This is a big bug bear of mine and it happens not only in sea side situations but on fresh water fisheries and rivers. Though most are very responsible, there are still too many fishermen who discard used nylon line carelessly; water birds get tangled up in it. It takes no time to put it in a bag, bring it home, cut it up and bin it. Swans ingested discarded lead shot, mistaking it for grit, that poisoned them before it was banned. You also have to ask yourself how much discarded rope and netting comes off small commercial fishing boats. I have seen gannet nests made up almost entirely of this sort of material, which they pick up at sea, but I expect a lot is responsible for seabird deaths.
Has anyone else noticed their energy levels change as they've got older?
All part of life’s rich tapestry
