European Starling - Sturnus vulgaris
Once a common bird in the British Isles, the starling is found in a wide range of lowland habitats including woodlands, parks and gardens. Starlings were introduced to many parts of the world during the 19th century including North America, South Africa, Australia and New Zealand.
These introductions were often initiated by European colonists wanting to introduce species from their native countries to their new homes abroad. One well-recorded example was the release of 100 starlings in New York, rumoured to be part of an attempt to introduce all the birds mentioned in Shakespeare’s plays to North America. Records of the releases and genetic analysis of invasive starling populations suggests that starlings were introduced several times in most countries.
In parts of its native range, including the British Isles and Finland, the starling has suffered huge declines and is of conservation concern, however, in many of the places it has been introduced, populations of this species have increased rapidly and it is currently listed as one of the IUCN’s Invasive Species Specialist Groups worst 100 invasive species. Population estimates in the USA alone range from 140-200 million birds. Starlings are also established expanding and expanding their range in Australia and are widespread throughout New Zealand.
Problems: Making themselves at home
Starlings have a natural distribution that ranges across most of Europe, parts of Asia and Africa. They are at home in a variety of habitats and climatic conditions ranging from Scandinavia to the Mediterranean and the Middle East.
Starlings look for suitable holes, usually in trees in which to build a nest and raise their young. In North America they have been found to be more aggressive than some of the native species that nest in tree holes. This means as well as reducing the availability of nest-holes to native species they can take over tree-holes in which native birds are nesting.
Recent studies in North America found that starlings did not cause a clear decline in native species numbers, but they have been shown to delay the breeding of some species and in high numbers they may locally inhibit and scare off native birds. Starling interference could have future impacts on native species already threatened by human activities such as habitat loss.
Problems: A public enemy
The problems caused by invasive starlings are intensified by their natural tendency to gather in large flocks outside of the breeding season and their association with human habitation. Flocks often contain thousands of birds that feed and roost together. Feeding flocks can cause huge damage to crops as well as creating mess and disturbance by eating food intended for livestock. Starlings may also nest or roost on buildings. Starling feed on insects, as well as seeds, fruit and plant matter and they may have a small role in reducing numbers of some insect pests.
A number of pathogenic micro-organisms have been found in starling faeces and and there is some concern that they may be carriers of diseases affecting both humans and other animals. However, they are not currently thought to be a major threat to human health.
Total eradication of starlings outside their native range is now considered to be impossible, as their numbers are so high, but where they interfere with agriculture or other human activities they may be controlled. Vulnerable crops may be covered with netting to protect them from being eaten and in some cases starlings may be trapped, shot, or poisoned. Many starling deterrents are also available including playbacks of starling distress calls.