By the way, it is the female that builds the nest, & they are usually built under the eaves of a house, under a bridge, or in culverts. They can have 2 broods a year, with 4-5 eggs each. Just by looks, there is no way I've read to tell the male & female apart, but sometimes the male is a little bit darker. I also read that they are big victims of the brown-headed cowbird. The female brown-headed cowbird will usually remove the phoebe's eggs & replace them with hers, & the phoebe rarely rejects them. If a phoebe egg actually hatches, it does it a few days later than the cowbirds, & ends up starving. 
I hope you end up with phoebe babies not cowbirds; you'll have to let us know how it turns out!
"So many sparrows, so little time!"
