Category Archives: Uncategorized

How crows responded to the eclipse, according to you

Back in August, I challenged my readers to submit their observations of how their local crows responded to the total (or partial depending on your location) eclipse that occurred on the 21st.  Six of you offered up your observations and suffice it to say they ran the gamut.  From completely typical behavior to massive gatherings deemed unusual, there was no pattern to the handful of observations that were reported.  Here’s my summary of what you observed:

Three people reported no changes in behavior, with one person even witnessing a crow flying overhead during the moment of totality.

Two people reported seeing more crows than usual and that they were more noisy.  Almost like a typical pre-roosting behavior but in the middle of the day.

One person reported that the birds were more quiet than usual, and remained quiet for 30min after the eclipse.

I myself failed to find any corvids during the totality but I did watch a sparrow (not identified to species) forage on the ground just before, and just after the totality.  I did not see where it was during the few moments of complete totality, though given its proximity to its position prior to totality I reasoned it must not have gone far and could have easily been foraging as before just without my detection.

Thanks for sharing your notes everyone!  Looking forward to the next round in seven years 🙂

1 Comment

Filed under Uncategorized

How will crows respond to the eclipse? 

Unless you’ve been living under a rock, you know that this coming Monday a total solar eclipse will cross the continental United States. Eclipses are significant moments in the lives of humans but scientists know less about how non-human animals respond to them. After all, opportunities to observe this phenomenon occur only a couple times a year, and its occurrence in the same geographical area is substantially more rare. The last total solar eclipse in the US was in 1979. Since then, not only has our technology to research this phenomenon evolved, but methods for the public to engage in eclipse related citizen science has exploaded. You can read about all the different opportunities here.


Of these opportunities, the one that excites me most is the California Academy of Science’s ‘Life Responds’. By using the iNaturalist app, CAS invites you to make and report observations of how a particular organism responds to the eclipse. The instruction are simple and you can read the full protocol here. I encourage all my readers to consider participating with any species you choose, BUT I thought it might be fun to host a mini crow-specific Life Responds challenge here on the blog. 

How will crows or other corvids respond to the eclipse?


To that end, I invite all of you to follow the Life Responds observation protocol, and in addition to sending your observations in via iNaturalist, email them to me or leave them in a comment here. I’ll then synthesize all your observations into a little mini report that we can all learn from and enjoy. Sound fun? I hope so! 

Remember, if you chose to participate, please follow the Life Responds protocol. While I’ll certainly accept general comments/observations, if everyone follows the same collection method our observations will be much easier to synthesize and interpret. 

Not able to be in the path of totality? No problem! Your observations are still invited and valuable. I’m particularly interested in whether or not Seattlites observe the crows abandon their daytime activities and head towards the roost as the light changes. I myself will be down in Oregon in the path of totality, so I’ll miss that observation. Hopefully I can locate a corvid from my observation spot in Oregon. If you have questions let me know, otherwise enjoy the eclipse and remember to protect your eyes 👀! 

12 Comments

Filed under Uncategorized

A story you might enjoy

Generally speaking, I don’t write posts advertising specific stories or news articles about my work.  I figure anything going in those stories is all stuff you can get firsthand here, and of course I link to all of them on my ‘In the Media’ page so they’re never far out of reach anyway.  But I wanted to put out a special post about Vicki Croke’s article for the WBUR’s The Wild Life blog.  Most of the time when people write about me, the blog is a footnote, a way to learn more if you wish, but not something mentioned specifically.  As a follower of this blog, I imagine you have some idea how much time and effort I put into it (as much a grad student’s life allows for it, anyway) so I was extremely flattered and honored when Vicki made the blog a focal point of the article.  Given the supportive community we have built here together, I thought you especially would enjoy reading this piece.  Let me know what you think of it in the comments and thank you for your continued presence here and passion for crows.

12 Comments

Filed under Uncategorized

Crow curiosities: Why was I attacked by a crow?

You’re minding your own business when seemingly from out of nowhere you are, or very nearly are, struck in the back of the head by crow.  It’s frightening, embarrassing, and in rare cases even painful.  So what prompted this unprovoked attack?

crow-attack-1

If you were to gauge the answer based on newspaper headlines you might believe that it’s because crows are evil, vicious or otherwise hellbent on tormenting us humans.  This choice of words communicates that crows are behaving as they are because they lack moral decency, which is both anthropomorphic and grossly misrepresents the biological cause of their behavior.

Rather than being a reflection of their species’ character, or The Birds come to life, crows are increasingly behaving this way right now because young crows are starting to venture out of the nest.  As I’ve talked about before, it’s not unusual for baby crows (and other birds) to leave the nest while still unable to fly.  Although their parents will continue to care for them after this for many months, these first couple weeks out of the nest are a particularly vulnerable time for young crows.  Their parents are therefore keen to protect their offspring, and are willing to come to blows with potential predators if necessary.  You may have no intention of harming or even coming near their offspring, but of course the crows have no way of assessing your intentions.  You are simply a big, powerful animal that is encroaching on their young, and they are driven to scare you away.  They are simply being protective parents.

DSC_0710

If you were my parents you’d want to keep me safe from big mammal-monsters too

The tricky thing is that because we might not be expecting to encounter young crows or because they are tucked away out of sight under a bush, it may not be clear that this is the cause of their behavior.  Trust me though, unless you have a history of wronging your local crows, attacks between May and September are nearly exclusively related to the protection of young.

crow_maskedman_-Keith-Brust

Although crows will dive bomb people who have wronged them in the past, during the summer the most likely explanation for attacks is defense of offspring.

So what to do?  As the kids grow up and become more independent the parents will relax.  So, if possible, you can simply avoid the areas you know to be high conflict for the next couple of weeks.  In fact, some newspaper outlets even make attack maps to help people navigate the streets of stressed out crow parents.  If this isn’t possible, carry an umbrella or simply walk with your hand on top of your head.  This may not keep them from giving you a good swoop or two, but it will generally prevent any real damage.

 

 

Leave a comment

Filed under Uncategorized

What’s in a (corvid) name?

Most people know various corvid species by their common names but have you ever wondered what etymologies inform their scientific names? Turns out it’s a pretty fun little exercise to find out!

img_56531.jpg

Before we get to breaking down individual corvids though, a quick word on scientific names more generally.  Scientific names always have the format: Genus species. Meaning, the first word in the name tells you what genus the plant/animal belongs to and the second tells you the species name specific to that organism. So for example crows, rooks, jackdaws and ravens are all in the same genus so their scientific names will all start with the same word: Corvus. The second word, however, will be unique to each species. This system of binomial nomenclature was first developed by Carl Linnaeus in the 1700’s.  By looking up the roots of an animal’s scientific name we can learn a thing or two about what he, (or whoever named it) was trying to highlight. Then again, sometimes they’re just fans of Beyoncé or Jonny Cash.

One more note: although scientific names are often referred to, informally, as Latin names, their roots may actually pull from many languages.  Though by far the most common languages are Latin and Greek.

As it happens, I have an old book of  root words I inherited from my late grandfather, Richard Swift. Something about having that book in my hands begged for this exploration in a way that having the breadth of the Internet at my fingertips never did. What can I say, a childhood spent in the library of my grandfather’s office has made me a sucker for old, smelly books. So let’s get started!

Common raven: Corvus corax
Common ravens are the biggest of the corvids (and in fact, the biggest of all the songbirds) so it makes sense their name might be the yardstick by which other corvids are measured. Cora literally translates to “crow, raven” so the common raven’s scientific name essentially just means raven.

DSC_2853

GO, the American crow

American crow: Corvus brachyrhynchos
Turning to American crows, we can see that yardstick I mentioned coming into play. Brachy means “short” and rhynch means “a beak or snout.” So the American crow’s full scientific name basically translates to the “short-beaked crow.”

junlge crow

Jungle crow, photo c/o Anne Kurasawa

Jungle crow: Corvus macrorhynchos
At this point, the meaning of the jungle crow’s name probably needs no explanation. The bird looks essentially like an American crow but with a more pronounced bill. Macr rhynch = large beak.

corvus_albus_-etosha_national_park_namibia-8

Pied crow, photo c/o Frank Vassen

Pied crow: Corvus albus
Alb means “white.” No mystery here.

house-crow444

House crow, photo c/o Benjamint444

House crow: Corvus splendens
Splen means “a badge or patch.” With grey sweater they sport, it’s likely the person who named them was trying to highlight this physical distinction.

thick billed raven

Thick billed raven, photo: Ignacio Yufera

Thick-billed raven: Corvus crassirostris
Sometimes, scientific names are precisely their common names. Such is the case here. Crass means “thick” and rostr means “beak.” This is a good example of where we see different languages influencing the names.  In this case, thick-billed ravens got the Latin root, whereas American and jungle crows got the Greek root for beak.

16757988474_95447ac3f6_z

Rook, photo c/o Pam P.

Rook: Corvus frugilegus
This one is less clear to me. Frugi means “useful, fit” and legus means “lie down; choose; or collect” depending on what language you pull from. My guess is it’s supposed to be ‘collect’ and the name refers to the more specialized bill they have for collecting insects.

Finally,

grey-crow

The grey or bare-faced crow, photo c/o B.J Coates

The grey crow: Corvus tristis
Trist means “mournful; sad.” I have a feeling I know the backstory for this one but I’ll leave it to my readers to see if they can figure it out. Leave me your best explanation (made up or researched) in the comments!

10 Comments

Filed under Birding, Corvid trivia, Crow curiosities, Uncategorized

Have you ever seen a caramel crow? 

Generally, when I receive emails with the subject line “interesting crow” it’s because the author noted some peculiar or amusing crow behavior they want to share, or because they spotted an unusual looking crow due to AKD, leucism or avian pox.  Rarely, it’s for none of these reasons and is truly a horse of a different color. Or in this case, crow.


Meet Al, a hatch year American crow whose natal territory overlaps with Tara Chafe’s property. According to Tara, Al is the second bird born in the last 5 years with this kind of color abnormality. The bird that she reports is its mother is leucistic, but as you can see below, she’s not a particularly dramatic case with maybe only one or a couple more white feathers.

al and mom.png

Without having observed Al myself I can’t confirm any of Tara’s observations, but from her perspective, Al appears to interact normally with the other crows, and doesn’t exhibit any other health issues. In fact, the first caramel crow that Tara encountered has gone on to mate and establish a territory in a nearby neighborhood and she still occasionally encounters it.

Understandably, Tara’s question to me was “what is going on here?” and initially, though I am by no means an expert in pigmentation, I didn’t expect it would be too much work to provide her an answer.  And with that my descent began.

alice.gif

It’s helpful to start by understanding what controls pigmentation in birds.  There are three different groups at play: melanins, carotenoids, and porphyrines1.  Melanin is probably the most familiar term, after all we possess a lot of it ourselves and the skin cancer melanoma is named for the melanin producing cells where it occurs.  In fact, there are three kinds of melanin: eumelanin, which controls dark browns and blacks, pheomelanin, which controls reddish hues, and neuromelanin which occurs only in the brain.  Carotenoids, on the other hand, are derived from plants and produce the red of a cardinal or the yellow of an American goldfinch.  Porphyrines, which are modified amino acids, can produce a wide variety of colors from pink to green, as observed in some of the more colorful corvids such as the Bornean green magpie and ceylon magpie.  Lastly, the structure of the feather also plays a role in color, particularly with respect to iridescence, but I’ll save that for another post.  Of most concern to us in this case is melanin, since that’s what’s controlling coloration in American crows.

Knowing this is an issue of melanin, I next wanted to identify how we might characterize this color aberration.  Older birders will describe this bird as leucistic, and historically that convention was considered accurate.  Contemporary semantics among pigmentation papers, however, have clarified leucism as a condition that “results from a complete lack of melanin from all or parts of the plumage”2,3. In other words, crows that are leucistic would be completely white in one or more feathers, which this crow is clearly not.  Without yet knowing exactly what’s going on here the more appropriate terms might be: “Schizochroism” meaning a lack of a single pigment, or “dilution” meaning an overall decrease in pigmention deposition2. A color mutation known as “brown,” meaning a qualitative reduction of melanin, has also been proposed3.

ZB in flight

A leucistic crow in flight

With this much information at hand, we might begin to think that this reddish/caramel colored bird has some issue with its eumelanin production that is giving way to more visible pheomelanin.  The trouble is, by all accounts crows do not produce pheomelanin3,4,5. So if crows do not produce pheomelanin what is going on here?

Fellow crow expert, and the much more knowledgeable in pigmentation than I am Dr. Jennifer Campbell-Smith, sees there being a few possible explanations.  The first is simply that we haven’t studied pigmentation across Corvus species thoroughly enough to say that crows such as American crows don’t produce pheomelanin.  After all, some Corvus species, such as the brown necked raven, certainly appear to express pheomelanin produced colors.  Perhaps American crows do produce a modest amount that has so far been difficult to detect, but is revealed in cases like this.  Alternatively, Jennifer suggests that even if American crows don’t typically produce pheomelanin they may still possess all the infrastructure for doing so. Perhaps in cases such as Al’s, the genes that regulate such production have been turned on. As an especially interesting side note, pheomelanin is a particularly energy intensive pigment to produce, and as such, there’s evidence of a correlation between larger brain sizes (including Corvus species) and low to undetectable levels of pheomelanin6.

20130404161111591

Brown necked raven (Corvus ruficollis) photo c/o Peter Nash

Another publication suggested that cases like Al’s are caused by incomplete oxidation of eumelanin3, but I am dubious of this paper because they claimed that corvids as a family do not produce pheomelanin, which blatantly untrue at worst or, if they meant Corvus, an egregious typo at best.

Ultimately, what I found was that rather than being a matter of a quick trip to the virtual library, an explanation for Al’s condition is currently unresolved by science.  Which is probably my favorite genera of science.  After all, what’s better as a scientist than embarking on the unknown or poorly understood?

al-close-up

This week’s #CrowOrNo picture

Many thanks to Tara for a truly interesting crow, and for agreeing to let me share Al’s story here.

  1.  https://academy.allaboutbirds.org/how-birds-make-colorful-feathers/
  2. Guay, P.J., Potvin, D.A., and Robinson, R.W. 2012. Aberrations in plumage coloration in birds. Australian Field Ornithology 29: 23-30
  3. van Grouw, H. 2013. What colour is that bird? The causes and recognition of common colour aberrations in birds.  British birds 106: 17-29
  4. Lee E, Tanaka H, Wakamatsu K, Sugita S.  2009.  Melanin-based iridecent feather color in the jungle crow.  Journal of Veterinary Medical Science 71: 1261-1263.
  5. http://www.sibleyguides.com/2011/08/abnormal-coloration-in-birds-melanin-reduction/
  6. Galvan I, Moller AP.  2011.  Brain size and the expression of pheomalanin-based colour in birds.  Journal of Evolutionary Biology 24: 999-1006.  DOI:10.1111/j.1420-9101.2011.02232.x

7 Comments

Filed under Uncategorized

Corvid of the month: Rooks

In honor of last week’s #CrowOrNo photo, I wanted to spend some more time spotlighting a corvid perhaps less well known to my fellow North Americans, the rook (Corvus frugilegus).

16757988474_95447ac3f6_z

Photo c/o Pam P.

Among corvids, adult rooks might be one of the most unmistakable species. Their naked, chalk colored chin, lores, and bill base gives their face an appearance resembling no other bird.  The grey crow, or bare-faced crow (Corvus tristis), shares a similar facial pattern but is easily distinguished by its rather blushing appearance and blue eyes.  In addition, whereas the grey crow is known mainly to the peoples of Papua New Guinea, rooks have one of the widest distributions of any corvid species, breeding from Sweden all the way to China.

(Hover over tiled photos for captions)

Of course, what made last week’s #CrowOrNo submission such a challenge was that the photo was not of an adult, but rather a first year bird.  With their nasal hairs intact, first-year rooks look something like a crow/raven hybrid. Although bill shape is, I think, the best tell, one other field marker to look for are their notoriously shaggy “pants” (belly and leg feathers) in contrast to crows and ravens.

The transition to bare-faced adult occurs during the bird’s first complete body molt when they’re around 10-15 months old.  This process can take as little as 25 days but for most birds occurs over the course of several months1.  The evolutionary reason for this loss may have something to do with their foraging habits, which consists largely of probing for worms, though this remains unclear.

Unlike many Corvus species which are more general with respect to their diet, rooks are fairly specialized to feed on the small worms that live among the roots of plants.  One consequence of this diet is that there are distinct boom and bust seasons.  In April and November, wet conditions make worms plentiful, but in other times of years drier conditions drive worms deeper and out of reach.  Since access to food can be precarious, rooks have adopted a rather unusual incubation strategy compared to most birds.  Rather that commencing incubation when the entire clutch is laid, which promotes the same hatch date, rooks start incubating the first egg as soon as it is laid.  This chick is born earliest, giving it a clear advantage over its future siblings.  If food becomes sparse only this chick will survive. If food remains abundant, the parents can provision enough to supply the larger, more dominant chick, and its younger siblings.2

4288377285_8ccb1800fb_z

Photo c/o Danny Chapman

Rooks are distinct from other corvids with respect to their behavior as well.  In contrast to crows or ravens, rooks are essentially non-territorial.  During the non-breeding season they are most commonly found in large foraging groups (much to the chagrin of local agricultural farmers, I imagine).  During the breeding season they nest in colonies, rather than individual territories, though they will defend the area around their nest and their mate as necessary.  A nest is often reused by the same pair year after year until it is razed by weather, or the pair is forced for some other reason to construct a new nest.  Like many other Corvus species, they maintain a socially monogamous life-long mate.3

Cognitively, rooks demonstrate many of the same skills that have brought some of their peers into the global spotlight. For example, when in the care of humans, rooks have demonstrated an astounding alacrity for tool use, though they are not known for manufacturing tools in the wild. For example, captive rooks have been shown to bend wire into hooks to extract food out of a tube like New Caledonian crows, or work together to solve problems like chimps (though unlike chimps, they do not appear to understand when cooperation is necessary or how it works).4,5

Taken together, these snippets of their biology and behavior demonstrate what unique members rooks are to the Corvus genus.  I envy my counterparts across the Atlantic and Pacific and encourage them to take a second look at the rook whenever opportunities present themselves.

24125829295_1ee4b11b9f_z

Photo c/o Paul Wilson

Literature cited

1.  Dunnet GM, Fordham RA, Patterson IJ. (1969).  Ecological studies of the rook (Corvus frugilegus) in North-East Scotland.  Proportion and distribution of young in the population.  British Ecological Society 6: 459-473

2.Green P. (1996). The communal crow.  BBC Wildlife 14: 30-34

3. Coombs CJF. (1960). Observations of the rook Corvus frugilegus in southwest Cornwall Ibis 102: 394-419

4. Bird CD, and Emery NJ. (2009).  Insightful problem solving and creative tool modification by captive nontool-using rooks.  PNAS 106: 10370-10375

5.  Bugnyar T. (2008).  Rooks team up to solve a problem.  Current Biology 18: R530–R532

10 Comments

Filed under Birding, Corvid diversity, Corvid of the month, Diversity, Uncategorized