Status of "Arlington Eagles"

[phaw...@comcast.net]

What have the “Arlington eagles,” KZ and Fae (the unbanded Female Adult Eagle with whom he most recently mated), been doing following apparent nest failure weeks ago? Nothing “permanent” has been resolved, but from reports from multiple observers, it appears that KZ and Fae are “hanging together.” As with many bird species, eagles’ reproductive systems atrophy noticeably in late spring and summer and hormone production drops. They don't waste a lot of time and energy maintaining and carrying a full-fledged active reproductive system that will not be used for considerable time. Birds will not copulate "meaningfully "for months. However, demonstrations of commitment and increased bonding are very important. Recently  KZ has been seen breaking off large sticks and carrying them to the old nest on the lower lake shore under Fae’s watchful eye. This is not to suggest that they are actively restoring that nest, unused for several years and in considerable disrepair. It does show that they are spending time together and have an interest in working on home maintenance and territorial integrity. Visibly working together on an old nest is like taking an option they can exercise on a nest site if they so choose at a later time. Pairs of many nonmigratory breeding raptors, including Redtails, can obtain "options" on proto-nests as well as unused and previously occupied nests in their general territory by performing minor maintenance work on sites in their territory to visibly demonstrate that it is occupied. (It’s comparable to camp grounds that require campers to leave some indication of site use, such as a tent or cooking stove, on a campsite before they register for the site.) This is typical behavior for an established territorial pair. KZ and Fae's “claim” to the Mystic Lakes territory might be challenged by adults wintering in the area, especially from October to January, but their activity indicates they are thinking and acting as a pair now that they have lots of spare time on their hands. (They don't spend a lot of time visible anywhere, but move around a lot throughout the watershed.)

     Note: I am recovering from knee replacement surgery, so have not been out daily to see personally what KZ and Fae are doing. However, I have been receiving reports on their behavior from multiple reliable observers, so aml confident in what I have described above.)  

 

Best,

Paul

 

Paul M. Roberts
Medford, MA 
phaw...@comcast.net

[dkbe...@gmail.com]

That's much like what we've seen from the Big Bear Lake eagles ("big bear eagle" on Youtube) who tried and failed to incubate two eggs during the fierce California storms this spring. Many mornings found the incubator completely covered with snow. After the failure of the nest, they have continued to come around to the nest [with the camera] and copulated and fussed with the nest. They even started construction on another one. Who knows what they will do next year, but the male has been especially industrious and they continue to roost together and hang out. Very sociable birds.

David Bean