Urban noise was found to reduce bird species diversity in the city of Edmonton, Canada (Proppe et al. 2013). The lower-frequency sound waves of the songs of some male songbirds were found to be missed by females in three of seven species studied, thereby producing incomplete or distorted signals. As a result females could conclude that a singing male was unsuited as a mate, reducing the likelihood that the pair would produce offspring. These results may help to explain why some areas that appear suitable for birds support only a relatively few species.
In the United Kingdom, the House Sparrow (Passer domesticus) population has been declining since the 1970s. Such a trend would hardly be considered a problem in North America where the House (or English) Sparrow has been regarded as a nuisance species since its unwise introduction into New York in 1850. But in the U.K., the House Sparrow is a native and cherished member of the avifauna. A recent study found that urban noise could prevent House Sparrow adults from hearing the cries of nestlings. Experiments with nest boxes showed that House Sparrow nests located where noise was greatest produced fewer chicks than boxes in low-noise areas. Negative responses to noise in other European species, especially the well-studied Great Tit (Parus major, the “Old World” chickadee and titmouse congener), are observed as disruptions of mating choices and of behavior more than of provisioning the young. The Great Tit, however, is responding to urban noise by singing at a higher pitch in some U. K. urban areas than elsewhere according to the BBC in a June 3, 2009 report!
In northern California, Barton and Holmes (2007) found greater nest desertion and abandonment, but also reduced predation of shrub nests within 100 meters of off-highway trails. Near noisy compressor stations in an Alberta, Canada boreal forest, Habib et al. (2007) studied pairing success and age distribution of the Ovenbird, a ground-nesting warbler. Results were compared to sites near similar but noiseless wellpads. They found significant reduction in pairing success (77% vs 92 %) near the compressors. Also, significantly more first-time breeders, which are likely to be forced by experienced breeders to accept sub-optimal sites, were found near the compressor stations. Various factors were probably involved, but noise was thought to be the ultimate cause. Noise appeared to interfere with the female’s ability to hear male songs at greater distances and/or to be interpreted as being of lower quality. In both cases, reduced nesting success was seen as an outcome of nesting near noise sources. In another paper, Francis et al. (2011) found that human-generated noise was disrupting bird communication at their study sites and that this stress affected species differently. Birds with low-frequency song signals were likely to avoid human-produced noise areas while birds with high-frequency song signals were relatively unaffected or, at least, did not vacate noisy areas.
In a different approach, this in California, Francis et al. (2012) evaluated noise effects on birds and their consequences for plant reproduction. Artificial flowers were deployed to quantify the role of Black-chinned Hummingbirds (Archilochus alexandri) in “pollinating” the flowers. There was a noise impact but also some unexpected findings.
The artificial flowers mimicked the local Ipomopsis aggregata, a self-incompatible, hummingbird-pollinated and probably pollen-limited, vine in the phlox family. Noise pollution indirectly increased artificial flower pollination by the hummingbirds which reportedly prefer nesting in noisy environments (mechanism unknown)! Associated with this finding was an increase in fruit-set of Ipomopsis in the noisy sites probably attributable to the hummingbird activity.
However the authors also substantiated that noise adversely affected animals that help disperse the seeds of Pinus edulis, the locally dominant pinon pine. These animals include the Western Scrub-jay, already known as a noise-avoider. These indirect noise impacts on seed-dispersing species help explain the presence of fewer pine seedlings in noisy areas and suggest that, if noise continues, there could be longer-term implications for tree composition of the local woodland community.
In yet another approach, Montgomery and Weatherhead (1997) employed buried mealworms to show that auditory cues are important to American Robins for detection of buried prey. Foraging success by robins is reduced when the birds are exposed to “white” noise. Interestingly, at the time of this work there was only one other study of the foraging techniques of robins and it concluded that robins used only visual cues to detect prey. The references below will direct the interested reader to other pertinent research that has not been discussed here.
abcbirds.org . American Bird Conservancy
Barton , D. C. and A. L. Holmes (2007). Off-highway vehicle trial impacts on breeding songbirds in northeastern California. J. of Wildlife Management 71: 1617-20 (Abst).
Francis, C. D., C.P. Ortega and A. Cruz (2011). Noise pollution filters bird communities based on vocal frequency. PLOS ONE. plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0027052
Francis, C. D., N.J. Kleist, C.P. Ortega and A. Cruz (2012). Proc. Royal Soc. B. 10.1098/rspb20120230
Habib, L., E.M. Bayne and S. Boutin (2007). Chronic industrial noise affects pairing success and age structure of ovenbirds (Seiurus aurocapilla) J. Applied Ecology 44, 176-84
Montgomery, R. and P.J. Weatherhead (1997). How robins find worms. Animal Behavior. 54,143-51.
Proppe, D.S., C.B. Sturdy, C.C.S. St.Clair (2013). Anthropogenic noise decreases urban songbird diversity and may contribute to homogenization. Global Change Biology 19:1075-84.