Pochards build their nests among black-headed gull colonies for protection and there are fewer black-headed gull nesting colonies across a number of European countries, including Norway, Germany and Latvia.
Explosions of plants and algaes in wetlands and waterways, caused by nutrients washing off farmland, has prevented pochards and other birds from diving for food.
The American mink has become a major wetland predator. The species was originally introduced and farmed in Europe for its fur, but escaped and is now considered to be an invasive species in many countries.
Despite the decline in migrating pochards, the number of them breeding in the UK has actually increased and the latest estimate is 653 pairs"
Report by JR