Abstract

In this paper, we describe a new subspecies of the Little Tern Sternula albifrons. We propose the name S. a. levantinus, the ‘Levant Little Tern’, reflecting the known breeding range of these birds. Levant Little Terns are, compared to Little Terns elsewhere in Europe (‘European Little Terns’) and Saunders’s Terns S. saundersi, generally darker on the upperparts and with a tendency to show a grey rump and uppertail-coverts, concolorous with the back and mantle. Levant Little Terns are intermediate between European Little Terns and Saunders’s Terns in biometrics and in some characteristics of the breeding plumage, such as the number of dark outer primaries. Genetic analysis shows that Levant Little Terns form a phylogenetic group with European Little Terns, distinct from Saunders’s Terns and from Little Terns in Japan, Korea and Australasia (S. a. sinensis). Surprisingly, the genetic data also show that Little and Saunders’s Terns are not each other’s closest relatives; Saunders’s Tern is a sister species to Least Tern S. antillarum of North America. The relationship between Levant Little Terns and the Little Terns breeding in the Persian Gulf requires further study.IntroductionThe genus Sternula includes the seven smallest species of tern, which are common in most parts of the world: the Least Tern S. antillarum in North America, the Yellow-billed Tern S. superciliaris and Peruvian Tern S. lorata in South America, the Little Tern S. albifrons across Eurasia and Africa, the Saunders’s Tern S. saundersi in South Asia, the Damara Tern S. balaenarum in southern Africa, and the Fairy Tern S. nereis in Australia (del Hoyo et al. 2020). Two of these species – the Little Tern and the Saunders’s Tern – breed in the Western Palearctic. The Little Tern is a common migrant breeder in Europe, North Africa and Arabia (Gochfeld et al. 2020a), while the breeding distribution of the Saunders’s Tern extends to the southeastern reaches of the region, in Egypt (Habib 2014) and Arabia (Gochfeld et al. 2020b), as well as breeding in East Africa and southwest Asia east to Pakistan.Distinguishing between these species can be a challenge, especially when dealing with individuals in non-breeding or immature plumage (Mullarney & Campbell 2022), though adults in breeding plumage can also be challenging (Malling Olsen & Larsson 1995a). In this paper, we describe the unique plumage characteristics and morphology of the Little Terns breeding in the Levant, Red Sea and northern Egypt (referred to from here on as ‘Levant Little Terns’). We address the differences between the plumages of these birds compared to both Little Terns in Europe (‘European Little Terns’) and Saunders’s Tern. In addition, we consider the possibility of misidentification between Levant Little Terns and extralimital records of both Saunders’s Tern and Least Tern. We also suggest areas of future research for further clarifying the status of Sternula terns in the Western Palearctic.