Characteristics of some animal calls

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Prepare an essay on the impact of deforestation on Bird communication

Destruction caused by human disturbance has had adverse effect on the various ecosystems. One of the major concerns is deforestation. Deforestation is an environmental catastrophe that converts forested area to non forested area for use such as arable land, urban use, logged area or wasteland. The act of deforestation generally removes the functioning ecosystem for wildlife. An ecosystem is a natural habitat of a wide variety of birds, reptiles, insects, animals and plants. Removal of vast areas of terrestrial biomes is destroying the habitat of numerous species of animals and plants which therefore decline and even causes extinction in a relatively short period, thereby threatening greatly to reduce genetic diversity. Deforestation is leading to ecological disaster such as:

Soil erosion

When vegetation is removed the topsoil and essential nutrient washed away dues to heavy rainfalls on the exposed soil. The underlying top soil is poor and the major of the nutrient is taken up in the vegetation. This means that replanting trees will not necessarily help to solve the problems of deforestation; by the time the trees have matured, the soil might be completely stripped of essential nutrients. Eventually, cultivation in the forest regions will be impossible, and the land will be useless. The soil erosion will lead to permanent impoverishment of huge land areas. (Brown, Katrina and DavidW.Pearce UCB Press, 1994) Trees have a favourable and stabilizing influence on the composition of the atmosphere, on the climate and on soil.

Disruption of hydrological cycle

When trees are cut down the water cycle is disrupted. The reduction in transpiration result in fewer clouds and less rainfall in the vicinity. Surrounding forests is threatened by desiccation.

  • Deforestation has profound effects upon regional climate, mainly by reducing rainfall. This accelerates desertification.
  • Forest is species-diverse zones where many still-unknown organisms exist. Forest provide home to more than 50% of the world's species. When trees are cut down very many more species are in danger that when other habitats are threatened.
  • Carbon dioxide is an essential raw material for photosynthesis by green plants. Atmospheric carbon dioxide levels are on the increase, and this contributing to 'greenhouse effect". Deforestation is reducing the effectiveness of a most significant "sink" for atmospheric carbon dioxide that is mainly important to phytoplankton.
  • Forest is poor in nutrients, and rare unable to retain, for any length of time, those nutrients that are released into the soil. In the rainforest in particular, virtually all the nutrients are in the organic matter of the forest canopy. When released by decay of dead matter nutrients are quickly reabsorbed into the plants of the living forest and are recycled. If the forest is felled and vegetation buried and dried, the soil does not maintain its fertility for long. The ash provides a short-lived supply of nutrient.


The foothill and valleys are free of running water which flows into rivers and streams thus preventing flooding around foothills and immediate valley and plains. The roots of these trees act as filtering systems, in that water penetrates downwards into soil so that flooding is minimal.

  • Logging and farming
  • Cattle grazing

There is no one easy solution as deforestation is caused by many things. One option is decreasing the need for the amount of products that are harvested from the rainforests. If all countries, especially developed ones, enforced programs that used recycling, the need for disposable products would be diminished and the loggers would not have a business. If the demand is cut off, there is no need for the supply. Other solutions involve money. One that could help to alleviate deforestation is providing aide to foreign countries so they give homes to those who are at high risk of becoming "shifted cultivators". The only way to ensure that we will not encounter any of the consequences of deforestation is to stop destroying the forests all together. We would have to stop cutting down all trees, no matter what our needs were. Since this is totally impractical as of now, the only thing we can do is use forest products in moderation. However this idea of moderation needs to be put into practice immediately. We as people should take care of this problem before it gets to the point where we can no longer fix it. (Brown, Katrina and David W. Pearce UCB Press, 1994). Deforestation reduces biodiversity by degrading environment for species. The forest aid in supporting species diversity through provision a habitat and species richness and interrelating relationships among each other is enable to increased.

Birds Communication

Bird communication is another species specific behavior pattern displayed amounts a variety of birds species. They create mean of communication through birds songs that maybe innate (eg yellow hammer) or both an innate and a learned component (eg. Black bird).The juvenile bird, when starting to sing produces a subsong similar to the song of parents. In these song birds, the male perform courtship displays to attract a mate. Many species move their head, wings or body part as an indication to female birds. The response from females may closely resemble the male's displays. These communications helps birds to survive, reproduce and increase species richness. Communication through bird calls can be between individuals of the same species or even across species. Mobbing calls are used to recruit individuals in an area where an owl or other predator may be present. These calls are characterized by wide frequency spectra, sharp onset and termination, and repetitiveness which are common across species and are believed to be helpful to other potential "mobbers" by being easy to locate. The alarm calls of most species, on the other hand, are characteristically high-pitched making the caller difficult to locate. (Marler, P. 1955 "Characteristics of some animal calls".)Innate behavior patterns vary in their rigidity. Repetition of instinctive behavior can lead o modifications derived from experience, causing instinctive acts to become more efficient. Motivation is derived from fundamental needs (food) and a capacity to learn (survival), all working together to varying degrees in the so called innate behavior. It is hypothesize that these bird communication develop through sexual selection and it indicates the fitness of birds. The communication among birds and the act of deforestation interrelates.

Generally this removal or destruction of significant areas of forest cover has resulted in a degraded environment with reduced biodiversity. The bird used the canopy of tree to nest and for shoring over tree tops. The forest provides wide species diversity especially birds. These forests provide 'home' for bird that they used for efficiently to provide the right kind of foods. When the trees are removed it takes away shelter and food source that some birds require. This has cause some birds to be extinct because of shortage of their specific food type and available tree for housing. Some birds are restricted to specific trees for nesting so this cutting down of trees cause the shifting of bird to new location which follows by new adaptations for survival. The way bird communicate from tree to tree provide signal of predator warning for other birds. Birds are mostly air dwellers that rely on the trees to attract mates. If the trees are removed the probability of finding a mate would be reduced and bird will have to shore during their breeding seasons to attract a mate. Woodpeckers rely on trees for food. They look for insects by boring into the bark of trees. The removal of trees would eventually cause these birds to reach the verge of extinction because no trees no food or allow them to drift to new locations where they can find trees to obtain food. Birds that used visual display to attract mate are also affected by the removal of trees because their habitat is destroyed, bird would not be able to recognize each other. Birds used a range of tree to set aside as their territories for feeding, mating and raising young. This allow both male and female to be ready for mating. The bird even uses these trees as spot of identification to keep themselves in their territory. The size of the territory varies with species eg song sparrows have territories that are as large as 300 square meters where they feed, mate and nest. Gulls, penguins and other water bird nest in large groups, but each male and his mate have their own territory.

Deforestation causes forest areas to transform into urban settlement where buildings are built and roads are created disturbing the functional wildlife and disrupting nature's call. The pollution of loud noise caused by the movement of vehicles and human interaction among themselves affects the bird call transmission decreasing the natural communication that was to meant to be for various necessity for bird's succession. Some birds used holes in trees to hibernate during hot day and beside the trees form a canopy prevent large amounts of sunlight on bird preventing heat stress which may be fatal for birds. In conclusion, the forest and bird survival is equally valuable to the survival of birds and decrease their extinction allowing scientist to survey the ecotourism and do specie count having a census of bird , exploring new species that has not be discovered.


  1. Marler, P. 1955 "Characteristics of some animal calls".
  2. (Brown, Katrina and David W. Pearce UCB Press, 1994).
  3. Macmillan.G etal , Life science, Glencoe division, New York publishing company.1994.