The main threats to globally threatened birds worldwide

Analysis of data held in BirdLife’s World Bird Database (2016).

There are a number of threatening processes driving declines in bird populations. Foremost among them are the spread of agriculture which puts 1,126 threatened birds (77%) at risk, logging and wood harvesting impacting 763 species (52%) and invasive species which threaten 473 (32%) of threatened species (BirdLife International 2016). In addition, residential and commercial development, hunting and trapping, livestock and ranching, and climate change are having serious negative impacts (see figure). While all of these threats have additive negative effects on species, climate change in particular often exacerbates other threats. All of these threats are taken into account in the IUCN Red List evaluation of species and contribute to their classification as globally threatened (Critically Endangered, Endangered or Vulnerable). High-impact threats affect the majority of the population and cause rapid declines, while low-impact ones affect the minority and cause slower, albeit still significant, declines. These threatening process impact species’ populations in a number of ways (see figure). Habitat destruction and degradation (driven by anthropogenic activities like logging and agricultural expansion) currently impacts 1,354 threatened birds (93%), while direct mortality and reduced reproductive success resulting from many of the processes listed above are affecting 54% and 33% of threatened species respectively (BirdLife International 2008).

The main stresses on globally threatened birds worldwide

Analysis of data held in BirdLife’s World Bird Database (2008).

Some threats can be reversed given enough resources, so targeted actions have been recommended for all threatened birds to directly address specific threats. When species populations become very small, even stochastic, unpredictable events like natural disasters (e.g. volcanoes, cyclones, drought) or pressure from problematic native species (e.g. increased competition or hybridisation) become very difficult to combat. Within healthy populations these threats may be more benign.