Concrete growth leaves Dhaka’s birds with fewer places to live

Researchers link Dhaka’s bird diversity to green spaces, warning that concrete expansion, pollution and wetland loss are putting growing pressure on the city’s urban ecosystem.

There was a time when mornings in Dhaka began with the calls of birds. Sparrows perched on house ledges, mynas sat on tree branches, crows lined up on electric wires and a variety of birds could be seen among the trees in parks. This familiar scene, however, is gradually changing.

The expansion of concrete structures, rapid urbanization, loss of water bodies and worsening air pollution are increasingly shrinking the habitats available to birds in the city. These changes are not merely a crisis for one group of animals; they are also a significant warning sign of growing pressure on Dhaka’s overall biodiversity and urban ecosystem.

A study published in the journal Ecology and Society in 2022 identified 106 bird species in Dhaka city. Of these, 80 were resident species, while 57 of the resident species were identified as potential breeders within the city.

The study drew on existing records from 1995 to 2017, as well as data from eBird and the Global Biodiversity Information Facility (GBIF). In addition, researchers conducted field surveys at 190 sites across Dhaka between February and June 2018.

During the field survey, researchers recorded 8,123 individual birds, representing 48 resident species. Crows were the most abundant, accounting for 13.2% of the recorded birds, followed by sparrows at 13% and mynas at 8%.

One of the most significant findings of the Dhaka study is that birds are more abundant and diverse in green areas. Researchers found an average of 12 bird species and 132 individual birds in green areas. In contrast, more heavily built-up areas had an average of only 6 species and 34 individual birds.

Concrete expansion is reducing diversity

Dhaka’s rapid urbanization has transformed the city’s landscape over the first several decades. Natural and semi-natural areas have increasingly been replaced by buildings, roads and other paved surfaces.

The Dhaka study found that an increase in impervious surfaces, such as concrete and paved areas, is associated with a decline in bird species richness. Conversely, areas with greater habitat diversity and more green spaces tend to support more birds.

Why are birds declining?

There is no single reason behind the decline of suitable habitats for birds in Dhaka. Several factors are working together.

Loss of trees: Large trees provide birds with nesting sites, shelter and food. When mature trees are removed to make way for buildings and roads, birds lose their habitat.

Loss of water bodies: Lakes, ponds and other water bodies provide food, breeding grounds and resting places for many species. Their disappearance particularly threatens water-dependent and wetland birds.

Expansion of concrete: The Dhaka study found a negative relationship between the amount of impervious surface and bird species richness.

Air pollution: A 2025 study covering five cities in Bangladesh identified air pollution as an important factor associated with bird diversity.

Noise pollution: Construction, traffic and continuous urban noise can interfere with birds’ communication and behaviour, making highly disturbed areas less suitable for some species.

Pesticides and chemicals: Reducing insect populations can also reduce food availability for insect-eating birds. In the Dhaka study, insectivore birds accounted for approximately 50 percent of the observed bird community.

Unplanned urban development: When urban development focuses primarily on buildings, roads and infrastructure while ignoring trees, water bodies, parks and green corridors, pressure on biodiversity increases.

What happens when birds disappear?

Birds are an important part of the urban food web and ecosystem. Some species help control insect populations, others disperse seeds, while scavenging birds help remove dead organic matter from the environment. Therefore, a decline in bird diversity is not simply a problem for birds. It can also signal broader changes in the urban ecosystem.

What can be done?

Making Dhaka more bird-friendly requires protecting the city’s remaining green spaces and wetlands. Mature trees should be preserved and local tree species that provide food and shelter for birds should be prioritised in urban planting programmes. Parks should not be excessively covered with concrete, while portions of shrubs, grassland and natural vegetation should be allowed to remain. Water bodies also need stronger protection. Simultaneously, the use of pesticides in urban green spaces should be reduced wherever possible. wildlife researcher Simanta Dipu said “Without greenery and food, birds will soon turn away from the city.”

Another important step would be to conduct regular bird censuses across Dhaka. Data collected year after year could reveal which species are declining, which are increasing and how different forms of urban development are affecting bird populations.

If the space for crows, sparrows and mynas continues to shrink, many more specialised bird species may eventually disappear from the city and with them could disappear parts of the trees, wetlands, insects, food webs and ecological processes that make an urban environment truly alive. The loss of birds from Dhaka, therefore, is not simply the loss of birds. It is the loss of a living urban ecosystem.

The author is Student at Dhaka College.