Common pochard and small populations are sometimes observed on the River Thames. Large numbers stay overwinter in Great Britain, after the birds retreat from Russia and Scandinavia. These are gregarious birds, forming large flocks in winter, often mixed with other diving ducks such as the tufted duck, with which they are known to hybridise. These birds feed mainly by diving or dabbling. They eat aquatic plants with some molluscs, aquatic insects and small fish. They often feed at night, and will up-end for food as well as the more characteristic diving. In number of countries the population of Common Pochard is decreasing
Bird tracks Bird tracks Bird tracking provides a way to assess the habitat range and behavior of birds without ever seeing the bird. Bird tracking falls under the category of tracking and is related to animal tracking. A guide to bird tracking has been published. Bird tracking is a tool used by naturalists to assess what birds are present in an ecosystem even if the bird is rarely seen. In the Pacific Northwest of the United States, a program called NatureMapping collects data by educating the public and having them pool their data in a citizen science application. Data can be collected