Interspecific conflicts over territory help pygmy to avoid hybridization and serve as a response to competition for limited resources. To such conclusion researchers from the UK and the US, analyzing data about interspecific competition for territory among passerines in North America. Their work, published in the journal Proceedings of the National Academy of Sciences, disproves that popular notion that birds fight with other species by mistake.
Many animals are jealously guarding their territory against the invasion of strangers. This is logical, if we are talking about the representative of their own species. Often, however, the object of the attack becomes the individual, which refers to another view. For a long time it was believed that such interspecific territoriality — just a by-product of intraspecific. In other words, the master attacks a stranger by mistake, mistaking him for a kinsman.
However, new evidence suggests that the protection of territory from other species has adaptive value. It can arise and persist when different species compete for a particular resource, for example, food or shelter.
A team of zoologists led by Jonathan Drury (Jonathan P. Drury) from Durham University carried out an extensive study of interspecific competition for territory on the example of North American passerine birds. After analyzing the literature, scientists have discovered that this behavior is typical for 104 species. This is 32.3 percent of the total number of passerine species in North America. Thus, interspecific competition is more common than previously thought.
According to the authors, in most cases, the birds come into conflict over territory with a representative of a particular kind. There are several factors that increase the chances of the formation of a pair of competing species. For example, birds that live in the same biotope have similar sizes and they nest in hollows, with a high probability to be involved in conflicts for territory. For species belonging to the same family, the important role played by another factor — the probability of hybridization. If two species are able to interbreed with each other, their males are very likely to respond aggressively to each other.
Based on these results the researchers concluded that interspecific conflicts over territory among birds does not occur by mistake. This behavior is an adaptive response to competition for limited resources, and a mechanism preventing hybridization between closely related species.
Different types of birds can not only compete, but to help each other. Some birds react to the alarm emitted by the representatives of another species. For example, great Tits coal Tits eavesdrop on signals Eastern Tits about the approach of a predator, and direct their visual attention to the search of objects that are similar to the image of the snake. This behavior was discovered in experiments by Japanese scientists.
Sergey Knee High