Crested Serpent Eagle Spilornis Cheela Research Articles

Seasonal diet partition among top predators of a small island, Iriomote Island in the Ryukyu Archipelago, Japan

Small islands tend to lack predators because species at higher trophic levels often cannot survive. However, two exceptional top predators—the Iriomote cat Prionailurus bengalensis iriomotensis, and the Crested Serpent Eagle Spilornis cheela perplexus—live on the small Iriomote Island in the Ryukyu Archipelago. To understand how these predators coexist with limited resources, we focused on their seasonal diets between which conflicts are considered to occur. To compare the diets, we used DNA metabarcoding analysis of faecal samples. In the summer, we identified 16 unique prey items from Iriomote cat faecal samples and 15 unique prey items from Crested Serpent Eagle faecal samples. In the winter, we identified 37 and 14, respectively. Using a non-metric multidimensional scaling and a permutational multivariate analysis of variance, our study reveals significant differences in the diet composition at the order level between the predators during both seasons. Furthermore, although some prey items at the species-to-order level overlapped between them, the frequency of occurrence of most prey items differed in both seasons. These results suggest that this difference in diets is one of the reasons why the Iriomote cat and the Crested Serpent Eagle are able to coexist on such a small island.

Parasitic Helminths and Arthropods of the Crested Serpent Eagle Spilornis cheela perplexus Swann, 1922 from the Yaeyama

Thirty-eight individuals of the Crested Serpent Eagle, Spilornis cheela perplexus Swann, 1922 collected between 2001 and 2009 from Yaeyama Archipelago, Okinawa, Japan, were investigated. A total of 11 helminth and two arthropod parasites, including seven nematodes (Eucoleus contortus, Baruscapillaria falconis, Aonchotheca caudinflata, Porrocaecum angusticolle, Procyrnea leptoptera, Microtetrameres accipiter and Synhimantus sp.), three trematodes (Basantisia ridwani, Strigea microbursa and Neodiplostomum georgesduboisi), an acanthocephalan (Centrorhynchus spilornae), a chewing louse (Craspedorrhynchus sp.) and a feather mite (Artamacarus sp.), were identified. Among these parasites, E. contortus, B. falconis, A. caudinflata, P. leptoptera, M. accipiter, Synhimantus sp. and Artamacarus sp. were the first host records for S. cheela, and all helminths and arthropods are the first host records from S. c. perplexus. With the exception of E. contortus, all helminths and arthropods were the first local records from the Yaeyama Archipelago.