Something is squeaking in the wall...can birds have babies this early?

[MrsTawdry]

Right next to me there is a sort of squeaking/tweeting noise...it's tiny...and it appears to be IN the wall about halfway up. The wall is an exterior one and I've often seen birds flying into the eaves...I live on the 2nd floor in a flat so I am close to the roof in my sitting room.

Is it mice? Rats? Baby birds? It's too "small" a sound to be grown birds I think...but do they have young in February? I know this isn't an AIBU but I want answers!

Yes if they found a warm spot they may have bred early. But i think it is more likely mice or rats. They squeak too!
Nothing you can do really except keep a lookout for mouseholes.

Don't think it's a bird, sorry!
Mice and rats breed all year and can climb walls - they can get through the smallest hole into the cavity. Keep your eyes open for droppings....