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!

Larry

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.