NC State study shows bird population estimates are flawedNovember 21, 2008Most 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. North Carolina State University |
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| Related Bird Population Current Events and Bird Population News Articles Study: Bird diversity lessens human exposure to West Nile Virus A study by biologists at Washington University in St. Louis shows that the more diverse a bird population is in an area, the less chance humans have of exposure to West Nile Virus (WNV). Brown tree snake could mean Guam will lose more than its birds In the last 60 years, brown tree snakes have become the embodiment of the bad things that can happen when invasive species are introduced in places where they have few predators. Unchecked for many years, the snakes caused the extinction of nearly every native bird species on the Pacific island of Guam. Birdsong not just for the birds Computer scientists from the University of Bonn, in conjunction with the birdsong archives of Berlin's Humboldt University, have developed a kind of 'Big Brother' for birds. This has nothing to do with entertainment, but a lot to do with the protection of nature. Diversity among bird populations found to reduce threat of West Nile virus A biologist and undergraduate student have discovered that what's good for an area's bird population is also good for people living nearby. Climate change creates dramatic decline in red-winged black bird population Global warming strikes again. A University of Illinois researcher reports that a red-winged black bird population in Ontario, Canada has decreased by 50 percent since 1972. Shift in feeding behavior of mosquitoes sheds light on West Nile virus outbreaks Since its introduction to the United States in 1999, West Nile virus has become the major vector-borne disease in the U.S., with 770 reported deaths, 20,000 reported illnesses, and perhaps around a million people infected. Early California: A killing field When explorers and pioneers visited California in the 1700s and early 1800s, they were astonished by the abundance of birds, elk, deer, marine mammals, and other wildlife they encountered. Bird fall-out measures radioactive fall-out Jim Clapp (University of Ulster) will reveal how bird droppings can be used to measure radioactive fall-out in the environment. Solid urate spheres found in bird excretions can be screened for man-made pollutants such as radioactive caesium, providing a new non-invasive way to monitor the environment. Mr. Clapp will present his latest results today at the annual meeting of the Society for Experimental Biology at Heriot-Watt University, Edinburgh (29 March - 2 April 2004). "This is a new method which does not interfere with the birds or with the environment" explains Mr. Clapp. "There is no need to sacrifice birds or disrupt them, which may cause them to leave their breeding site Green Isle Survives In The Urban Environment Fortunately, green spots still remain on the map of Moscow tending to be located in the suburbs of the city, in the valleys of the rivers, away from the densely populated communities. Among them there are several little spots which are surrounded by the city being isolated like isles in the ocean. One of them is the forest park of the Timiryazev Agricultural Academy, which makes part to the Petrovsko-Razumovskoye natural preserve. Long ago the forest was planted especially for the professional training of forestry specialists Russia is famous for. For this purpose the forest was regularly checked up - from time to time the biologists used to count all the plant and animal species in the fore More Bird Population Current Events and Bird Population News Articles |
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