This year’s annual wirebird (St Helena plover) census shows an increasing population trend, but there’s still no room for complacency. Dennis Leo and Rebecca Cairns-Wicks from the St Helena National Trust update us on this UK Overseas Territory species.
Photo: David Higgins
Each year the National Trust working with volunteers carries out an island-wide count of the wirebird population. The census provides information about how well the population is doing - long-term trends in the population size help us to identify whether conservation management efforts are being effective.
Wirebirds are predominantly found in two main habitats on St Helena: dry, mid-altitude pasture and semi-desert areas. In these areas the grass or other broadleaved herbs are low and with some bare ground. The birds also like open views to help early detection of approaching predators.
The census covers 31 locations around the island, and was first started in 1988/9 and has been carried out annually since 2005/6. The 2016 wirebird census was led by Eddie Duff and Kevin George, and an astounding 559 adult wirebirds were counted, the highest ever recorded. At the same time, 86 juveniles, 52 chicks and 55 nests were also counted.
Wirebird numbers in locations that have been under active predator control and pasture management have shown an increase in numbers. Deadwood Plain recorded the highest number (106) since 1988/89. Rather surprisingly, numbers have continued to improve in Prosperous, despite the disruption from the airport project.
The National Trust has been carrying out a programme of predator monitoring and control at the core sites of Deadwood, Man and Horse, and Upper Prosperous since 2011. The Trust has been supported in this work with grants from the Department for Environment Food and Rural Affairs (Defra), DFID’s Overseas Territories Environment Programme, and the Royal Society for the Protection of Birds (RSPB).
The greatest threats to wirebirds are predation, by cats and to a lesser extent rats and the common mynah, and vegetation changes due to invasive species. Where these threats are managed, the population shows a positive response. Increased survival and productivity in areas such as Deadwood will also help maintain numbers in other areas where they have been less successful through recruitment. However, what this also means is that if we stop controlling feral cats and rats and don’t manage invasive species, we can expect the population of wirebirds to fall back again.
This year’s count and positive population trend is a reflection of years of hard work by many people reaching back over the last decade. The long-term vision of the Wirebird Species Action Plan (2007, updated 2011) is for the people of St Helena and Wirebirds to find a way to happily co-exist – allowing St Helena to develop and the wirebird to thrive. We cannot afford to get complacent and we remain dedicated to sustaining these gains through extending predator control and habitat restoration work.