An updated list of parasitic cuckoos and their hosts in China

Avian brood parasitism is a unique reproductive behavior in which parasitic birds depend on other species to incubate their eggs and raise their offspring. In China, there are 20 species of cuckoos in the family Cuculidae, order Cuculiformes, of which 17 species are parasitic cuckoos. This makes China one of the countries with the largest number of parasitic cuckoo species worldwide. Understanding the host utilization of cuckoos provides fundamental data for studying the coevolution of cuckoos with their hosts. We collected information on cuckoo hosts from the literature, photographs provided by birdwatchers, and online short video platforms, combined these data with our field observations, and summarized the parasitic cuckoos and their host species in China. A total of 1155 parasitism events were counted, involving 12 parasitic cuckoo species and 87 bird host species. These hosts belonged to 26 families, among which Muscicapidae was the most diverse with 19 species, accounting for 21.8% of the total hosts, followed by the families Phylloscopidae and Leiothrichidae with 8 species each, accounting for 9.2% of the total hosts recorded. The Common Cuckoo (Cuculus canorus) had the largest number of host taxa with 38 species, accounting for 43.7% of the total host species. This study adds 14 host species that have not been reported in China. However, for five species, the Jacobin Cuckoo (Clamator jacobinus), Banded Bay Cuckoo (Cacomantis sonneratii), Violet Cuckoo (Chrysococcyx xanthorhynchus), Common Hawk-cuckoo (Hierococcyx varius), and Whistling Hawk-cuckoo (Hierococcyx nisicolor), information regarding host utilization is still lacking.