M. Le Corre

Light-induced mortality of petrels: a 4-year study from Réunion Island (Indian Ocean)

Abstract We report the results of a study of light-induced mortality of petrels at Reunion Island which holds two endemic endangered species, Barau’s petrel ( Pterodroma baraui ) and Mascarene petrel ( Pseudobulweria aterrima ), together with an endemic non threatened subspecies of Audubon’s shearwater ( Puffinus lherminieri bailloni ). We collected 2348 birds attracted to lights between January 1996 and December 1999, among which 70% were Barau’s petrels and 29% were Audubon’s shearwaters. We found also three specimens of the very rare Mascarene petrel. Most grounded birds were fledglings (94%). Light-induced mortality was seasonal and linked with the breeding schedule of each species. At least 20–40% of the fledglings of Barau’s petrels produced annually are attracted by lights. Light-induced mortality is a recent perturbation at Reunion Island. Thus, the effects of this disturbance on the population dynamics of these long lived seabirds may be hard to detect at the present time, but they are likely to occur in the near future. Conservation actions are proposed to limit the light-induced mortality together with other actions and long-term studies focused on the most endangered species.

The diet of feral cats on islands: a review and a call for more studies

Cats are among the most successful and damaging invaders on islands and a significant driver of extinction and endangerment. Better understanding of their ecology can improve effective management actions such as eradication. We reviewed 72 studies of insular feral cat diet from 40 islands worldwide. Cats fed on a wide range of species from large birds and medium sized mammals to small insects with at least 248 species consumed (27 mammals, 113 birds, 34 reptiles, 3 amphibians, 2 fish and 69 invertebrates). Three mammals, 29 birds and 3 reptiles recorded in the diet of cats are listed as threatened by the IUCN. However, a few species of introduced mammals were the most frequent prey, and on almost all islands mammals and birds contributed most of the daily food intake. Latitude was positively correlated with the predation of rabbits and negatively with the predation of reptiles and invertebrates. Distance from landmass was positively correlated with predation on birds and negatively correlated with the predation of reptiles. The broad range of taxa consumed by feral cats on islands suggests that they have the potential to impact almost any native species, even the smallest ones under several grams, that lack behavioral, morphological or life history adaptations to mammalian predators. Insular feral cat’s reliance on introduced mammals, which evolved with cat predation, suggests that on many islands, populations of native species have already been reduced.

Serological evidence for the circulation of flaviviruses in seabird populations of the western Indian Ocean

Birds play a central role in the epidemiology of several flaviviruses of concern for public and veterinary health. Seabirds represent the most abundant and widespread avifauna in the western Indian Ocean and may play an important role as host reservoirs and spreaders of arthropod-borne pathogens such as flaviviruses. We report the results of a serological investigation based on blood samples collected from nine seabird species from seven islands in the Indian Ocean. Using a commercial competitive enzyme-linked immunosorbent assay directed against the prototypic West Nile flavivirus, antibodies against flaviviruses were detected in the serum of 47 of the 855 seabirds tested. They were detected in bird samples from three islands and from four bird species. Seroneutralization tests on adults and chicks suggested that great frigatebirds (Fregata minor) from Europa were infected by West Nile virus during their non-breeding period, and that Usutu virus probably circulated within bird colonies on Tromelin and on Juan de Nova. Real-time polymerase chain reactions performed on bird blood samples did not yield positive results precluding the genetic characterization of flavivirus using RNA sequencing. Our findings stress the need to further investigate flavivirus infections in arthropod vectors present in seabird colonies.

Isolation and characterisation of 16 polymorphic microsatellite loci for the sooty tern (Onychoprion fuscatus; Sternidae), a super-abundant pan-tropical seabird, including a test of cross-species amplification using two noddies (Anous spp.)

We isolate and characterise 16 polymorphic microsatellite loci for the super-abundant, pan-tropical sooty tern (Onychoprion fuscatus), facilitating population genetic studies. In 70 samples from two breeding colonies, the total number of alleles per locus ranged between 5 and 21, observed heterozygosity ranged from 0.143 to 0.942, while estimated null allele frequency varied from −0.131 to 0.273. Polymerase chain reaction (PCR) conditions were optimised across loci, enabling multiplexing and rapid multilocus genotyping. These 16 loci will be useful for future studies of genetic diversity and population structure, and can be used as a proxy through which to assess ecosystem function and change. We additionally test cross-species amplification in the brown (Anous stolidus) and lesser (A. tenuirostris) noddies, illustrating a use of these microsatellites in other related Sternidae species.