Sunday, February 23, 2020

Silent and Subtle

Common Ravens are unique! They are the world's largest songbird. As such, they do not have the curved bill or long talons of an eagle or a hawk. Ravens rely on their intelligence more than their physique. Their most overlooked physical gift maybe their color. I heard a new phrase this week which seems to apply, 'Black conceals and white reveals.' When ravens settle into the shadows they seem to simply disappear. As songbirds, they can be bold and loud, but they can also be silent and subtle.

If you wander through their territory it is highly likely that they are watching you, even if you do not notice them at all. I do not think it was an accident that Edgar Allan Poe chose a raven to star in his most famous poem. Their intelligence feels obvious. They seem more similar to humans than any other avian species.

On the other hand, when they choose to be heard they can be very hard to miss. I first saw ravens in the Arboretum, almost one year ago. Ever since I have been wondering, Would they stay? Would they adapt to the constant presence of humans? Would they find adequate food? Would all our mechanical noises be too much for them? This week, for the first time, they may have finally made their intentions known.

Common Ravens exist all around the world and even though I do not comprehend their language, scientists think that the ravens may have different versions of their 'language' depending on where they live. In Birds of North America (BNA)*, I found the following comment regarding ravens, 'Recent evidence suggests that there are local dialects and individual-specific calls so that the total vocal repertoire may be virtually limitless.' That certainly sounds a lot like humans, except that ravens can vocalize sounds which we can only dream of making.

*Enggist-Dueblin, P. and U. Pfister. (1997). Communication in ravens (Corvus corax): call use in interactions between pair partners. Advances in Ethology 32:122.

When compared with American Crows, Common Ravens have longer wings which help them make use of wind currents and up-wellings. Crows have shorter, rounder wings and their nearly constant wingbeats give them away. You can read more about how they compare by Clicking Here. Another new phrase, which I just learned lately, is 'If it's rowing, it's crowing!' This seems like an excellent memory tool for distinguishing distant crows from ravens. Thank you, Bev.

For the last year, I have been waiting and hoping to see signs of nest building. This week, I was lucky to see at least two ravens moving through the upper branches of tall trees. As they worked they seemed to appear only momentarily before blending back into the shadows.

They seemed to prefer the tallest of the native trees and they worked on limbs which were quite high but with cover overhead.

On Monday, it became evident that the ravens were nest building. I was somewhat surprised to see them carrying green branches with foliage still attached. I wondered if the foliage might indicate that their nest is nearing completion.

However, they also carried branches without foliage.

They worked at two different sites. Surprisingly, I cannot find any mention of ravens building two nests at one time. BNA* says, '... Nonetheless, despite more than 1,400 research reports and articles on this bird in the scientific literature, there are many gaps in our expanding knowledge of this fascinating species.'

I also could not prove that I saw only one pair of ravens, maybe there were two pairs, but I doubt it. The 'nest' sites seem simply too close for comfort.

The next day, I saw one of the ravens chase a Red-tailed Hawk out of the Arboretum. Red-tails and Ravens are of a similar size but the hawk is endowed with the talons and tools of a predator. The second raven trailed behind the first one, apparently ready to provide air support if needed. The first raven's courage and indignation carried the day. The hawk's focus was on escaping.

Both the hawk and the secondary nest site were roughly the same distance from the primary site. Plus, each following day, as I visited the Arboretum, I heard a raven calling near the primary site, although, I seldom saw them. I am excited to say that, this year, I believe the Ravens will be raising young in and around the Arboretum.

In both cases, the trees were tall and the foliage thick. I have not actually seen either nest. I can only infer from what I have observed.

At present, I have no plans to publish their potential nest locations. I do not know how much attention might be too much for the Ravens. Plus, I would not want to deprive anyone of the joy and mystery I have experienced. Following their sounds and movements with reverence makes every new reveal an incredibly satisfying experience. I know and respect that they are making a choice to reside close to us. This common existence is a treasure to be protected and an incredible opportunity to enrich our urban lives. When I am in their territory, I too strive to be silent and subtle. So far, it has certainly been worth the effort!

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

Larry

*Recommended Citation

Boarman, W. I. and B. Heinrich (1999). Common Raven (Corvus corax), version 2.0. In The Birds of North America (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.476

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.

Until the leaves come out, I cannot be absolutely positive whether this is a native tree species. However, I believe there is only one primary native species that has been showing yellow male catkins, like these, during the last month. Which one is it?

Scroll down for the answer.

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Red Alder: Old, decomposing Red Alder trees have provided nest sites for our local Pileated Woodpeckers for the last eight years.

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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

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As a reward to those who have read this far, let me recommend this week's post by my friends Dan, Craig and Joy at:

https://pedersenwrites.blogspot.com/2020/02/390-get-ready-for-rufous.html

Sunday, February 9, 2020

An Eagle's IQ

Marsha and Monty are the newest pair of Bald Eagles that nest on Union Bay. Marsha, on the left, is slightly larger and her white head feathers never seem as clean as Monty's.

They often sit on top of the old world cedars just north of the Waterfront Activities Center (WAC). This location, on the southwestern shore of Union Bay, is obviously their favorite hunting roost. By clicking on this Union Bay Map you can get a more precise idea of the location.

(Roosting locations for all three pairs of Union Bay Bald Eagles are indicated by white diamonds. Clicking on the diamonds will bring up clarifying descriptions. By the way, a significant number of other updates have been added to the map.)

This is Monty struggling to break a branch off a cottonwood tree near their nest on Sunday.

Marsha, being larger, has less of an issue procuring a branch from a cottonwood tree on the north side of The Cut.

Currently, the Montlake Cut nest is not too impressive. Last years nest, as well as their original 2018 nest, fell apart as the eaglets grew. The resulting struggles of last year's young can be read about in these posts:

Cutter and Bay and

Cutter Thrives

Once again, the parents are rebuilding the nest on the southeast corner of the Montlake Cut. By the end of March, the nest should once again be at least large enough to hold Marsha and this year's eggs. Marsha and Monty get credit for their tenacity, but their engineering and construction skills are still a bit suspect.

By the way, do you know why their nesting location may be the best nest site in King County?

This October photo shows their nearest neighbors, Talia and Russ. This pair nests on the north side of Union Bay, in the old Talaris property. However, they commonly roost in the first cottonwood immediately north of the WAC. This roost is quite close to where Monty and Marsha prefer to sit. Both locations are shown on the Union Bay Map.

By mid-winter, the leafless tree looks pretty bare, but it is almost always the same pair in the same spot. Even the winter wind does not disturb their hunting focus.

A couple of years ago, I watched Russ pulled grass from an offshore island. He then carried it directly back towards their Talaris nest, which certainly helped to validate which pair I was watching.

The next week, when the sun broke through they landed on the nearby log. Both of them called out their greetings. Clearly, this little island and log are in the southern part of their territory.

Commonly, when an eagle from either pair heads directly out over the water, all four of these eagles take to the air. There is lots of circling, diving and calling as they enforce the invisible boundary between their territories.

Lately, I have occasionally seen Monty or Marsha wander over the line apparently looking for food, whenever Talia and Russ were not nearby. Often, the northern pair will notice the incursion and the two of them will come streaking across the bay to chase the invader away. As apex predators, eagles tend to take whatever they can easily get. I have never seen them actually fighting. Apparently, intimidation is less risky.

During the last few weeks, there have been as many as five Bald Eagles in the cottonwood tree on the north end of Foster Island. Most of them appear to be immature, like this one, which is most likely a second-year eagle. From the second through the fourth year immature eagles are generally as large as adults, but size does not translate to skill. Mature eagles must learn to be capable hunters in order to feed themselves and their hungry offspring.

This secondary hunting roost on Foster Island typically belongs to Eva and Albert. It is also shown on the Union Bay Map.

Eva and Albert are the local Bald Eagles that nest in Broadmoor on the south side of Union Bay. They generally defend Foster Island, the 520 light posts, Duck Bay and the Arboretum.

I suspect the five eagles are hungry transient eagles stopping by to hunt for food. Last Saturday, as we watched, one of the young flew out over the bay and dived at American Coots. Finally, it wore itself out and gave up. I have seen adults fly out over the bay, pick off some food and return with no visible delay.

The young are not all the same age. This one looks like it may have an eyestripe indicating it is most likely a third-year Bald Eagle.

Last Saturday, I believe I saw Eva and Albert circling overhead high above the transient eagles. I suspect the reason they did not attempt to drive them out of their territory is simply a matter of numbers.

This week's best example of an eagle exerting its influence, when the odds were in its favor, was sent in by Jeff Graham.

A male Common Merganser, on the left, approaching a female.

Jeff sent in the following photos and reported, "...A common merganser came up with a fairly large fish. Just then a gull aggressively flew at it and the merganser dropped the fish.

The gull plucked it out of the water. It flew over to the dock just off the boat rental building.

A mature eagle flew right at the gull and the gull dropped the fish on the dock.

The eagle came down and ate the fish. So interesting to watch....The eagle flew off to the nest tree across the Cut when it was done eating."

Thank you, Jeff!

The Bald Eagle in Jeff's photos was operating in Monty and Marsha's territory. It flew to their nesting tree and sure looks like Marsha to me.

By the way, Marsha and Monty's nest site is optimally placed because the complete Lake Washington watershed drains through Montlake Cut. This means all seagoing fish that enter or exit the watershed must pass below Monty and Marsha's nest. Looking down from a hundred feet in the air, with the sun behind you must make the migrates quite easy to see.

When it comes to nest building Monty and Marsha may not be engineering geniuses but in regards to site selection, they are certainly sitting on the upper side of the bell curve. Mature Bald Eagles often catch prey on the first pass, consistently extort fish from smaller birds and carefully choose when to defend their territories. It may be impossible to accurately estimate an eagle's IQ, but it is obvious they calculate optimal odds with ease.

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

Larry

Going Native:

1) Learn and leave established native flora undisturbed.

3) Scatter seeds from nearby native plants in a similar habitat.

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.

What species of duck is this? Is it native to our area?

Scroll down for the answer.

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Ruddy Duck: This is the more subtly-colored female of the species. The shape of the female is virtually the same as that of the male. Both, have a relatively large head and bill with a fairly long and stiff tail. They are native to Washington and most common in our area in the Winter.

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The Email Challenge:

My email address is: LDHubbell@Comcast.Net

One more photo as a reward for reading this far.

This is Marsha, in 2018, feeding a fishtail to one of her young in the nest.

Saturday, February 1, 2020

Leap Frog

The male Townsend's Warbler might be the least frog-like bird on the planet. The exquisite alternation of black and yellow is so eye-catching that the green on the back is hard to notice. From a physical perspective, this small patch of green may be the only thing about this bird that sort of resembles a frog.

The female (and immature birds of either gender) have additional green coloring in many places, often where the males have black. The throat is an exception. It is black in the mature males but in the others, it is mostly yellow. For more gender comparisons, and a link to the history of this unique winter-flowering Mahonia, visit the 2018 post entitled, 'Living Sunshine'.

Curiously, of all their body parts it is their wings that may have the closest connection to the concept of leapfrogging. While you ponder that, try not to imagine frogs with wings.

Here is an example of a mature male's black throat.

According to Birdweb, in the winter, Townsend's Warblers are uncommon around Puget Sound. However, among neighbors who live near the Arboretum, a number report seeing these warblers at their feeders. Also, whenever watching the hummingbirds in the winter-blooming Mahonia, it is not surprising to see one of the Townsend's Warbler wandering through the blossoms.

Hummingbirds hang in the air while feeding at the blossoms and then in a flash, they zip to the next flower or chase a competitor away. The warblers on the other hand land before quickly inspecting the blossoms for small creatures. Soon, they flutter and leap to the next flower. Using peripheral vision, a flash of motion suggests a hummingbird while a bouncing blossom or branch generally indicates a warbler.

The occasional kinglet hovers less than the hummers and bounces blossoms less than the warblers.

The warblers do not linger long. They either find food or not and in a moment they're gone.

The insects they find must be very small as I never see what they eat.

Since spotting the bird is a bit of a challenge, it is not surprising that photographing their food is even more difficult - maybe next year.

By the way, did the comment about frogs-with-wings make you think of bats? Just curious, whether anyone else made that connection. Frogs are amphibians and bats are mammals, still, maybe it's the bat's featherless wings that seem almost fitting for a frog.

Not only do the warblers eat small creatures, but sometimes they feed on honeydew. Honeydew is the sugary excretion provided by scale insects that consume sap from plants. Apparently, the sap contains more sugar than the insects need. So they pass the excess while searching for other required nutrients. (It would sure be handy if human bodies had this ability.) All About Birds. says Townsend's Warblers primarily find honeydew-producing insects on oak trees.

In the book, Where Song Began, the author, Tim Low, mentions that honeydew, and similar substances, are produced in such volumes in Australia that birds large and small become quite aggressive about it.

It turns out the leapfrogging connection to wings is related to migration.

Birds of North America (citation below) mentions that there are at least two different migration patterns among Townsend's Warblers. Curiously, virtually all of these warblers migrate and breed in the western part of North America. In the U.S. these birds are most generally found between the Pacific Coast and the crest of the Rocky Mountains. During warm weather, they reproduce as far north as British Columbia and even south, central Alaska. During cold weather, they winter as far south as Costa Rica and throughout much of Mexico. This highlighted link will take you to the All About Birds Range Map. It is a bit more precise than my verbal description.

Oddly, some scientists suspect that the birds which breed near the Canadian coast winter in Oregon and California, while the birds which breed even further north winter in Mexico and Costa Rica. One way to physically distinguishing these two groups of birds is the length of their wings. The birds which fly the farthest have longer wings.

There is still much to learn about Townsend's Warblers. There may be additional migration patterns that still need to be studied and understood. In any case, I find it fascinating that long wings are a waste of resources for the less adventurous birds, At the same time, they are a plus for those birds involved in the lengthy migration, which leapfrogs past the shorter-winged warblers of the same species.

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

Larry

Recommended Citation

Wright, A. L., G. D. Hayward, S. M. Matsuoka, and P. H. Hayward (1998). Townsend's Warbler (Setophaga townsendi), version 2.0. In The Birds of North America (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.333

Going Native:

1) Learn and leave established native flora undisturbed.

3) Scatter seeds from nearby native plants in a similar habitat.

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.

What species of frog is this? Is it native to our area?

Scroll down for the answer.

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American Bullfrog: They are native to the eastern portion of North America. They are invasive in Union Bay and will eat smaller native frogs and other aquatic creatures. On the plus side, they provide a larger meal for the native herons. The ridge behind the eye, curving down around the 'ear-like' structure is a key for identification.

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The Email Challenge:

My email address is: LDHubbell@Comcast.Net

One more photo as a reward for reading this far.

This is a native Pacific Tree Frog. They are about one inch long. It was photographed on Foster Island. (I am guessing that the depth of the Bullfrog's mouth opening, from front to back, is also about one inch.)