1198 pairs of roseate terns and 2478 pairs of common terns have nested in the Azores during 2009.

The birds were distributed by the nine islands of the archipelago, especially on the island of Flores where 35% of the roseate tern population and 20% of the common tern population nested.

Despite its largest coastal extension, the island of São Miguel registered the lowest population level.

Surprisingly, no bird has nested on the Praia Islet, off Graciosa, as this islet had concentrated 44 % of the Azorean common tern population and 72% of the roseate tern population in 2006. 

It is also important to mention the return of the roseate tern in 2009 to the Feno Islet on Terceira, where the largest colony of the Azores has nested, 263 pairs (22%). This return is due to the successful eradication of rats from the islet in joint action of the Regional Veterinary Laboratory, the Environmental Services of Terceira, the IMAR and the Department of Oceanography and Fisheries of the University of the Azores.

The total roseate tern population was, once more, the largest population in Europe, representing nearly 48% of the total population.

The 2009 Common Tern Census was carried out by the IMAR and the Department of Oceanography and Fisheries of the University of the Azores under the MoniAves Project funded by the Regional Secretary for the Environment and the Sea.