Exploring birdlife on the Calf of Man

Rory Walsh visits the once rat-infested islet which today is back as a vital breeding spot for the Manx shearwater

Discovering Britain

View • Costal • Isle of Man • Web Guide

Follow the Isle of Man’s Sound Road all the way south and you reach a car park. Beyond the sea wall, the Calf of Man is clearly visible. This offshore island is just half a mile away but only accessible by boat in good weather. During stormy spells, the Calf can be isolated from the wider world for days. There are more lighthouses (three) there than permanent residents.

Despite its name, cattle no longer graze the Calf’s slate outcrops. The only livestock today are rare Manx Laughton sheep, known for their brown wool and conical horns. Technically an islet, the Calf of Man covers 616 acres. Though small, its location is hugely important for native and migratory seabirds. ‘It’s one of the jewels in our crown,’ says Lynsey Clague from Manx National Heritage, the charity that looks after the Calf.

Ornithological surveys began on the Calf in 1959. Three years later the whole islet became a designated Bird Observatory. From March to November, Manx National Heritage employs two wardens to live on the Calf where they monitor and record the bird population. Last year over 8,000 were ringed from 79 species, including puffins, razorbills, kittiwakes and Manx Shearwaters.

The wardens arrive to document Manx Shearwater migration patterns. Shearwaters spend the winter in South America, then visit the Calf to breed from March to July. The Calf of Man was where the birds were first officially sighted, hence their name. Rather small for seabirds, Shearwaters nest on the ground with their eggs in burrows, but these habits make the birds and their eggs vulnerable to predators.

As a result, visitors to the Calf are limited and dogs are banned. While people work hard today to protect these birds, in the past humans had a devastating effect on them. Surrounded by water, the Calf of Man was rat-free for centuries. That changed in 1781 when a shipwreck off the Calf allowed a colony of rats to flee onto the land. Hungry rats found that the slow-moving, breeding Manx Shearwaters made for easy pickings and the birds were almost wiped out.

In 2012, Manx National Heritage began a project to eradicate the rats by placing traps across the Calf. The results have been successful. ‘The Shearwater population is estimated by monitoring their burrows,’ explains Clague. ‘At the turn of the millennium, only 23 burrows on the Calf were thought to be occupied. Monitoring in 2019 produced an estimate of 600 to 700 Shearwater pairs.’ The Calf of Man is a rare example of people helping wildlife to escape the rat race.