anybody who lives in an area with a lot of seagulls knows what is about to happen. the car is going to need a wash, not only because of the new ugly spot on the roof but that spot happens to be corrosive to the car's paint. luckily for me, this time it is not my car. living close to the sea has many positive sides but this particular issue is one i face regularly.
so i did a little research about these all too common droppings. birds excrete their waste through their cloaca or vent, both urinary and digestive waste together in the same dropping. mammals dilute their urinary tract waste with water but water is heavy. water in a bird's body adds weight that could inhibit flight so birds need to strictly limit how much they carry. one of the systems they have evolved is by excreting undiluted urinary waste as a thick acidic white paste consisting of concentrated uric acid and ammonia salts. the dropping also contains digestive waste or feces which includes some remains of digestive enzymes.
in order to survive birds need highly efficient digestive systems which include powerful enzymes to quickly break down the food they eat. some of these enzymes get excreted in the feces and essentially begin digesting the car paint. while not a big issue with seagulls, the feces of other birds with diets of berries and fruit contain chemicals which give the berries their color and many of these can leave a stain in addition to problem of corrosion.
on top of this, the sun heats up and expands the clear coat of the paint and softens it while the droppings dry out and harden, thereby bonding the droppings with the otherwise smooth glossy paint. when the paint cools at night it contracts but now includes the not so smooth and glossy bond from the droppings. so it's a double whammy- corrosion and distortion and maybe even a stain to boot.
meanwhile the seagull is merely gaining a position where it gets a good overview it's surroundings. the bird is completely ignorant of the damage it is doing never mind the chemistry and physics of car paint. it must be presumed to be innocent.
or maybe not- the jury is still out on that.
