however a bird can not adapt it's behavior to avoid polution, also ddt caused the eggs to have thin shells (Among other problems) the ddt problems where felt primarily in the reproduction of the birds an dsurvivability of hatchlings, which didn't give them a fighting chance at adapting.
however a physical danger targets adult birds, and can be eaily avoided, by just avoiding the areas around them. most animals will learn to avoid an area that is littered with the bodys of their relitives.
for example, deer in an area that has been hunted avoid people, they even learn to adapt to our hunting seasons. (how many times have you hunters seen deer everywhere, and then on the opening day of hunting season you see none?) while deer in areas where hunting is banned or that have little or no human presence are extreamly comfortable around people.