🇵🇪 Peru · The Coast
Santuario Nacional Lagunas de Mejía is one of those places that surprise you by contrast: in the middle of the desert coast of southern Peru, where it hardly ever rains and the landscape is sand and sea, a strip of lagoons, totora beds and green marshes suddenly appears, packed with birds. It's the only protected wetland on Peru's entire southern coast and a vital stop for thousands of migratory birds crossing the Pacific, which makes it a paradise for anyone who enjoys nature and wildlife watching.
Set at the mouth of the Tambo river, next to the Mejía resort and near Mollendo (Arequipa), the sanctuary brings together a mosaic of environments —freshwater and brackish lagoons, totora beds, gramadal grasslands, beaches and the Tambo estuary itself— that shelter a remarkable variety of resident and migratory birds. 195 bird species have been recorded, 75 of them residents that nest in the sanctuary or its surroundings all year round.
This guide gathers the practical side of visiting: how to get there from Mollendo or Arequipa, what to expect from its trails and viewpoints, the best season for birdwatching and what to bring. It's a quiet destination, ideal to pair with the beaches of Mejía and Mollendo and to understand why these coastal wetlands are so important and, at the same time, so fragile.
The wetlands at the mouth of the Tambo river have been an oasis of life on the desert coast since ancient times, used by pre-Hispanic cultures settled in the Tambo valley and along the coastal strip of what is now Arequipa. The ecological importance of these lagoons, as a refuge for resident and migratory birds on one of the most arid coasts on the planet, led to their formal protection: on 24 February 1984 Santuario Nacional Lagunas de Mejía was established in order to conserve this wetland, unique on Peru's southern coast. It's now run by Sernanp and forms part of the network of wetlands of international importance, as well as being a landmark on the migratory routes of the American Pacific. Its value lies as much in the biodiversity it holds as in its role as a 'rest stop' for birds traveling thousands of kilometers between the northern and southern hemispheres. The full history and the ecological detail are on our history page.
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Origins, formation and what the sources say.
A cluster of lagoons and marshes in the middle of the desert coast of southern Peru looks, at first glance, like a paradox. The Arequipa coast is one of the most arid areas on the planet, part of the great desert that runs along the Peruvian-Chilean seaboard, where rain is exceedingly rare. And yet, at the mouth of the Tambo river, next to the Mejía resort, there stretches a band of green wetlands full of life. The key is the water, which arrives by two routes: what the Tambo river itself brings down from the Arequipa Andes, and the groundwater that surfaces near the shore.
Those inputs of fresh water, combined with the closeness of the sea and the influence of the tides, create a mosaic of environments: freshwater lagoons, brackish lagoons, totora beds, gramadales (floodable grasslands) and the estuary itself where the river mixes with the ocean. That diversity of habitats in a small space is what explains the enormous biological richness of the place. In a setting where water is the scarcest thing there is, these wetlands work as an oasis that concentrates life.
Coastal wetlands like Mejía's are dynamic, fragile ecosystems: they depend on a delicate balance between the river's flow, the level of the water table and the action of the sea. Changes in water use upstream (irrigation in the Tambo valley), climate variation or human pressure can upset that balance. That's why conserving them is so important and so delicate.
Long before there were beach resorts or protected areas, the coast and the valley of the Tambo river were home to pre-Hispanic populations who knew how to live off the resources of the sea, the river and the wetlands. The coastal strip of southern Peru was occupied by cultures that fished, gathered shellfish and hunted birds in these rich environments, and that farmed the fertile valleys watered by the rivers coming down from the Andes.
The Tambo valley, home today to a prosperous farming industry, was from ancient times a corridor of life in the middle of the desert. The coastal cultures of the south, linked to traditions that ran the length of the Peruvian coast, depended in part on wetlands like Mejía's for water, for totora (used to build boats and roofs) and for wildlife. These places were also meeting points between the resources of the sea and those of the interior.
With the arrival of the Europeans and, later, with the consolidation of the Republic, the area turned more and more toward intensive farming in the Tambo valley and toward the growth of the port of Mollendo, which in the nineteenth and early twentieth centuries was one of the main ports of southern Peru and Arequipa's natural outlet to the Pacific. The Mejía resort emerged as a summer spot for Arequipa families. All this human settlement coexisted with the wetlands, which kept up their ecological role until, in the twentieth century, their value led to formal protection.
Through the twentieth century, the advance of agriculture, the building up of the beach resorts and the pressure on the water of the Tambo valley began to threaten the wetlands of Mejía. At the same time, awareness was growing, in Peru and worldwide, of the importance of wetlands as ecosystems vital to biodiversity and, in particular, to migratory birds. Mejía was no ordinary wetland: it was —and still is— the only protected wetland on the whole southern Peruvian coast, an irreplaceable link in the chain of resting places birds use along the Pacific.
For those reasons, the Peruvian state decided to give it legal protection. On 24 February 1984 Santuario Nacional Lagunas de Mejía was established, a category of protected natural area meant to conserve the habitats and wildlife of the place untouched. The sanctuary covers around 690 hectares taking in the lagoons, the totora beds, the gramadales, the beach and the mouth of the Tambo river. It is run today by Sernanp (Servicio Nacional de Áreas Naturales Protegidas por el Estado).
The creation of the sanctuary sought to reconcile conservation with the human activity next door: farming in the Tambo valley, the resorts of Mejía and Mollendo and small-scale fishing. It's an always demanding balance, because the wetlands depend on water from the river and from the water table, resources agriculture wants too. Formal protection, though, was a decisive step in making sure this oasis of life in the desert went on doing its ecological job.
The real treasure of Santuario Nacional Lagunas de Mejía is its birds. More than two hundred species have been recorded in this small wetland, an extraordinary figure that combines resident birds —which live here all year— with migratory birds that arrive in certain seasons from very far away. The residents include ducks, coots, herons, grebes and various birds of the totora beds; the visitors include shore and water birds that travel thousands of kilometers.
The explanation for so much richness lies in continental geography. The migratory birds of the northern hemisphere that travel south in the boreal winter follow routes along the American coasts, known as migratory corridors. On those long journeys they need 'service stations': places to rest, feed and build energy back up. On the hyper-arid coast of southern Peru, where fresh water and wetlands are exceedingly rare, Mejía plays that vital role. Without places like this, many birds could not complete their migrations.
That makes the sanctuary a site of interest for conservation not only nationally but internationally. It's why it's a favorite destination for birdwatchers and nature photographers, and why its protection reaches beyond Peru's borders: looking after Mejía means looking after one link in a network of wetlands that sustains birds from across the continent. The southern summer (November to March) is the best time to take in this richness, when the migratory birds arrive.
Like every coastal wetland, Mejía's lives under constant pressure. Its greatest vulnerability is water: the sanctuary depends on the flow of the Tambo river and on the water table, resources also demanded by the intensive farming of the Tambo valley, one of the most productive agricultural areas in southern Peru. Competition for water, the use of agrochemicals that can reach the lagoons, and changes in the river's regime are real threats to the health of the ecosystem.
Other pressures pile on top: the urban spread of the resorts, the presence of visitors who, without due care, can disturb the birds or degrade the habitats, and the effects of climate change on water regimes and migrations. Sernanp's management tries to balance strict conservation of the area with orderly use for environmental education, research and nature tourism, putting in trails, viewpoints and an interpretation center that channel visits without damaging the wetland.
Conserving Mejía is, at bottom, a story about nature and human activity living side by side in an extreme setting. Showing that it's possible to keep a wetland full of life alongside prosperous farming and busy beach resorts is the sanctuary's great challenge. For visitors, understanding that fragility is part of the experience: walking Mejía with respect, staying on the trails and not disturbing the birds, is a contribution to keeping this oasis here for future generations and for the birds that, every year, depend on it to survive.