due to the suboptimal mountain and woodland terrain. Expansion has since slowed even further due to direct competition between the two similar species where they overlap in southwestern France and northwestern Spain. Major declines in populations have been observed from 1980 onward in Sweden, Finland, northern Russia (Karelia) and the Baltic States, and smaller declines in much of the rest of northern and central Europe. The bird has been adversely affected in these areas by intensive agriculture, and in several countries it has been red-listed due to population declines of more than 50%. Numbers dwindled in the United Kingdom by more than 80% between 1966 and 2004; although populations in some areas such as Northern Ireland were stable or even increased, those in other areas, mainly England, declined even more sharply. The overall decline seems to be due to the low survival rate of young birds, which may be caused by changes in agricultural practices. The intensive farming methods used in northern Europe mean there is less pasture and meadow habitat available, and the supply of grassland invertebrates needed for the nestlings to thrive is correspondingly reduced. Relationship with humans Benefits and problems Since common starlings eat insect pests such as wireworms, they are considered beneficial in northern Eurasia, and this was one of the reasons given for introducing the birds elsewhere. Around 25 million nest boxes were erected for this species in the former Soviet Union, and common starlings were found to be effective in controlling the grass grub Costelytra zealandica in New Zealand. The original Australian introduction was facilitated by the provision of nest boxes to help this mainly insectivorous bird to breed successfully, and even in the US, where this is a pest species, the Department of Agriculture acknowledges that vast numbers of insects are consumed by common starlings. Common starlings introduced to areas such as Australia or North America, where other members of the genus are absent, may affect native species through competition for nest holes. In North America, chickadees, nuthatches, woodpeckers, purple martins and other swallows may be affected. In Australia, competitors for nesting sites include the crimson and eastern rosellas. For its role in the decline of local native species and the damages to agriculture, the common starling has been included in the IUCN List of the world's 100 worst invasive species. European, or common, starlings are habitat generalists meaning they are able to