In the first part of this series I introduced you to the 1970’s book ‘The World’s Vanishing Birds’ and proceeded to show how some of the African birds in the book are doing currently compared to when the book was published. This week I will show you a selection of the endangered Seychelles birds that are included in the book and will be taking a look at what their fate has been in the past 43 years.
The Seychelles is a country comprised of an archipelago of over 116 islands, located in the west Indian ocean just north of Madagascar. Because of the remote nature of these islands and the fact that they are separated from the mainland by a considerable distance, the wildlife is rich and there are a large number of endemic species. Birds can colonise remote islands more easily than other animals and once there they are prone to genetic and behavioral changes resulting in new species being formed over time – consequentially the Seychelles have quite a few endemic birds that bear similarities to mainland species.
The Seychelles Kestrel (Falco araea) looks rather similar to other Kestrel species but is small and its colours are bright, in the book it states that the Kestrel is limited to the single island of Mahe with a population of just 30 individuals. Reasons for its decline are stated as predation of eggs and young by rats and cats and introduced Barn Owls taking nest sites. Today the bird is listed as ‘Vulnerable’ yet it seems in a better position now than it used to be; the population is estimated at 800 individuals and can be found on three or more additional islands to Mahe. The Kestrel was actually re-introduced to Praslin island in 1977, yet current problems include habitat loss from logging, egg predation by rats, loss of nest sites to Barn Owls (still), wildfires, housing development and reduced prey availability (it only eats small lizards) due competition from owls and cats.
The Seychelles Scops Owl (Otus insularis) is a small brown owl species found in high cloud forests, my 70’s book describes the species as present only on the island of Mahe with a population as low as around 20 birds with none having been seen since 1959. Reasons for its rarity are listed as competition from the alien Barn Owl and deforestation. Current knowledge is a little less gloomy than the book states in 1972, yet the future for this cute owl is by no means rosy. Listed as ‘Endangered’ by the IUCN, it is still restricted to the single island of Mahe but new population estimates suggest it is stable with about 250 individuals spread throughout the cloud forests (which is still hideously low). There is habitat loss at the bottom edge of the forests as houses creep up the slopes, rats and Barn owls (again) predate both adults and eggs, nest sites are hard to find as Mynah birds take them. Taking into account the fact that the entire world population survives in the mountains of one small island in the middle of the ocean there is the threat that a single disaster such as disease or a new introduced predator, or a change in climate, could render this wee owl extinct.
Next we have the attractively plumaged Seychelles Magpie-robin (Copsychus sechellarum) which at the time my book was published in 1972 was inches from extinction as the population was limited to just Fregate island with a total of 16 individual birds! It doesn’t get closer than that, yet somehow it survived into the nineties with just twenty birds, at which point Birdlife International stepped in with a recovery programme. They translocated birds to four other nearby islands which are all now home to small but stable populations (with the population spread over several islands the species is now much safer). The total population over all five islands currently stands at around 244 individuals – a considerable improvement, though the Magpie-robin is still categorised as Endangered – but what caused the initial decline and has it been sorted? My book claims that feral cats and loss of breeding sites to Mynahs were the main problems, the IUCN states that cats certainly started off the decline but rats, pesticide poisoning and reduction of insect prey (due to loss of native trees to introduced species) may all have contributed – sea-level rise is listed as a potential future threat.
Finally we have the delightful-looking Seychelles Paradise Flycatcher (Terpsiphone corvina); the males are all blue-black with a fluffy crest and very (relatively) long tail streamers, females lack the tail but have a chestnut brown back and white belly. The book does not state how many were left in 1972 but it says the population is falling and restricted to one island – La Digue. It goes on to say that logging, predators and disturbance by man are threats to its survival. After researching this bird I found out that at the time of my book’s publication this flycatcher species had only 50-60 individual birds remaining on Earth. Amazingly the species has made something of a recovery; the population has increased over the last 20 years and now stands at between 140-190 individuals, on top of that 23 birds were translocated to Denise island in 2008 to start a new population. The IUCN makes it clear that the most significant threat to this bird (and the cause of its initial decline) is habitat loss and fragmentation – compounded by nest predation by rats – housing developments and plantations have caused this decline in habitat quality.
From these five birds we can see clearly that island species suffer greatly from introduced animals and plants, this is clear all over the world, especially as most are not used to predators or live in a delicate balance with their few natural enemies. Habitat loss is a major threat to all wildlife across the world and in all habitats, yet on islands the threat is felt more keenly due to the limited land area, and as each island is separated by the ocean from its neighbors species have trouble dispersing to other suitable areas.