"bald eagle facts
•bald eagles eat primarily fish, carrion (dead animals), smaller birds, and rodents. their most important non-carrion food is fish, which they catch by swooping down and grabbing fish that are near the surface of the water.
•the number of nesting pairs in the lower 48 united states increased from fewer than 450 in the early 1960s to more than 4,500 adult bald eagle nesting pairs in the 1990s. today, there are an estimated 9,789 nesting pairs of bald eagles.
•bald eagles are found in large numbers in certain areas during the winter (known as roosts). these winter roosts are located in areas where prey are plentiful. winter roosts are protected under federal law, and managed with a buffer zone to reduce human disturbance. as winter ends, the eagles return to their summer nesting/hunting areas.
bald eagle research
in the winter of 2009, volunteers from an audubon group conducted a survey of roosting bald eagles at four locations in an area in the lower hudson river valley. the data below show the average number of eagles sighted and the number of visits made by the volunteers each month. among the other data collected were percent ice cover and percent cloud cover on the surface of the water. the eagles fly freely between these four sites, depending on a variety of conditions.
some of the data are shown in the table below.
state one reason why the number of eagles sighted showed a change at all four sites between february and march"