Urban Wildlife in Sri Lanka’s Growing Cities

Sri Lanka is often celebrated for its national parks and wilderness areas, but some of the island’s most fascinating wildlife encounters now happen far from protected forests. As cities expand and green spaces shrink, many species have adapted to life alongside people. From rooftops to drainage canals, from wetlands to back gardens, urban wildlife has become an increasingly visible part of Sri Lankan city life.

Where Wetlands Meet Skyscrapers

Colombo is Sri Lanka’s most well-known example of urban wildlife coexistence. The city’s remaining wetlands, such as Thalangama, Beddagana, and Diyasaru parks, act as vital refuges for birds, reptiles, mammals, and amphibians. Water monitors, crocodiles, otters, and an astonishing variety of birds are regularly spotted within city limits.

These wetlands help control flooding, improve water quality, and provide green breathing spaces for people. At the same time, encroachment, pollution, and illegal dumping threaten these ecosystems. Colombo shows both the promise and the fragility of urban nature –  where wildlife can survive, but only if space and protection are maintained.

Thalangama Wetlands

Just a short drive from central Colombo, the Thalangama Wetlands represent one of the city’s most remarkable natural refuges – a vast freshwater landscape of marshes, ponds, canals, and paddy fields that supports a surprisingly rich array of wildlife and plant life. This area originated around man‑made irrigation tanks, including the historically important Thalangama Tank, which has supported local agriculture and water supply for centuries while also providing vital habitat for nature.

Today, Thalangama stands out as a biodiversity hotspot within the rapidly expanding urban environment. More than 100 species of birds have been recorded here, from graceful purple herons and little egrets to pheasant‑tailed jacanas walking atop floating vegetation and sociable lesser whistling ducks grazing open water surfaces. Waders, kingfishers, storks, and migratory waterbirds make regular appearances, especially in the cooler months when water levels fluctuate and food becomes abundant.

But birds are only part of the story. The wetland harbours butterflies and dragonflies that dance above reeds and open water, reptiles such as water monitors that bask on riverbanks, and small mammals like purple‑faced leaf monkeys in adjacent scrublands. The mosaic of open water, marshland vegetation, and edge habitat help sustain this surprising mix of urban wildlife – making Thalangama a favorite among birdwatchers, photographers, and nature lovers alike.

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Beddagana Wetlands

Adjacent to the Diyawanna Lake, Beddagana Wetland Park is a serene remnant of wetland habitat that has been protected and enhanced as a public nature park. Declared a wildlife sanctuary and later redesigned as an urban wetland park, this 18‑hectare area combines swamps, natural ponds, waterways, and scrubland to form a lush landscape alive with biodiversity.

The park is particularly celebrated for its birdlife, with both resident and migratory species drawn to its calm waters and reed beds. Herons, egrets, kingfishers, duck species, and occasional raptors can be seen here throughout the year, while butterflies and dragonflies thrive in the hospitable vegetation across the landscape.

Raised boardwalks and shaded trails invite visitors to explore quietly through these wetland habitats, offering glimpses of fish flickering beneath the water’s surface, amphibians hiding in water’s edge vegetation, and birds nesting among the reeds. As a natural escape within a busy city region, Beddagana is both a wildlife sanctuary and a peaceful retreat for those seeking connection with nature.

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Kolonnawa Wetlands

The Kolonnawa wetlands form part of the broader network of marshes, canals, and water bodies around Colombo, creating a subtle yet vital habitat for urban wildlife. Here, slow‑moving channels and vegetated banks provide feeding and resting sites for wetland birds, from herons and egrets to smaller waterfowl, while open water and edge habitats support insects, fish, and reptiles.

Though close to industrial and residential areas, these wetlands act as wildlife corridors, helping birds and small animals move between larger green spaces and other urban wetland patches. The presence of diverse aquatic vegetation helps sustain invertebrates and fish that form the base of the food web, while the surrounding scrubland and trees offer perches and shelter for passerine birds.

Kolonnawa showcases how even modest patches of wetland can contribute to urban biodiversity resilience, connecting habitats and providing pockets of ecological richness within a built environment that often feels distant from nature.

Diyasaru Park

Hidden behind Sri Jayawardenepura’s Parliament complex lies Diyasaru Park, a 60‑acre urban wetland that has been intentionally restored and developed as a multifunctional ecological space. Originally marshland, it now comprises marshes, flooded woodlands, lakes, ponds, boardwalks, and observation zones, designed to celebrate and protect wetland biodiversity within the heart of Greater Colombo.

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Diyasaru supports an astonishing range of life. Over 80 species of wetland birds – including both resident and migratory visitors – find food, shelter, and nesting sites among its waters and reeds. On any given morning you might spot colorful kingfishers or elegant herons, while the flutter of butterflies and the iridescence of dragonflies animate the air above the water.

The park’s ponds and channels also shelter fifteen fish species, including several endemic to Sri Lanka, and support reptiles and amphibians alike. Otters and purple‑faced leaf monkeys are occasional visitors, and part of the park is specifically reserved for threatened fishing cats, underscoring Diyasaru’s importance as a conservation area even in an urban setting.

Beyond wildlife observation, Diyasaru functions as an educational and research hub. It features bird‑watching towers, boardwalks, ecology labs, a herbarium, and environmental study areas that draw students, researchers, and citizens interested in wetland ecology and conservation – all within a few kilometers of Colombo’s city centre.

Seethawaka Wet Zone Botanic Gardens

Located near Avissawella, the Seethawaka Wet Zone Botanic Gardens is Sri Lanka’s newest major botanical garden, established to function both as a research centre and conservation area for wet zone plant species, many of which are threatened or vulnerable in the wild. Opened to the public in 2014, it covers over 40 hectares of former rubber and tea plantation land that has since been transformed into a richly biodiverse garden.

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Seethawaka’s location on the edge of the wet zone – adjacent to Indikada Mukalana Forest Reserve – allows it to support a mix of rainforest trees, understory plants, streams, and wetland fringes. The garden plays an important role in ex‑situ conservation, meaning rare and endemic rainforest species are cultivated and preserved here away from their original forest habitat.

A tropical stream and rich soils help sustain a wide variety of wet zone flora, from towering trees to delicate ferns, palms, and flowering shrubs. This diversity, in turn, attracts butterflies, insects, and birds that rely on specific plants for nectar, shelter, or nesting material. As both a conservation site and outdoor classroom, Seethawaka connects visitors to Sri Lanka’s broader wet zone biodiversity and highlights the role of botanical gardens in safeguarding plant heritage.

Horagolla National Park

Horagolla National Park, one of Sri Lanka’s smallest national parks, is a rare patch of low‑country evergreen forest located in a semi‑urban area of Gampaha District. First designated as a wildlife sanctuary in the 1970s and later elevated to national park status, Horagolla preserves a mosaic of evergreen tree species such as horas (Dipterocarpus zeylanicus), godapara, kekuna, and kithul cane, which create a dense, humid forest habitat.

This forest supports a variety of wildlife adapted to shaded understories and rich leaf litter. Among the fauna are small mammals like giant squirrels, mouse deer, and foxes, while the avifauna includes colourful forest species such as parakeets, black‑headed bulbuls, barbets, and Asian koels. Reptiles including pythons and cobras are also part of this woodland ecosystem, adding to its ecological complexity.

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As one of the few protected forest areas within reach of Colombo, Horagolla functions as an essential green refuge and ecological stepping stone. It helps connect fragmented forest patches in the region, offering habitat continuity for species that would otherwise struggle to survive in heavily altered landscapes.

Kerawalapitiya

Located near Wattala just north of Colombo, Kerawalapitiya has emerged as an unexpected hotspot for urban birdlife – even though it sits beside industrial zones and a large waste processing area. What might seem like degraded or marginal land has, in recent years, become a magnet for birders and nature lovers because of the unique mix of habitats and its position along a major migration flyway.

The area combines marshy wetlands, drainage channels, open sandy patches, and adjacent patches of disturbed vegetation, which together create a mosaic of microhabitats. These draw an astonishing variety of birds, especially during the migratory season, when species moving between breeding and wintering grounds pass through Sri Lanka’s western corridor.

For many birders, Kerawalapitiya became especially famous in late 2021 and 2022 when several rare and unusual wagtail species were recorded here – including the Masked Wagtail (Motacilla alba personata), the White Wagtail (Motacilla alba), and the short‑tailed wagtail (Motacilla ocularis) observed near sandy waste areas and marsh edges. These sightings drew attention not just because of the species involved but because they occurred so close to Colombo, in a place not traditionally thought of as a birding site.

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Beyond wagtails, the site has recorded a rich array of species that reflect the ecological variety of the area. Birdwatchers have noted Temminck’s stint, little stint, paddyfield pipit, yellow wagtail, Kentish plover, common sandpiper, barn swallow, zitting cisticola, and many other waterbirds and open‑habitat species.

Perhaps most remarkable are the rare vagrant and migratory species that have made international birding news. In late 2022, observers documented the Black‑winged Pratincole (Glareola nordmanni) – a species not previously recorded in Sri Lanka or South Asia –  along with several other uncommon migrants such as the Eastern Marsh Harrier and Ortolan Bunting, all at Kerawalapitiya.

The reasons this site attracts such diversity are partly ecological and partly incidental. The wetlands and open water provide feeding and resting sites for waterbirds and waders, while the piles of organic waste near the processing site attract large numbers of insects, making the area a predictable feeding ground for insectivorous birds during migration peaks. Its location near the Western Flyway – a major bird migration route down Sri Lanka’s west coast – makes it an important stopover for migratory species moving between Asia and the Middle East or Africa.

Anawilundawa International Ramsar Wetland Sanctuary

Situated between Chilaw and Puttalam, the Anawilundawa Wetland Sanctuary is one of Sri Lanka’s most ecologically important wetland systems and one of the country’s designated Ramsar Wetlands of International Importance. Spanning nearly 1,400 hectares, Anawilundawa is a rare landscape where three distinct ecosystems converge – freshwater wetlands, mangrove swamps, and coastal saltwater habitats. This ecological meeting point has made it one of the island’s most important refuges for birds, fish, reptiles, and mammals.

Anawilundawa is particularly celebrated as a bird sanctuary, attracting over 150 species of birds, including a significant number of migratory visitors during the northern winter. Large congregations of herons, egrets, openbills, cormorants, ibises, purple swamphens, pheasant-tailed jacanas, and many species of waders gather here across the open waters and marsh edges. During migration season, the wetland becomes a vibrant resting and feeding ground for birds arriving from as far as Central Asia and Eastern Europe.

Beyond birds, the sanctuary shelters remarkable biodiversity. Surveys have recorded 47 species of fish, 11 amphibians, 34 reptiles, 21 mammals, and nearly 80 butterfly species, making it one of the most biologically rich wetland landscapes in Sri Lanka. Its mangroves and freshwater swamps also support endangered and endemic plant species, while seasonal marsh forests known locally as wew thaawulla create important breeding grounds for both aquatic and terrestrial wildlife.

What makes Anawilundawa particularly unique is the relationship between traditional human land use and biodiversity. The same irrigation systems that sustain rice cultivation also sustain wildlife, making it a powerful example of coexistence between community and ecosystem. Today, it remains one of Sri Lanka’s finest birdwatching destinations – a living reminder that wetlands are not empty spaces, but dynamic landscapes of life, history, and ecological balance.