Three tiny hatchlings at the San Diego Zoo Safari Park have given the Socorro dove breeding effort a boost.

A Socorro dove hatched at the park, then a second bird 10 days later, and another on April 23. The species is exceptionally rare. Only about 200 Socorro doves remain, and all live in captivity.

The species was last recorded in the wild on Mexico’s Socorro Island in 1972. Since then, it has survived through a network of zoos. The breeding effort, known as the Socorro Dove Project, aims to release some birds back to their native habitat by 2030.

“These recent hatches represent a significant source of hope and progress for Socorro dove conservation efforts,” Jenna Stallard, wildlife care manager for birds at San Diego Zoo Safari Park, told Smithsonian magazine. “Each successful hatch is an important step toward securing the future of this species, making every milestone incredibly meaningful.”

The San Diego hatchings follow other recent births. In 2025, eight Socorro doves hatched at Chester Zoo in England, and Whipsnade Zoo had a hatchling in August. Bird Paradise in Singapore also had two chicks hatch in August and September last year, the first for that site.

About 50 institutions across three continents now care for Socorro doves as part of the breeding program. In San Diego, the wildlife care team described the doves as “bold and curious,” and said the hatchlings have progressed rapidly and fledged from the nest.

The birds are native to Socorro Island, a 132-square-kilometre volcanic island in the Pacific Ocean about 595 kilometres off Mexico’s western coast and about 402 kilometres from the tip of Baja California. It is the largest of the four Revillagigedo Islands.

The doves disappeared from the wild after major changes to the island. More than 150 years ago, humans brought 100 sheep to Socorro. By 1960, that population had grown to 5,000. The feral sheep overgrazed vegetation and destroyed nest sites in the southern part of the island.

In the 1950s, Mexico built a naval base on the island, and cats were introduced by its residents. Juan Esteban Martínez Gómez, a scientist with Mexico’s Institute of Ecology who is leading habitat restoration efforts on the island, said the damage had already been done by the time cats arrived.

“When the sheep destroyed that area, they were damaging the Socorro dove so bad that when cats arrived, the doves were already in deep trouble,” he told Smithsonian magazine.

He added: “The ‘main factor’ that sealed the doves’ fate was the destruction of their habitat.”

The Cornell Lab of Ornithology has said the Socorro dove is more of a walker than a flier, a trait that “may have hastened its decline” after cats arrived.

The current captive population descends from 17 doves collected during a 1925 expedition by the California Academy of Sciences.

Before any birds return to the wild, conservationists are working to make Socorro Island suitable again. John Ewen, a professor in species recovery at the Zoological Society of London’s Institute of Zoology, said the birds need dense vegetation and low nesting areas.

“These birds spend a lot of time on the ground and prefer to build their nests lower to the ground rather than in high trees, so dense forestry and bushes for them to nest in are essential,” he told Smithsonian magazine.

Mexico declared the Revillagigedo Islands a Biosphere Reserve in 1994. Between 2009 and 2012, teams removed sheep from Socorro to help vegetation recover. Martínez’s teams have also been planting native trees on the island since 2015.

As far back as 1960, scientists understood that the relationship between the birds and the island’s endemic forest is “so tight,” Martínez said, “you couldn’t harm forest without harming birds or vice versa.”

He added that “if you want to recover … the birds, you need to recover vegetation.”

At Africam Safari near Puebla, captive Socorro doves live in aviaries with trees native to Socorro Island. The zoo joined the breeding program in 2013, and a year later recorded the first hatching of a Socorro dove on Mexican soil since the species vanished in the wild.

Conservationists plan to plant selected areas of the island, then let the birds help spread seeds further. “The Socorro dove is a very important seed disperser,” Martínez said. “It’s a bird that pretty much eats all the fruits of these endemic trees of Socorro Island.”

He said reintroduction is still some time away, but “within one or two years, this is probably going to happen.”

Conservationists, working with the Mexican Navy, have built an aviary on Socorro Island to receive the birds. New arrivals will be quarantined, then moved to a release pen and later into the wild. After release, they will still need monitoring.

“There has to be a program that protects the doves in the area where they are being released,” Martínez said.

Some feral cats remain on the island. But Martínez said doves in zoos have kept their natural reflex against aerial predators such as the endemic Socorro red-tailed hawk. A 2016 study also reported “clear indications in the recovery of vegetation cover and improvement of soil quality” after sheep were eradicated.

Scientists say years of captive breeding have also produced information that could help the return. Ewen said researchers have documented the doves’ “breeding behaviors, pair bonding and nest sites—important information that will help with their conservation and establishing a self-sustaining population in the wild.”

Zoos have also found that Socorro doves show a drop in reproductive potential after about five or six years of age, so younger birds will likely be used for release.

“We are hopeful for the best, and we need to be also prepared for a new round of challenges that that new phase is going to bring,” Martínez said.

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