings but parent birds probably collect enough of them, in Spring, even if they feed at the birdfeeder.) When insects are scarce during Winter the birds are supposed to migrate North. You may help a bit by adding multivitamins to the mix but it might not be the whole solution. It's complex.
Maybe this should also be considered in the colder parts of America?
A study in Melbourne on dying Red-Wattle birds presented the evidence of vitamin deficiency. In this case the cause of the problem was the planting of popular honey-rich shrubs from Western Australia that flowered all year-round, as well as the use of artificial feeders.
Billy the Bus, those insect zappers - I agree we'd rather have our bats and birds and our butterflies and moths.
                                                Cheery-bye Joy