A key annual event in the recovery of Bald Eagle populations takes place January 4-18, when hundreds of citizen scientists take to the field for the 34th annual Midwinter Bald Eagle Survey.
“The survey is a true public-private partnership with hundreds of volunteer citizen scientists taking part, in addition to federal, state, and NGO biologists. Forty-three states continue to actively participate, with over 740 standardized survey routes across the country,” said Wade Eakle, the 2012 national survey coordinator and an ecologist for the U.S. Army Corps of Engineers.
The data are collected during a two-week window every year; then sent to a national database set up to monitor eagle populations in the lower 48 states. It is part of a national effort to identify important winter habitat and develop a total population index for the wintering eagle population. Approximately 44% of the surveys are conducted from vehicles. 18% are conducted from fixed wing aircraft; 8% are collected from boats; and 7% are conducted by helicopter.
“Collecting data over the long-term helps scientists and wildlife managers monitor the health of Bald Eagle populations. The power of this survey is continuity,” Eakle said. “Because it’s been run every year since 1979, we have a lot of confidence in what we can now say about the status of wintering Bald Eagles in the United States.”
“We rely on citizen scientist volunteers to help cover the territory with accuracy and precision, he said. “Many come back year after year and collect data in all kinds of weather. Without their dedication and expertise this critical database would not be possible.”
Bald Eagles were officially declared an endangered species in 1967 in all areas of the United States south of the 40th parallel, under a law that preceded the Endangered Species Act of 1973. In June 2007, the U.S. Department of the Interior took the Bald Eagle off the endangered species list – making it one of a handful of species to fight its way back from the brink of extinction.
"As the length of the Bald Eagle time series grows with each annual survey, the potential scientific applications for the information increase, far beyond what was ever envisioned at the time that the survey was first initiated," commented U.S. Geological Survey Director Marcia McNutt. "Each citizen volunteer who has put in the time, care, and effort in the more than 30 years that this survey has been undertaken should be proud of being part of an exceptionally effective effort in wildlife research, recovery, and management."
Brian Millsap, National Raptor Coordinator with the U.S. Fish and Wildlife Service, Albuquerque, NM, applauds the dedication of the hundreds of volunteers that continue to collect this important data. “The information gathered on population trends and habitat is increasingly important to permitting decisions being made by the Service for renewable energy and other projects,” Millsap said.
Each year the survey data are compiled to help create a long-term trend analysis. A new 25-year-trend analysis for the years 1986 – 2010 is due out this spring. Past survey results are available online.
"Periodic analyses of the counts are a key," said Eakle. "They are useful to scientists working to analyze the effects of climate change, habitat loss, and other impacts on Bald Eagles."
Users can retrieve “actual count” data used in the analysis as well as summary information for individual survey routes. They also can obtain estimates of count trends for different regions and states.
The American Eagle Foundation recently announced it will help enhance the web database and make it easier to interpret through a grant to the Northwest Alliance for Computational Science and Engineering at Oregon State University in Corvallis. NACSE hosts and maintains the survey websites in partnership with USACE and USGS.
AEF Grants Administrator Bob Hatcher said the foundation is happy to help fund the Midwinter Bald Eagle Survey website enhancements for 2012.
New web analyses will improve user’s ability to interpret national and regional trends, including climate and other contributing factors.
Hatcher, who coordinated surveys in Tennessee from 1978 to 2001 while serving as Tennessee's Endangered Wildlife Coordinator, said the results were always useful but he found it challenging to fully interpret fluctuating trends by state, and by region. For example, midwinter count trends in many southern states have been only slightly positive and even negative in Arizona, while in the Great Lakes and New England count trends are significantly more positive.
The National Wildlife Federation began the survey in 1979, and the USGS organized and coordinated it from 1997 to 2007. In 2007, the USGS established a partnership with the USACE to maintain the long-term, national coordination of the survey, data analysis, and reporting.
USACE plays a significant role in recovery efforts of the Bald Eagle by supporting eagle conservation, including breeding season and midwinter surveys, management of habitat, education, and outreach. The geography of USACE projects has also been vital to Bald Eagle populations. USACE manages over 450 man-made lakes within the continental United States and has jurisdiction over approximately 24,000 miles of inland navigation rivers. USACE reservoir projects encompass approximately 11.6 million acres of land and open water habitat, with the total shoreline length exceeding the entire coastline of the United States.
Media interested in covering the event, please contact your state coordinator (PDF).
Photos of past midwinter bald eagle surveys are available online.