Studies from Israel and abroad have found that birds do not chirp only for courtship purposes, and that they have a complex language that affects their choice of who to communicate with and how - even during migration
If you have looked at the sky in the last few weeks, you may have seen large flocks of birds passing overhead. Magellanics, herons and pelicans arrive in Israel - which is an essential stopping point for the birds that set out on their autumn migration from Europe and Asia towards Africa. Canadian researchers Found Different species of birds communicate with each other even during migration, and a new Israeli study shows that the language of birds is much more complex than the familiar courtship chirps.
"Humans became interested in the sounds of birds thousands of years ago," says Yael Leonard, a doctoral student in the laboratory of Prof. Oded Berger-Tal at Ben-Gurion University of the Negev, who studies communication and bird migration and how noise pollution affects them. "The ancient man created whistles that imitate their voices, and their singing that attracted the human ear and heart is mentioned, among other things, in the Bible, in Greek sources and in folk tales."
According to her, in the past the focus of research was mainly on the courtship song of the male to the female, and only in the last decades did they begin to engage in research on birds that chirp not only for the purposes of finding mates. "With the entry of women into the research field of bioacoustics, awareness and concern increased that females also sing songs or communicate in extensive and complex vocal communication."
"Chirps while flying require energy from the birds and expose them to predators. Therefore, their calls must have a reason." Photo: Zdeněk Macháček, Unsplash
The language of migration
So far, the questions examined in studies of bird communication in migration have focused on the quantification of migration in a more technical way and less on the messages that the birds pass between themselves. "Researchers used microphones placed on towers and lighthouses to pick up the sounds made by the birds and thereby quantify migration waves - that is, when there is a significant migration of a large number of birds at once," explains Leonard.
study Canadian published in 2023 changed the picture when he examined how the birds communicate during migration. "Chirps while flying require energy from the birds and expose them to predators. That's why their calls should have a reason," says Leonard. The research findings revealed that birds of different species with a similar chirping sound will fly closer to each other and migrate together - so it is possible that their language is similar and therefore they manage to understand each other. According to her, birds do not have a universal language for communication just as there is no such language in humans. "Different species have a slightly different language, but we know that they have the ability to listen to other species and sometimes extract information from it."
Native or learned communication?
"The Canadian research raises the question of whether these voices evolved evolutionarily in birds that migrate together, and that use shared communication between the species to avoid predators and gain orientation - or perhaps it is not evolutionary and it is a matter of learned voices," says Aya Mark, a graduate of the Department of Ecology, Evolution and Behavior at the university Hebrew in Jerusalem. She did her research on the vocal repertoire of the local species, the yellow-bellied nightingale, in the laboratory of Dr. Oren Kolodani, jointly supervised by Prof. Yizhar Levner and Dr. Yoni Wortman from Tel-Hai College.
In her research, Mark tried to answer this question when she studied two populations of nightingales - one from the north of the country and the other from Jerusalem. "When we characterized the vocal units of the nightingales, we saw that they have a very wide vocabulary, and that the words are made up of basic units that we called syllables," she explains. "We found that the syllables are similar between the different populations, even between the distant ones (Jerusalem and Kibbutz Yiftah, for example) and therefore there may be a genetic component to them." That is, it is possible that the syllables produced by birds are influenced by innate traits and are therefore similar in both bulbul populations. According to her, compared to the syllables, it was found that the vocabulary is very different between the populations (even between close populations such as in Agmon and Kibbutz Yiftach). These differences suggest that the words are learned and therefore different in each population, and yet, they still consist of the same syllables.
"All of these suggest that bulbuls have a local culture that is expressed in a complex language and a unique repertoire that characterizes each population," she explains and adds that the research found that both males and females produce complex sounds, so that each and every one of them has a part in shaping or preserving the culture. "Further research on bird communication, especially flight calls and calls outside the context of courtship, will allow us to deepen our understanding of the genetic and learned components of calls, and their role in ecological and evolutionary processes. Hopefully he will also help us preserve those species.'
Yellow-yellow nightingale. Photo: Baresi franco, CC BY-SA 3.0
background noises
Israel is considered an important transit point for migratory birds, and every year hundreds of millions of them pass through the country's skies, in the autumn and spring seasons. Migration entails many dangers for them - injury from turbines wind, destruction and loss of habitats, collision in the vessel aviation And the climate crisis also contributes its part when it causes them precede או to arrive late to their destination. ״noise pollution It is another factor that is important to take into account," says Leonard. "We produce a lot of noise by airplanes and helicopters, so we can assume that it masks considerable parts of the communication between birds in flight and thus impairs their ability to convey messages in the air."
And speaking of noise, does the war affect the birds' ability to communicate? According to Leonard, it is likely that it is. "The noises of the war may significantly affect stress and various behaviors in birds such as eating and communication," she says. "Other studies in the world that examined aircraft noise, mine explosions or military training found that such powerful noises have a negative effect on animals."
Leonard emphasizes that the latest studies show the importance of communication between birds because it is a language with content and meaning. "Birds don't chirp just for mating purposes, and their communication has very significant aspects for sharing information and sharing resources, as well as dialogue between different species and between different couples. That's why it's important that we minimize our negative impact on their ability to communicate," she concludes.
More of the topic in Hayadan:
