Has anyone heard of this – had a gal just call me and said that they found a bluebird nest and 1 blue egg inside one of their martin houses (they have two big ones & about 26 nests). They also have another active bluebird nest which has 4 babies in it, hatched the same day as mine, last Saturday, so I guess she knows what a BB nest/egg looks like. Other than robins (which as not cavity nesters), what bird would lay blue eggs? Is this common or really a very odd occurrence?
Thanks, Gin – I gave this info to the gal who told me this. She just told me that it WAS a starling’s nest & egg, so the mystery is solved. She & her husband are really into taking care of their martins & bluebirds and use justifiable means to dispose of the two species who harm their birds.
My very first bluebirds I ever had, Nested in my martin house with tree swallows on the back side. So they do nest in them if nothing else is available. That is what got me hooked on eastern bluebirds and I built 3 houses for them afterwards.