KEANEKARAGAMAN SPESIES BURUNG DI HUTAN MANGROVE PULAU KELAGIAN BESAR PROVINSI LAMPUNG

The existence of mangrove forests is very important in an area because as a habitat for various types of wildlife, especially birds. This study aims to determine the diversity of bird species in the Kelagian Besar Mangrove Forest, Lampung Province. Data on bird species diversity was obtained by the IPA (Indices Ponctual Abundance) method. Data collection of bird species by recording the type and number of individual birds found. Species identification also uses the method of bird recognition directly by people who know the birds in the area such as the local community or an expert on birds. Data obtained in the field are then analyzed using the Shanon-Winner diversity index formula. The results found 27 species of birds from 21 families with a total of 741 individual birds in the Kelagian Besar Mangrove Forest. While the diversity index value is 2.26 with medium index criteria. There are 8 protected bird species, namely the black-necked darautaut (Sterna sumatrana), the white-wing daralaut (Chlidonias leucopterus), the oyster daralaut (Gelochelidon nilotica), the white belly eagle (Haliaeetus leucogaste), the brontok eagle (Spizaetus cirrhatus), oyster belly Rhipidura javanica), sabine seagulls (Xema sabini), and large fissures (Fregata minor).

Flexibility in migratory strategy contrasts with reliance on restricted staging and overwintering grounds for Sabine’s gulls from the Canadian High Arctic

Sabine’s gulls (Xema sabini) undertake the longest migration of any gull, a trans-equatorial journey between Arctic breeding and southern hemisphere wintering areas. For such long-distance migrants, quantifying within- and between-individual variation in migratory strategy is key towards understanding resilience to environmental variability encountered over migration. We tracked 22 birds on 32 migrations from the Canadian Arctic to evaluate strategies and quantify flexibility among individuals and years. All birds undertook extended stopovers in a geographically-restricted staging area halfway through migration in the California Current System in both directions. Individuals were otherwise flexible in most aspects of migration but were repeatable in arrival date and duration of the southbound staging phase. Routes taken during southbound migration and overlap in overwintering areas were significantly larger within the same year than among years. Overall, birds showed high individual flexibility in migratory strategies but made similar decisions to one another in the same years. Every year, all birds showed repeatable, consistent reliance on the staging grounds as a key stopover site in both directions. This suggests Sabine’s gulls adjust to environmental change in many aspects of their migration but may be vulnerable to climate change and other anthropogenic influences during critical stages of the journey.

Birds of Mansel Island, northern Hudson Bay

A recent review of bird distributions in Nunavut demonstrated that Mansel Island, in northeastern Hudson Bay, is one of the least known areas in the territory. Here, current information on the birds of Mansel Island is summarized. A list published in 1932 included 24 species. Subsequent visits by ornithologists since 1980 have added a further 17 species to the island’s avifauna. The list includes 17 species for which breeding has been confirmed and 10 for which breeding is considered probable. The island seems to support particularly large populations of King Eiders (Somateria spectabilis) and Tundra Swans (Cygnus columbianus) and the most southerly breeding population of Sabine’s Gull (Xema sabini) and Red Knot (Calidiris canuta; probably).

Diet dichotomy between two migrant seabirds breeding near a high Arctic polynya

High Arctic polynyas are predictable areas of open water, which offer long-distance migrant seabirds a reliable source of food during a period when they have to replenish and accumulate energy for reproduction. Investigating the interaction between species nesting sympatrically in the vicinity of polynyas should provide insights into the role that such oceanographic features play for pre-breeding seabirds. We used stable isotopes (δ 13 C and δ 15 N) to compare the diet of two ground-nesting seabirds, Sabine's gull ( Xema sabini ) and Arctic tern ( Sterna paradisaea ), nesting on an island adjacent to a recurring polynya in the Canadian high Arctic in 2008 and 2009. We show that, unlike Arctic terns, the diet of Sabine's gulls appears to include a non-negligible amount of terrestrially derived prey during early incubation, and that overall both species segregate their dietary niche during pre-laying and early incubation.