Territorial Fidelity to Nectar Sources by Purple-throated Caribs, Eulampis Jugularis

—We present the first record of territorial site-fidelity across multiple years by Purple-throated Caribs (Eulampis jugularis) on three different islands in the eastern Caribbean: St. Kitts, Dominica, and St. Vincent. Marked male Purple-throated Caribs were monitored throughout the flowering season of their main nectar resources, Heliconia caribaea (St. Kitts and Dominica) and H. bihai (St. Vincent), both native perennial herbs. Individual males were observed defending the same Heliconia patches for 3 years (St. Vincent), 4 years (St. Kitts), and 5 years (Dominica), and remained near these patches even when they were not in flower. The territorial behavior and resource dependence of Purple-throated Caribs on native heliconias likely have a key role in the coevolution of this specialized plant-pollinator interaction. Received 17 March 2011. Accepted 2 August 2011. Territoriality is a costly and often complex behavior involving exclusive possession and/or defense of an area against conspecific and heterospecific animals (Carpenter 1958; Brown 1964, 1969; Pyke 1979). Territorial defense of food resources is common by nectar-feeding birds (Gill and Wolf 1975, Cruden and Hermann-Parker 1977, Frost and Frost 1980, Armstrong 1992, Evans 1996). Non-hermit hummingbirds (Trochilinae), in particular, defend nectar-rich flower patches from both conspecific and heterospecifics (Wolf and Hainsworth 1971, Kodric-Brown and Brown 1978, Cotton 1998, Temeles et al. 2005). Territories, in some species, also function as central breeding areas for males to attract females by offering them flowers rich in high-energy nectar (Wolf 1975, Temeles et al. 2005, Temeles and Kress 2010). Territorial defense by hummingbirds may vary in duration from several hours a day (e.g., Stiles 1978, Cotton 1998) to several days, weeks or months per year (e.g., Temeles et al. 2005). Territorial defense by hummingbirds of the same areas over multiple years, however, has been rarely reported (but see Bassett and Cubie 2009). Specifically, territorial fidelity by hummingbirds, where the same individual uses the same plants for consecutive years, is undocumented. Species in the Heliconia (Heliconiaceae) are primary sources of nectar for hummingbirds in the Neotropics, and territorial defense of Heliconia flowers by hummingbirds is common (Linhart 1973, Stiles 1975, Kress 1983, Dobkin 1984). Heliconias on the islands of the eastern Caribbean are a primary and predictable source of nectar for hummingbirds, especially the Purple-throated Carib (Eulampis jugularis) (Wolf and Hainsworth 1971, Wolf 1975, Temeles and Kress 2003, Gowda and Kress 2008). Only two native species of heliconias occur on the islands of the eastern Caribbean: H. bihai and H. caribaea. The flowering season of H. caribaea ranges from March to July with a peak in May, although rarely individual plants may produce single inflorescences from August to February. In contrast, H. bihai flowers all year with a peak in April (Gowda 2009). Male Purple-throated Caribs, depending on the island, defend feeding and/or breeding territories of either H. caribaea or H. bihai, or both, whereas female Purple-throated Caribs traplineforage at undefended plants or rarely defend feeding territories (Wolf 1975; Temeles et al. 2005, 2006). Heliconia plants are long-lived (Berry and Kress 1991), and individual birds may use the same plants over successive years. We report on long-term territoriality and sitefidelity of Purple-throated Caribs of the same patches of heliconias over several years on St. Kitts, Dominica, and St. Vincent, three islands in the Lesser Antillean Archipelago of the Eastern Caribbean. We also report on additional food plants used by this species.