TV naturalist Chris Packham has condemned the hanging of dead crows outside his home in the New Forest as “ghastly”.
It comes as the licensed shooting of crows has been halted after a challenge by his Wild Justice campaign group.
Natural England has revoked licences for controlling 16 species of bird, including several types of crow.
Mr Packham posted a picture of the crows on social media and said opponents were “lashing out”.
What is believed to be his address has also appeared in an online post urging people to dump dead lambs at his property.
WARNING: This story contains an image some may find distressing
Mr Packham said: “All it does is strengthen my resolve to make the UK countryside a better place for wildlife and the people who live and work there.
“In a very sad and perverse way this ghastly action indicates that I’m making progress.
“As I’ve always said ‘I’m not here to make friends – I’m here to make a difference’.”
A Hampshire Constabulary spokesman confirmed a report of criminal damage has been made with the incident believed to have taken place between 20:00 on Wednesday and 06:50 BST on Thursday.
Wild Justice was set up by Mr Packham and other campaigners to take legal cases on behalf of wildlife against public bodies.
In February it challenged the general licences that allow farmers to shoot birds including wood pigeons, jackdaws and magpies that damage crops or attack livestock.
A statement said: “We haven’t changed the law, we have merely shown that the current system of licensing of killing of certain species of birds, developed and administered by a statutory wildlife agency, is unlawful now and presumably has been for decades.”
Natural England said it revoked three licences for controlling certain wild birds following the challenge and was working on “alternative measures” that would allow lawful control of the bird species to continue where necessary.
The move provoked a backlash from farmers groups and others.
A Change.org petition calling on the BBC to “sack Chris Packham” had received more than 70,000 signatures by Thursday afternoon.