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Saturday, January 21, 2017

A Full Circle

The eyelid and the nictitating membrane both partially close just prior to the bill impacting the tree.

While rereading last week's post, I began to question whether the male pileated woodpecker was really the young male, Squall, or his father, Chip. I was also curious where the woodpecker was roosting, e.g. spending his night's. 

On Sunday afternoon, I returned to Foster Island in hopes of finding the woodpecker and possibly his roost. Luckily, he was there. The first photo (from last Sunday) made me confident I was looking at the same bird, especially when compared with the next photo which was from the preceding Friday. 

In both photos we can see a faint supercilium, the thin white line starting above and in front of the eye. It gets thicker behind the eye and then recedes toward the back of the head. Also, consistent in both photos is the dark little notch, which hangs down from the back portion of the black eyestripe, just below the far end of the supercilium. Clearly, we are looking at the same bird in both photos, but I was still uncertain whether it was Chip or Squall.

Hoping to see the bird return to its roost for the night I follow it around the north end of the island for a couple of hours. At 4:20 p.m., just before sunset, the bird flew to a nearby tree. The tree was taller than the one where he had been feeding. He purposefully climbed the tree and immediately took off from the top. Evidently climbing requires less energy than flying to the same height. He headed off in a straight line, flying south and slightly west and apparently leaving Foster Island. Last Winter, I observed a male pileated flying a similar trajectory. At the time I was further south, along the shore of Duck Bay and it was also just before sunset. In both cases the male birds appeared to be heading towards the nest site where Chip, and his mate Storm, would raise Squall and his two sisters in the Spring of 2016. 

Early on Monday, I returned to the north end of Foster Island and found the same bird again. During this visit he worked his way down and searched for food below these two conks. The location on the tree was low enough that I realized I could determine the bird's length, if I returned with a tape measure.

On Tuesday, I photographed the site and compared the results. I estimated the size of the bird at fourteen inches. I have read from multiple sources that male pileated woodpeckers can reach up to nineteen inches in length, however individual sizes can vary significantly. The small size seemed to reinforce the idea that this might be the younger of the two males. 

Sadly, at this time I did not spot any pileated woodpeckers in the area. I searched most of Foster Island and when the rain began in ernest, I packed up the camera and headed for home.

Just as I neared the walking bridge on the southwest side of Foster Island I heard a pileated call. Much to my surprise I found what was clearly the same male pileated woodpecker. He was hanging on the stump of the dead tree which held Storm's 2016 winter roost.

In November of 2015 Storm, who I ultimately learned was Chip's mate, excavated a northern flicker's nest. I had watched the flicker build the initial nest earlier in the year. Storm  made the abandoned nest large enough that she could spend her nights there. This roost worked fine until February 2016 when a windstorm broke the top off of the tree. The break happened right where Storm had weakened the tree by enlarging the hole. The tree top landed in the canal below. I call this area Cottonwood Downs since the surrounding cottonwoods, usually killed by local beavers, often fall and end up in the canal.

In November of 2015, long before his son Squall was hatched or conceived, Chip came and inspected Storm's winter roosting spot. Imagine my surprise when I pulled up this old photo. I immediately compared Chip's features with the male bird I have been watching for the last few days. The supercilium and the eyestripe notch were consistent. At this point it became obvious that the little fourteen inch bird must be Chip, not Squall.

All of the above photos of Chip have been from the left side. I included this photo from the right side (also from November 2015) to show that the distinctive features are similar on both sides.

Having started on this adventure of researching and comparing pileated features in old photos I decided to continue through 2016. This would help me to be sure that Squall's features are different from his father's.

In February 2016, Chip and Storm feed on a fallen cottonwood southeast of Foster Island.

This close up of Storm, from March of 2016, shows a faint supercilium, which starts and ends behind her eyes. It also displays the red color of one of her irises. Storm's 'black' forehead and malar stripe are common distinctive features for female pileated woodpeckers. In mature males both of these areas are bright red.

This photo shows Chip and Storm mating in early April of 2016. This took place to the west of Duck Bay. This photo shows that Storm is smaller than Chip, which is normal among pileated woodpeckers. Given that Chip is only fourteen inches long, I suspect Storm may be just twelve inches in length.

In early May, this photo shows Storm feeding one of her young in the nest. The young bird's grey malar stripe, which will ultimately turn black like Storm's, denotes that she is a female. 


Here Storm is regurgitating food for her young nestlings. I suspect the young birds are about a week and half old at this point and that the eggs were initially laid in mid-April.

Chip provides a later feeding on the same day. Here we see that there are three young birds. Their faint but obvious coloring shows them to be two females and a male. The male was so noisy and insistent that I decided to call him, Squall.

Five days later, around mid-May, the colors of the young birds have visibly darkened. Their young feathers are short but obvious. Even at this early point Squall's supercilium is shaped differently from Chip's. Squall has a small white arc which is positioned behind his eye.

This photo and the following were taken on May 31st, just after Squall fledged. For pileated woodpeckers learning to fly and leaving the nest seems to happen all at once. Once they escape the nesting tree they seem to have no problem with living outside the box. 


Although, I do remember laughing when I watched Squall trying to land on this paved surface. I suspect it was his first landing on a manmade surface which he could not grip with his claws. He landed on his belly and then struggled to get up on his feet.

Squall's supercilium is not precisely the same on both sides, but in both cases it stays behind the eye, unlike Chip's. The irises of the young bird are actually a grey-blue color but it can be hard to see them clearly in shaded photos. While studying Squall's unique features I began to wonder whether they might change as he matured.

This link to the post called, Family Time, shows more photos of the young birds and contains links to other related historical posts about Storm.

In early June, I found Squall working on a telephone pole in Montlake. At the same time, Chip was working on a second pole a block and a half to the south.

In these photos Squall's supercilium remains consistent and distinctive. Did you notice his tongue searching inside the telephone pole?

Later in the same day, Chip posed for photos from both the left and... 

...the right. The dark descending little bump on the lower back portion of his eyestripe is obvious in both photos. Also, at this point his bright yellow irises are still quite different from Chip's. These photos were taken near Elderberry Island just to the west of Duck Bay.

Towards the end of the month, on June 26th, Chip is still supplementing Squall's food supply. At this point, the young bird's 'red' coloring is still slightly orange and not as brilliant as his father's crest.

On July 8th, one of Squall's sisters still has dark eyes and her crown has also not yet reached its full flaming potential.

 On July 13th, one of the sisters displays her ability to help the forest recycle itself.


She is looking more and more like Storm.

However, when we see Storm with the sister in the background there is a noticeable difference in the color of their crests.

This August 9th photo of Squall is one of the last set of photos I have of him. His iris is starting to turn yellow, like Chip's, but if you zoom in close you can see that the outside of the iris is still dark in color. Also, you can see his supercilium is clearly behind his eye.

In November, I saw Chip, and Storm, high in the top of a dead snag. They were just to the northeast of the Wilcox Bridge in the Arboretum. 

Based on what I have just read in Birds of North America (see Citation below) it is logical to assume that the young birds had already moved on. The scientists say that starting in the Fall the young leave their parents and begin wandering. By Spring, they will be looking for their own territories and mates.

On Tuesday afternoon, I watched Chip leave the remains of Storm's old roost and fly east above the Cottonwood Down canal. He called repeatedly as he moved from tree to tree. 

Finally, from out of the rain, came an answering call and Storm flew in from the direction of the Beaver Lodge Sanctuary. After feeding nearby the two birds turned and headed west.


They returned to the old half-a-snag which was Storm's primary roost last winter. Storm was much more active and moved around from one tree to the next, feeding voraciously. Chip sat calmly, watching from the top of the broken snag. Due to the poor light and I was unable to see Storm's red eyes, but her other features and her behavior, along with what I read on Bird's of North America, ultimately made me positive this must be Storm.

These last two photos show her 'shivering' in the rain. I suspect this behavior is actually an attempt to get more air between her feathers to help her stay warm.

Having skimmed through the last fifteen months of Chip and Storm's lives and having ended up back at the tree where we started does make me feel like the story has come full circle. I still do not know where Chip and Storm are roosting - which provides a mystery I hope to solve in a future post.

Have a great day on Union Bay...where pileated woodpeckers live in the city!

Larry


Recommended Citation

Bull, Evelyn L. and Jerome A. Jackson. (2011). Pileated Woodpecker (Dryocopus pileatus), The Birds of North America (P. G. Rodewald, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America: https://birdsna.org/Species-Account/bna/species/pilwoo









9 comments:

  1. Larry, your blog is a treasure. Thank you for doing it every week. I visit a lot of the same places you do but I have poor vision and my two small kids scaring all the birds away. One of these days I'll actually see one of these birds and thanks to you I'll know them!

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    1. Chris,
      Wonderful! It is great to hear that my efforts are helping to raise awareness of our wild neighbors.
      I should have mentioned in this post how the dead alder snags that the pileated have nested in, for the last two years, have both fallen over. Alder trees may not be on the prime horticulture list but the woodpeckers sure could use some more in the pipeline. Planting new alders now will help your children to find nesting pileated woodpeckers - in the city - when they grow up. Thanks for following along!
      Larry

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  2. I have seen numerous ~1/2, or 2x3, or 2x4 inch rectangular holes excavated by these birds, in cedar trees, but recently saw a huge ~6X8 inch or bigger hole in the side of a cedar tree that had a pileated woodpecker working on it. Have you seen any very large holes like this or is the one I saw just an aberration? It wasn't a cavity entrance it was just a tapered hole similar to the small holes. But it was huge.

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    1. Yes! I have seen them make large holes just for food. In soft wood I have seen them make holes large enough to climb into in 45 minutes. In a externally healthy cedar tree, with harder wood, I estimate it takes about twice as long to make a similar sized hole. The bottomline is if there is an ant or ant larva chamber inside a tree they sense the food and go for it - which explains the taper. Once they reach the actual site they can use their tongues to reach around inside. I suspect that only if they sense more food beyond the reach of their tongues do they widen the hole beyond the tapered shape. Check out the holes in these photos:
      http://unionbaywatch.blogspot.com/2016/01/a-river-of-wood.html

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    2. Thanks for the reply. I've seen that series of photos and it is amazing how much work that they can do. The hole I saw was in green, healthy wood, in an apparently healthy tree. I've carved some wood myself so I know it took much more energy than chipping away rotten wood. It did penetrate to what looked like a soft core though, and it was low, so maybe the ants or termites were working their way up the center of the tree from the ground and it was worth the effort. Thanks for the great work and the insights on what you're seeing.

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  3. great photos and updates! Thanks!

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