"Used to work at a zoo, cold weather makes the animals more active so go on a chilly day or first thing in the morning to see the best show from the animals.
Also, those free roaming peacocks are really stupid and sometimes go in the lions exhibit and get torn up."
MapleTopLibrary
You have never lived on a boat with wild birds overhead in masse, because some birds can definately choose WHEN they go. For survival they can release before flight, to gross out a predator, or mark territory/flight path. Or they can hold it near their nests to avoid attracting attention. No animal as evolved as a bird would leave pooping up to pure chance.