Mission: To promote the appreciation of wildlife and increase harmony between humanity and nature.

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Sunday, October 21, 2018

The Eagles Return

Monty and Marsha are back! Our local Bald eagles, who we watched build, populate and then lose their nest, have returned to Montlake. Once the nest was out of the tree and their young were out of the nest the adults apparently felt free to leave. I suspect they went searching for an alternative, end-of-summer food source. Hopefully, they located a crystal clear stream teeming with salmon. In any case, they look healthy and ready to embark on a whole new annual cycle of reproduction.

In previous posts, you may have read about their nest being built, the nest falling and finally about our attempts to return the healthier of the two young eagles to the nest site. If not you can read the stories by clicking on these links.


After the nest fell and the eagles disappeared, questions flooded my mind. Will we ever see their young again? Will the adults Monty and Marsha return to their newly established territory? If so, will they rebuild their nest? If they rebuild, will they build at the same site or choose an alternative?


As of this week, at least we know they have resumed occupation and control of their territory. Specifically, I watched them and the Talaris pair go airborne and defend their common border. It was like watching a flashback to the last winter and spring. 

I am often asked how I identify individual eagles. I must admit it is virtually impossible to be one hundred percent positive about any particular bird, without an identification band. However, there are hints and clues which help. For example, the three pairs of breeding eagles on Union Bay have specific territories which they defend. Primarily, the establishment and maintenance of their territories appear to be done by occupying favorite roosting spots, especially when a competing pair of eagles is nearby.

The photo above, from earlier this week, shows Monty and Marsha at their favorite perch on top of the Deodar Cedars immediately north of the University of Washington (UW) Waterfront Activities Center (WAC). 

Normally, when Monty and Marsha are in the cedars their northern neighbors come south and occupy the first Cottonwood tree immediately north of the cedars. This older pair of eagles, nest in a cottonwood tree on the old Talaris property just to the northeast of the Center For Urban Horticulture. I identify this pair by watching them travel back and forth between their nest site and this popular location where they defend their southern border.

In a related example, last January I watched them venture down to the shore, just north of the cottonwood, and pull up grass which they carried back to their nest site. 

Individually, within each pair of Bald Eagles, the males are generally the smaller bird. Looking at this photo and back at the photo of the Talaris pair in the cottonwood tree it is obvious that the smaller male is on the left in each photo.

In this photo of Monty and Marsha, it is less obvious which is the larger bird. However, there is another useful clue. The area around their eyes is slightly different. Let's take a closer look.

The bird on the left has a noticeably heavier 'eyebrow', which casts a sizable shadow.

The eagle on the right has almost no eyebrow and by comparison far fewer shadows around the eye. From experience, I know that Monty has fewer shadows and that Marsha has the more intimidating look. On a cautionary note, the angle of the bird's head relative to both the sun and the observer can change the perception of shadows. The nice thing about this particular photo is that both birds were looking in almost precisely the same direction at the same time.


Similarly, if we look back at this photo from December, early in their nest building process, their eyeshadows and size are still obvious and consistent. Once again Monty is on the left.

In this December photo, from a couple of days earlier, the minimal eyebrow seems obvious but distant. At this time another critical identifier for Monty was the feather gap in his right wing. He was in the process of regrowing one of his secondary flight feathers. This week one of the first things I attempted to do was to check whether the same secondary feather was still partially missing.

In this photo from Wednesday, we can see that one of his secondary feathers is not quite grown in. However, I believe it is the first secondary instead of the third. Apparently, the feather which was missing in December has been fully replaced and another one is getting close to full length. 

If I understand the numbering of eagle flight feathers the primaries are counted by starting with the most forward feather - what would be equivalent to our pointing finger. This is the first primary. The count then proceeds in increments of one as we circle around the end of the wing and back towards the body. The tenth feather is the final primary for Bald Eagles. After this point, the next eight feathers are the secondary flight feathers. 

Here is another shot of Monty coming in to land in the cedars next to Marsha on Thursday. Even though a branch obscures a portion of his wing it is possible to count around and determine that it is his first secondary feather which is not as long as the others.

About ten minutes earlier this extremely bold Great Blue Heron made my mouth drop with amazement. It landed on Monty and Marsha's favorite perch.

Moments before Monty had been on the same branch. I had to wonder was the Great Blue Heron unaware that eagles eat herons?

In late July an eagle-eyed neighbor spotted the carcass of a Great Blue Heron nestling hanging below Monty and Marsha's nest.

A few days later I noticed the leg of an adult-sized Great Blue Heron laying below the nest site. Clearly, Monty and Marsha will eat a lot more than fish. I have seen full-sized Mallard wings below the nest and I watched one of the adults bring a rat to feed their young.

As I watched the heron, I felt the shadow of an eagle pass over my head. The large predatory bird made a beeline for the cedars.

Luckily, the heron was paying attention and immediately abandoned its position.

When the eagle turned I was able to catch a quick photo. The dark tips of the tail feathers provided another surprise. This bird was not Monty or Marsha or any one of the other four resident Bald Eagles on Union Bay. The tail feathers on all the local resident eagles are completely white. I also noticed that this eagle's fifth primary on each wing was only halfway grown in. This bird is nearly mature and probably in its four or fifth year. 

The two references to 'the fifth' made me think of Beethoven's Fifth symphony - bop, bop, bop, boom. Which inspired the idea of calling this eagle, Beethoven. I doubt the established eagles will allow Beethoven to hang around long, but you might want to keep I eye out for the unique tail feathers and the partial grown missing primaries. This is a perfect example of how we can attempt to repeatedly identify a specific bird.

Clearly, my methods of identifying individual birds are not perfect. But the close observation of unique features while also paying attention to their habitual behaviors certainly increases our odds. My acronym for the process is UFAB. UFAB stands for Unique Features And Behaviors. 

On Thursday, as I watched, Monty and Marsha flew across the southwest portion of Union Bay and landed in one of their secondary perches - the tallest tree on Marsh Island. The distance and the angle of the light made my photograph useless, but this behavior was one I had seen many times before and it helped reinforce my belief that Monty and Marsha have returned to Union Bay.

By the way, Portage Bay is also inside Monty and Marsha's domain. I have watched them come and go between their nest site and Portage Bay multiple times.

I wonder, How soon will they begin building a new nest? Will they use the same tree they used last year? Will we see Beethoven again? The mysteries of eagles never end.

Can you guess which of one the four resident Bald Eagles, discussed in this post, is in this photo? The answer will be in the Going Native section below.

Have a great day on Union Bay...where nature lives in the city!

Larry

Going Native:

Without a well-funded Environmental Protection Agency, it falls to each of us to be ever more vigilant in protecting our local environments. Native plants and trees encourage the largest diversity of lifeforms because of their long intertwined history with our local environment and native creatures. I have been told that even the microbes in the soil are native to each local landscape. My hope is that we can inspire ourselves, our neighbors and local businesses to respect native flora and to support native wildlife at every opportunity. I have learned that our most logical approach to native trees and plants (in order of priority) should be to:

1) Learn and leave established native flora undisturbed.
2) Remove invasive species and then wait to see if native plants begin to grow without assistance. (If natives plants start on their own, then these plants or trees are likely the most appropriate flora for the habitat.)
3) Scatter seeds from nearby native plants in a similar habitat.
4) If you feel you must add a new plant then select a native plant while considering how the plant fits with the specific habitat and understanding the plant's logical place in the normal succession of native plants.

My intention in my weekly post is to include at least one photo each week and visually challenge us to know the difference between native and non-native lifeforms.




From what type of trees did these leaves fall? Are they native to Union Bay?








Scroll down for the answer.

















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i believe the three types of trees and leaves, from top to bottom, are a leaf from an oak tree which originated in the eastern part of North American, possibly the Northern Red Oak, a leaf from a Black Cottonwood and a leaf from a Bigleaf Maple. The last two are native to Union Bay.








The last eagle photo shows Monty. The critical determining factors are his lack of eye shadows and he is sitting on the Deodar Cedar branches which are one of his favorite perches.


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The Email Challenge:

Over the years I have had many readers tell me that Google is no longer sending them email announcements regarding my posts. Even more frustrating when they go to 're-sign-up', hoping that will enable them to once again start receiving the announcements, they get a message which says 'Sorry, you are already signed up.' Google has not responded to my requests for help with this issue. 

My functional work around is to setup my own email list and each week I manually send out a new post announcement. If you are experiencing the issue and would like to be added to my personal email list please send me an email requesting to be added. Thank you for your patience!


My email address is LDHubbell@comcast.net



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2 comments:

  1. I am always delighted reading and seeing your continuing saga of our eagles. Thank you!

    ReplyDelete
    Replies
    1. You are certainly welcome. Thank you for following along!

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