Biosecurity is the practice of protecting places from the threats to wildlife posed by introducing new diseases or types of plants or animals that do not naturally occur there. Seabirds often choose to nest on islands with no land predators and are particularly vulnerable to introduction of predators.
At Biosecurity for LIFE we are working hard to raise awareness of the threat of invasive predators and put in place systems to prevent their accidental introduction to islands.
In particular we will be focusing our efforts on 42 specially protected islands that are designated for breeding seabirds.
Rats are one the most successful invasive mammals worldwide. They are incredibly adaptable, take advantage of any food source, breed quickly and are easy to accidentally transport. They are also very good swimmers, for example a brown rat will comfortably swim a kilometre in calm waters, and may swim a lot further. For seabirds they are bad news as they will prey on eggs, chicks and even adults of some species.
More commonly regarded as a pest of food stores mouse populations can quickly grow when food availability is high. On seabird islands they can predate eggs and chicks of smaller species, especially storm-petrels. On islands in the Southern Ocean (for example Gough and Marion), mice have even taken to predating the much larger albatross species.
Populations of feral cats have caused the extirpation and extinction of many species on islands around the world. These highly skilled hunters can cause severe declines in adult breeding seabirds at their colonies.
Stoats are native to the UK mainland but not our seabird islands. Excellent hunters capable of taking on prey larger than themselves, they will hunt adult birds as well as raid nests for eggs and chicks. Stoats can easily be transported in animal feed and bedding, and they are excellent swimmers. A stoat has been recorded swimming over 3.5 km in open water!
Originating from North America these excellent swimmers can easily move between islands that are close together, and will comfortably swim 5 km or more in good conditions. During the seabird breeding season, they will target the eggs and chicks but will take adult birds too. Known to stash food when availability is high one individual can quickly destroy large numbers of nests.
Hedgehog are native to the UK mainland where they face serious declines and are of conservation concern. Hedgehogs are not so keen on swimming and are unlikely to travel as stowaways, but once taken to an offshore island they are not native to, they can cause serious negative impacts to all ground-nesting birds through predation of eggs and young.
You can take responsibility for your own biosecurity by following these important steps before visiting your island destination:
The UK is home to around 10% of the global population of this very charismatic seabird. Puffins typically form life-long bonds and return to the same nesting site ever year, where they lay their one egg in a burrow.. They are highly colonial and favour sites free from mammalian predators. Puffins are now considered to be at global threat of extinction.
The UK holds roughly 20% of the global population of this smart-looking seabird. They tend to lay their one egg out of sight in crevices among cliffs and boulders or on small ledges.
This highly gregarious seabird nests in large colonies and is the most abundant UK seabird. Colonies occur on steep cliffs where they can be seen jostling for space. These cliffs are safe from most mammalian predators. No nest is built, with their one egg laid onto bare rock.
The smallest seabird in the world, the European storm-petrel spends most of its life at sea, returning to land only to breed. Nesting occurs mainly on rocky offshore islands free from mammalian predators, which is critical to their success. One egg is laid later in the summer than with most other seabirds, and chicks sometimes fledge as late as November.
Almost 60% of the global breeding population of Gannet, the North Atlantic’s largest seabird, occur on UK islands. Gannets nest in large colonies and lay one egg each year.
The UK hosts five species of breeding tern: Arctic, Sandwich and Common are the most abundant with Little and Roseate considerably scarcer. All species are highly migratory outside of the breeding season and have some of the longest migrations of all bird species. Terns are ground-nesters and occur in gregarious colonies, mainly located in low-lying coastal areas.
Almost 80% of the world population of Manx shearwater breed in the UK. Manx shearwater only land at breeding colonies, where they nest in burrows, on dark nights. These birds form a life-long bond with their partner and return to the same breeding site every year to reaffirm that bond, and the parents take turns to incubate their single egg and feed the chick. Before they fledge chicks stargaze from burrow entrances to help them find their way back when it is their turn to breed.
The Isles of Scilly, 26 miles of the tip of Cornwall have five inhabited islands (St. Mary’s, St Agnes and Gugh, St. Martins, Tresco and Bryher) with a population of 2,000 mainly living on St. Mary’s. Scilly is home to 13 breeding species of seabirds including puffins.
Seabirds are arriving back to our cliffs and islands, the focus of our blog this week is #Skokholm, #Skomer and #Middleholm famous for their #puffins and #Manx shearwater.https://t.co/51qpH9f4uP— biosecurityforlife (@biosecurityLIFE) April 14, 2020
Photo: Tara Proud pic.twitter.com/CQ4qidTp4V
At Biosecurity for LIFE we are focused primarily on 42 island special protection areas (SPAs) in the UK that are designated for breeding seabirds.
As indicated on the map, these islands are spread around the coastline of the UK including parts of England, Wales, Scotland and Northern Ireland.