Common Name: Sao Tome Grosbeak
Scientific Name: Crithagra concolor

Distribution: Endemic to the island of Sao Tome in the Gulf of Guinea, where it is found exclusively in low numbers in the mature deciduous forests in the central and souther part of the island.

Biology: The Sao Tome Grosbeak is a rare and enigmatic Fringillid with a poorly described biology. A elusive forest bird, the species was at one point considered extinct for almost a century until it was rediscovered in 1991. Since then the species has only been seen infrequently by most, and is one of the least studied of all Sao Tome’s endemic species.
Yet in recent years more targeted fieldwork have been conducted to uncover more of the Grosbeaks behaviour.

The species forages mainly in the canopy and feeds on vegetable matter, including fruits, berries and flower buds. As its heavy beak indicates, the species is specialised in larger seeds yet its diet appears to be quite diverse and not restricted to those large seeds. Until recently literally nothing was known about the species breeding behaviour, yet following fieldwork conducted by AvianTracker in September of 2022, the nesting behaviour was described with both photos and videos (see below). Based on this one record the species appear to breed in monogamous pairs at the beginning of the rainy season.

The species is quite vocal, and one of the easiest ways to located it is by its loud whistling call, that easily penetrates the humid air of the lush forest that the species call home.

IUCN Conservation Status: Critically Endangered

The Sao Tome Grosbeak is one of the worlds rarest birds, with a global population size estimated to be as little as 50 individuals. However, due to its poorly known and secretive lifestyle this population estimate might not reflect the real population size and further research is needed to give a more precise approximation. In recent years individuals has been observed at locations that the species was thought to be absent from, lending credence to the possibility that the species may be more widely distributed than once thought. The main threats to the Sao Tome Grosbeak is habitat destruction and fragmentation, along with predation by introduced mammals like rats and Mona monkeys (Cercopithecus mona).
It has been hard for conservationist to construct a thorough protection plan for the species because of its obscure lifestyle, yet recent fieldwork (anno 2022) may help this development.