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

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Saturday, March 28, 2015

The Mating Game

Mating and nest building are highly intertwined in the lives of cooper's hawks. Last week's post focused on nest building. This week, we look from the female's point of view, at the other half of the process.

While the male is nest building, or hunting, the female sits nearby. Here, she is grooming her tail feathers. 

The female is perfectly capable of hunting, instead she often calls incessantly for the male to bring her food. There must be some logic to this approach. Possibly, she is conserving energy, that will be invested in eggs. It also might be a test, for the male to prove he is capable of providing food, for her and their young. Since the males often work on multiple nest sites, she may also be evaluating the site.

In any case, the female seems to spend the bulk of her time, maintaining her appearance.

The females are generally larger than the males and they tend to dominant the relationship. The website, All About Birds, says, "the females...specialize in eating medium-sized birds", about the size of the males. Size, isn't the only advantage the females bring to the relationship. Often a female will require a male to bring branches to their new nest, not to mention food, before she will allow mating to occur.

When the female is satisfied, with the male's work ethic, she assumes an inviting posture.

 The male is very aware of the invitation and appears quickly.

The orange-coloring on the male's chest shows he is older and more mature. In this case, maybe because the female is younger, the size difference is not obvious.

Their long tails help them maintain balance while mating.

 When the male spreads his wings, he resembles an acrobat, balancing on a tightrope.

The male's talons appear above the female's shoulder. 

 He must grasp some of her feathers, hopefully nothing more, to maintain his position.

 To help with their balance, the female spreads her wings as well.

 The whole process seems incredibly precarious.

 In seven seconds...

 ... they are finished.

 The male pauses, briefly, beside the female.

 She hardly seems to notice when he has gone.

 The male moves to a neighboring cedar tree and begins searching…

... for nest-sized branches. If you zoom in on his right talon you can see he is still carrying a tuft of her feathers. In five minutes the male leaves the area.


Earlier this week, below the nesting site of the cooper's hawks, a barred owl was attempting to sleep its way through the day, when...

 …three crows flew in and began "cawing", loudly. There does not seem to be many creatures that can intimidate crows. The owl turned its head away and tried to ignore them. Suddenly, I heard the "kekking" of a cooper's hawk. 

This male, most likely the one we have been watching in the last two posts, landed just above the owl and the crows. Not only were the crows instantly quiet, they seemed to evaporate, as well. When I looked up, the crows were gone. The hawk went on about its business and the owl went back to sleep. Defending the nesting territory, is evidently, another role in the mating game.

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


Cooper's Hawk Update: 

Note: To read some very informative corrections to this story, from Martin Muller, please read the update section at the end of the post called, Masters of Deception(4-16-2015)

By The Bay:

Sasha from the University of Washington Botanic Gardens asked me to let you know that Connie Sidles is teaching this very special birding class in April.

UW Botanic Gardens: Where Did Birds Comes From?
Monday, April 20, 7-8:30pm
UW Botanic Gardens - Center for Urban Horticulture, Douglas Classroom, 3501 NE 41st St, Seattle, WA 98105

Union Bay Natural Area (aka Montlake Fill) hosts some 259 different species of birds, everything from the largest swans (with wingspans of 7 feet) to the tiniest songbirds (bushtits, with a wingspan of 6 inches). Some of our birds are so dull they have almost no color at all, though their voices can be very sweet (warbling vireos are a good example). Other birds croak like frogs but glisten like gems (wood ducks). Where did this spectacular diversity come from? The short answer is: from dinosaurs. The long answer is: 150 million years of evolution.

Master birder Connie Sidles describes the latest discoveries of fossil birds and their ancestors, and the most current theories about how birds have evolved from the distant past. Sidles studied paleontology at the University of Chicago and has written four books about nature as she observes it at Montlake Fill.

Cost: $15; $20 after April 13th
Register online or by phone (206-685-8033)

Saturday, March 21, 2015

Investment Versus Expense

This male cooper's hawk is looking into the future and making some tough choices. 

Not only must he select... 

 …just the right branches but… 

...he may also be wondering whether his nest building efforts are an investment or an expense. 

Those of us who are not accountants might legitimately ask, What's the difference?

Here is the first example that came to mind. When I was young my uncle introduced me to his grandfather, who had sold sewing machines to farming families, in the early part of the 20th century. Sewing machines were new and expensive, but the farming families could easily justify the investment. A machine would pay for itself, by saving time that would otherwise be spent sewing clothes by hand. 

When the traveling salesman bought his inventory, the sewing machines were an investment. The machines would eventually sell for more than the initial cost. The cost of feed for the traveling salesman's horse, which pulled the wagon that carried the sewing machines, was an expense. The feed did not increase in value, it was just a cost of doing business.

Male cooper's hawks often create more than one nest. Sometimes the extra nests are not even used. It makes one wonder why the hawks go to all the effort. Maybe they create the extra nests as a secondary option in case predators discover the first nest or the first nest is blown out of the tree. Maybe the extra nests are decoys to distract predators. Another possibility is, that an extra nest shows that the male has the energy and skill to provide for a growing family e.g. to attract a mate. A nest used to raise young is an investment, but the extra nests seem a bit more questionable. What do you think? Are they an investment or an expense?

By the way, the long feathers in the photo above are tail feathers, not wing feathers. 

Relative to other birds, the cooper's hawk has a very long tail that helps it maneuver between branches with ease. Here the male jumps off the nest, heading out to secure more branches, without even opening his wings. He uses his tail like a rudder to guide his body through the tangle of maple branches. The male always searches for small dry branches high in the trees. He never exposes himself to the risks, like off-leash dogs, that would come from picking up branches off the ground.

 While the male works at building the nest, a young female observes the process.

She constantly shifts position to keep the male in view while he flies back and forth between the nesting tree and nearby douglas firs or western red cedars. The coniferous trees seem to have much more brittle branches that are more easily removed from the trees. While watching the birds a piece of broken branch landed on my head and stuck in my hair.

The youth of the female is evident from the dark, vertical, teardrop-like, stripes on her chest. This indicates she hatched out last year and is in her second calendar year. Even though she is young, she is old enough to take a mate.

The more mature male has orange irises, instead of yellow, and reddish-orange horizontal bars on its chest. 

In this photo you can see that the male is wearing jewelry, e.g. bands around his legs. The female has not yet been banded.

Ed Deal has been banding cooper's hawks and peregrine falcons, in our area, for a number of years. The goal is to learn more about the birds and help them to thrive. Historically, cooper's hawks were shy and choose to stay away from cities. The last couple of years the number of cooper's hawks in Seattle appears to be growing. It seems like most parks, and even just neighborhoods with large trees, have cooper's hawks. 

(Just like barred owls, cooper's hawks also catch rats. Studies show that rat poison does bio-accumulate in birds and kill them. Rat traps are just as effective and much less dangerous to birds, pets and the environment.)

The key to tracking and learning more about the birds is the bands. Ed applies purple bands to the left leg of male birds. Orange bands are applied to the right leg of females. Both genders have metallic bands applied to their opposite leg.

There are unique codes printed on the colored bands. In this case the male has the code "3 over 3" on his purple band. This band was applied by Ed's colleague, Martin Muller, during the bird's first summer in July 2013. According to Ed's records, this bird was spotted again in August 2013 and then in October 2014.

If you would like to help track cooper's hawks you will need a pair of binoculars and a willingness to get a stiff neck while searching the tree tops. It also helps to listen for their calls. Ed sent the following set of links to help identify the calls of cooper's hawks.

An adult female: http://ibc.lynxeds.com/video/cooper039s-hawk-accipiter-cooperii/two-frontal-views-adult-perched-looking-around-calling-soft  A female will also make the "kekking" sound, like the males.

After you follow this link click on either "Food delivery to nest" or "Begging calls of chicks"

Now is an especially good time to watch for cooper's hawks because our big-leafed maple trees have not yet leafed out. If you spot a male bringing branches to a tree, I would be happy to pass new locations on to Ed, so he and his team are aware of the potential nesting sites. (My email is: ldhubbell at comcast dot net.)

All About Birds says, a study of cooper's hawk skeletons showed... 23 percent had healed over fractures to there chests. (Look under Cool Facts.) 

If you watch the way they fly between branches and around trees you will understand why.

The other day, while photographing a woodpecker, two birds flew past me very quickly.

They were way too fast for me to identify, but the first bird sounded like a very anxious robin.

They wove between the trees, with the second bird immediately behind the first. Given that we were not far from this nest, plus the speed and the close pursuit, I suspect the robin was fleeing from one of the cooper's hawks. They passed within 2 or 3 feet of me before disappearing into the underbrush. It made the hairs on my neck stand up. It also made me happy to be bigger than a cooper's hawk.

While writing, I just watched a crow breaking a branches off our neighbor's tree and flying away with them. Spring is here. Nest building is under way. We are beginning the most exciting time of the year! Hopefully, all the nests being built are wise investments, that pay high dividends.

Have a great day near Union Bay…where cooper's hawks nest in the city! 



By the way the PNW Nature Blog Scavenger Hunt that started last week has been extended through Sunday night. Last I heard, some of the prizes may still be available.

The goal is to answer a nature question on each of a variety of PNW nature blogs, just one question per blog.

The Union Bay Watch question is, "What treasure is scheduled to be hidden next to the ponds at the Union Bay Natural Area?" You will need to read last week's post to find the answer. You can scroll down or click the following link.

To learn the rest of the questions and the other nature blog locations please visit:


Monday, March 16, 2015

Hidden Treasures


This week Union Bay Watch is proud to participate in the PNW Nature Blog Scavenger Hunt. 

Your goal is to answer a nature question on each of a variety of PNW nature blogs, just one question per blog.

The Union Bay Watch question is, "What treasure is scheduled to be hidden next to the ponds at the Union Bay Natural Area?"

To learn the rest of the questions and the other nature blog locations please visit:


Northern Flickers tend to blend in with their surroundings. From the back, while working in your yard, they might even be mistaken for a large robin. 

When you stop and take a closer look at our most common Union Bay woodpecker, you notice the richness of the alternating colors. You see the tan-brown on the back and top of the head, the grey of the face, the off-white of the belly highlighted by the random but somehow uniform black dots and in the males you notice the bright red malar stripe.

From the front you can see the black crescent that looks like a dark bib. If you watch closely when the flicker flies away, you will see a bright white rump as they ascend into the foliage of a tree. However unless you watch very closely, you are unlikely to see the flicker's hidden treasures.

Our local northern flickers only display their orange feathers when competing for mates or territory. These displays happen quickly and are not aimed at humans, so capturing the colors feels like finding a hidden treasure. This female is hoping to gain the affection of a male.

The male is interested in something but…

 …the question is…

 …Is he interested in either one of the females that are attempting to gain his attention? As you can see in this photo, the undersides of their wings are also covered in orange.

Maybe the male was just playing hard to get, because when one of the females gets closer, he does turn and provide her with his own tail display.

Although hidden to the camera, it looks as though the female is responding with a similar display. The other female immediately springs into action.

She drops to a lower position and begins a nearly upside down display, which is clearly aimed at the male.

 Although she gives her best effort, the male seems mesmerized with the closer female.

When the first female decides to do an aerial display, the second gives up and leaves.

I wonder if the bright orange shafts, displayed on the top side of the tail feathers, are the source of the red-shafted name for our local variety of the northern flicker. If so, it seems like a more appropriate name would be an orange-shafted northern flicker.

The beautiful colors and displays of the mating process end in nest making, egg laying and raising young. The young in the nest are the flicker's ultimate hidden treasure. Can you pick out the hidden treasure in this photo? 

Around The Bay:

The shorelines around the main ponds, at the Union Bay Natural Area (UBNA), have historically provided food and rest for 29 species of migrating shorebirds. The planned 520 mitigation would cover and surround these shores with native plants, denying shorebirds a key stop in their migration. 

Click Here to read why local experts, Connie Sidles, Dr. Dennis Paulson and the Seattle Audubon, are against this portion of the mitigation.

Ironically, there are many other Union Bay shore areas which desperately need the native plants included in the mitigation plan

Examples include this shoreline on the southeast side of Foster Island (as pictured above) or the shoreline near the mouth of Arboretum Creek, which looks similar. These shores are covered with invasive ivy, holly and blackberries, unlike the shores of the ponds at the UBNA. The alternative shorelines would clearly benefit from the mitigation efforts.

Please sign the Seattle Audubon petition and ask the Washington State Department of Transportation (WSDOT) to relocate the 520 shoreline mitigation work, which is currently planned for the ponds at the UBNA. The millions of dollars being spent should be applied where the need is clear and uncontested. Speak up for the shorebirds by asking WSDOT, "Please do not hide the treasured shores of the UBNA ponds."

Click Here to see shorebirds in action.

Click Here to sign the Seattle Audubon petition.

Have a great day on Union Bay…where shorebirds hope to migrate!