Wildlife experts are hoping to attract rare birds back to the Hertfordshire countryside using water buffalo.
Four water buffalo will graze at the meadow during the summer
Four of the animals - Claudia, Paula, Holly and Ashley - now call a wet meadow at Rye Meads Nature Reserve, near Hoddesdon, their summer home.
Herts and Middlesex Wildlife Trust will use the buffalo during warmer months to graze on plant life in areas unsuitable for lawn mowers and other animals.
They hope grazing will make vegetation suitable for ground nesting birds.
Park warden Ellie Minns said the Romanian water buffalo will tackle sedges and rushes, which can take over the site, and help floodplain plants re-establish their numbers.
In turn, this will allow more plant and insect life to return to the meadow and encourage birds such as lapwings, redshank and snipe to nest in the area in the spring.
"A diversity of plant, insect and animal life is vital to the meadow and the buffalo will be playing a key role in helping us to encourage the return of breeding birds," she said.
"At over a ton in weight (about 1,200kg) each, these friendly and gentle giants are capable of polishing off serious amounts of vegetation, so they'll be very welcome summer visitors".
The four females normally live at Lee Valley Park Farm but have been lent to the trust until September.