To our WVEC Eagle Cam Viewers
Several viewers have expressed concerns about the banding of the bald eagle chicks on Wednesday March 31 and we do hear you and appreciate your interest in these eagles. The three of us, Dr Bryan Watts, Libby Mojica and myself, who will be involved in the banding have combined over 80 years experience working with and banding raptors. Our lives have been dedicated to learning about and teaching others about their lives and how we can best live with them in our world. Please read the statement below from Dr Watts. I hope you will understand that the health and safety of these birds is always our first concern. – Reese Lukei, Jr
I wanted to write to assure everyone interested in the Norfolk Botanical Gardens bald eagle nest that the banding event on Wednesday will be safe for the birds and with the forecast of good weather should be a great event for observers.
Other than the obvious issues of disturbance, nest condition, etc., there are two major milestones that we evaluate when considering whether or not it is safe to band chicks. The first is whether or not the chicks are old enough to thermoregulate on their own. When eaglets hatch they are not able to maintain their own temperature without warmth from the adults. That is why the female is consistently present and broods closely during cool days and nights. Disturbance should be kept to a minimum during this period since flushing the female away from the nest may leave the chicks vulnerable to exposure. However, the chicks reach a physiological transition around 14-15 days of age when they are able to maintain their own temperature. This milestone is typically linked to a change in the female’s behavior and she begins to assist with hunting and does not brood except during rainy or very cool periods. The second milestone is whether or not the birds can “hold” a band. If the chick’s feet are small enough to allow the band to slip down over the foot this may lead to problems in development. The fleshy parts of the feet of most raptors grow to adult size well before most other body parts. This allows them to reach another important milestone which is self-feeding at a very young age compared to other activities such as flying. Because of their rapid growth, eaglets that are 15 to 16 days of age are easily able to hold bands.
Although we are able to safely band eaglets over a wide range of ages including near fledging, likely the ideal time window (if we are just banding) is between 18 and 28 days. At this age, the chicks have reached important safety milestones but are very complacent and pliable. Chicks of this age mostly eat and sleep and so often sleep through the banding event and wake up back in the nest. Banding at this age is safer for both the chicks and the banders.
Bryan D. Watts, Ph.D.
Mitchell A. Byrd Professor of Conservation Biology
Director, Center for Conservation Biology
College of William and Mary