Bald Eagle Nest Monitoring Etiquette

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Bald Eagle Nest Monitoring Etiquette

Received these important and useful suggestions from Phil Martin and am pinning this to the General FORUM.

Below is a great article I think you should post to educate folks. This article was authored by the Iowa Department of Natural Resources.


Bald Eagle Nest Monitoring Etiquette

For many Bald Eagle enthusiasts there is little more exciting than watching their favorite birds become parents and raise young. Seeing our national symbol go through the process of nesting is a thrilling and satisfying experience. These once endangered birds have been successful enough at raising eaglets to be removed from the Endangered Species list. That being said, Bald Eagles remain protected by the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act. They are also, as a species, sensitive to human activity. Too much disturbance to nesting eagles can have a negative impact on nest success. The last thing any Bald Eagle lover would want is to unintentionally cause a nest to fail or to produce fewer young. Fortunately, there are precautions that you as a citizen scientist can take to limit the amount of stress you cause the birds that you are monitoring.

Disturbance is defined as any activity that changes an eagle’s behavior. For example, if an eagle stops preening to study you then you have disturbed the eagle. Disturbances fall on a spectrum from minor (such as in the example above) to major (flushing from the nest). The impact of disturbance on nest success can also vary from minor to major, up to causing a nest to fail, and frequent disturbance can cause a cumulative effect, meaning that frequent minor disruptions can be as problematic as infrequent major disturbances. Most of the time an eagle’s behavior will tell you that he/she is uncomfortable long before the point of flushing, and learning these behavioral cues will help you know when your behavior is causing stress to the birds. The first sign of agitation to watch for is a simple change in eagle behavior, such as the example above. If a bird does not stop what he is doing as you approach, he is probably not bothered by you. If he does stop what he is doing but resumes his activity after giving you a once over, you are also probably not bothering him and so are safe to continue observing. If, however, the bird does not resume his task or becomes more agitated you should back away until the eagle becomes comfortable again. An eagle that is alarmed by your presence will progress from simply watching you to sitting up in an alert posture and may begin vocalizing. As the bird’s agitation increases it might start shifting in the nest/on its perch, raising its wings, leaning forward and preparing to fly and otherwise looking anxious until it finally flushes from the nest.

Just like people, eagles have different comfort levels when it comes to disruption. Some birds seem unfazed by hikers walking within 100 feet of a nest while others are bothered to the point of flushing by any human activity within 1000 meters. Anecdotal observation seems to indicate that the eagles that choose to nest in close proximity to humans or areas with lots of human use are generally more tolerant of human activity while those birds that choose remote territories are more sensitive to disturbance. Nest stage also seems to affect how eagles respond to human activity. For example, eagles seem to have their lowest threshold for disturbance during courtship, pair formation and nest building. If we make the birds acutely uncomfortable during that critical period they are much more likely to give up on their site than they would be if disturbed when the eaglets are a few weeks old. Given these variations in behavior, there are some general guidelines for reducing disturbance that you can adjust based on the habits of each nesting pair.

The United States Fish and Wildlife Service (USFWS) recommended that active nest sites not be approached beyond a distance of 330 feet. In addition, you should do your best to have some sort of

screen or blind between you and the nest, as research shows that eagles are more likely to be bothered by an activity when it happens in full view. Of course, you as an observer need a clear view of the nest to gather accurate data about what the eagles are doing, so you’ll need to work out a balance between seeing the nest and staying out of sight. Sometimes a road will offer an ideal vantage point for viewing a nest. In general, if a pair knew about a human activity prior to moving in and still chose the site, they will be tolerant of that activity, and that certainly applies to road traffic. In addition, birds in general seem to be less bothered by people in a car than people outside of one, and so cars make excellent bird blinds. If there is a place along a road that provides both a safe place for you to park and a view of the nest, you probably have found a great observation point. If you prefer to use a spotting scope over binoculars to watch the nest, window mounts are a fairly inexpensive and practical way to use your scope from inside your car. In some situations you might be able to climb out of your car and stand with the car between you and the nest, which still creates a sight buffer between you and the birds while giving you more range of motion and perhaps an easier view of the nest. As before, however, be sure that you park in such a way as to provide no danger to yourself or any other motorists. If the nest is not visible from the road or is remote enough that no roads take you within viewing distance of the nest, you might want to consider scouting out a good place to view the nest prior to the nesting season, keeping the USFWS buffer distance of 330 feet in mind and taking into account how the landscape changes when the trees have leaves. Again, take your cues from the eagles and adjust your viewing spot accordingly.

With prior planning, an understanding of eagle behavior and attention to those behavioral cues, you can have a successful and enjoyable nest monitoring experience. Things to keep in mind are:

Sensitivity to disturbance varies amongst individuals and across regions. Learn about the eagles in your region and adjust these guidelines accordingly.
As a rule nesting eagles will be more sensitive to disturbance early in the nesting process; during nest building and incubation; be especially careful to avoid disturbance during this time.

Eagles seem to be most alarmed by disturbances they can see; provide a visual buffer between you and the birds. Cars make excellent blinds.
Respect a distance buffer using 330 feet as a rough starting point. If the eagles in your region prefer a much larger physical distance from humans, learn what constitutes a comfortable distance for those birds. In all cases, use the birds’ behavior as your guide and adjust your distance accordingly.

Recognize the signs of agitation in Bald Eagles Enjoy yourself!