Are birds or bats pollinating agents?

Some birds certainly are. There is a separate group given to the Honey Eaters, Meliphagidea, and in New Zealand at least this includes Tui and Bellbird. Hummingbirds are honey eaters - indeed without such a high-energy food, they would have difficulty.

The Silvereye aka Waxeye are the birds that come in early spring and pollinate my peach trees, before it is warm enough for the honey bees.

I don't know about Bats - but they are insectivorous, and may pollinate as a by-product of insect hunting.