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

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Saturday, November 21, 2015

Windstorm Refugee

On Tuesday afternoon, the wind blew the top out of this living cottonwood tree on Foster Island, right beside the 520 freeway. Wood that is exposed to oxygen and moisture turns dark over time, unlike the light-colored wood which was freshly exposed by the storm. 

On the ground, the matching piece of the tree also displayed dark interior wood. My immediate thought was some poor creature just lost a beautiful home. The access hole and the remnants of moss reinforced my assumption that this hollow was quite likely a place of refuge. Unfortunately, I could not find any clear evidence to show what kind of creature might have been using the site. I left feeling a bit sad because homes like this are especially precious in the city. Usually they are found in dead trees, which are often removed during the construction of our highways, homes and parks.

Nature requires a wide variety of life to enable a functional ecosystem. Here is a partial example. On Union Bay the beavers eat the living bark from the base of the cottonwood trees which stops the flow of nutrients and kills the trees. Over time the trees fall and provide branches for the beaver's lodge, but in the meantime, the wood in the standing dead trees softens up and attracts ants. The ants eat the wood and create galleries in which they lay their eggs. The ants, their eggs and their larva attracts woodpeckers, who excavate holes and eat the ants. Occasionally, the holes are perfectly shaped to become nests for wood ducks, mergansers, barred owls, squirrels and dozens of other wild creatures. Fortunately, the Washington Park arborists understand this cycle and leave standing dead trees throughout the Arboretum. 

Wednesday afternoon I heard the sound of a pileated woodpecker near Foster Island. When I located her, my first thought was, "A female eating ants in a dead cottonwood tree."

As I looked closer, I saw she was actively removing wood from the tree, similar to when Elvis builds a nest. In my experience, Elvis and Priscilla feed in the Arboretum but do not roost or nest there, so this was a bit of a surprise.

A moment later, I remembered seeing flickers nesting in precisely the same place in the same tree back in April. It was at this point I realized this pileated woodpecker found an existing nest site, which was a bit small for her, and she was enlarging it. 

This made me suspect that she had just lost her previous roost since she was actively expanding a new site. I wondered if she might have been previously residing in the cottonwood by 520. Her behavior and the fact that she was alone made me conclude that she was not Elvis's mate, Priscilla. One way or another, she certainly seemed like a new refugee seeking shelter. 

I am thinking Storm seems like an appropriate name for this new female. As darkness fell, she disappeared into her new home.

Thursday morning she remained in the roost for an hour or so, sticking her head out from time to time, before finally resuming her excavations.

Mid-morning she left to find food.

Mid-day the renovations continued before she left for dinner.

At the end of the day, Storm carefully approached the roosting site from below...

...before calling it a night once again.

On Friday morning the work continued...

...suddenly Storm heard the call of another pileated woodpecker. As if by instinct she replied.

Notice how in the last three photos her crest becomes erect. I believe this is a sign of apprehension...

...because she immediately high-tailed it back into her roost.

A male pileated, presumably Elvis, flew swiftly in to investigate.

His crest is also fully erect as he cautiously inspects Storm's new site from a nearby tree.

Deciding to look a bit closer, he lands below Storm's new home.

He walks slowly up the tree before peering into the roost. 

Immediately, he flew away to a nearby tree. He hung around inspecting the tree for less than five minutes before leaving, presumably, to continue his feeding. Elvis did not seem overly concerned about a new female in his territory. Once spring returns, and nesting season begins, Elvis may become more territorial. It will be interesting to see if he allows Storm to hang around. Foster Island does seem to be on the northeast periphery of his territory, but if she encourages a new male in the area, her refugee status could get revoked.

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


Silhouette Challenge:

Can you determine what type of bird this is? The answer will be in next week's post.

Last week's silhouette belonged to a stellar's jay. The outline of a crest, while having a beak shorter than a pileated woodpecker, virtually limits the local possibilities to a stellar's jay.

Saturday, November 14, 2015

In Black And White

When we say something is "black and white" we mean it is clearcut, simple and obvious. The black and white head of a black-capped chickadee helps to make it one of the most obvious birds in North America. The fact that they call out their own name, "Chickadee, dee, dee", whenever they sense danger, makes it even easier to recognize them. However, there is more to a chickadee than meets the eye.

If you walk through the Arboretum you are likely to spot a chickadee looking for food while hanging from a twig or a bud. Sometimes the weight of the bird is enough to pull the bud free of the tree.

This bird balanced both itself and its newly liberated cottonwood bud while it mined for food. 

I suspect the chickadee is eating a tiny larva, a small bug or a failed little seed. Since chickadees generally weigh less than half an ounce, you can imagine how tiny the minature morsel of food must be.

Cottonwood buds are permeated with a sticky, sap-like goo. In the book "Northwest Trees" by Arno and Hammerly, they say the buds are "...filled with a sticky reddish substance that has a sweet resinous smell, and looks and feels like a mixture of honey and strawberry jam."

Obviously a gooey, sticky bill does not appeal to our little friend. Lacking a napkin, the bird does the next best thing, it wipes its beak on the branch. This habit must have started fairly early in the bird's evolutionary tree as I have seen eagles, owls and even hummingbirds using the exact same technique.

The gooey residue can be seen on the branch just to the right of the bird. 

Not everything about a chickadee is obvious or easy to see. For instance, we usually think of chickadees as having black eyes. However, if you look closely you can see that their irises are actually brown and only their pupils are black. 

Another surprise for me was when I learned that a chickadee's song is very different than its call. Their songs sound like, "Fee, Be." The first note is about a fourth higher and two or three times longer than the second note. To hear the sound click on the phrase, All About Birds, then scroll down and select the audio link entitled, "Typical Song."

All About Birds also mentions that, "Flocks have many calls with specific meanings, and they may contain some of the characteristics of human language."

During the fall, chickadees cache food to help them make it through the winter. 
Surprisingly, they store each saved item in a different location. Apparently, the birds in colder climates need more food and therefore more storage locations. The Birds of North America explained all this and then went on to say that scientists have discovered that chickadees in Alaska have larger hippocampus regions that than their family members in more southern states. (Please see the citation below - Thank you, Martin) Apparently, the increased spatial capacity helps them remember where they have stored all their food. I wonder if this means that chickadees who reside on Mt. Rainer are smarter than the ones that live in Seattle.

This year I have watched chickadees finding seeds in hornbeams...

...and in spruce trees...

...but so far I have never noticed them caching their food. The birds have a vested interest in making sure that they are not seen while hiding their winter supplies. If I pay close attention maybe someday I will get to photograph the process. Nature is amazingly rich in behaviors, diversity and colors. Luckily, even with chickadees, not everything is in black and white.

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


Silhouette Challenge:

Can you determine what type of bird this is? The answer will be in next week's post.

This photo from last week shows an American Robin. As I looked closely at this silhouette, I realized that I was not sure I could see a difference between the outline of... 

...a robin and....

 ...the outline of a varied thrush. They are both local birds. They are both part of the thrush family, they are very similar in size, they both like small fruit and their beaks are very similar in shape. 

The only differences I could find, after looking at hundreds of photos, has to do with the top of the head. The top of a thrush's head is always perfectly smooth and rounded. In the photo of the robin you can see the slightest disruption in the line of the head and more of a peaked shape on the top. Granted these are very minute differences, so if you guessed either one of these two birds, give yourself full credit for a correct answer.

This time of year if you happen to see a flock of robins eating berries or small fruit. Stop and look closely. Every so often, I find that a few of the most shy "robins" turn out to be varied thrush.

Foote, Jennifer R., Daniel J. Mennill, Laurene M. Ratcliffe and Susan M. Smith. 2010. Black-capped Chickadee (Poecile atricapillus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/039

Sunday, November 8, 2015

An Owl in Autumn Gold

The leaves have turned to gold in the Arboretum. The young barred owl's youthful down is gone. With fresh, new feathers it is beginning to look a lot like its parents. 

In fact, if the young owl had taken a stately pose, stayed in the shade and just winked once or twice, I would have guessed it was one of the parents.

Instead, the owl leaped from tree to tree, chasing and being chased by jays.

It tried to hide in the large crotch of a big-leaf maple...

...but the stellar's jays were not so easily fooled.

The owl tried intimidation, which kept them at a distance, but it had no impact on their corvid attitudes.

 This photo was from a few days later, however the attitude was precisely the same.

When the owl quit playing, the jays moved on. 

While trying to determine if my daughter's dog, Ginger, was fit to eat...

 ...its exaggerated head movements reinforced my belief in its youth.

It soon moved to another tree and when it heard the sound of a squirrel it began to stretch, before moving silently closer.

It was the squirrel's lucky day. The young owl was unable to catch the speedy rodent.

Over the next few days, I have seen no sign of the owl, but I have noticed a squirrel in the area. The squirrel seems unable to open its left eye.

I suspect the young owl will be back, with the thought of one-eyed squirrel on the menu. It should be a fairly even contest. The inexperience of youth against a quick, but optically-challenged squirrel. 


After the post about crows fighting, two weeks ago, Carl Bergstrom sent in this surprising email.

Subject: Crow fights

Hi Larry,

Just last night I marveled at your photo series of the crow battle from your Union Bay Watch blog, thinking that despite watching crows for decades I'd never seen a protracted on the-ground fight like this.

Then today on the way to work, just a few blocks from Union Bay, I saw six crows tumble from a telephone wire down onto a side street. They dove down faster than usual, so I looked to see what they were up to. To my surprise, two were locked in a struggle much like the one you pictured. The other four were jumping around, cawing loudly, pulling at the combatants and I think as least one of them was pecking at the underdog. I pulled the car over, and got out to watch. Before I could get into iPhone photo range, though, a car came down the side street and the crows all flew back to the telephone wires. (I think the loser fled).

Anyway, I just wanted to let you know how much I enjoyed that blog post and what a kick it was to see something like that in person the very next day.

With my best regards,

Later, Carl mentioned asking Professor Marzluff what he thought about crows fighting. As luck would have it, Professor Marzluff presented at the Washington Ornithological Society meeting this week. His presentation was about his new book, Subirdia, which was very interesting. (I am thinking gift idea!)

Anyway, I had the chance to ask what he thought might have caused the fight. He said crows are very territorial, even though they roost together at night, during the day they will go to great lengths to defend their territories.

I believe he also mentioned that as younger birds mature there is more competition. My understanding is that this time of year might be the prime time for territorial fights. This is when the young birds leave the care and feeding of their parents and venture out to find their own place in the world.

I didn't think to ask about seeing hundreds of crows calmly feeding together around Husky Stadium during the days after big football games. I suspect they must call a territorial truce anytime they have an all-you-can-eat affair.

Have a great day on Union Bay...where nature fights, feeds and lives in the city!


Silhouette Challenge:

Can you determine what type of bird this is? The answer will be in next week's post.

This photo, from last week, shows a belted kingfisher. The keys that help with identification are:

a) The bill length relative to the body.
b) The hovering position in the air, with a downward fixation and
c) The tiny little feet.

Great Job! - To the reader who posted the answer earlier in the week.