Sabine's gull insect larvae taken include terrestrial and aquatic beetles, springtails, craneflies, mosquitos, midges, and flower flies (Syrphidae). Sabine's gull The Sabine's gull ("Xema sabini"), also known as the fork-tailed gull or xeme, is a small gull. Its generic placement is disputed; some authors treat it as the sole species in the genus Xema as Xema sabini, while others retain it in the genus "Larus" as Larus sabini. The Sabine's gull breeds in colonies on coasts and tundra, laying two or three spotted olive-brown eggs in a ground nest lined with grass. It is very pelagic outside the breeding season. It takes
Swallow-tailed gull photoreceptor cells. A study of melatonin levels of swallow-tailed gulls found them to have no measurable daily melatonin rhythm, whereas a day-feeding gull that was chosen for comparison had the expected higher night time melatonin level for day active birds. High melatonin levels generally make birds sleepy. It is still unknown whether the melatonin levels are a cause or an effect of the swallow-tailed gulls' nocturnal activity. The swallow-tailed gull is a near-endemic breeding bird of the Galápagos Islands, although a few pairs nest on Malpelo Island off the coast of Colombia. When not breeding, it is totally pelagic, flying