Posts Tagged birds
Being ‘bird-brained’ merits reconsideration
First off, writing this blog from my winter home in Florida, I appreciate the sensibility of snowbirds who abandon their northern climes every fall. Smart! Furthermore, studies show that avian brains, specifically crows and ravens (collectively known as “corvids”), can accommodate statistical thinking—a skill that many humans lack based on my experience as an educator. Researchers from the University of Tübingen worked this out via a clever experiment that required crows to assess the probability of getting a treat based on prior experience pecking at differing images.
“True statistical inference requires subjects use relative rather than absolute frequency of previously experienced events. Here, we show that crows can relate memorized reward probabilities to infer reward-maximizing decisions.”
Johnston, et al, Crows flexibly apply statistical inferences based on previous experience, Current Biology, Volume 33, Issue 15, 7 August 2023, Pages 3238-3243
This gives new meaning to the saying that “if the p-value is high, the null must fly.”
Going all out to save the birds
Posted by mark in Nature, Uncategorized on February 10, 2023
Last summer a cute little bird smacked into our patio door. It stood stunned long enough for me to get this closeup.
I see lots of cardinals (my favorite!), finches, sparrows and other backyard birds all year round. Others—robins and the like—come only when the weather warms up. However, I don’t recall ever seeing one in pretty pastels of brown and yellow. This beautifully colored creature does not pop out for me as one of the 23 most common birds in Minnesota. What could it be? Google Lens provides a clue by identifying it as a warbler. Along this line, based on what’s pictured on internet (even narrowed to warblers, many appearing similar), I’m going with this being a female (juvenile?) common yellowthroat. Do you agree?
Happily, this cute little yellow-throated bird flew off soon after its stunning encounter with our house and never came back to knock on our door. However, from time to time a bright-red male cardinal takes issue with its rival staring back from our bay windows. I’ve tried to ward these aggressors off by taping CDs shiny-side-out to the middle of the glass. However, that never works. Now, thanks to a heads-up from New York Times,* I know why: This new study by College of William & Mary biologists shows that window films increase avoidance of collisions by birds but only when applied externally.
“Bird collisions with windows kill more than a billion birds per year.”
Professor John Swaddle, lead scientist of first experimental study to compare the effectiveness of window films when applied to internal versus external surfaces of double-glazed windows
The researchers randomly divided 72 zebra finches into 4 groups via a two-factor, two-level factorial that varied type of film—BirdShades (not commercially available yet) vs Haverkamp—and location on the glass surface—interior vs exterior. No worries—their ingenious flight-testing facility featured a net that prevented window-bound birds from head-on collision.
By the way, in this interview by W&M News (check out the picture of his student showing the “proper technique for holding a zebra finch”), Swaddle says that “silhouettes of animals or birds don’t tend to work in part because they’re generally too spaced out.” So, when our windows again come under attack by angry birds, I will use many CDs (putting a plentiful pile of unused and obsolete media to good use)—not just one—and duct tape them to the outside—not the inside. I just hope that the neighbors don’t complain about the blast of solar radiation going back their way.
*“Those Window Stickers to Prevent Bird Strikes? There’s a Catch.”, Catrin Einhorn, Feb. 2, 2023 (Updated Feb. 7)
Groundhog Day: Looking forward to spring and the arrival of robins
Puxatawney Phil saw his shadow this morning, thus forecasting 6 more weeks of winter. Most people in the USA took this as a bad sign that spring will not come early—the prediction when Phil does not see his shadow. However, we hardy Minnesotans do not mind 6 more weeks of winter whatsoever.
A sure sign of spring comes with the sighting of the first robin in my yard—typically later than Phil’s more pessimistic forecast. I looked for statistics on the annual migration of robins from the USA National Phenology Network but, though this bird is their most frequently observed animal with over 190,000 records, nothing came up readily on dates of first sightings in my region of the country.
In any case, I will be very happy if the robins do beat the 6-week forecast for spring as they did in 1996 per this report—arriving in Minneapolis on March 12th of that year. Until then, I can only enjoy this lovely video of American robins produced by Lesley the Bird Nerd who grew up north in Ontario—the next stop in the bird’s spring migration after Minnesota.
What got me thinking so early in the year about robins was a report in the Royal Society last week on “The limits of egg recognition: testing acceptance thresholds of American robins in response to decreasingly egg-shaped objects in the nest”. Check out the bizarre fakes—robin-egg blue, of course—pictured here . Evidently it’s not the shape that matters, for example, a pointy eight-sided egg stayed in the nest, but, rather, the size. Those that looked big enough to be put in by a cowbird, a parasitic species, got tossed out. The robins also rejected eggs that were too thin.
“They seem to be quite hesitant about rejecting eggs when the variable that we changed was not natural,” Dr. Hauber said, referring to the angular, pointed eggs. “Robins don’t know what to do with it, because they’ve never evolved to respond to it.”
Quote reported by New York Times in their interview of lead-author Mark Hauber, a professor of animal behavior at the University of Illinois, Urbana-Champaign.
I am tempted to dig up the collection of Dungeons and Dragons dice left behind by my two sons after they moved out and put them out in the bird house this spring to see what happens. Just joking—I like robins too much to do anything so inhospitable. It is very weird, though, that they are so bird brained about egg shapes.
Beware of birds making stick bombs in your backyard
Posted by mark in Nature, Uncategorized on April 13, 2020
One advantage of being home-bound during this COVID-19 pandemic is spending more time watching the birds. I especially like the cardinals who flock to my feeder in a variety of plumage being male, female or juvenile. However, the finches are fun to see as well, particularly the yellow ones. The other day a blue jay came by to provide a bit of blue for the color mix.
While greatly appreciating birds, I failed to recognize their superior engineering skills until reading this New York Times article about avian nest construction. They report how researchers at University of Akron used a ‘smushing’ chamber to measure how bird-homes bounce back after being compressed.
“We hypothesize that a bird nest might effectively be a disordered stick bomb, with just enough stored energy to keep it rigid.”
Hunter King, experimental soft-matter physicist, University of Akron*
I now feel a lot smarter saying “smushing”, it being a scientific term used by world-class physicists. However, I’m more interested in the stick-bomb bit. This is explained best by Popular Mechanics in their report (stemming from the same scientific study by Hunter et al) on Why the Humble Bird Nest Is an Engineering Marvel.
As a fun project to while away the time indoors, build your own stick bombs using popsicle or jumbo sticks such as those available here.
The stick bomb illustrated in this video by Brain Coach Don offers a great deal of excitement, but I do not recommend it for building bird nests—ha ha. The difference is them making ones that are disordered and thus nonexplosive.
*(Mechanics of randomly packed filaments—The “bird nest” as meta-material, Journal of Applied Physics 127, 050902 (2020))