In chemistry ( I work with process inks at work in flexographic
equipment) a pH value less than 7 is ACIDIC [ you stated it was BASIC ].
A pH value greater than 7 is BASIC (or alkaline if you prefer).pH value
of 7 (water) having a neutral value in either acidity or alkalinity.In
either case though you could be right on the effects of bird
droppings,because either pH extreme can damage a paint finish.