Dialects in Bird Songs
Overview of Dialects in Bird Songs
Regional dialects in humans are closely linked to culture, belonging, and identity, indicating an individual’s roots and background and can offer us insight into how people from different regions communicate.
Similar to local dialects in human speech, birdsong has been observed to vary according to location, with distinct differences recorded in individual populations of the same species.
Read on if you’re interested in learning more.
The Linguistics of the Avian World
Just as human-spoken dialect can reflect a person’s background, origin, or hometown, the same is true for birdsong. A Song Sparrow singing in Boston may, to the trained ear, sing a song that varies slightly in tone, pitch, or melody from a bird of the same species in Baltimore.
Some species are born with the innate ability to sing, and their song is replicated from generation to generation. Others learn songs from listening to their parents and neighboring birds, and it’s these species that are most open to variations in dialects.
Studying regional birdsong provides insight into another way in which bird species adapt to their different habitats. Birds’ vocalizations may be influenced by their surroundings, with songs undergoing subtle but distinct changes between rural and urban settings or from one state or country to another.
Pictured: A Song Sparrow. Birdsong has been observed to vary according to location, with distinct differences recorded in individual populations of the same species
Understanding Bird Song Dialects
Dialects exist in birdsong and refer to the variations in song pitch, tone, and melody between different groups of birds within the same species. Similar to accents and dialects in human speech, birds are also capable of developing their own unique forms of their standard species' song.
Read on to learn more about how dialects form and what may influence these variations.
What are Bird Song Dialects?
Variations in the tune and pitch of the warbling notes and phrases heard from treetops and woodlands may not always be obvious to the casual listener, but birds themselves can distinguish between these subtle differences.
Different bird populations may have distinctly different calls and songs that vary according to their geographical location. A particular population may have developed its own particular twist on a traditional call, while the same species living on the other side of a state or country may sound noticeably different.
Pictured: An Eastern Towhee singing from the tree top
Formation of Dialects
One theory on how dialects form in birdsong is that a number of songbird species learn their songs from older, more experienced birds in their immediate community. This subgroup of songbirds is known as oscines.
In oscines, learning occurs during the earliest, most critical phase of their development, and young birds mature with the ability to replicate the songs they become most familiar with. Where the older birds may have altered their song to survive in a particular environment or habitat, these amended songs are then passed onto the young, and become their core song, which they then pass on to their own offspring.
Other songbirds, a group known as suboscines, however, are born with an innate ability to reproduce their species’ traditional songs and are less influenced by the tunes they are exposed to. They do not need to hear a song repeatedly before they are able to sing it themselves and show little geographical variation in the pitch or tone of their melodies.
Environmental factors that influence the development of dialects include the level of human and traffic noise in city environments, with birdsong adapting to be heard above the ambient noise.
Birds rely on song for communication, courtship, and territory defense, and if their original song cannot be heard, they need to adapt in order to survive and ensure the continuation of their species.
Pictured: A Blackbird. Birds rely on song for communication, courtship, and territory defense
Regional Variations in Bird Songs
Case Studies of Bird Species with Notable Dialects
The study of regional variations in birdsong is a hot topic for current research, with many ongoing studies into how song may differ among a single species according to where they live.
A 2009 study focused on common blackbird songs in two separate populations only around 4 miles apart. The first group lived in the the heart of the Austrian city of Vienna while the second study population lived in woods outside of the city.
Each morning, the peak singing time for songbirds, song was recorded and analyzed. For the city-dwelling birds, the pitch of the loudest part of the song was much higher than that of the birds living in the woodlands. Also, city birds sang fewer notes than the rural birds, at a much faster pace without pausing, and sang much earlier in the morning, possibly to beat the noise of rush hour traffic.
White-crowned sparrows offer another well-documented example of dialect differences that have evolved in bird species according to where they live.
Studies of three separate populations in different parts of California demonstrated variation in pitch, frequency, and duration, depending on the location and level of urbanization. City-dwelling birds were louder and higher in pitch, and their songs were faster-paced, almost rushed in comparison to the more leisurely songs of the rural birds.
Audio clips and spectrograms – visual representations of sounds – are used to analyze and compare regional variations in birdsong between different regions, which contributes to our understanding of bird communication and behavior and how these evolve through time.
Pictured: A White-crowned Sparrow. This species offer another well-documented example of dialect differences
Adaptive Significance of Dialects
One theory, supported by numerous records and observations, is that birdsong in urban areas has evolved to be louder and significantly different from that of the same species in rural settings.
City-dwelling birds have a noticeably higher pitch than those living in the countryside, and it’s suggested that the reason behind this is to make themselves heard above the noise of urban traffic.
Birds only a few kilometers away may not recognize the songs of their fellow species, which could have a negative effect on future populations.
Song plays such a vital role in mate selection, and if birds relocate to new areas and are not familiar with the differences in dialect in their new location, their song may not be attractive to potential mates. It may also result in territorial defense being less effective, as songs of rival males with different dialects may not be effective in keeping their own territories secure.
Pictured: European Goldfinch. City-dwelling birds have a noticeably higher pitch than those living in the countryside
Studying Bird Song Dialects
It wasn’t until the 1950s that the first official scientific studies into dialects in birdsong began, with ornithologists recording observations initially by transcribing melodies by hand, and later using technological methods to further our knowledge of this fascinating topic.
Keep reading if you’re interested in finding out more about research into dialects in birdsong.
Research and Discoveries
Peter Marler, a British ornithologist, was one of the first researchers to investigate differences in song of birds of the same species. He noted that Chaffinches sounded differently, depending on where in the Scottish valleys they were living, and later noted similar findings about White-crowned Sparrows in different regions of California. Marler used sonograms to record birdsong and compare the read-outs between individual populations.
Investigations into song acquisition followed in the 1960s and 1970s, with baby birds placed in isolation chambers away from other birds, and their vocalizations tracked.
Interestingly, the research showed that some birds were born with the innate ability to sing the songs of their species. However, others that rely on listening and repetition to develop their vocal skills, did not progress beyond babbling.
One theory suggested from analysis of how birds develop different dialects is that individual birds make a small mistake when singing, and this mistake or deviation is then replicated by their young and passes into their accepted version of the tune, becoming an avian equivalent of oral tradition.
Pictured: A Chaffinch in song. Peter Marler, a British ornithologist, was one of the first researchers to investigate differences in song of birds of the same species
Citizen Science
A wide range of opportunities exist around the world for participants to join a growing network of citizen science projects and become involved in vital research into birdsong, and its impact on diversity, habitats, and how it is affected by noise pollution.
Bird enthusiasts are encouraged to use a smartphone to make a digital recording of birds singing in their local area and upload it to an online database that can then track any differences between birds of the same species in a particular area.
The One Earth project is one such example of a citizen science initiative, which maps observations and allows users to listen to audio clips and make an important contribution to biodiversity research.
Pictured: An American Robin singing from the branch of a tree
Summary
By understanding the impact of how changes to the traditional songs of birds can influence how they attract mates, successfully defend territories and communicate with others of the same species, we are able to learn more about bird behavior and evolution.
Just a handful of seemingly minor variations from a typical song can have a significant impact on whether a bird will be successful in attracting a mate or successfully keep rivals off their territory.
With advances in technology and recording methods, it’s possible that we’ve only just scratched the surface in research into birdsong dialects and the fascinating role they play in the wider field of bird communication.