Ocyplanus proeses

The Andean Flamingo is distinguishable by its delicate and pale pink plumage, accented with striking black flight feathers visible only during flight. Adults have a distinctively long neck and legs adapted for wading in deep water. Their bill is characteristically bent, with a yellow base and a black tip, perfectly designed for filter feeding. Males and females are similar in appearance, although males are slightly larger. Juveniles are identified by a more subdued greyish-pink plumage, which gradually brightens as they mature. Unlike other flamingo species, the Andean Flamingo has three-toed feet, a rare trait among its relatives. In flight, they exhibit a graceful silhouette with an outstretched neck and legs trailing behind, demonstrating their aerodynamic efficiency. When at rest, they often stand on one leg, a behavior thought to conserve body heat. Confusion with the closely related James's Flamingo can occur, but the latter is generally smaller, with a more intense pink hue and different bill coloration. Observers can distinguish the Andean Flamingo by its unique three-toed feet and subtle pink coloration.

The Andean Flamingo primarily feeds on small organisms found in saline and alkaline lakes, including algae, diatoms, and tiny crustaceans. Their specialized bill is adapted for filter feeding, allowing them to efficiently separate food from mud and water. Seasonal diet changes occur as they exploit different food resources available at varying altitudes. During the breeding season, they rely heavily on the abundance of diatoms, which are rich in carotenoids, enhancing their pink coloration. In winter, their diet may diversify to include more small crustaceans and larval insects found in lower altitude wetlands. Flamingos typically feed in the early morning and late afternoon, when conditions are cooler and predators are less active. Their foraging technique involves stirring the water with their webbed feet, creating a current that brings food particles within reach.

The social structure of the Andean Flamingo is characterized by large, cohesive flocks that provide safety in numbers. These flocks engage in elaborate courtship displays, including synchronized marching and head-flagging, essential for pair formation. Despite their social nature, flamingos exhibit territorial behavior during the breeding season, defending nesting sites from intruders. Flocking patterns change seasonally, with larger congregations forming during migrations and dispersal following the breeding period. When confronted by predators, such as foxes or large birds of prey, the Andean Flamingo relies on its sharp eyesight and group vigilance to detect threats early, taking swift flight if necessary. Daily activity patterns are influenced by environmental conditions, with flamingos most active during cooler, low-light periods. During midday, they often rest or preen, conserving energy and maintaining their plumage.

The Andean Flamingo constructs nests from mud and small stones, forming conical mounds that elevate their eggs above the waterline, protecting them from flooding and temperature fluctuations. These nests are typically clustered in large colonies on the shores of saline lakes. Females lay a single egg per breeding season, which both parents incubate for approximately 27 to 31 days. After hatching, the chicks are cared for by both parents, who regurgitate a nutrient-rich 'crop milk' to feed them. Fledging occurs at around 75 to 80 days, but young flamingos may remain with the colony for several months, gradually gaining independence. The species usually raises one brood per year, although in optimal conditions, some pairs may attempt a second. Nesting success is heavily dependent on stable water levels and abundant food resources.

The vocalizations of the Andean Flamingo are a series of low, goose-like honks and softer murmurs, often described as rhythmic and slightly nasal in quality. These calls serve a variety of functions, from maintaining contact within flocks to reinforcing pair bonds during courtship. Alarm calls are sharper and more urgent, alerting the colony to potential dangers. During the dawn chorus, their calls become more frequent and intense, synchronizing with the first light of day. Compared to other flamingo species, the Andean Flamingo's vocal range is relatively limited, yet it plays a crucial role in their social interactions, particularly in large flocks where visual cues may be less effective.

• 1Despite their large size, the Andean Flamingo can fly at speeds of up to 60 km/h, covering long distances during migration.
• 2The species is one of only three flamingo species found in South America, and it is the only one with three-toed feet.
• 3Andean Flamingos can live up to 20 years in the wild, relying on their social structure for survival.
• 4They feed almost exclusively in brackish water, a habitat too harsh for many other species, reducing competition for food.
• 5Their specialized bills can filter over 30 liters of water per day, efficiently extracting tiny food particles.

Currently listed as vulnerable by the IUCN, the Andean Flamingo faces several conservation challenges, including habitat destruction, water pollution, and climate change impacts. Population trends have shown a decline due to these threats, particularly in critical breeding grounds. Conservation efforts focus on habitat protection and restoration, such as the establishment of protected areas and international cooperation under the Ramsar Convention. Historically, populations fluctuated with wetland availability, but recent human-induced changes have exacerbated these fluctuations. Continued monitoring and international collaboration are essential to ensure the long-term survival of the species, given its sensitivity to environmental changes.