Sadly, the Mute Swan cygnets in the reservoir all died of lead poisoning, as did all the Canadian Geese, young and old.
The one in the picture should be able to fly away from this hell-hole, which since then has been cleared of the fireplace, and surrounding area's topsoil, hopefully improving things.
The lead comes from stolen cables the hobos living nearby used to put on the fire in the middle of the night to melt the plastic and the lead off said cables, so that they next day can go to the ironmonger's, and collect their reward.
When geese and swans feel ill they like to eat charcoal, thus killing themselves, slowly but surely!