POCHARD DECLINE INVESTIGATION

More predators and less gulls are among the reasons being suggested for the recent decline of Pochards. An investigation in the latest issue of Wildfowl, the international scientific journal of the Wildfowl & Wetlands Trust (WWT), looked at why the number of Pochards migrating to the UK for winter has decreased by 60% since the 1980s, despite the number that breed here doubling over the same period. This decrease reflects widespread declines in breeding numbers recorded elsewhere across Europe. A paper by 29 researchers from across Europe says several changes are likely to have contributed to the Pochards’ decline. Firstly, the decline of Black-headed Gulls, whose colonies are used for protection by many other nesting birds, including Pochards, is suggested. An increase in the amount of nutrients washed off farmland may also have played a part. They prompt explosions of plants and algae in wetlands and waterways, preventing Pochards from diving for food. Finally, predators may be involved. Mink, escaped from fur farms, plus introduced Raccoons and Raccoon Dogs, have become major wetland hunters. Wildfowl Editor and WWT Research Fellow Dr Eileen Rees said: “Waterbirds live complex lives and their wetland habitats are entwined with our own need for food and water. Waterbird populations are often spread across nations and continents, and they’re highly mobile, breeding, staging and wintering in different places.”