While there are approximately one hundred of the world's more than ten thousand known bird species that lay their eggs in the nests of other species, the cuckoo is the only bird in Hungary that behaves like that. This phenomenon is known as interspecific brood parasitism.
“This is a reproductive strategy that seeks to reduce the parent's ‘investment’ as much as possible. In fact, apart from the laying of the eggs, the egg-laying parent has no other ‘costs,’ because it entrusts a host species, a surrogate mother, if you like, to hatch, feed and rear its young. So the original parent, in a narrow sense, has no reproductive costs other than laying eggs,” said Jenő Nagy, a researcher at the University of Debrecen.
A senior research fellow of the Department of Botany at the Faculty of Science and Technology, conducted and prepared a study on this topic as part of an international research team. The research project investigated whether host species that make nests easily accessible to breeding parasitic birds will actually be more likely to be chosen for hosts.
“In fact, nests can be almost anything from a very simple scoop or scraper to a small spherical structure hung on a branch. I could even say that there is a species of pigeons that puts a few thin twigs across a larger branch and that is already considered a nest if it can hold the eggs. On the other hand, certain birds of prey, such as eagles, for example, lay a large, plate-shaped, well-kept nest. In our research, we classified nest types into several major categories: the scoop-shaped nests, the cup-shaped nests, the nests with a lid, often with a tunnel-like entrance, and the nests in a burrow,” said the researcher.
Birds that take in eggs other than their own and raise other birds' offspring are called host species. There are about 1700 such species known in the world. Some birds, such as the cuckoo, choose only a few host species, such as the reed warblers, the robins, the barn swallows or the reed buntings. Yet, there are also extreme cases. There is a bird species in America that parasitizes up to 200 species. The study examined a total of 6200 species and the results supported the hypothesis that parasitic species most often choose host species whose nests are easily accessible.
“The chief motivation behind our investigation was to further understand the evolutionary mechanisms involved in survival and reproduction, which are put in place by the host to protect itself against brood parasitism and by the brood parasitic species to increase its own reproductive success. We wished to figure out what the essential features of the nest are that drive this ‘arms race’ in the avian world,” said Jenő Nagy in summary.
The study entitled “Nest architecture influences host use by avian brood parasites and is shaped by coevolutionary dynamics,” for which Jenő Nagy has been awarded the publication prize Gróf Tisza István Debreceni Egyetemért Alapítvány és a Debreceni Egyetem Publikációs Díja [Publication Prize of Count István Tisza Foundation for the University of Debrecen and the University of Debrecen], was published in a prestigious international scientific journal.
Press Centre-TB
