Pest (Crows) require a city size of 12.
The [ Replaces Pest (Crows) ] info is replaced by [ +1 +1" ] info (the opposite of the "Pest (Crows)" building effect) when the "Pest (Crows)" exist in the city.
This is probably caused somehow by the "Show Actual building Effect" game option code.
This one: [ Replaces Pest (Crows) ] is only shown if you don't have the building it replaces.
The [ Replaces Pest (Crows) ] info is replaced by [ +1 +1" ] info (the opposite of the "Pest (Crows)" building effect) when the "Pest (Crows)" exist in the city.
This is probably caused somehow by the "Show Actual building Effect" game option code.
This one: [ Replaces Pest (Crows) ] is only shown if you don't have the building it replaces.