Data Zone
Gang-gang Cockatoo © David C Simon/Shutterstock
In September 2022, BirdLife launched the fifth edition of its flagship science publication, State of the World’s Birds, summarising the key developments in bird science and conservation over the last four years. This annual update profiles a selection of case studies from the report, which synthesises the latest knowledge and evidence about the changing conservation status and trends of the world’s birds (STATE), the threats causing birds to decline (PRESSURE), and the conservation actions being taken to improve their status (RESPONSE).
BirdLife International is the official Red List Authority for birds, responsible for assessing and documenting the global extinction risk of all 11,000+ species for the IUCN Red List. Following transparent expert discussions on BirdLife’s Globally Threatened Bird Forums, the 2022 Red List update saw 45 species uplisted to higher threat categories due to a genuine deterioration in status, while just 12 were downlisted to lower threat categories due to an improvement in status.
New satellite imagery revealed rapid forest loss in many parts of the tropics, leading to multiple forest-dependent species being elevated to higher categories of extinction risk. For example, in Southeast Asia, Malay Crestless Fireback Lophura erythrophthalma has been uplisted to Critically Endangered having lost nearly 70% of its forest habitat since 2001; in Central America, White-throated Shrike-tanager Lanio leucothorax is now Near Threatened due to accelerating tree cover loss in recent years; and in Africa, Chirinda Apalis Apalis chirindensis is now Vulnerable owing to rapid deforestation along the Zimbabwe-Mozambique border. The impacts of climate change are also increasingly evident, with drought, heat waves and wildfires leading to the uplisting of several Australian species such as Fernwren Oreoscopus gutturalis and Gang-gang cockatoo Callocephalon fimbriatum.
But some species provide reason for hope. New Zealand’s Black Robin Petroica traversi has been downlisted from Endangered to Vulnerable following a remarkable recovery thanks to the efforts of the New Zealand Wildlife Service and Department of Conservation. Once reduced to a population of just five birds (including only one fertile female) due to predation by introduced mammals (particularly rats), this species now has a stable population of 300 birds as a result of targeted actions including translocation to different islands and cross-fostering of chicks with a closely related species.
Number of species in each IUCN Red List category (numbers in red indicate the net change since the previous year's assessment).
The most comprehensive long-term monitoring data for birds come from Europe and North America, where surveys started around 50 years ago. These data reveal significant declines in certain groups of birds, such as grassland/farmland specialists and long-distance migrants. Data on long-term trends in bird abundance are much scarcer in other parts of the world, but there is increasing evidence that population declines are occurring around the globe. Recent reports have highlighted declines in resident, insectivorous and specialised species in the agricultural countryside of Costa Rica. In Kenya, 19 of 22 raptor species have declined since the 1970s, while Uganda’s forest and savannah specialist species have also suffered declines. Citizen science is helping to fill data gaps in some countries, revealing declines in grassland/shrub, forest and wetland specialists in India and seabirds off south-eastern Australia.
Declines in groups of bird species around the world
The Red List Index (RLI) measures trends in extinction risk over time (illustrating its inverse: survival probability). The RLI for birds has shown a steady decline over the last three decades, indicating an overall increase in extinction risk. Since 1988, 93 species have been downlisted to a lower Red List category due to a genuine improvement in status, but this is outweighed by the 436 species that moved to a higher category of threat because of a genuine deterioration in their status. Estimates based on these trends predict an overall effective extinction rate (the average probability of extinction per species per year) of 2.17 x 10-4/species/year – six times higher than the rate of outright extinction since 1500.
The Red List Index of species survival for birds
Analysis of data from BirdLife’s latest species assessments for the IUCN Red List shows that the threats affecting the greatest number of the world’s threatened bird species are (in descending order) agriculture, logging, invasive alien species, hunting and trapping, and climate change. These same threats also emerge highly from monitoring of Important Bird & Biodiversity Areas (IBAs) by the BirdLife Partnership.
The relative importance of different threats to globally threatened bird species.
Wandering Albatrosses Diomedea exulans (Vulnerable) are at high risk from bycatch because their large foraging ranges expose them to multiple fisheries across national and international waters. In a recent project led by BirdLife, data from loggers that record positions of birds and detect radar transmissions from nearby fishing vessels were integrated with the locations of individual vessels to identify areas, gear types and flag states (fishing nations) representing the greatest bycatch risk. For Wandering Albatrosses, this shows that they are at the highest risk of interacting with fishing vessels during their incubation and chick-rearing periods. Out of 251 tagged birds, 43% showed close attendance at fishing vessels, with the greatest overlap occurring with demersal longline vessels flagged to South Korea.
Albatrosses surround a fishing vessel in Argentina © Leo Tamini
The majority of Key Biodiversity Areas (KBAs) contain infrastructure. Currently, at least 37% of KBAs identified for birds contain urban areas, while at least 76% contain roads, resulting in increased accessibility which facilitates further urban development, illegal hunting, logging and spread of invasive species. Urban areas are also associated with high levels of light pollution, which can negatively impact migratory species in particular. More than 80% of all KBAs are at least partly covered by light-polluted night skies, while more than two-thirds lie entirely under artificially bright skies.
Percentage of Key Biodiversity Areas identified for birds that overlap with urban areas in each region
Birds show that with effective conservation action, species can be saved and nature can recover. The most important action for the greatest proportion of threatened species is to effectively protect, safeguard and manage the most critical sites for their conservation – Important Bird and Biodiversity Areas (IBAs). During implementation of the 2013-2020 BirdLife Strategy, 450 IBAs were designated as protected areas through advocacy of BirdLife Partners. For example, in 2022, following extensive work by Aves Argentinas (BirdLife Partner), Ansenuza National Park was established in central Argentina, protecting the globally important Mar Chiquita Lagoon and the half a million migratory waterbirds that it supports, including the Vulnerable Andean Flamingo Phoenicoparrus andinus).
BirdLife Cyprus, together with the UK BirdLife Partner, RSPB, have been systematically monitoring illegal songbird trapping in the Republic of Cyprus and the Eastern Sovereign Base Areas for the last 20 years. This active covert surveillance has been used to inform on-the-ground action by enforcement officials, resulting in one of the most successful campaigns against illegal poaching globally. Since surveys began in 2002, mist-netting activity within the survey area has decreased by 84%. However, the battle is not yet won. A recent relaxation of deterrent legislation, together with reduced capacity in enforcement teams, resulted in worrying signs of an increase in trapping activity in autumn 2021.
Illegal bird trapping activity in Cyprus during 2002-2021
In 2021, BirdLife International partnered with the Asian Development Bank (ADB) and the East Asian-Australasian Flyway Partnership to develop a long-term ‘Regional Flyway Initiative’ to protect, manage and restore at least 50 priority wetlands across ten Asian countries, with an initial financing commitment of $3 billion from the ADB. The initiative will build upon ongoing activities in the region through partnerships with key stakeholders such as national governments, civil society, development agencies and the private sector. This partnership will work together to conserve biodiversity; maximise economic and social benefits; invest in nature-positive, socially-inclusive development; and tackle climate change. This innovative, large-scale approach, in which the benefits of nature are internationally recognised and integrated into decision-making across society, is key to conserving widely dispersed but interconnected sites.
Asia’s wetlands provide vital habitat for species such as Spoon-billed Sandpiper Calidris pygmaea (Critically Endangered) © Kajornyot wildlife photography.
BirdLife's work on State of the World's Birds is generously funded by the Aage V. Jensen Charity Foundation.