We’ve all noticed birds singing, whether we’re walking in the countryside or simply from the window of our house. We may notice that each species has a specific song, but what drives these beings to express such melodies? Ethology is an area of science that studies animal behavior and presents an approach that can answer the above question. In 1963, Nikolaas Tinbergen stated that animal behavior can be explained based on 4 categories called “the 4 why’s of Ethology”: Causal Mechanism or Physiology; Development or Ontogeny; Evolution or Phylogeny and Function or Ecology. Throughout this article, we will explore “why birds sing” according to Nikolaas‘ perspective.
If you want to learn the basics of Ethology, check out our article about it.
Physiology: What is the origin of birdsong?
Birds have a set of specific mechanisms in their brains, with neural circuits, for example, the HVC- High Vocal Center, responsible for the sequence of sounds emitted, and the Ra- Robust Nucleus of the Arcopallium, produces motor signals for the development of song, that react to environmental stimuli, for example, temperature and photoperiod, and end up controlling song.
Development: Learning how to sing
Consider that learning to sing in birds depends on the species, but generally occurs in the first few months of the individual’s life.
Juvenile birds first learn to sing by listening to and memorizing the songs of adults of their species, parents play an important role in this process. Secondly, when the juveniles are more developed, they begin to imitate these vocalizations, first simpler and later improving them until they reach the “perfect” song of the adults in their population.
Evolution: Exertion of selective pressures
Firstly, we need to understand that we can “know” an organism evolved from another because we can trace that evolution. This is their phylogenetic history. This is then reflected on similarities between species, either on morphological characteristics or color patterns. Fossilization are a way to understand the whole phylogenetic history of a certain species, or even a certain clade. But with vocalization we can’t determine that, vocalization doesn’t fossilize.
All existing avian orders possess a syrinx–the sound-producing organ in birds. Some of them lost it due to a specific selective pressure, but more on that on another article. The presence of the Syrinx on all the birds is a strong evidence that it evolved from a common ancestor. This means that that ancestor was already able to produce a specific sound. It is really plausible that birdsong originated in dinosaurs and is now present on avian dinosaurs.1
There is a huge diversity of songs, some simpler and others more complex, where each species has a specific song.
Throughout evolution, individuals have been subjected to different selective pressures, such as the complexity of their environment, which has made them evolve and adapt their songs to the conditions of the environment and their needs in different ecosystems, giving rise to a huge diversity of adaptive songs.
Function: What is the function of birdsong?
Singing in birds has determining adaptive functions that enable the survival of the species as well as its reproductive activity:
- Attracting a mate for reproduction: most males display more complex songs in order to attract females, who choose them according to this complexity, as it is seen as a higher degree of genetic ability.
- Protection and delimitation of territory against competitors and predators.
- Social communication within the population itself, like distribution of tasks, foraging and nest organization.
Curiosities
Here are 3 examples of bird species whose songs are particularly distinctive:
- Brown sicklebill, a bird from New Guinea that stands out for its strange appearance and its unique song, it produces rapid, high-pitched sounds that resemble a machine gun.
- Common Loon, a bird from North America, with one of the most melancholy songs in nature. Many consider that its song creates an almost supernatural atmosphere, since its song resembles howls and laughter.
Conclusion
Based on this way of explaining animal behavior presented by Nikolaas Tinbergen, we can see that birdsong is the consequence of a set of physiological, behavioral, evolutionary and selective mechanisms, presenting a greater complexity, than it appears.
So, whenever you hear a bird singing, you know that there’s a lot more behind it!
Footnotes
Thank you for reading. If you’re curious and want to learn more, go to the “articles” section or click on the sidebar on the right. Every week there are new articles published and new curiosities, stay tuned! Subscribing to our Newsletter will notify you when a new article drops.
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