Context: The State of the World’s Birds, an annual review of environmental resources was recently published.

Key Findings of the Study

• 48% of the extant bird species are undergoing population decline.
• 13.5% of 10,994 recognised extant species are currently threatened with extinction.
• Alongside tropical forests, natural grasslands emerge as a habitat that is particularly threatened.
• Threat of natural grasslands has been particularly worrying for North America, Europe and India.
• It highlights the need for conservation as birds are sensitive indicators of environmental health.

Threats Contributing to Avian Biodiversity Loss

• Direct overexploitation: Humans eat 14% and use 37% of the surviving bird species as exotic pets.
• Land-Cover and Land-Use Change: conversion and degradation of primary natural habitats and consequent loss of biodiversity.
• Habitat Fragmentation and Degradation: Disturbance events like selective logging, wildfires, overgrazing by domestic animals, and defaunation by hunting can reduce habitat quality, leading to degradation.
• Hunting and Trapping: Hunting for food (for example, bushmeat), for sport, for trade, or in response to human-wildlife conflicts, can be a driver of habitat degradation.
• Impact of Invasive Alien Species: Predation by introduced mammals such as rats, mice, cats, dogs, and pigs are a major historical driver of avian extinctions.
• Disease: Introduced and domesticated bird species may also pose a risk to wild birds, particularly in insular systems through enhanced disease transmission.
• Infrastructure, Energy Demands, and Pollution: proliferation of new powerlines, buildings, pollutants (like oil spills) which already kill hundreds of thousands to millions of birds every year.
• Climate Change: It affects the migratory birds who face the problem of phenological mismatch.

Solutions to Loss of Avian Diversity

• Protection and effective conservation of key sites.
• Site-based conservation is the single highest priority action for 76% of threatened bird species.
• Broader-scale policy measures to retain and restore natural habitats in wider landscapes and in the oceans.
• Identification of species and habitats which are in greatest need of conservation interventions.
• Conducting reliable estimates of population abundance and change.
• Novel and more effective solutions applied at scale for demand reduction for over harvested wild birds.
• Monitoring green energy transitions that can impact birds if inappropriately implemented
• Eradication of populations of invasive alien species.
• Shifting human societies to economically sustainable development pathways.