A misfortunate moorhen we found on the fringes of our local reservoir, tangled in discarded fishing line - as if the litter left by fishing parties isn't enough. I waded out to free the bird hoping there would be no lasting damage, hopes that were dashed when we discovered the line ran up into the moorhen's beak and down its throat. Doing what seemed best at the time we broke off the line to make it as short as possible, collected up the rest, and let the bird free to allow a private death without the stress of being in the open - it was very exhausted and clearly wasn't long for this world.
It's a real shame the interests of fisherman and birdwatchers must conflict so badly. We both must want a clean and healthy environment to pursue our hobby, it's what our respective game surely need.
Since birds are so highly prone to being affected for good and bad by human influences, I suppose it's up to those of us alert our of own impact, to make sure it's a good one.