Sterna trudeaui

Abstract: We recorded eight species of birds in the Laridae family on the Ilha Comprida beach (southern Sao Paulo State, Brazil), during weekly censuses over 3 years (1999, 2000, and 2001). These species were grouped into three clusters by their abundance, permanence, and time of beach-flat use. The first cluster was formed by Larus dominicanus, Sterna eurygnatha, and Sterna maxima, which were in high abundance and present on the flat in all years. The second cluster included Sterna hirundo and Sterna hirundinacea. Sterna hirundo were seasonally abundant, and all individuals migrated to North America during the reproductive season. Sterna hirundinacea were always present for short periods. The third group included species of low abundance: Sterna superciliaris, Sterna trudeaui, and Larus maculipennis. The number of species and the number of individuals probably fluctuated because of migration or movement between neighboring beaches.

Abstract: BREEDING DISTRIBUTION AND ABUNDANCE OF GULLS AND TERNS IN THE BAHIA SAN BLAS PROTECTED AREA, BUENOS AIRES.— The knowledge of seabird breeding distribution and abundance is important for their management and conservation. We present information on the breeding of gulls and terns gathered between 2006-2013 at the Reserva Natural de Usos Multiples Bahia San Blas, Buenos Aires Province. We recorded the nesting of eight species, in most cases in mixed- species colonies. During 2013, we counted 3635 nests of the Kelp Gull (Larus dominicanus) distributed in 4 colonies, 359 nests of the Olrog's Gull (Larus atlanticus) in 2 colonies, 6 nests of the Brown-hooded Gull (Larus maculipennis), 841 nests of the Royal Tern (Thalasseus maximus), 195 nests of the Sandwich Tern (Thalasseus sandvicensis), 265 nests of the Snowy-crowned Tern (Sterna trudeaui) distributed in 3 colonies, and 21 nests of the South American Tern (Sterna hirundinacea) in 2 colonies. The Gull-billed Tern (Gelochelidon nilotica) did not breed in the area in 2013, but did so in the previous seasons. We observed breeding activities in a total of six sites, although not all of them were used in all breeding seasons. While the Kelp Gull, the Olrog's Gull, the Royal Tern and the Sandwich Tern used the same sites among seasons, the Brown-hooded Gull, the Gull-billed Tern and the Snowy-crowned Tern changed sites among years. Monitoring programs should include several visits throughout the season at all identified sites, so as to ensure detection of bird breeding activity. In addition, the accessibility of visitors to colonies suggests the need for planning of human activities in the protected area given the sensitivity of these species to human disturbance.

Abstract: Nest site selection in Brown-hooded Gull (Larus maculipennis), Trudeau's Tern (Sterna trudeaui), and White-faced Ibis (Plegadis chihi) was studied in a mixed colony in a south Chilean tule marsh. By breed- ing in nests in the vegetation above the water as well as in floating nests, the gulls used more variable nest sites than the terns and ibises. Nest sites were selected with a maximum distance to the shore and in areas with small tule stands that offer sites close to open water. Site preferences overlapped between gulls and

Abstract: Censuses of six tern species were carried out in the inlet of Lagoa dos Patos, southern Brazil, and on the beaches just north (along 50 km) and south (60 km) from this site. The Common Tern (Sterna hirundo) was the commonest species between October and March, with maximum abundance in January (14,100 individuals). Abundance peak for the South American Tern (Sterna hirundinacea) took place in the austral winter, with maximum values of 1,500 birds. Trudeau’s Tern (Sterna trudeaui) and Amazon Tern (Sterna superciliaris) had similar seasonal patterns occurring during all months, with abundance peak in the non-breeding period, between January and July. The maximum number of Trudeau’s Tern was estimated to be 440 birds in April and 400 in June, and that of Amazon Tern was 210 birds in April and 230 in May. A maximum of 300 Royal Terns (Sterna maxima) were recorded in September, 280 in June and 280 in July, but the species was found in every month. The Cayenne Tern (Sterna eurygnatha) was also found eve...