Featured Research

from universities, journals, and other organizations

Kestrels, other urban birds are stressed by human activity

Date:
May 10, 2013
Source:
Wiley
Summary:
American kestrels, small colorful falcons often seen perched along roadways, are abundant in urban and agricultural areas. Shorter grass makes insects, snakes, mice and other prey more visible, and signposts, fences and telephone poles provide excellent perches. However a new study shows that even species considered “tolerant” of human activity may be adversely impacted by human disturbance; Kestrels nesting in close proximity to roads and developed areas had elevated stress hormones and high rates of nest abandonment. The apparently favorable location, then, becomes an ecological trap.

American kestrel.
Credit: Copyright Boise State University

American kestrels, small colorful falcons often seen perched along roadways, are abundant in urban and agricultural areas. Shorter grass makes insects, snakes, mice and other prey more visible, and signposts, fences and telephone poles provide excellent perches. However a new study from scientists at Boise State University in Idaho shows that even species considered "tolerant" of human activity may be adversely impacted by human disturbance; Kestrels nesting in close proximity to roads and developed areas had elevated stress hormones and high rates of nest abandonment. The apparently favorable location, then, becomes an ecological trap.

The peer-reviewed paper "Reproductive failure of a human-tolerant species, the American kestrel, is associated with stress and human disturbance," was published in the British Ecological Society's Journal of Applied Ecology (May 10, 2013). Boise State University graduate student Erin Strasser, now with the Rocky Mountain Bird Observatory, and Julie Heath, a professor in the Boise State Department of Biological Sciences and Raptor Research Center, conducted the research.

Strasser and Heath conducted research along one of Idaho's major expressways, Interstate 84, and in suburban and rural areas south of the state's capital city of Boise. Since 1987, researchers from Boise State and the U.S. Geological Survey have monitored a number of nest boxes located along the area's roadways, in people's back yards, and in sagebrush-steppe habitat.

In this study, Strasser and Heath were interested in understanding how human-dominated landscapes affect breeding kestrels, with particular attention paid to the link between disturbance, stress and nest failure. The two monitored the boxes to determine nest fate, and collected a small blood sample from adult birds. The researchers were looking at corticosterone levels, which indicate stress levels (the equivalent in humans is cortisol). Corticosterone can lead to behavioral and physiological changes that allow individuals to cope with stressful situations, while suppressing other activities such as reproduction.

The data showed that female kestrels nesting in areas with high human activity, such as along noisy roadways, have higher corticosterone levels, but males do not. This could be because females spend more time in the nesting box and thus are exposed more often to stressors such as vehicle noise. Too much ambient noise may make it difficult for them to assess the level of danger, leading to higher stress levels and increased vigilance behavior, decreased parental care or the decision to abandon their nest. Kestrels nesting in high disturbance areas were almost 10 times more likely to abandon their nest than those in more isolated areas, and this effect lessened the further a nest was from the road.

"We hypothesized that this was a mechanism for how humans are impacting wildlife," Heath said. "To birds, areas with human activity may be perceived as a high-risk environment."

Given that the vast majority of land in the continental United States is within a mile of a road, wildlife increasingly are exposed to chronic levels of road noise. The resulting increase in stress levels could cause fundamental changes in physiology and behavior across species inhabiting human-dominated environments, which over time could lead to population declines.

As scientists continue to connect the dots between human disturbances and the resulting long-term effects on wildlife, changes already are yielding positive results. Research conducted in preserve areas, such as state parks, has led to reduced speeds and attempts to limit noise, although noise mitigation, while locally effective, may not protect widespread populations such as kestrels from the pervasive threat of traffic noise.

The study concludes that until regulations or economic incentives are developed to encourage engineering innovations that result in quieter roads, projects in areas of human activity with favorable habitat should be discouraged to decrease the risk of ecological traps. In the meantime, Boise State's nesting boxes have been moved from freeway locations to more suitable areas.

"Birds evolved in an environment that was not dominated by humans," Heath noted. "In recent history, human roads and structures have left few areas untouched. We're just starting to understand the real consequences."


Story Source:

The above story is based on materials provided by Wiley. Note: Materials may be edited for content and length.


Journal Reference:

  1. Strasser, E.H. and J.A. Heath. Reproductive failure of a human-tolerant species, the American kestrel, is associated with stress and human disturbance. Journal of Applied Ecology, 2013

Cite This Page:

Wiley. "Kestrels, other urban birds are stressed by human activity." ScienceDaily. ScienceDaily, 10 May 2013. <www.sciencedaily.com/releases/2013/05/130510102025.htm>.
Wiley. (2013, May 10). Kestrels, other urban birds are stressed by human activity. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2013/05/130510102025.htm
Wiley. "Kestrels, other urban birds are stressed by human activity." ScienceDaily. www.sciencedaily.com/releases/2013/05/130510102025.htm (accessed September 23, 2014).

Share This



More Science & Society News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Costs Keep Mounting

Ebola Costs Keep Mounting

Reuters - Business Video Online (Sep. 23, 2014) The WHO has warned up to 20,000 people could be infected with Ebola over the next few weeks. As Sonia Legg reports, the implications for the West African countries suffering from the disease are huge. Video provided by Reuters
Powered by NewsLook.com
Ebola Cases Could Reach 1.4 Million Within 4 Months

Ebola Cases Could Reach 1.4 Million Within 4 Months

Newsy (Sep. 23, 2014) Health officials warn that without further intervention, the number of Ebola cases in Liberia and Sierra Leone could reach 1.4 million by January. Video provided by Newsy
Powered by NewsLook.com
Obama: No Nation Gets Pass on Climate Change

Obama: No Nation Gets Pass on Climate Change

AP (Sep. 23, 2014) In a forceful appeal for international cooperation on limiting carbon pollution, President Barack Obama warned world leaders at the UN Climate Summit on Tuesday that the globe's climate is changing faster than efforts to address it. (Sept. 23) Video provided by AP
Powered by NewsLook.com
Overcrowding Has Public Schools Going Vertical

Overcrowding Has Public Schools Going Vertical

AP (Sep. 23, 2014) Pricey real estate and overcrowding have forced urban and suburban school districts to get creative. In Atlanta and outside Washington, that means converting high rise commercial buildings into vertical learning environments. (Sept. 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Science & Society

Business & Industry

Education & Learning

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins