Bird builds nest in birdhouse but never lays eggs? (1 Viewer)

[idreos]

I have a bluebird house and for two years a small sparrow size bird busily bilds a nest in it of twigs over several days, but it never lays eggs and seemingly abandons the nest..
Is this in the normal range of bird behavior?

 

[Nutcracker]

If it's a House Wren, yes, that's normal - the male of a pair builds several nests, and then the female choses the one she likes best for use.

 

[fugl]

House Sparrow another possibility as unpaired males sometimes start nests which they abandon once they acquire mates.