Egg Shell Identification

[Colin2016]

Been finding egg shells like the one in the picture when taking dog for walk. These are always on the road not under bushes as if they are from a nest.

Can anybody identify which bird has laid it?

[Shallot Man]

Blackbird.

[retropants]

1” wide? That’s quite big, I was thinking pigeon or dove perhaps. Is it white or blue? Hard to tell.

[Geoff]

I thought pigeon family by the size but my ancient Observer's Book of Birds' Eggs has them all as white, doesn't include the now common collared dove but I've found a reference that says "white oval eggs are smooth and glossy, and about 31 mm by 23 mm in size". Ducks are also white in the book so why is there a colour duck egg blue? The only big plain blue wild bird one I can find is heron described as "beautiful delicate greenish-blue not glossy" but they are only supposed to lay early in the year. There are some pale blue hen eggs. I think you'll have to look for what birds are in the area.

[Colin2016]

It is white.
There are loads of pigeons & collard doves here but not seen any blackbirds, usually see them when they are looking for worms.
Thanks you both for your help.