By Jim Smith, PPL consulting naturalist
Posted on April 11, 2007

Greetings from Holtwood,

I’m posting a picture of an empty nest and issuing a very sad report.

The Holtwood Dam eagle nest — active for the last eight years — has failed this year. There are a number of scenarios that could explain this. I will list a couple after giving a little background.

The last report showed the female turning an egg. This female, however, was a young 4-year-old.

The old female may have died, and the male quickly mated with this one. This is the reverse of the first nesting in 1999 in which the female was mature and the male a sub-adult.

This younger female had a different “disposition” and an obvious lack of experience.  She began incubation at the end of February or early March.

In mid-March, observers saw a juvenile eagle land in the nest, which is not unusual.  Young eagles return for the first year or two to their nest site, but are usually chased off by one of the parents.

However, the incubating mom was not the juvenile’s mother. The nesting eagle was probably terrified. Dad came in much later and feathers flew as he drove the intruder out. So scenario No. 1 is that the nest failed because of traumatic activity.

Scenario No. 2 is the most likely. Observers noted that on April 3 — the expected hatching time for the first egg — the nest was empty for at least three hours.  Temperatures then were below freezing.

Subsequent dates had both eagles in and out of the nest, each evening one lying in the nest as if trying to continue incubation. The picture is since then, showing a well-built nest, but no sign of life.

The success of a nest depends almost 80 percent on the female eagle. A young male and mature female — such as the pairing in 1999 — is no problem. Pairing a young female with mature male — as happened this year — is precarious.

Eagle watches still will be conducted as scheduled, but now we will look for nest-building ospreys and travel the canal trails for migrant songbirds.

Jim Smith, Consulting Naturalist
PPL Holtwood Environmental Preserve
Holtwood, Lancaster County, Pa.