We are accustomed seeing a few Red-footed Boobies on Bird Island. Each year during our Sooty Terns studies in June-July we see 10 to 20 in the evenings, roosting among the larger number of Great and Lesser Frigatebirds (mainly the latter) that roost every night in tall Casuarina trees towards the southern end of the Sooty Tern nesting area. A few of the boobies can be seen during the day but most leave the trees, presumably to feed.
During our stay on Bird Island in June and July this year we counted up to 40 Red-footed Boobies on some evenings. Most are young birds in various stages of plumage development, some all brown juveniles but most with varying degrees of lighter brown or white feathers in their plumage. Fully adult birds, with largely white plumage and black wing tips, are rarely present.
During the late afternoon of 23 August, we were walking along the eastern side of the Sooty Tern colony when we noticed a flock of around 20 Red-footed Boobies arriving at the island from the north-west, the direction from which many thousands of Sooty Terns were also arriving. Seeing such a large group of boobies was, in our experience, unusual, but as we continued watching more and more boobies arrived, both in further flocks of around 15-20 birds and in smaller groups of 1 – 5 birds. From ground level it is not easy to see all of the birds roosting in the Casuarina trees but from the arrival we witnessed and the number of birds we could see in the trees we guessed that there were more than 300 Red-footed Boobies.
This was remarkable and the following two evenings we watched the arrival of boobies by standing on the north-west beach form 1800 h onwards to get a better view of the birds’ arrival. This allowed us to count the birds more accurately as they flew over us. On both evenings we counted just over 350 Red-footed Boobies. As we had seen from birds in trees earlier, most of them were young birds with varying amounts of brown and white in their plumage.
When roosting in the trees, Red-footed Boobies generally huddle tightly together. This behaviour is very different from that of the Frigatebirds, which tend to space themselves out along the branches. Interestingly, we gained the impression that Casuarina trees hosting large numbers of Red-footed Boobies had fewer roosting Frigatebirds than previously. It is also noticeable that Frigatebirds are now roosting in Casuarina trees that were not formerly used, but whether this is a result of the large number of Red-footed Boobies occupying the Frigatebirds’ formerly preferred trees we cannot say.
We know that since the 1970s the number of Red-footed Boobies that nest in Seychelles has increased, and that they have recently begun breeding on Marie Louise Island in the Amirantes. Might the influx of young birds to Bird Island lead to the establishment of a nesting colony here? We keep our fingers crossed! Bird Island already hosts and extraordinary nesting seabird population, involving millions of individuals of seven species. The Red-footed Booby would be a welcome addition!