Bushtits are very small birds, similar in weight to Anna's Hummingbirds.
Last week, in the light of the setting sun, I felt very fortunate to find a flock of Bushtits plundering a tree, just south of the new Sky Bridge.
Bushtits do not exactly remind me of pillaging pirates. They are incredibly cute, especially when they huddle together to stay warm as night approaches. They do not seem to have any concept of personal space. They seem to embody the concepts of sweet, kind and gentle. So, I cannot blame you if the thought of Bushtits plundering a tree made you chuckle.
Still, I have not yet discovered a description, that adequately reproduces the widespread, nonstop flickering movement of a couple of dozen Bushtits, while they microscopically examine every crack, cranny, and crevice, interspersed with the split-second capture and consumption of nearly invisible prey. The loosely organized flocks typically finish feeding on a bush or tree in mere minutes. Then, suddenly, they are gone, moving on to their next feasting opportunity. Perhaps, plundering is an apt description of a Bushtit feeding frenzy.
Whether feeding in native Ocean Spray in late summer...
...or in the winter in a non-native, flowering Mahonia, trying to see what they eat is a challenge.
Springtime is the exception, especially, when they are bringing food to young in the nest. It is almost the only time I see Bushtits with visible food. In this photo, the nest is the vertical mass of moss and lichen on the left.
This tighter view makes the nest somewhat easier to see. The dark spot, in the upper portion of the photo, is the entry portal to their sock-like nest. Click Here to learn more about how they build nests.
(If you are not aware of the relationship between keystone plants, caterpillars, and the optimal food for young birds, Click Here to learn more.)
This long-bodied, winged insect is the largest food item, I have ever seen a Bushtit catch.
By the way, did you notice the bright yellow coloring outlining the mouths of the young birds? This temporary, bright coloring of their gapes helps the adults find the target location.
Back at the tree by the Sky Bridge, the light was perfect and, by chance, the angle of observation was about right too. My good luck enabled a few interesting photographs.
Curiously, this Bushtit removed something from the small branch and was inspecting it closely, while holding it with its right foot.
A moment later, the item was in its bill. Given the intensity of its focus, at the end of a cold day in January, I suspect the tiny morsel was food.
Birds of the World referenced a study that included hundreds of Bushtits. The study concluded their diet was 81% insects and spiders (see Footnote 1 below) and 19% vegetable matter. This item looks to me like it is about the size of a scale insect.
The mass-to-surface ratio of Bushtits (5.5) is such that they need to eat 80% of their body weight per day, at 68 degrees ambient temperature, to maintain their weight. This is according to a 1982 study referenced in Birds of the World (see Footnote 2 below). Logically, they must need even more food during the cold of winter.
Repeatedly, I saw Bushtits stop, hold and inspect something in their "fists." I don't remember ever seeing Bushtits doing this before.
It happened multiple times, while I watched. I don't remember seeing any other bird species, around Union Bay, hold something like a human might hold an ice cream cone.
I do remember seeing Bald Eagles, Barred Owls, Cooper's Hawks, a Merlin, and even Steller's Jays using a foot to hold down their food while feeding., i.e. usually stabilizing it against a branch, while they reduce it to bite-sized pieces. With this "new" Bushtit behavior they look much more thoughtful, almost analytical.
This behavior also shows the incredible strength of Bushtits, relative to their body weight. They have to use their other foot to hold their weight. If they become the least bit wobbly they would not be able to focus on the object "in-hand". Of course, their long tails do help a bit with balance.
I did a quick search of the internet and found research that describes birds using their feet like hands. The term used to describe it is, "Pedal Dexterity." (Click Here to read about their findings).
It is exciting to observe a new behavior, or at least one that is new to me, by a species which I have watched for hours. It is also mystifying to try and understand what exactly they are doing. If these were scale insects that they were eating, surely they had encountered and eaten them before. Plus, they had to be able to see them well enough to pick them off the tree. What do they learn by holding and inspecting the morsel even closer?
I wonder, Could there be tiny insects and small bits of vegetation that resemble each other? Maybe the Bushtits were trying to make sure they ate the most energetic food source possible on a cold winter's day? or Perhaps some scale insects have toxins or just taste bad? So, maybe they are carefully picking the good ones? or Maybe there is something else going on, to which I am totally oblivious.
In any case, it is wonderful that nature is full of intriguing and unresolved mysteries.
Have a great day on Union Bay...where nature lives in the city and Black Birders are welcome!
Larry
Going Native:
Each of us, who breathes the air, drinks water, and eats food should be helping to protect our environment. Local efforts are most effective and sustainable. Native plants and trees encourage the largest diversity of lifeforms because of their long intertwined history with our local environment and the local native creatures. 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 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. (When native 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.
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Keystone native plants are an important new idea. Douglas Tallamy, in the book "Nature's Best Hope ", explains that caterpillars supply more energy to birds, particularly young birds in their nests, than any other plant eater. He also mentions that 14% of our native plants, i.e. Keystone Plants, provide food for 90% of our caterpillars. This unique subset of native plants and trees enables critical moths, butterflies, and caterpillars that in turn provide food for the great majority of birds, especially during the breeding season.
Note: Flowering plants and trees, i.e. those pollinated by bees, are also included as Keystone Plants.
This video explains the native keystone plants very nicely:
https://www.youtube.com/watch?v=O5cXccWx030
The Top Keystone Genera in our ecoregion i.e. Plants and trees you might want in your yard:
Additional content available here:
https://wos.org/wos-wp/wp-content/uploads/2022/10/Native-Plant-Resources-10-7-22.pdf
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In the area below, I am displaying at least one photo with each post to help challenge us to know the difference between native and non-native lifeforms.
The following tree trunks belong to native trees. Do you know them by sight?
A)
B)
C)
D)
E)
Scroll down for the answers.
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A) Western Hemlock - They only native tree I know that will grow on top of a stump.
B) Western Redcedar - The Tree of Life to the First People of the PNW i.e. supplies housing, transportation, clothing and much more.
C) Grand Fir - The only true fir in this group.
D) Red Alder - Old trees (circa 50 years) make a wonderful home for Pileated Woodpeckers.
E) Douglas-fir - The most common species of tree in the PNW forests. When mature its thick bark resists Sapsuckers.
Curiously, the common names for two of our most important PNW tree species are misleading. Douglas-firs are Pseudotsugas (meaning false hemlock) and not really firs. Western Redcedars are Thuja plicate which are better described as Arborvitae and not real cedars. I believe this is why there is a hyphen in Douglas-fir and why Redcedar is sometimes spelled as a single word.
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The Email Challenge:
In response, I have set up my own email list. With each post, I will manually send out an announcement. If you would like to be added to my personal email list please send me an email requesting to be added. Something like:
Larry, Please add me to your personal email list.
My email address is:
LDHubbell@comcast.net
Thank you!
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The Comment Challenge:
Bottom Line:
If you write a long comment, please, copy it before hitting enter. Then, if the comment function fails to record your information, you can send the comment directly to me using email.
My email address is:
LDHubbell@comcast.net
Larry
Final Photos:
More Nest Building:
Footnotes:
1) Recommended Citation
Sloane, S. A. (2020). Bushtit (Psaltriparus minimus), version 1.0. In Birds of the World (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.bushti.012) Chaplin, S. B. (1982). The energetic significance of huddling behavior in Common Bushtits (Psaltriparus minimus). Auk 99:424-430.
