It happened on the B3081 near Verwood - he had to be cut free by firefighters.
Marine Pollution Cases 'Devastating'
Nearly 3,000 birds have been killed or injured by a chemical spill in the English Channel, conservationists said.
The RSPB, RSPCA and local wildlife charities described it as one of the worst UK marine pollution incidents in decades and said it was more devastating than the MSC Napoli disaster six years ago.
About 20 species have washed up covered in the substance on beaches across the south coast of England since February.
The RSPB said the death toll has exceeded the number affected by the MSC Napoli beaching off Devon in 2007.
The birds have been affected by the chemical polyisobutene (PIB), a lubricant used to improve engine performance. It can be legally discharged when ships wash out their tanks.
Wildlife charities want international action to stop the chemical, which does not break up easily, being discharged into the sea.
The RSPCA, RSPB, Devon, Cornwall and Dorset wildlife trusts and the British Trust for Ornithology said an estimated 2,400 birds had died and more than 500 live but ``disabled'' birds had been rescued and taken for treatment.
The true death toll is thought to be even higher, they said.
It said PIB becomes strongly adhesive in the sea, coating the birds and restricting their movements and their ability to feed.
Tony Whitehead, from the RSPB, said: ``This is one of the worst marine pollution incidents in decades, bringing to mind other disasters going right back to the Torrey Canyon in 1967.
``It has sadly already exceeded the number of birds affected following the beaching of the MSC Napoli in Devon in 2007.
``This is another sobering reminder of the fragility of our marine environment and a wake-up call that we must work much harder to give proper protection to our precious sea life.''
Adam Grogan, from the RSPCA, said: ``The dumping at sea of this lethal chemical must be stopped.
``It was heartbreaking enough after the first incident in February to see so many birds arrive at our centres in such a poor state.
``The sticky substance coated their feathers and made it difficult for them to feed and move so staff had to work around the clock to wash it off and get them fit enough to survive in the wild again.
``For it to happen twice in quick succession is inexcusable and unacceptable.''
The charities have urged members of the public to sign petitions by Avaaz and 38 Degrees to support their call for a ban of dumping chemicals at sea.
Post-mortem examinations have been carried out on hundreds of the dead birds by the British Trust for Ornithology and the results are due to be published within the next few weeks.
Violent crime was up 37% in the last year. Police say it's mainly due to a change in how offences are recorded.
Anne-Marie Ellement took her own life after claiming she'd been raped by two colleagues.
48 Zany Zebras sculptures were sold off to raise money for Marwell Zoo.
Recently Played Tracks
Deposit £10 to get a £40 Welcome Bonus - That's £50 to play bingo, slots and more!*
Over 50 tracks to make you feel-good. New album out now...
Find your local four day weather report here.
What's happening on the roads where you are?
Make Heart the soundtrack to your day and you could be a winner with great prizes up for grabs throughout the day.
Find out more about some of the companies advertising on Heart.
Get some great ideas on how to advertise your business on radio, online and on mobile.