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

On Instagram: @unionbaywatch

Monday, November 30, 2020

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

Have a great day on Union Bay...where nature lives in the city and Black Birders are welcome!

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. I hope 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. 

(By the way, my friend Tom Brown pointed out that the application named 'Wildflower Search' is extremely helpful. Click on the highlighted link to see for yourself.

Also, Jane Lundin has created a small package, with a lot of critical information that looks quite handy, and light, for backpacking in the mountains in Springtime. It is titled, Mountain Wildflowers of Washington.)










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.





 








Scroll down for the answer.











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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?

















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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 workaround is to set up 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



Two final photos for the persistent:



Sunday, November 22, 2020

Hermit Habits

A Hermit Thrush belongs to the same family as an American Robin. In the fall and winter, similar to a robin, they can act a lot like a frugivore.

If you adjust for size and compare the silhouette of a Hermit Thrush and an American Robin I suspect they would look quite similar. They are both members of the Turdidae or Thrush family. However, there are dramatic differences in plumage, size, and song.

Sadly, this week, I did not get to hear the haunting song of a Hermit Thrush. (Clicking Here will enable you to hear a recording though.) Luckily, I did hear their soft "chuff" call, which is virtually identical to a call made by Varied Thrush.

A Hermit Thrush weighs less than half as much as a Robin. To my eye, it appears even smaller.

I remember seeing one a few years ago crushing a Sorbus berry it found on the ground. It took some time to reduce the fruit to a manageable size. American Robins (and Varied Thrush) have no problem with the size of a 'normal' Sorbus berry. 

This year, I was lucky to find a flock of Hermit Thrush, in the Arboretum, focused on an apparently unique, Asian Sorbus. This particular tree seems to have smaller than average berries, which allow the Hermit Thrush to swallow them whole. 

This is also the first time I remember noticing that the swallowed berry causes a temporary protrusion in the lower throat on its way south.

Sometimes, the Hermit Thrush will sit for a moment while the berry descends into its digestive tract.

At other times, similar to a Robin, after initially swallowing two or three berries it will abandon the fruit tree. They seldom go far. Generally, they sit somewhere nearby while waiting for the urge to consume more fruit. 

An American Robin will often choose an elevated perch in a tree. A Hermit Thrush, on the other hand, is more likely to pick a lower spot in a bush, beneath a small tree, or in the undergrowth. 

Even when sitting, a Hermit Thrush is seldom still. They will often raise their reddish tail and flick their wings. I wonder if this behavior scares insects into moving or silently signals their companions. 

To me, Hermit Thrush appear to be nervous birds. Their behavior looks like I feel when I drink too much coffee. Maybe, they are internally calm - but I doubt it.

Even though we have other spotted Thrush species that breed in Washington state this is the only one that winters here. Lucky, for us.

There are three other small, similar-looking, spotted Thrush species that breed in Western North America e.g. the Veery, the Swainson's Thrush, and the Gray-cheeked Thrush.  The latter is not normally found in Washington state.

Note: There are five other Thrush species in Washington state which are quite distinctively different e.g. without spots in their adult plumage.

Amazingly, Birds of the World (BOW) says that we have 12 subspecies of Hermit Thrush in North America.  However, BOW does not have a map laying out the ranges for all the subspecies. (It makes me wonder if mapping their ranges might be an interesting task for a budding ornithologist.) Locally, Birdweb says we may have four Hermit Thrush subspecies in Washington state. 

Personally, I find this incredible complexity of life keeps me humble while I work to expand my knowledge and understanding.

An interesting, bite-sized, piece of information is learning how to tell a first-year Hermit Thrush from one that is more mature. The tiny buff-colored line across the upper wing, e.g. the tiny pale coloring at the end of the upper coverts, indicates this is a Hermit Thrush who hatched out this year.

This week, as the fruit on the Sorbus tree, disappeared the corresponding number of Hermit Thrush seemed to also decline.

As mentioned above, I have generally assumed the flicking of a bird's wings was to frighten insects. (Inspiring a bug to move makes it easier for a bird to see them.) However, waving your wings above fruit does not make the berries any more obvious, although, I guess the downdraft might make them move.

Notice how the 'fish' hook on the back of the tongue helps to push the fruit down the throat. We might argue whether it is pushing or pulling. However, the tongue runs underneath the berry enabling the hook to apply pressure from the far side.

By the way, the reddish-brown tail, contrasting with the grayish-brown back, is unique to the Hermit Thrush species.

Curiously, a light vertical line on the underside of an upraised wing can be seen in seven out of the eight species of the Thrush family found in Washington State. Can you guess which species does not have a vertical line in the middle on an upraised wing?

Occasionally, a Hermit Thrush will almost hover in the air while harvesting a berry. I wonder if they can detect some variation in color that makes that particular piece of fruit look irresistible?

When they stop and look around before snatching the next piece, I wonder if they are watching for danger?


Maybe, they are just trying to understand that odd clicking noise - coming from my camera.

On the other hand, most of the time...

...I feel positive...

...they are totally focused on the fruit.

Have a great day on Union Bay...where nature lives in the city and Black Birders are welcome!

Larry

PS: The Washington Thrush without the white central line under the wing is an American Robin.

Recommended Citation

 Dellinger, R., P. B. Wood, P. W. Jones, and T. M. Donovan (2020). Hermit Thrush (Catharus guttatus), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.herthr.01

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. I hope 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. 

(By the way, my friend Tom Brown pointed out that the application named 'Wildflower Search' is extremely helpful. Click on the highlighted link to see for yourself.

Also, Jane Lundin has created a small package, with a lot of critical information that looks quite handy, and light, for backpacking in the mountains in Springtime. It is titled, Mountain Wildflowers of Washington.)










What species is this? Is it native to Union Bay? 





 








Scroll down for the answer.











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Mountain Bluebird: This beautiful thrush is native to Mt. Rainer, Mt. St. Helen's, and various locations east of the Cascades, but sadly not Union Bay. 

The eight species of Thrush that can normally be found in Washington State, at some point during each year, are the:
  • American Robin
  • Varied Thrush
  • Veery*
  • Hermit Thrush*
  • Swainson's Thrush*
  • Townsend's Solitaire
  • Mountain Bluebird
  • Western Bluebird
* These three have spotted breasts in adult plumage. 

Although, I have not seen them all myself, I understand that the juveniles of the other five species may also have spotted breasts.














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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 workaround is to set up 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






One more photo for the persistent:
This is a non-native, white-berried variation of Sorbus that can also be found in the Arboretum.