I'm selling my $32m private island so I can enjoy my golden years - but some pesky birds are ruining the deal of a lifetime

A private island with stunning views of the Miami skyline has hit the market for $31.5 million - but its potential sale has sparked outrage among environmentalists.

In 1985, Miami resident Finlay Matheson spent $36,000 to buy Bird Key island, and after 40 years, he has decided now is the perfect time to sell.

Speaking to DailyMail.com Matheson said: 'I'm 80 years old and the Miami real estate market is hot. Now's the time to do it'.

But the island's undeveloped status means it is currently a sanctuary for birds and other wildlife. And environmental advocates fear its potential sale to a developer who may build residential property on the island, destroying the oasis.

Pictured: The $31.5 million island, Bird Key listed for sale. The city of Miami is seen in the background

Bird Key sits just 500 yards offshore, south of the 79th Street Causeway, according to the listing. It is 37 acres in total, with around four acres of land surrounded by about 33 acres of 'submerged land in sparkling blue water'.

It has been an important bird habitat for hundreds of years, so much so that a British surveyor named it 'Bird Island' back in 1770. 

Christopher Boykin, chief development officer of Miami Waterkeeper, told the Guardian that losing Bird Key to residential developers would be 'too painful to bear.'

'Right now, it’s a natural island as it’s been for centuries, and to see it turned into condos would just be a blight on our community, a blight on south Florida, and would just be too painful to bear,' he said. 

The island is 'valuable to fish and many other species of marine life, as well as the birds. Its biodiversity, the wealth of life, makes Bird Key a really special and magical place,' he added.

Bird Key is also full of Mangroves - trees that are protected by the Florida Department of Environmental Protection.

Yet according to county property records, Bird Key is zoned for residential use which theoretically means that if it is sold, houses could be built.

As the listing states: 'The ONLY privately owned island, zoned RESIDENTIAL with sights of Miami’s skyline, amid the clear beautiful, blue waters of the Bay - with no traffic or people - is for sale!'

'Only four owners have been able to claim ownership to this gem,' it continues. 'It is a golden opportunity for a developer to acquire and use for environmental mitigation, or one could acquire it to donate it to the public as an environmental treasure, or finally a very lucky individual may create Miami’s most exclusive address, because this gem is zoned residential'. 

NBC Miami reported that the island as a whole, not just its trees, is on Miami-Dade County's registry of threatened environmental lands, which could complicate things for interested buyers wanting to turn the land into a residential community.

Jose Francisco Barros, president of the Tropical Audubon Society, shares Boykin's concerns and told NBC Miami that if any construction were to occur on Bird Key following a sale, it would likely involve destroying existing wetlands.

Boykin hopes that a conscientious buyer, such as a government agency, will buy Bird Key with the intent to protect it. But with a $31.5 million price tag, he's doubtful.

'It’d be wonderful, of course, if the island was purchased by someone that would preserve it, whether it be the federal, state or county government,' Boykin said. 

Finlay Matheson has been the owner of Bird Key for nearly 40 years and has put it on the market while prices are 'hot'

Bird Key sits just 500 yards offshore, south of the 79th Street Causeway, according to the listing . It is 37 acres in total, with around four acres of land surrounded by about 33 acres of 'submerged land in sparkling blue water'

Christopher Boykin, is an environmental advocate who primarily tries to preserve Florida's water. Boykin was given permission to clean up Bird Key by Matheson in 2018 and proceeded to remove thousands of pounds of trash off the island

NBC Miami reported that Miami-Dade County, where Bird Key is located, made an offer to buy the island 'as recently as last year' with the intent to protect it under the Environmentally Endangered Lands (EEL) Program. 

The mayor of Miami-Dade County, Daniella Levine Cava, told multiple local outlets that the owner rejected the offer.

'My administration has been closely following the process at Bird Key and made a purchase offer that unfortunately did not meet the owner's expectations,' Cava said in a statement.

'We are eager to find alternatives, including state or federal support, to purchase this property and expand the footprint of our Biscayne Bay protection programs.'

Yet Matheson told DailyMail.com he hasn't received or heard of any such offer. 

'Nobody from any governmental organization, whether it be the city, the county, or the state has ever contacted me or made me an offer,' he said.

He explained that a broker had reached out last summer to ask if he'd entertain an offer that might have been from Miami-Dade County, but that he was not sure who did the appraisal as he never received a copy of the document. 

DailyMail.com reached out to Cava's office for comment. 

Matheson added that the criticism he has received from environmental groups is unfair, pointing out that Bird Key has been on the county's list of environmentally endangered lands for years.

'My attitude is, these environmental groups and the county and the state have had every opportunity to do something, and they haven't done it. So, now I put it on the market, and I'll sell it to somebody who comes in with a reasonable offer,' he said. 'I have a clear conscience in selling the island.' 

Matheson had previously hoped that a government agency or private environmental group would make him an offer and preserve Bird Key better than he could, the Miami Herald reported in 2012. 

Matheson was eager to clean up the island but said he was 'hampered by the difficulty of mooring a big enough boat nearby to transport the trash.'

He went on to enlist the help of none other than Boykin, who is opposed to Matheson's decision to put Bird Key up for sale, to lead a cleanup effort. 

Boykin and 17 volunteers transported 1,850 pounds of trash off Bird Key in 2018, the Herald reported in 2019.

A year later on Veteran's Day, Boykin and 25 volunteers returned and disposed of a further 2,700 pounds of garbage. 

Matheson told DailMail.com that he hasn't spoken to Boykin in 'several years.' 

Jose Francisco Barros, president of the Tropical Audubon Society, said any construction on Bird Key would devastate the existing wetlands, disrupting many species native to the island

A glimpse at the untamed terrain on Bird Key, which is home to birds, marine life and state-protected Mangrove trees

Miami-Dade County Mayor Daniella Levina Cava has said her office has made an offer to buy Bird Key from Matheson but it was rejected. The reason for the deal falling through is unknown

Matheson said he has previously paid for a bird study to be done on the island, as well as a sea grass study. He also said that he had fish and wildlife signs posted around the island to keep people away, but that those signs have since disappeared.

He described himself 'a good custodian' of Bird Key, adding that he's 'been out there many times' but decided against using the land for anything.

The Matheson family is a wealthy clan that's been active in Miami since at least 1908 when industrialist William John 'W.J.' Matheson (great grandfather of Finlay Matheson) bought land on Key Biscayne, a larger island off the coast of South Miami.

W.J. Matheson developed a coconut plantation there that also had a school, a commissary and a zoo, according to the Village of Key Biscayne.

The Matheson family later donated the 800 acres of land that used to be a coconut plantation to form what is now Crandon Park.

Finlay Matheson now owns a 4,268 square foot home not too far away from where his family got their start in Key Biscayne.