Bird Bulletin 2

Great news received from Catherina – as of 30th July 2 pairs of magpie robin have commenced nest building in their newly established territories. This shows that the birds have settled and found their new home appropriate to their needs. Catherina will keep the birds under close scrutiny in order to ascertain whether breeding has commenced. Check back regularly for updates!

Invasive species are considered the primary threat to the native biodiversity in Seychelles and it is the removal of mammalian predators from Denis (cats in 2000 and rats in 2002) that has enabled the introduction of rare species like the fody, warbler and magpie-robin to the island. There are however other invasive species issues that are of concern to the magpie robin introduction on Denis.

The Common Myna (Acridotheres tristis) – introduced quite early on in the human history of the Seychelles, the Myna is a highly intelligent and adaptable species that can utilise a broad ecological niche. The species has spread throughout the central archipelago and is a common sight on Denis. The Myna poses a double threat to the magpie robin as a competitor for nesting sites and as a potential predator of eggs and nestlings. As such we will, in the coming months, be exploring means of controlling the Mynas in order to facilitate the establishment and expansion of the robin population on Denis.

The Barn Owl (Tyto alba affinis) was introduced to Seychelles in the 1950s in a misguided attempt at rat control. The barn owl prospered however on the much easier pickings of roosting seabirds. The decline of the white tern (Gygis alba) on many of the granite islands, has been attributed to barn owl predation. The barn owl has also been connected in the past to the loss of 2 or 3 magpie robins on one island. The barn owl however has not previously been recorded on Denis and it was hoped that the isolation of the island may keep it safe. It was with considerable concern therefore that I read in a recent addition of the NPTS publication “Birdwatch” that a barn owl has taken up residence on Bird Island, the nearest island to Denis. What’s more Bird is in fact more isolated from the central archipelago than Denis! Barn owls kill seabirds in a distinctive manner that can be identified from the remains of their prey and they also develop favoured locations for feeding so we have now incorporated the examination of dead white terns into our normal observation routine such that should a barn owl arrive on Denis we can take the appropriate measures to protect our native bird populations.