News & Press Releases from The Delaware Valley Eagle Alliance

Historic 4-Chick Bald Eagle Nest


©2009 John and Yoke DiGiorgio
The Delaware Valley Eagle Alliance announces the successful fledging of four bald eagle chicks from a nest along the Delaware River in Northampton County, PA.

Directors, John and Yoke DiGiorgio began recording their observations and documenting, through photography and documentary film, starting the first week in April 2009. The first chick was observed that first week in April. The fourth chick was observed and documented on April 27, 2009. PA Game Commission was notified and provided with documentary film confirming the historic event.

Clutch size in bald eagles generally varies between 1 and 3, with 2 being the most common. Reports in the literature of 4- egg clutches are very rare, with some suggesting that they result from two females laying eggs in the same nest. In 1986 on the Chesapeake Bay, a 4-egg clutch was successful with no sign of an extra female. An account was never published.

The DiGiorgios have completed capturing fourteen weeks of footage documenting this historic event, from the time that the 4 chicks were first observed through several weeks after they fledged (first flight).

John DiGiorgio stated that, based on when we first observed the appearance of each of the chicks, we estimated that there was a one and a half to two week age difference between the oldest chick and the youngest chick. Chick #1 was visibly larger and more developed than the younger three and chick #4 was visibly smaller and less developed than the older three. This remained the case up until they fledged.

Feeding this 4-chick brood was a time consuming activity and involved both adults. DiGiorgio recalls filming on a particular evening in May where, over a two and a half hour time span, the adults brought in a total of five fish and fed the chicks continuously. The chicks formed a semi circle around the adult and were each fed a small portion of the fish at a time. The adult would then move to the next chick, and the next, and the next and return to the first to start again. The adults did not appear to favor one chick over another. All were fed, even the youngest. Very little aggressive behavior between the chicks was observed prior to fledging, even during feeding. Fledging occurred during the 3rd week in June with chick #1 fledgling first, chicks #2 and #3 fledgling two days later and finally chick #4 three days after that.

A documentary film is being developed, with the plan to premier it during EagleFest 2010 (scheduled for Saturday, January 16, 2010 in Narrowsburg, New York), an annual event that the DiGiorgios founded and organize. The DiGiorgios are also collaborating with Dr Bryan Watts, Director, Center for Conservation Biology to co-author a research paper that documents this rare event. The paper will present an account of this nesting event in the context of current thought regarding limitations on clutch and brood size in bald eagles. Dr. Watts has monitored more than 6,000 nesting attempts by bald eagles and has never recorded a 4- chick brood. He states that "it is truly incredible for such an exceedingly rare event to be so well documented".

Press Release (PDF)