Raptor bird
Indeed, Africa and Asia are experiencing concurrent vulture crises ( Pain et al., 2008 Ogada et al., 2016), which contribute to obligate scavengers being the most threatened avian feeding guild, globally ( Buechley and Şekercioğlu, 2016).
The obligate scavenging behavior of vultures particularly exposes them to dietary toxins while their slow life histories prevent populations from rebounding quickly ( Buechley and Şekercioğlu, 2016). Old World vultures are especially imperiled, mostly because of intentional and unintentional poisoning ( Buechley and Şekercioğlu, 2016 Ogada et al., 2016 McClure et al., 2018). Further, most groups of raptors have lower Red List Indices ( Butchart et al., 2007) than birds do generally ( McClure et al., 2018) – thus the average raptor is at greater risk of extinction than the average bird. Raptors remain understudied with ten species receiving one-third of research attention and one-fifth of species being virtually unstudied ( Buechley et al., 2019).
Even of raptor species listed as Least Concern by the International Union for the Conservation of Nature (IUCN), 38% are in decline ( McClure et al., 2018). Over half of raptor species are experiencing population declines and 18% are threatened with extinction ( McClure et al., 2018). Raptor populations are currently of conservation concern. For example, Turkey Vultures ( Cathartes aura) provide an estimated $700 million in ecosystem services by consuming roughly 1,000 tons of carrion per year ( Grilli et al., 2019). Raptors (orders Accipitriformes, Cathartiformes, Falconiformes, Strigiformes, and Cariamiformes Iriarte et al., 2019 McClure et al., 2019) particularly perform important cultural and ecosystem services ( Markandya et al., 2008 Donázar et al., 2016 O’Bryan et al., 2018 Aguilera-Alcalá et al., 2020). Such bird declines lessen ecosystem function ( Şekercioğlu et al., 2004), because birds play important roles including as pollinators, dispersers, scavengers, and predators ( Whelan et al., 2008). Even common species are experiencing declines ( Ceballos et al., 2017), with bird populations declining by an estimated 29% across North America declining since 1970 ( Rosenberg et al., 2019). Since the year 1500, a minimum of 159 species of birds have gone extinct and many populations of extant species have been lost ( Ceballos et al., 2017 BirdLife International, 2019). Birds have not been spared from such defaunation ( Dirzo et al., 2014 Ceballos et al., 2017). Our results should serve as a framework for discussion of the relative conservation status of bird orders, especially raptors, which are in need of increased conservation attention.Įarth is experiencing a sixth mass extinction – losing species at a rate thousands of times higher than between extinction events ( Ceballos et al., 2010, 2015).
Raptors have both greater proportions of threatened and declining species than non-raptors and Accipitriformes has greater-than-average proportions of threatened and declining species, even if Old World vultures are removed from the analysis. We also show that the proportions of threatened species in each order are correlated with the proportion of declining species. Our results reveal heterogeneity across bird orders in proportions of threatened and declining species, with some orders having greater or lower proportions than the Class-wide proportion. We further examine whether raptors are more threatened or declining than non-raptors and whether the order Accipitriformes is particularly threatened even when excluding Old World vultures – which are especially imperiled.
We examine the International Union for the Conservation of Nature’s (IUCN) Red List to determine which orders of birds have proportionally more or fewer species listed as threatened or declining compared to the Class-wide average. The Peregrine Fund, Boise, ID, United Statesīirds, especially raptors, play important roles in ecosystems.