The tern season on Aruba is normally from March till August. In March experts assume that the birds are searching for probable nest sites. During daytime they are foraging out on the sea. In general the public sees the birds at lay in April and May. The critical period for breeding terns is when they are searching for a nesting site, are in lay and when they are rearing their chicks. If at the site there is too much nuisance like a prolonged presence of humans, the birds may nest elsewhere or abandon their eggs or even chicks. In the past nest site abandonment has been noticed on Aruba as a result of a firework show that used to be held on the reefs. Different tern species have different breeding periods and even within a specie there might be a difference in the breeding period. The latter can occur with birds that have abandoned a previous nesting site and are nesting over again. Therefore it is difficult to define the critical period for nesting terns on Aruba
About 10 tern species nest on Aruba, of which 4 are regionally or globally threatened. The specie that nests in highest numbers on Aruba is the Sooty tern (Sterna fuscata); they can nest in pairs up to 6000. The tern specie though for which Aruba is an important bird area is the Cayenne tern (Sterna sandvicensis eurygnatha). They nest in pairs up to 5000 and experts believe this is about 30% of their world population. The Least tern (Sterna albifrons), Bridled tern (Sterna anaethetus) and Brown Noddy (Anous stolidus) nest on Aruba up to pairs of 100. The other tern species, like the Common tern (Sterna hirundo) and the Roseate Tern (Sterna dougalli), nest in pairs lesser than 100.
For more information contact the Department of Agriculture, Husbandry and Fisheries.
[Information courtesy of Mr. Facundo Franken of the Department of Agriculture, Husbandry and Fisheries (DLVVM) - Nature Management]