I have bluebirds nesting in the bluebird house in the front yard. They build their nests so quickly.
And I had a titmouse (I think) start building a nest in the bluebird house in the garden but I worked in that flower bed for a day or two and I think they gave up on the nest site. But they had covered the bottom of the house with moss - if they don't continue, I'll clean it out and maybe some birds will come along. I still have some weeds to pull out but the weather has been cold and rainy this past week. Hoping for sunshine now that it's April.