A bird made a nest in my fern! :) Will she find the water I sat out for her? When will her eggs hatch?

This might be a House Finch..as they do like to build their nests in hanging plants. Most perines (perching birds) eggs hatch in about 2 weeks time and the babies fledge the nest at about 2 weeks as well...so they should be leaving by the time you move. Just leave the water there, and the female may find it. Birds obtain most of their water from the food they eat..so even if she does not go for the water..she should be fine.