Bird excrement comprises; Ammonia and urine as white crystals of uric acid (pH 3.0 - 4.5) a small organic compound, which is produced by the breakdown of protein during digestion, and is excreted by reptiles and birds. Uric acid is also the end product of nitrogen catabolism in birds Ammonia is a mixture of nitrogen gas and hydrogen gas; with moisture as a catalyst it becomes Ammonium Hydroxide, which is caustic.
Heat and water act as a catalyst; a vehicle paint surface temperature of >90.oF creates a very aggressive reactivity of the Alkaline, Uric Acid and Ammonia. This will cause surface etching, so they should be removed without delay, at lower temperatures (> 40.oF or less) there’s no reactivity and therefore little or no etching.
Most organic waxes (Carnauba) and some inorganic wax (Collinite) are more resistant to environmental hazards then synthetics, although an Acrylic polymer offers limited resistance. Being a sacrificial coating, the best way to avoid clear coat etching is too remove the environmental acid, along with the wax as soon as it’s noticed; but given enough time acid will compromise the clear coat whatever its protection.
No wax or polymer sealant can provide a permanent shield against acidic bird excrement, as they are all incompatible with strong acids. Even the latest nanotechnology coating or CeramiClear only offers resistance to acid etching; although an Acrylic does offer a limited resistance. A product like Collinite 845 Insulator Wax is probably the most durable non-organic wax product, and but this will only provide enough of a barrier to enable it to be removed quickly before causing too much damage to the paint film surface.