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Saturday, November 28, 2015

Storm Watch

This morning, just before dawn, the sunlit moon looked somewhat egg-shaped in the western sky. I was waiting near Storm's new roost to see how she handled the sub-freezing temperatures. 

In case you did not read the previous post, this photo from last week shows Storm just outside her new roost in a cottonwood snag located near Foster island and Duck Bay.

For the first time this fall, on Thanksgiving morning ice extended across Duck Bay all the way to Nest Egg Island. 

Each morning since, has felt slightly colder.

This morning, as the sun turned the eastern sky pink, Storm peaked out of her roost. A bewick's wren moved silently around the tree below her. A spotted towhee "mewed" softly in the underbrush. A crow coming from the northwest landed in the top of Storm's tree. The crow was carrying human food, not doubt an Apple Cup leftover. 

Storm took turns glancing out at the frozen world and then shrinking back into the protective warmth of her roost. The feathers under her chin appeared to have a white frosting.

Over the period of thirty minutes, Storm slowly progressed, sticking her head out slightly farther with each external observation. 

During this time the sun gradually warmed the air and moisture formed into fog around Nest Egg Island. Nearly invisible, "the ghost" of a white gull drifted overhead. 

Storm silently sampled the air with her tongue before deciding on indoor work. The falling wood chips provided evidence of her efforts. Surprisingly, it turned out that I was not the only one watching out for Storm this week.

On Tuesday, not too long before sunset, I heard a mature male pileated calling softly. He flew directly in and landed in a tree top high above Storm's roost. Given our limited daylight it was actually just after 3 p.m. in the afternoon.

For ten minutes or so he looked in every possible direction.

While looking north, he suddenly began calling out in a very loud voice.

Faster than my eye could follow, Storm flew in from the north. She barely landed in a nearby tree before quickly moving to her roost.

Silently, she disappeared inside.

She glanced out a few times while the male kept watch above her.

Soon, the male moved to some distant cottonwoods. He appeared to feed for a few minutes before flying off in the direction of the Don Graham Visitor's Center. Whether he stopped or kept moving towards Interlake Park I could not see. 

In the past, I would normally assume a mature male pileated in this area was Elvis. For a year or two he even had a mark on his neck that allowed me to be positive of the identification. Elvis and his mate have raised young in Interlake Park for at least four years, and often feed together on Foster Island, in the Arboretum or even on top of light poles around Montlake.

All About Birds says, "A Pileated Woodpecker pair stays together on its territory all year round. It will defend the territory in all seasons, but will tolerate new arrivals during the winter." This male's behavior seems more than tolerant, it actually seems protective.

Elvis and Priscilla raised three young this spring. They hatched out two females and a male. One female was apparently hit by a vehicle on 23rd near Interlaken, and did not survive. 

The questions in my mind just keep on coming. Could this be the other young female? Is this male actually Elvis and is he still watching out for one of his progeny? Is this a second unrelated mature female encroaching on Elvis and Priscilla's territory? Has something happened to Priscilla? Is Elvis courting a new bride? Is this male not Elvis at all?, but a new male in the area? If this is a new male, has Elvis been replaced or is this new competition? Will there be a territorial dispute come spring? Who would have guessed there could so much mystery surrounding a Storm Watch.

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.

Last week's silhouette belonged to a cooper's hawk. I can be positive because he was a banded bird that I have seen more than once. However, given the similarity between cooper's hawks and sharp-shinned hawks, either answer deserves full credit. The predatory beak and the long tail should be indicative in this area.

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