It
comes as no surprise that New York City is a noisy place. Cars are honking, people are yelling, and
it seems like construction never ends.
However more than simply adding to the crabbiness of New Yorkers, these
urban sounds are causing major wildlife concerns. Noise pollution is one of the most prevalent yet also most
overlooked causes of modern pollution.
New York City and other major metropolitan areas are overwhelmed by
acoustic pollution and the animals, specifically songbirds, are being affected. However, the songbirds of urban areas
are changing their behaviors and passing their new songs on to the next
generations. Songbirds are
changing with the changing environment, and it is because of acoustic
pollution.
Three
recent studies have been conducted on the subject of songbirds and noise
pollution and all have come to similar findings. Birds that sing on a low frequency are unable to communicate
with their young or with potential mates[1][2][3]. These studies were conducted with sparrows
(Schroeder), the great tit (Halfwerk et al.), and a variety of urban oscines,
or songbirds (Rios-Chelen et al.).
All of these studies found that their urban birds had difficulty when
they sang at a low frequency because it was either matched or masked by the
ambient noise pollution.
However,
these studies also noticed that birds were changing their songs to react to
their environment. The longer the
bird communities were exposed to urban noise pollution, the higher the
birdsongs became. As Rios-Chelen
explains, “song learning or song plasticity allows birds to achieve a greater
adaptation of their songs to the acoustic conditions of the environment in
which they live” 3. These
three studies universally found that birds with the capacity to learn a new,
higher frequency song had higher fitness levels by being able to communicate
with their young and with potential mates123.
These
studies show evidence that the ability to adapt one’s birdsong is a genetic
trait. Some oscines, ones that
apparently did not have the ability to adapt their songs on their own were also not
able to copy the birdsongs of others2. Additionally, the ability to change a
birdsong was found to be passed down through generations, with offspring of
changed birds to have higher frequency songs and be able to increase their song
frequencies1.
The
sounds of urban areas are changing and that is causing urban songbirds to
change. Birds that are unable to
change their songs to overcome acoustic pollution are both dying out and
abandoning their young. Only the
birds that can change their tune and increase their song frequency are able to
survive and mate. No wonder people
say it’s hard to be single in New York City.
Word Count: 447
[2] Halfwerk,
W., Sander BOt, Jasper Buikx, Marco van der Velde, Jan Komdeur, Carel ten Cate,
and Hans Slabbekoorn, Low-frequency songs lose their potency in noisy urban
conditions, Preceedings of the National
Academy of Sciences, v. 108 no. 35.
[3] Rios-Chelen,
A.A., C.SaLaberria, I. Barbosa, C. Macias Garcia, and D. Gil, The learning
advantage: bird species that learn their song show a tighter adjustment of song
to noisy environments than those that do not learn, Journal of Evolutionary Biology, p. 2171-2180.
I'm curious how these three studies were conducted. Were they all done in New York City, or multiple urban centers? Also, were these observational studies or were they done in some kind of controlled environment? And was there a control group in any of the studies?
ReplyDeleteHas the change of songs had any kind of effect on animals/organisms that directly or indirectly associate with the birds? For example on predators that rely on the songs to locate the birds?
ReplyDeleteDo birds that are able to change their songs have a different vocal apparatus from those who cannot? I would think that the basic mechanics of making sounds have been conserved throughout avian evolution. The difference then might be in the brain circuitry, which would imply that the birds are consciously singing in a higher register.
ReplyDeleteThis is really interesting. I wonder if the birds have a greater range in their song frequency or if it is a shift away from the lower frequencies.
ReplyDeleteThat's exactly what I was thinking. It seems more likely that noise pollution is selecting for birds with higher frequency songs, not for birds with a greater range or flexibility. Christina, you say that what is genetic is the "ability to adapt one’s birdsong," but I wonder if scientists have distinguished yet whether the birds are actually individually more flexible in their singing or whether the birds that are surviving simply have higher frequency songs?
DeleteThe singing frequency seems like it's linked to the sexual selection. What is the criteria of the selection based on singing on an environmental without the noise pollution? Can we still conclude the noise is the selection pressure if the birds still tend to mate with ones with higher frequency songs?
ReplyDeleteAs noise pollution and bustle in the city increases, will it eventually reach a point where the songbirds are no longer able to increase their frequency enough to overcome it? If this threshold is reached, will birds be forced to find a new method of communication or will they simply become rarer or extinct in these urban areas? I wonder if in more rural areas, with changes of frequency of common sounds like car engines but not necessarily increasing the amount of noise, birds have also changed their songs since industrialization, etc.
ReplyDeleteI like that you talk about noise pollution- that is often overlooked and yet it an affect bird songs and even human health! It was very interesting that the change in birdsong was a heritable change in the NY birds and not just a plastic trait.
ReplyDeleteLike Aydan, I am also interested in this ability to adapt one's birdsong as a genetic trait. What do you mean by genetic? Are there physical differences in the vocal apparatus that are inherited? Is it a difference in the brain activation or perhaps the enlargement of a certain brain area? I find it curious that these birds are not able to simply mimic and learn new ranges/songs. Unless, as Aydan suggests, the birds are consciously singing at a higher register. Do the offspring of these adaptive birds automatically communicate at a higher register, or do they learn from their parents?
ReplyDeleteThis is really interesting... I wonder if there is a breaking point with the sound pollution. Is there a certain point where even birds who are capable of higher pitch songs can't communicate. I also wonder if this is only a problem in areas where there is a lot of noise. Of course New York City is an extremely loud place, but I wonder if the same logic works in areas where birds with low pitched songs have an advantage. Does the selection depend on the amount of noise pollution, or the pitch of the birds song?
ReplyDeleteI think that the breaking point that you mention will never be an issue because either the birds will adapt to the loud environment or they will simply leave the loud areas and congregate in a quieter place. I also think that there would be certain places where low pitched songs have an advantage. The world is so large and full of such diverse environments that surely there is a place for low-pitched birds.
DeleteI wonder if different cities select for different frequencies of song... For example areas with trains and metro systems may have different noise pollution than areas with only cars, and some cities have higher frequencies of one kind of car than another (coming from the California bay area, I was shocked by the number of loud pickup trucks and Suburbans here - and where are all the blue priuses?!?) all of which might combine to create a unique "sound fingerprint". It would be very interesting to compare evolution of birdsong in different areas and study the effects of the differing sounds of these cities on the bird populations.
ReplyDeleteFor the birds I wonder if there is a limit to the frequency they can produce and if they would evolve to accomodate that if their threshold is reached. Also, how do the birds select mates in normal situations without all the noise?
ReplyDeleteReally interesting topic! Like Emily and Briona I'm wondering if there would eventually be a point when they cannot sing higher than the noise pollution and would have to develop other ways of communicating. I also wonder if there has been any movement of birds with generally lower frequency songs out of very noisy areas with similar frequencies?
ReplyDeleteI am also wondering the same thing as Emily Crowder above. Before I came to Rice I was a student at NYU, in the middle of New York City. I understood peoples' concern with light pollution (I could never see the stars!!!!) or waste pollution (don't get me started on the trash in some places), but I never even considered noise pollution and its effects on "wildlife" in New York City. While there may not have been too many varieties of birds in NYC, I always appreciated seeing animals in their, more or less, natural habitats and it kind of makes me sad to see your very clear findings that the hustle and bustle of NYC does not only effect the people but also these birds. Thanks for the article!!!
ReplyDelete