Five robin chicks were rescued moments before their nest was crushed, said the wildlife charity which saved them.
The feathered five were found "live and very hungry" by South Essex Wildlife Hospital, which said the box had been thrown into a skip.
"How could anyone be so cruel and heartless?!" asked the charity in a post on Facebook.
The charity is now caring for the chicks and nursing them back to health.
"Infuriatingly this box was thrown into a skip containing five live and very hungry baby robins this week," they wrote.
"Fortunately they were found moments before they were about to be crushed and brought to us where they are now safe and cared for along with many others that need our help."
The charity, which is based in Orsett near Grays in Essex, also issued a reminder about how people should treat birds' nests if they come across them.
"It is a criminal offence to disturb or destroy and active bird's nest. You must leave them alone!" they wrote.