Abstract:[Objectives] Woodpeckers, important primary cavity excavators and controllers of wood borers, are highly dependent on forests. They are regarded both as umbrella species and indicator species in the forest ecosystem, and have important conservation and ecological-research significance. With a high dependence on forests, woodpecker populations are very sensitive to the changes in forest cover. Since the 20th century, global forest habitats for woodpeckers have been dramatically reduced and fragmented with the widespread changes in land use, threatening the survival and reproduction of this group. This study aimed to explore patterns of extinction risk and research status of woodpeckers and to lay a foundation for further woodpecker conservation and research. [Methods] We searched the IUCN Red List and BirdLife International online database, 1988﹣2023, to extract data on global changes in the number of woodpecker species and their threat levels; continent-by-continent numbers of woodpecker species and proportions of threatened species; and the major factors threatening the survival of worldwide woodpeckers. Using Google Scholar and online databases, we also collected and categorized the subjects of woodpecker-related articles. [Results] From 1988 to 2023, the number of threatened woodpecker species has increased each year, some species have increased their threat levels, and population trends have also declined. There are 254 species of woodpeckers worldwide. In the past 33 years, the number of threatened species increased from 7 to 18, and the proportion of species threatened increased from 3.4% to 7.0% (Table 1). Of the 18 threatened woodpecker species, 16 experienced population decrease, only 1 threatened species has stable population (Table 2). There are 83 species of woodpeckers in Asia, of which 12.0% are threatened, the highest proportion among all continents. There are 93 species of woodpeckers in South America, of which 6.4% are threatened. There are 56 species of woodpeckers in North America, of which 5.3% are threatened (Table 3). There are currently no threatened species in Africa and Europe, with 36 and 11 woodpecker species, respectively. Agriculture, biological resource use (wood harvesting and hunting), and grazing are the major threats to woodpeckers (Fig. 1). A total of 1 024 articles were searched, involving 140 species of woodpeckers. Since 2001, the number of articles on woodpeckers has rapidly increased. From 2011 to 2020, the number of articles was the highest, with a total of 340 (Fig. 2). Leuconotopicus borealis was the most studied species (162 articles), followed by Dendrocopos major (120 articles) (Table 4). The research primarily focused on nesting (129 articles), habitat selection (122 articles), foraging behavior (112 articles), reproductive behavior (99 articles), and population status (66 articles), among other ecological aspects (Table 5). [Conclusion] Recent studies provide a basis for the accumulation of biological and ecological knowledge regarding woodpeckers. However, there are still many species have not been studied, attention should be paid to ecological studies to determine their habitat needs. In the context of global climate change and the rapid loss of biodiversity, more extensive and in-depth research is needed. Our study comprehensively analyzed the conservation and research status of woodpeckers worldwide, provided a reference for subsequent woodpecker research and conservation.
