The discovery of a female Florida panther lying with a broken leg on a verge outside the town of Naples, south of Tampa, triggered a widespread rescue dash.

Conservationists, who had previously fitted a tracking collar to the animal, were aware she had recently given birth. The kittens would not survive long on their own, they realised, and so an urgent search for them was launched.

Eventually two of the three were found and reunited with their mother. Her leg was treated by vets from White Oak Conservation Foundation and the trio were eventually reintroduced into the wild.

It was the first time a Florida panther family had been rescued, rehabilitated and released back into the wild together, and an image of the two young males – anaesthetised prior to a final pre-release check-up – was taken by wildlife photographer Carlton Ward. His picture is one of a series he has taken of Florida panthers, images that will receive a highly commended award at the Wildlife Photographer of the Year ceremony at the Natural History Museum in London this week.

Facebook Twitter Pinterest Vets carry two of the anaesthetised “kittens” into the clinic for a check-up before they are released. Photograph: Carlton Ward Jr/CarltonWard.com

“There are only about 200 adult panthers now left in the wild in Florida,” Ward told the Observer last week. “However, these animals are now facing a series of new threats to their numbers: the spread of housing across their last habitats in southern Florida, and the construction of new roads, which bisect their ranges.”

Florida panthers once roamed across the south-eastern US. However, by the middle of the last century hunting and habitat loss had reduced their population – now isolated to a pocket of southern Florida – to about 30 to 40 adults. The animals were heading for extinction but were saved when they became one of the first to gain federal protection under the Endangered Species Preservation Act. Hunting of the panther was outlawed and some land set aside for reserves, such as the Big Cypress national preserve, near Naples.

As a result, Florida panther numbers have slowly risen over the past 50 years, with the adult population now standing at more than 200.

But new threats to the Florida panther – a subspecies of puma, or mountain lion – are emerging. Florida is losing more than 100,000 acres of rural and natural land each year to provide homes for the massive influx of people moving into the state. It is estimated that a third of a million people are settling in Florida every year.

In addition, new roads are being built across the panther’s last reserves and there have been worrying numbers of deaths. About 30 panthers a year are killed on the state’s roads, according to Ward. In addition, ranch lands used by panthers to move around are now being sold to housing estate developers, which threatens to cut off essential wildlife corridors.

Facebook Twitter Pinterest Cowboys herd cattle at Buck Island Ranch near Lake Placid in central Florida. Photograph: Carlton Ward Jr/CarltonWard.com

Yet panthers play a key role in protecting Florida’s environment, added Ward, who has been studying and photographing these highly endangered carnivores for several years. “For example, they help to control numbers of white-tailed deer, coyotes and hogs, which all cause considerable amounts of ecological damage.”

As result, Ward is campaigning for the preservation of ranch lands in the state and for the construction of more barrier fences and dedicated wildlife crossings. The need for action is urgent, he added.

Recent photographs – taken by Ward using remotely triggered cameras – indicate that the Florida panther is beginning to extend its range slowly northward and has recently crossed the Caloosahatchee river, which cuts across much of south Florida. Crucially, these images were of female panthers. In the past, males – which patrol ranges of up to 200 square miles – have been spotted in northern Florida but until now they had no chance of finding a mate. Ward’s photographs of a female and two offspring moving northwards offer new hope that the panther’s range can be extended. “However, we have to find ways to protect these new reserves and to build up numbers of Florida panthers to ensure their future survival,” said Ward.

Wildlife Photographer of the Year, Natural History Museum London, 18 October 2019 – 31 May 2020