Here is a recent post from the Union Bay Watch Blog published by Larry Hubbell, long-time local photographer and birder.
Masters of Multitasking
Monty, the male Bald Eagle from Montlake Cut, is already searching for nesting material.
In Western Washington, Bald Eagles and Black Cottonwoods go together. It is not just because dark brown feathers look like an extension of the "Black" bark or because bright yellow bills blend-in among yellow leaves.
Cottonwood branches, especially the leaders, are easy to break, particularly when compared to similar-sized branches from most other Northwest trees. Picking them off from the tops of the trees provides convenient nesting materials, without the danger and effort required to elevate broken branches from the ground.
Maybe even more importantly, Cottonwoods prefer to grow with their "feet" in the water. Bald Eagles prefer to hunt for aquatic creatures like ducks and fish from elevated perches with a water view. With their incredible visual acuity, they can look out over the water and see hunting opportunities from miles away. Bald Eagles value real estate much like humans. They clearly share our three standard real estate attributes, "Location, Location, Location".
Also, sitting near the top of a tree allows the Eagles to monitor their territory, i.e. watching for intruders, and enables them to defend their territory at a moment's notice. Their first attempts at defense usually involve loud warning calls. Their secondary tactic is to give chase. This normally means flying directly at the intruder, followed by circling up, to gain a height advantage. If that does not do the job they will often begin diving at the offender. They seem to avoid actual physical contact if at all possible.
Monty and Marsha, as seen last week, in the Black Cottonwood north of the Waterfront Activities Center. This is a new and surprising development.
Another important reason Bald Eagles have a special relationship with mature Cottonwood trees are the forks. Black Cottonwoods generally have a major set of forks, in the trunk, near the bottom of the upper quartile. These relatively high sets of branches provide excellent nest sites.
By comparison, Douglas Fir, Western Red Cedar, Western Hemlock, Sitka Spruce, and other native conifers tend to have their smallest branches in the upper half of the tree. Even, Bigleaf Maples and Pacific Madrones, which tend to have bigger forks than the conifers, generally have their major forks at a much lower level than Black Cottonwoods.
By the way, Bald Eagle nests can easily weigh hundreds of pounds. Birdweb says they can even weigh as much as two thousand pounds!
In the Spring and Summer, the branches and leaves above the nests provide some cover from airborne predators and shade from the sun. The timing works perfectly for eggs and eaglets in the nest.
Based on the behavioral changes, that I have observed, I suspect our local female Bald Eagles often lay their eggs during the first week of Spring. Birdweb suggests up to a month earlier is common in Washington state.
We are about four months away from Spring and yet Monty is already bringing branches and refurbishing last year's nest.
***** A Special Thank You *****
to
Jerry Pinkepank
On November the 18th, Jerry sent in the following photo and text. As best I can tell, Jerry (and Aaron) were the first folks in Montlake to notice Monty and Marsha's nesting preparations for the Spring of 2021.
"Aaron and I have been watching for activity at Monty and Marsha’s nest and this afternoon we lucked onto them engaged in the nest repair and rebuilding that you told us to expect." --Jerry
(Jerry particularly liked the way Marsha held her head in his photo.)
Since then, Monty has continued to occasionally bring additional branches.
Often, smaller birds will spend just a week or two, in the Spring, highly focused on nest building. Our local Bald Eagles seem to weave their nest building in among their normal hunting and territorial activities. Nest preparation is part of a nearly year-round process that proceeds to egg-laying, incubation, feeding, protecting, and finally training the young to find food. In the Fall, soon after the young strike out on their own, the adults begin the process again.
Of course, smaller birds usually complete their nests much more quickly - while hoping no one noticed their efforts. Most birds want their nests to be well-hidden from predators. Eagles on the other hand are avian apex predators. Their approach to nesting is vastly different.
Bald Eagles tend to centralize their nests in their territory and make little effort to hide the location. Often, they sit proudly in nearby treetops, while their dark-versus-light coloring seems to advertise their presence to potential intruders. Plus, since they tend to use the same nest site year after year, they are clearly not trying to hide the location.
While appearing to simply sit in a treetop, advertising their presence, might be considered a third type of task that a Bald Eagle can accomplish - in addition to looking for food and watching out for intruders. A fourth could be digesting previously swallowed food. Eagles, like many other birds, swallow their food quickly so they can move to a safer location before completing their digestion. Even when Bald Eagles appear to be doing nothing, they may actually have a lot going on. I consider them, Masters of Multitasking.
Curiously, unlike our local Bald Eagles, many are migratory. The All About Birds range map implies that Bald Eagles who nest in the interior of Alaska and Canada apparently migrate to warmer locations during the Fall and Winter. I assume this must accelerate their Late Winter or Early Spring nest-building activities. It would be interesting to know if the increased effort, related to migration, lowers their reproductive success as compared with Eagles who are not migratory.
Earlier this week, Marsha moved out of the nest so Monty could add a new branch. In past years, I have seen her occasionally bring a branch to the nest, but it seems to me that most of the shopping and lumber lugging falls to Monty.
Speaking of falling, during the Summers of 2018 and 2019 their first two nesting attempts were at best a partial success. Those nests came apart before the young could learn to fly. With some help from PAWS, URC and others their young survived and ultimately fledged. In the Spring and Summer of 2020, for the first time, their nest remained intact until the young one fledged.
Monty's increasing experience may have been a factor in the survival of the 2020 nest. Raising just one offspring, Tsuloss, instead of two, may have also helped by reducing the activity and stress on the nest.
This week, Monty was once again searching a nearby Cottonwood for candidate branches.
How he selects the right one is a mystery.
It must be small enough to break, while also being as large as possible to maximize the contribution to the nest.
In the past, I have occasionally seen Monty hanging upside-down and flapping his wings when he apparently misjudged his, or the branch's, size and strength. I am hoping it is a learning process and his judgment is improving.
Nonetheless, from time to time, he can bring in some impressive pieces of lumber.
This Fall, for the first time, Monty and Marsha are evidently expanding their territory.
During the last three years, the northern limit to their territory was clearly aligned with the dark green, Old-World Cedar trees above the sailboats on the right side of this photo. The boundary ran east-to-west bisecting Union Bay.
Here is a slightly closer look.
With great regularity one, or both, of the pair could often be seen sitting on top of the Cedars.
This photo, from last February, shows Monty or Marsha flying towards the Cedars while their northern neighbors, Russ and Talia, sit in the Cottonwood. Since Monty and Marsha's arrival in the Fall of 2017, this Cottonwood tree has consistently appeared to be the southern limit of Russ and Talia's territory.
My assumptions about these Eagles are based on where they go when they leave the trees. Monty and Marsha consistently head south to other perches in their territory while Russ and Talia consistently head north - usually towards their nest site northeast of Yesler Swamp.
By the way, if the Cottonwood tree looks a little less dense in current photos, it is because a major south-facing branch broke off this year. It is not uncommon for Cottonwood branches to break as Cottonwoods are fast-growing and not the strongest of trees.
This Fall, for the first time, Monty and Marsha have been flying into and sitting in the Cottonwood to the north of the Old-World Cedars.
They have also been seen defending their new more northern territorial boundary.
Birdweb says Bald Eagles can live as long as forty years. If Monty and Marsha were five years old when they began nesting on Union Bay that would make them at least eight years old now. I suspect they are still gaining in strength and confidence. Russ and Talia, the more established pair with the northern territory, maybe growing older and potentially might be starting to decline.
Just like with human societies, apparently, Bald Eagles experience ebbs and flows of power. This Winter, it will certainly be interesting to watch where the two pairs choose to sit on Union Bay and how often all four take to the air to renegotiate their shared territorial boundary
What species do these two tallest conifers belong to? (The ones directly behind the old shell house.) Are they native to Union Bay?
Here is a slightly closer photo. Although, I am thinking, the nearly perfect symmetry in the previous photo might be a better hint.
By the way, Monty, and in this case, Marsha, have taken to occasionally sitting on this upper eastern branch. It provides them a highly elevated view of their Union Bay hunting territory while also enabling them to monitor their nest site.
These cones should be the best hint of all.
Answer:
Neither of these trees are native to Union Bay. They are primarily native to Northern California.
Given their size, I wonder when they were planted?
Two final photos:
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