Columba erythrothorax

The Socorro Dove is a medium-sized pigeon, easily identifiable by its striking rust-colored breast which contrasts with the slate-gray head and back. Adults exhibit a subtle iridescence on their necks, adding a sheen that catches the sunlight. Juveniles, however, tend to have a duller appearance, lacking the full iridescent quality of adults. Males and females show little to no sexual dimorphism, making them challenging to differentiate in the field without close observation. The Socorro Dove can be confused with the Mourning Dove due to similar size and shape, but the latter lacks the Socorro's distinct reddish hues. In flight, the Socorro Dove presents a compact silhouette, with strong, steady wingbeats characteristic of the Columbidae family. Its posture while perching is upright and alert, often observed when the bird was still prevalent in the wild. The absence of prominent color bands on its wings further distinguishes it from some closely related species. Field identification relies heavily on spotting the unique coloration and listening for its distinctive calls, particularly in captive environments where it remains.

The Socorro Dove's diet primarily consisted of seeds, fruits, and berries found within its forested habitat. Seasonal variations in food availability meant that the doves adapted their diet to include whatever was in abundance, from the seeds of native shrubs to the fruits of endemic trees. Foraging typically occurred on the ground, where these doves would walk while pecking at fallen seeds and fruits. In captivity, their diet includes a mix of grains, pellets, and fresh fruits to mimic their natural nutrition as closely as possible. The size of the seeds and fruits consumed by the Socorro Dove varied, with a preference for medium-sized items that could be easily ingested. Feeding tended to occur during the cooler parts of the day, such as early morning and late afternoon, to avoid the midday heat. This feeding schedule was also likely when their natural food sources were most accessible.

The Socorro Dove displayed intriguing social and territorial behaviors, with pairs forming strong, monogamous bonds. These doves were known to be territorial during the breeding season, defending their chosen nesting sites vigorously against intruders. Courtship displays included soft cooing and gentle bowing motions, with males often puffing out their chests to display their rust-colored plumage. Unlike some other dove species, the Socorro Dove did not form large flocks. Instead, it was usually seen in pairs or small family groups. In response to predators, these doves relied on their cryptic coloration to remain unseen among the underbrush. Their daily activities were divided between foraging, resting, and preening, with a marked increase in vocal activity during the early morning hours. Captive Socorro Doves retain many of these behaviors, providing valuable insights into their natural history.

The Socorro Dove constructed simple nests using twigs and leaves, typically located in the forks of trees or dense shrubs. Nest sites were chosen for their relative safety and proximity to food sources. A typical clutch size for the Socorro Dove consisted of one to two eggs, with both parents sharing incubation duties over a period of approximately 14 to 16 days. After hatching, the young doves, known as squabs, remained in the nest for about two weeks before fledging. Parental roles were shared, with both males and females involved in feeding the young through regurgitation of crop milk. The Socorro Dove's breeding season was largely dictated by food availability, with one or two broods possible per year depending on conditions. In captive breeding programs, these natural nesting habits are closely monitored and supported to ensure the successful rearing of chicks.

The Socorro Dove's primary song consists of a series of soft, mournful coos, often described as a low, repetitive 'coo-coo-coo'. These vocalizations serve both to establish territory and to attract mates. Call notes are softer and less frequent outside of the breeding season but remain an integral part of the dove's communication repertoire. Alarm calls are sharper and more urgent, used to alert others of potential threats. In the early dawn, a chorus of coos would have resonated through Socorro Island's forests, though this is now only experienced in captivity. The sounds of the Socorro Dove can be likened to those of the Mourning Dove but with a distinct, deeper quality that sets them apart.

• 1The Socorro Dove was last seen in the wild in 1972, marking over 50 years of its extinction in natural habitats.
• 2With a wingspan of about 50 cm, the Socorro Dove is comparable in size to a common pigeon but with distinct coloration.
• 3Captive breeding programs have expanded to over 100 individual Socorro Doves, aiming for genetic diversity.
• 4The Socorro Dove is one of the few bird species to have a dedicated rewilding project focused on reintroduction.
• 5Unlike many doves, the Socorro Dove does not exhibit iridescent patches on its wings, making its identification unique.
• 6Efforts to control feral cats on Socorro Island are ongoing, crucial for the reintroduction of the doves.
• 7The Socorro Dove is a symbol of hope and resilience in conservation circles, inspiring similar projects worldwide.

The Socorro Dove is currently classified as extinct in the wild by the IUCN. Historically, its population decline was driven by habitat destruction and predation by introduced species, such as cats and rats. Current conservation efforts focus on captive breeding and habitat restoration on Socorro Island. Population trends in captivity are stable, with a small but growing number of individuals being managed internationally. Reintroduction efforts aim to restore a self-sustaining population on Socorro Island, contingent upon the successful removal of invasive species and habitat recovery. Historically, the Socorro Dove was common on its native island, but without intervention, it faced inevitable extinction. Concerted efforts by organizations like the Socorro Dove Project are crucial in reversing this fate.