Mom on the Go

My mailbox friend has been a busy lady; that lone egg we spotted last week has four new siblings. So that means we’re about to have five loud, messy (read: pooping) baby birds just outside our front door. (Only 3 are visible in this shot) We’re not sure what kind of bird she is, as we haven’t gotten a good glimpse of her. If I happen to peek in when she’s in the nest, she flies directly into my face – which is totally startling and Hitchcockian - and then around the corner where I can’t see her. Care to help me figure out who has taken up residence in the mailbox? The few facts I do know are: -she’s brown (that narrows it down) -she has a thin, long pointy beak (I think – maybe it just seems that way when she’s aiming for my face) -the eggs are light brown with speckles -the nest is tunnel-like The chickadees have long since hatched and left their nest in the birdhouse out back, as have the robins, as evidenced by these: I’m decent at bird identification, but this chick has me stumped. Any ideas? (It’s not a sparrow.)