SAVE THE BIRDS

Bird Vulnerability to Climate Change

As with other wildlife, birds live in suitable habitat along with their evolution. They have been able gradually evolve to adapt extreme weather of hot desert and cold pole. But abrupt climate change put their adaptive ability in jeopardy.

The speed at which the climate is now changing is unprecedented in the history of human civilisation. While birds have survived ice ages and periods of natural warming over geological timescales, those changes occurred slowly enough for evolutionary adaptation and habitat shifts to keep pace. The rapid anthropogenic warming now underway compresses these changes into decades rather than millennia, leaving little time for species to respond.

Forest-dependent birds face a particularly acute combination of threats. As the climate shifts the conditions that define suitable habitat, these species must either move or adapt. But the fragmentation of forests by roads, agriculture, and human settlements has broken the landscape into isolated patches, making it difficult for bird populations to track shifting habitat conditions across degraded terrain.

IUCN Data on Threatened Species

The IUCN have shown us that even for the non threatened bird species, quarter of them is vulnerable to climate change. This figure is worse in the threatened species that most of them (more than 80%) are vulnerable to climate change.

These findings represent a sobering assessment of how broadly the climate crisis will affect avian biodiversity. The 25 percent vulnerability figure for non-threatened species means that even populations currently considered secure face meaningful risks from projected changes in temperature, rainfall, and seasonality. When species are already dealing with other pressures — habitat loss, invasive species, hunting — climate change can be the additional stress that pushes them across the threshold into threatened status.

For the more than 1,200 bird species already classified as globally threatened, the 80 percent climate vulnerability figure is deeply concerning. These species are already struggling to survive in a world shaped by human activity. Adding climate change to their challenges dramatically reduces the prospects for their long-term persistence, even in cases where other conservation threats have been partially addressed.

The Role of Forest Protection

The figure could still change to worse if we fail to preserve the forest.

Tropical and subtropical forests represent the primary habitat for the majority of the world's bird species. Protecting these forests is therefore not simply a matter of carbon storage or biodiversity conservation in the abstract — it is a concrete and immediate intervention on behalf of the birds that depend on them for their survival.

International mechanisms such as REDD+ offer a pathway to fund forest conservation at the scale required to make a meaningful difference for birds and for the climate. By creating economic value for standing forests, these mechanisms have the potential to compete with the financial incentives that currently drive deforestation, shifting the economics of land use in favour of conservation.

The connection between forest conservation and bird protection reinforces the case for protecting natural forests rather than replacing them with plantations. Plantation forests, whether of timber species or oil palm, support only a fraction of the bird diversity found in natural forest. Policies that allow the conversion of natural forests to monoculture plantations — even where the overall forest cover appears stable — represent a serious threat to avian biodiversity.

Frequently Asked Questions

Why are birds particularly vulnerable to climate change?+

Birds are highly sensitive indicators of environmental change because they rely on precise ecological cues — temperature, rainfall, day length, food availability — to time breeding, migration, and moulting. As climate change alters these cues in unpredictable ways, birds can find themselves out of synchrony with the insects, flowers, and other resources they depend on, a phenomenon known as phenological mismatch.

Many bird species have evolved to occupy specific ecological niches that are closely tied to particular habitat types, elevational ranges, or latitudinal zones. As climate change shifts the boundaries of these zones, species may be unable to track suitable conditions quickly enough, particularly when their habitats are fragmented or degraded. Mountain species face the additional problem of having nowhere higher to go when warming pushes their habitat zone to the summit.

Migratory birds face compounded challenges, as they must cope with changing conditions across multiple continents and at multiple stopover sites. If conditions degrade at any point along a migratory route — including at wintering grounds in the tropics — the entire population can suffer. Tropical deforestation, which destroys the wintering habitat of many migratory species, is therefore a direct threat to birds that may breed far from the equator.

Extreme weather events, which are becoming more frequent and intense with climate change, pose acute threats to bird populations. Late spring frosts can kill nestlings and eliminate the insect prey on which chicks depend. Intense storms can destroy colonies of seabirds and shorebirds. Prolonged droughts can eliminate wetlands that entire populations of waterbirds rely on during critical periods of their annual cycle.

What does the IUCN Red List tell us about birds and climate change?+

The IUCN Red List of Threatened Species is the world's most comprehensive inventory of the conservation status of plants, animals, and fungi. For birds, the Red List is maintained in partnership with BirdLife International, which conducts detailed assessments of all known bird species to determine whether they qualify as Critically Endangered, Endangered, Vulnerable, Near Threatened, or Least Concern based on criteria related to population size, range, and rate of decline.

Climate change has been identified by the IUCN as a significant threat to a large proportion of bird species. Assessments have found that even among species not currently classified as threatened, a substantial share — approximately one quarter — face meaningful risks from projected climate changes. This finding underscores that the impacts of climate change on birds extend far beyond species already on the brink of extinction.

For threatened bird species, the picture is considerably more alarming. The IUCN data indicates that the majority of species already assessed as threatened are also vulnerable to the additional pressures imposed by climate change. When a species is already dealing with habitat loss, hunting, or invasive predators, the extra stress of a changing climate can be sufficient to push it toward extinction.

The Red List assessments are updated continuously as new data becomes available, allowing the conservation community to track trends in species status over time. The systematic incorporation of climate vulnerability into Red List assessments has made the list an increasingly important tool for identifying which species need the most urgent conservation attention and which habitats are most critical to protect.

How does forest conservation help protect bird species?+

Forests, and especially tropical forests, support a disproportionately large share of the world's bird diversity. More than half of all known bird species are dependent on forests for some or all of their life cycle. Protecting forests therefore provides a direct and immediate benefit to the majority of bird species facing threats. No other single conservation action offers such broad protection for avian biodiversity.

Structurally complex old-growth forests, with their multiple vertical layers, large standing dead trees, and diverse understorey, support communities of specialist species that cannot persist in simplified or degraded habitats. These specialists — cavity-nesting birds, canopy frugivores, forest floor insectivores — are among the most vulnerable to deforestation and represent some of the most distinctive and ecologically important members of forest avifaunas.

Forest conservation also helps birds by maintaining ecosystem services on which they depend indirectly. Intact forests sustain the insect communities that provide food for countless bird species during breeding. They maintain the fruit and seed resources that support resident and migratory frugivores. They buffer stream temperatures and water quality, supporting the aquatic invertebrates on which riparian and wetland birds forage.

In the context of climate change, forests provide refugia — areas where species can persist as conditions change around them. Large, intact forest landscapes allow species to shift their ranges within the forest, tracking suitable conditions as temperatures and rainfall patterns change. Maintaining connectivity between forest patches is particularly important for enabling this kind of climate-driven range shift.

What are Important Bird Areas and why do they matter for conservation?+

Important Bird and Biodiversity Areas (IBAs) are sites that have been identified using internationally agreed criteria as being of significance for birds and biodiversity. The IBA programme, coordinated by BirdLife International, has identified more than 13,000 sites in over 200 countries using criteria related to the presence of threatened species, range-restricted species, biome-restricted assemblages, or congregations of migratory or colonial birds.

IBAs provide a science-based framework for prioritising conservation action. By identifying the specific sites that are most critical for birds, the programme helps governments, conservation organisations, and funding bodies direct limited resources to where they will have the greatest impact. The IBA network forms the backbone of many national and international bird conservation strategies.

In Indonesia, a significant proportion of IBAs fall outside formally protected areas, making them particularly vulnerable to conversion and degradation. Many of these unprotected IBAs are in natural production forests that are legally available for logging concessions or conversion to plantations. Advocating for the protection or sustainable management of these forests is therefore central to conserving Indonesia's extraordinary avian diversity.

The IBA programme also provides a monitoring framework through which the conservation status of sites can be tracked over time. Regular assessments of the condition, pressure, and protection status of IBAs help identify where conservation action is most urgently needed and where existing measures are proving effective. This evidence base is critical for holding governments and land managers accountable for the protection of priority bird habitats.

Can bird populations recover if forests are protected and restored?+

Evidence from around the world demonstrates that bird populations can recover significantly when forest habitats are protected from degradation and allowed to regenerate. Secondary forests — those regrowing on previously cleared land — can recover much of their original bird diversity over time, particularly if they are large and connected to primary forest areas that serve as a source of colonising species.

Active forest restoration can accelerate recovery. Replanting with diverse native species, removing invasive plants and predators, and creating habitat features such as nest boxes can speed the return of bird species to restored areas. In some cases, translocations of locally extinct species have been used to restore populations to areas where habitat quality has been re-established.

However, recovery is not guaranteed and is not equally achievable for all species. Forest specialists that require large territories, old-growth structural features, or very specific microhabitats may not return to restored areas even when the forest canopy has been re-established. Extinction debt — the delayed loss of species from an area even after habitat loss has stopped — means that some species may be lost from restored landscapes decades after the initial disturbance.

The lesson for conservation is that primary forest protection must remain the priority. While restoration has an important role to play in reconnecting fragmented landscapes and expanding the overall area of forest habitat, no amount of restoration can fully replicate the biodiversity and ecological complexity of intact old-growth forest. Preventing deforestation remains the most effective and cost-efficient strategy for maintaining bird diversity.