Pollutants in urbanized areas: Direct and indirect effects on bird populations

Abstract

Industrialization, traffic, intensification of agriculture, and development of human lifestyle in general during the last century have resulted in elevated levels of various chemical compounds in our environment. Especially in urbanized areas, harmful substances are produced in such quantities that they can have a deleterious effect on the development, survival, and reproduction of organisms. Many bird species have adapted to living alongside with humans and even discovered new resources within the urban lifestyle. However, these birds are in greatest risk of being harmfully effected by various chemicals. This chapter reviews the effects of heavy metals and organic pollutants on avian populations in urban areas. Case studies are brought together in order to gain comprehension on how well we understand the role of these pollutants as factor influencing the well-being of urban bird populations. The examples highlight the fact that pollutants do not have only direct physiological effects but also indirect effects through, e.g., decreased food availability. As populations of many urban bird species are declining, new research developments for pollution studies are also proposed.