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

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Saturday, October 12, 2019

A Frugivoracious Thunger

Cedar Waxwings are frugivores... 


...meaning they eat fruit. This plant is a non-native Cotoneaster. 

Cedar Waxwings will eat insects, but unlike Swallows, insects are not their primary source of food. Did you notice the varied length of the tail feathers? This is a nice example of new feather growth. 

If you zoom in on this photo you will see hundreds of small dark smudges. Each one is an insect. On October 1st, the Waxwings were darting out from the upper branches of this cottonwood and picking insects out of this 'cloud' above Foster Island.

Insectivores love insects and carnivores prefer meat. In each case, the 'vore' portion of the word implies 'prefers to eat'. 


In early September, I found waxwings eating these black berries on a small tree near the western entrance to Yesler Swamp. I was not familiar with this particular type of tree. Luckily, I ran into JP, a Gardner at the Center for Urban Horticulture.

A few days later, JP sent me an email explaining that the small tree is a Chokecherry

A week later, I returned to see how the Waxwings were doing. The tree had been virtually stripped. I found only one cherry left and no Waxwings. They had a voracious appetite for the chokecherries.

In spite of their refined and elegant appearance, waxwings do not always dine in a slow and civilized fashion. This tree is a Chinese Sorbus. The fruit is slightly larger than the fruit of either the Cotoneaster or the Chokecherry.

For the last few weeks, the Waxwings have been descending and feasting on this specific type of Sorbus in the Arboretum. 

Apparently, the fruit is at just the right level of ripeness. I suspect it is the abundance and possibly the size of the fruit which has slowed them from simply stripping these trees bare.


In spite of the name, the fruit of the Chokecherry is small and easy for the Waxwings to swallow. The fruit of this Sorbus being slightly larger creates more of a danger of choking.

To test the fit this waxwing extends its hooked tongue and pulls the fruit into its mouth. This is quite different than a grebe or a heron which throws its head back and lets gravity help pull the fish down.

Here is a side view of the hooked tongue. The rear-facing hook is a highly functional tool.

The bird obviously must be debating whether or not this delicious piece of fruit will satisfy its appetite or stick in its throat and kill it.

A split second later the fruit 'pops' forward. Clearly, the Waxwing was not comfortable with the fit. It mashed the fruit a bit before trying again. This process was repeated over and over by dozens of Waxwings stationed throughout the Sorbus tree.

Occasionally, a piece of fruit would pop completely out of a waxwing's mouth. Sometimes this may have been a rejection due to the size at other times it was accidental. Most of the waxwings would let the fruit fall and simply select another piece. Only once, did I see a waxwing chase a piece of falling fruit. It was a juvenile bird and it flew halfway to the ground before turning back. 

Cedar Waxwings seem to have a universal fear of eating fruit off the ground. Either that or they have very good manners. On the other hand, American Robins, feeding in the same tree, have no problem landing on the ground in search of fallen fruit.

By the way, the mottled look on the chest of a waxwing indicates it is a juvenile. However, this is a very short-lived plumage, by January it will be gone.

By New Year's Day, they will develop a more elegant plumage which is quite similar to what this adult is wearing. 

Surprisingly, only a small percentage of adult Cedar Waxwings develop their namesake waxy-red wingtips, like this bird. The little red dot almost above the leg is a new feather just beginning to grow out. While the red dots that are closer to the tail are on older more fully formed flight feathers.
 
Their hunger is so strong they often hover while looking for the perfect piece of fruit. Like with hummingbirds, it is surprising that the energy expended is adequately offset by the fruit consumed.

They tend to descend on the trees in flocks and attack the fruit...

 ...from every possible angle.

 
Sometimes, they hang upside down while searching through the leaves. (Younger birds like this one appear to have smaller and sharper yellow tips on their tail feathers.)

Surprisingly, there are multiple ways to hang upside down.

I suspect the odd looking angles for grasping their prize are all about twisting it free. Maybe if the fruit is properly ripe it just pops loose.

This fruit was being twisted so that the orange underside has been revealed.

Between this photo, and the next one, you can see the range of a single bird's twisting effort.

Their focus displays the intensity of their appetite. I think their desire for fruit is so strong that the term frugivore is an understatement. I suggest we refer to them as being frugivoracious.

Also, I wonder if waxwings distinguish between hunger and thirst. When waxwings are eating fresh fruit do they require any water? Could they be similar to young Bald Eagles - who spend their first few months in a nest without a source of water. This implies to me that for some creatures hunger and thirst may seem like a single appetite or at most slight variations on a single theme. 


For example, I suspect the growth hormone in trees, which causes leaves to reach out and compete for sunshine and oxygen, might be the same hormone that causes the roots to grow and grasp for moisture and nutrients. It seems unlikely to me that nature would develop different systems for doing similar activities unless there was a specific benefit for each unique approach.


Could it be that a bird's desire to consume might be more precisely stated in a single word? For some avian creatures might their thirst and hunger be more properly combined and called...thunger? 


If you ask me to use this new word in a sentence I would say, It appears to me that Cedar Waxwings have a frugivoracious thunger.
 
By the way, if you have read the new report regarding the serious decline in bird species you will be happy to hear that the Cedar Waxwing population is stable. Click Here to read the section labeled Conservation which reviews the waxwing population.

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

Larry

Going Native:

Without a well-funded Environmental Protection Agency, it falls to each of us to be ever more vigilant in protecting our local environments. Native plants and trees encourage the largest diversity of lifeforms because of their long intertwined history with our local environment and native creatures. I have been told that even the microbes in the soil are native to each local landscape. I hope we can inspire ourselves, our neighbors and local businesses to respect native flora and to support native wildlife at every opportunity. I have learned that our most logical approach to native trees and plants (in order of priority) should be to:



1) Learn and leave established native flora undisturbed.

2) Remove invasive species and then wait to see if native plants begin to grow without assistance. (If natives plants start on their own, then these plants or trees are likely the most appropriate flora for the habitat.)
3) Scatter seeds from nearby native plants in a similar habitat.
4) If you feel you must add a new plant then select a native plant while considering how the plant fits with the specific habitat and understanding the plant's logical place in the normal succession of native plants.



My intention in my weekly post is to include at least one photo each week and visually challenge us to know the difference between native and non-native lifeforms. 






Do you see the bird in this photo? Is it a Union Bay native?
























Scroll down for the answer.














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Brown Creeper: It is a northwest native and can be found around Union Bay year-round. 

This is simply a closeup of the prior photo - in which the bird is in the middle.
























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The Email Challenge:

Over the years I have had many readers tell me that Google is no longer sending them email announcements regarding my posts. Even more frustrating when they go to 're-sign-up', hoping that will enable them to once again start receiving the announcements, they get a message which says 'Sorry, you are already signed up.' Google has not responded to my requests for help with this issue. 

My functional workaround is to set up my own email list and each week I manually send out a new post announcement. If you are experiencing the issue and would like to be added to my personal email list please send me an email requesting to be added. Thank you for your patience!




My email address is LDHubbell@comcast.net







3 comments:

  1. Love those Cedar Waxwings -- a real favorite. Thank you for such a close-up look into their world and habits.

    ReplyDelete
    Replies
    1. Dan,

      You are welcome! I certainly love the Fall bird photos and commentary which you, Craig and Joy put together on your blog this week at: https://pedersenwrites.blogspot.com/2019/10/371-backyard-birds-of-fall.html Thank you!

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  2. As I was enjoying this look at the frugivoracious thunger of Cedar Waxwings, I came to the shot of the choke cherry, and felt a rare thrill of recognition. Choke cherries grew in abundance on the Montana ranch where I grew up, and when they were ripe, we kids ate them greedily, without dismounting, as we rode horseback along the creeks where they line the banks.

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