Insecticides harm insectivorous birds by attacking the foodchain.
Pesticides form an important part of modern agriculture and other vegetation production systems including horticulture, silviculture, floriculture and olericulture (vegetable production). Worldwide use of pesticides is estimated at about 2 million tons per year of which 75% are consumed in Europe and USA and 25% in the rest of the world. Still, pesticides cover only 25% of the cultivated land area. Of the total pesticides used, insecticides make about 30% i.e. 0.7 million tons while the major chunk of the remaining consists of herbicides.
In principle, the registration requirements of this group of agrochemicals (others being chemical fertilizers and plant growth regulators) include no impact on non-target organisms. It will appear, however, that quite a few components of the man-made or natural ecosystem are affected negatively by most of the pesticides used. This is particularly true of insecticides that are meant to control insects that cause damage to the members of the target vegetation. What happens, however, is that non-target insects also become victim to indiscriminate usage of such substances. It is reported frequently that world population of honeybees has significantly reduced over the years as a result of excessive usage of certain chemicals meant to control insects. An agricultural insecticide suspected of being behind the collapse of bee colonies in all parts of the world is apparently also triggering a fall in bird populations.
In this article, we intend to demonstrate how insecticides have damaged some other ecosystem components and a natural mix of beauty in terms of birds that live on insects. These insectivorous birds form a beneficial component of the overall ecosystem and perform functions that are of benefit to the humans as well as other living entities.
The insectivorous birds represent species that feed mainly on insects, spiders and other invertebrates. True insectivorous birds, such as Warblers and Robins, have slender bills adapted for grasping these tiny animals, while birds like Thrushes possess more robust beaks suitable for larger items. Most insectivores will also eat at least some plant material, as with Blackcaps taking berries in autumn, and conversely most other birds, (even seed eaters), feed on insects at times.
Populations of common insectivorous birds like Starlings and Swallows are also declining in farmland areas with high levels of the neonicotinoid insecticide imidacloprid. This is shown by an analysis of detailed data on local bird population trends and environmental factors, which include imidacloprid concentrations in surface water. It is well know now that neonicotinoids, attack a number of crop pests but they also leach into water and soil where they can kill insects other than their intended targets.
The damage to the insectivorous birds is not only of concern in agricultural areas, but for natural ecosystems like forests as well. Forest disturbances and increased urbanization has affected small insect-eating (insectivorous) birds weighing less than 15 g the most. Several factors are involved in the loss of small birds from cities. The two most significant factors are: i) small birds are always vulnerable to predation from larger species and ii) the use of insecticides in the households including lawns and other landscapes. The inhibition of small insectivorous birds at the hands of bigger predator birds is most common during the breeding season because eggs and nestlings are unable to escape. Several species of large birda, notably the Pied Currawong, have become more common in cities. They are voracious nest predators and it is likely that Pied Currawongs have an impact on the small birds by limiting their ability to reproduce.
Excessive usage of insecticides in the households also means elimination of food for small insectivorous birds. It will not be surprising therefore to see less and less small birds around the livelihoods. The message therefore is that in order to maintain beautiful biodiversity created by nature, indiscriminate usage of chemicals especially insecticides be avoided to the maximum possible.You can follow us on Facebook, Twitter, or Google+ for more updates. Otherwise fill in the subscription box above, or subscribe to our RSS Feed.