Featured Research

from universities, journals, and other organizations

Bird Population Estimates Are Flawed, New Study Shows

Date:
November 29, 2008
Source:
North Carolina State University
Summary:
Most of what we know about bird populations stems from surveys conducted by professional biologists and amateur birdwatchers, but new research shows that the data from those surveys may be seriously flawed -- and proposes possible means to resolve the problem.

European robin. Researchers found that even small amounts of background noise, from rustling leaves or automobile traffic, led to a 40 percent decrease in the ability of observers to detect singing birds.
Credit: iStockphoto/Andrew Howe

Most of what we know about bird populations stems from surveys conducted by professional biologists and amateur birdwatchers, but new research from North Carolina State University shows that the data from those surveys may be seriously flawed – and proposes possible means to resolve the problem.

Bird populations are the focus of thousands of environmental research and monitoring programs around the world. A group of researchers led by NC State's Dr. Theodore Simons has been evaluating factors that confound estimates of bird abundance. For example, background noise can influence the ability of observers to detect birds on population surveys, and can result in underestimates of true population size.

In order to explore these questions, Simons and others worked to develop "Bird Radio:" a series of remotely controlled playback devices that can be used to accurately mimic a population of singing birds. Researchers could then control variables, such as background noise, to see whether it affected birdwatchers' ability to estimate bird populations.

The study found that even small amounts of background noise, from rustling leaves or automobile traffic, led to a 40 percent decrease in the ability of observers to detect singing birds. What's more, said Simons, "we also learned that misidentification rates increased with the number of individuals and species encountered by observers at a census point." In other words, the researchers found that traditional means of estimating the abundance and diversity of bird species are flawed due to complications such as background noise and the accuracy of the data observers collect on surveys of breeding birds.

But the Bird Radio research also points the way toward possible solutions. Simons explains that the Bird Radio findings are helping researchers develop better sampling methods and statistical models that will provide more accurate bird population estimates. For example, researchers are attempting to identify data collection methods that will help account for background noise or other outside factors in estimating bird populations.

The research, "Sources of Measurement Error, Misclassification Error, and Bias in Auditory Avian Point Count Data," is published in the upcoming book "Modeling Demographic Processes in Marked Populations Series: Environmental and Ecological Statistics, Vol. 3" (Springer, 2009). Simons, a professor of biology and forestry at NC State and an assistant unit leader of the U.S. Geological Survey's North Carolina Cooperative Fish & Wildlife Research Unit, was the lead author of the study. The research was co-authored by Dr. Kenneth H. Pollock, professor of biology and statistics at NC State; John M. Wettroth, an engineer with Maxim Integrated Products; Dr. Mathew W. Alldredge, who was a research associate at NC State; and Krishna Pacifici and Jerome Brewster, who were both graduate students in biology at NC State.


Story Source:

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


Cite This Page:

North Carolina State University. "Bird Population Estimates Are Flawed, New Study Shows." ScienceDaily. ScienceDaily, 29 November 2008. <www.sciencedaily.com/releases/2008/11/081121080819.htm>.
North Carolina State University. (2008, November 29). Bird Population Estimates Are Flawed, New Study Shows. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2008/11/081121080819.htm
North Carolina State University. "Bird Population Estimates Are Flawed, New Study Shows." ScienceDaily. www.sciencedaily.com/releases/2008/11/081121080819.htm (accessed August 1, 2014).

Share This




More Plants & Animals News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) 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:
from the past week

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