Love songs, war cries and lies: Understanding the language of birdsong

When a bird sings, it is not performing for us. It is speaking to the world it belongs to. — David Abram

In Act 3, Scene 5 of Shakespeare’s Romeo and Juliet, the lovers spend the night together after their secret wedding. It is here that their first argument unfolds. Romeo prepares to leave after hearing a birdcall, assuming it to be the rising call of a lark. Juliet insists that it is not yet daybreak. She tells him that he has mistaken the nightingale’s song for that of the lark. Romeo, however, remains certain that it is the lark announcing the morning.

The difference between the nightingale and the lark is as vast and as narrow as night and day. These birds mark the duality of the lovers’ relationship: union and separation, night and morning, life and death. Shakespeare must have known the significance of birdsong at daybreak. For centuries, humans have relied on birds to infer time, weather, and even a sense of safety. Yet it is important to remember that just as the lark in Shakespeare’s play was not on a mission to warn the lovers of their separation, birds around us do not sing for our amusement. As American ecologist and philosopher David Abram aptly remarks, they are speaking to the world to which they belong.

But what is this world? And how do birds use their voices to live, to survive and to reproduce? I begin with Romeo and Juliet to open a discussion on the not-so-secret and very vocal love lives of birds.

Whether monogamous or polygamous, birds sing during their breeding season. In monogamous species, males (and in some cases females) sing from a particular place and at specific times to signal readiness to build a nest and raise offspring. Polygamous birds sing to attract mates. Ornithology broadly distinguishes between two kinds of vocalisations: birdsong and bird calls. Vocalisations produced during the breeding season are categorised as birdsong. These are longer, structured, and often show regional variation within the same species. Bird calls, by contrast, are shorter and simpler sounds used throughout the year for non-reproductive communication. While birdsong signals breeding activity, territoriality and residency, bird calls convey immediate information about danger, location, or social interaction.

An example from my hometown, Sangli (Maharashtra), remains etched in my memory. One June morning, as I lay in bed, I heard a male Common iora calling “teee, teee, teee, teee.” The time was exactly 5.46am. I woke to this call every morning at the same time. The presence of the Iora was not surprising, but the precision of his behaviour was. He perched on the same branch of the same tree, day after day, delivering the same call. As I observed him, I realised he was receiving a response. The reply, however, came not from a female, but from another male claiming territory nearby. The two males argued through song while the female quietly listened. Over time, I noticed changes in the timing and duration of their calls. Eventually, one male succeeded in attracting the female. Once the pair was formed, the winning male stopped singing.

Another evening, in May, I heard a very different call. It was twilight. The sky still held a bluish tint, and the mango tree in my neighbourhood was heavy with leaves and ripening fruit. A lamenting call rose from the tree. It was a male Grey-bellied cuckoo, a member of the cuckoo family known to lay its eggs in the nests of other birds. The bird fell silent after a while, only to call again before dawn. This became a routine. Every day, around 3am.

Who was the bird calling? Cuckoos do not build their own nests. Instead, they lay eggs in the nests of species such as the sunbird, Common Iora, tailorbird, which are known to unknowingly raise cuckoo chicks. The bird was calling for his mate, responding to the presence of other birds building nests nearby. I have observed sunbird pairs raising cuckoo chicks. The cuckoo nestlings were three times larger than the adult Ioras, who tirelessly fed the enormous young birds.

Speaking of feeding, it is important to consider allofeeding and its role in mating. Allofeeding refers to the act of a male feeding his female partner just before mating. This behaviour is common among raptors and other birds. I have observed it in long-tailed shrikes, red-vented bulbuls, and green bee-eaters. Once, during a walk in the Dandoba hills, I saw a pair of long-tailed shrikes perched close together. The male flew off briefly and returned with a large grasshopper, which he offered to the female. After she ate it, the pair mated and gave a mating call.

Why do birds feed their partners before mating? Is it courtship, flattery or bonding? The answer lies in survival. At the time of mating, the female carries eggs. After mating, the fertilised eggs begin to take a shape and the female lays them in the nest the pair builds. These tasks demand significant energy. The male feeds her to support this effort and secure the future generation.

Birdsong itself varies according to its audience. Songs directed at rival males are often simple and repetitive, while those aimed at females are more complex and elaborate. Red-vented bulbuls and Indian blackbirds are notable examples of this distinction. Birdsong is shaped by ecological constraints, reproductive strategies and evolutionary history. It is not universal in form or meaning. Loud or soft, simple or complex, solitary or shared, each song arises from specific needs. Recognising this does not diminish the pleasure of listening. Instead, it deepens it. When we begin to hear birdsong as language, we hear intention where we once heard ornament. The world sharpens, grows more complex, and in that complexity, birds speak not to our longing for beauty, but to the enduring work of survival.

Sharad Apte is a bird sound recordist from Sangli, Maharashtra. This article is drawn from his book, Why Birds Sing: Science of Bird Song, translated from Marathi by Rujuta Khare and Zai Gulmohar.