PROCELLARIIFORMS OF MARANHÃO: FIELD DATA ON SPECIES OCCURRENCE AND PHENOLOGY IN A NORTHERN BRAZILIAN COAST

Abstract

Procellariforms are pelagic seabirds found worldwide. They are more abundant in cold waters, but several species are found in tropical oceans. They are not expected to be abundant in Northern Brazil, but even this being true, a number of birds should be found in the region. So, the few number of reports suggest that the region has been strongly undersampled. Between 2008 and 2016, I have performed 20 land-based and 10 fishing boat daily surveys in Central Maranhão coast, in several sites between Maiaú Island and Caburé beach. I have included also some previous occasional records, and compared all these data with the few available reports from the literature. Indeed, procellariform numbers were not high; however, I found around 120 birds from nine species. Among them, birds from the Calonectris diomedea group (either C. borealis, C. edwardsii, or both) seemed to be regular in the region as a small wintering population in December and January. Oceanites oceanicus could be regular in small numbers as a post-breeding migrant in April. And Ardenna gravis has been reported several times, but up to now data are insufficient to show any well defined phenological pattern.