Category Archives: Birding

My first caramel crow 

A few months ago I was both bewildered and delighted when someone emailed me some photographs of a brown crow that regularly visited them.  I had never seen such a bird myself, and was eager to arrive at an explanation for the crow’s strange caramel-colored appearance.  If you follow the blog, you know that I came to realize there was little to offer by way of explanation.  Instead, this color abnormality presents a rather fascinating mystery of conflicting opinions and an overall dearth of science.

So, after penning my answer I tucked this bird away in the back of my mind and moved forward with the science more relevant to my PhD.  Namely, testing how different crows across the Seattle area respond to dead crows.

To this aim, I spend my days wandering the neighborhoods of Seattle looking for crow families to use for my experiments.  Since I need lots of data points it means I encounter lots (think hundreds) of individual crows.  And wouldn’t you know it.  Sometimes the twain shall meet.

Its mate first caught my eye because, of course, I was looking for black things, not blond things.  Even after I registered the bird, I instinctively thought pigeon.  But then it called, and I realized what was happening.

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At 60m away with my naked eye, I first mistook Blondie for a friendly pigeon.

I FOUND A CARAMEL CROW!  And not just a caramel crow, but a caramel crow with a mate and three fledglings.  A black mate and three black fledglings.  Which suggests that whatever is going on is either recessive or not genetic.  It also shows that, for at least this one caramel bird, the color abnormality did not prohibit it from successfully reaching sexual maturity or finding a mate.  After speaking with the neighbors, it appears “Blondie,” as they call it, has been in the neighborhood for several years and it’s possible she’s not the only caramel crow, though I never confirmed any others.  Outside of that, I can’t say much more from a scientist’s standpoint that I haven’t said before.  So I’ll simply finish the post with a photo story of Blondie.  Enjoy!

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Meet Blondie

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Blondie looks just as good in flight.

 

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Blondie and its mate.  Since I discovered this bird after its nestlings had already fledged, I have no way of determining its sex.

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So beautiful in this juniper tree!

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Blondie’s fledglings were typical looking crow kiddos.

The next batch of images are probably one of the most hilarious bits of fledgling dramatics I’ve ever seen.  It is a scene familiar to many parents I’m sure.  Forgive me for taking my scientist hat off, but I couldn’t help but add some anthropomorphic captions.

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Hello parent I am hungry.

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DID YOU HEAR ME, I SAID I’M HUNGRY.

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(whispering) help, parent, I need sustenance for my growing body.

 

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(muffled whispering) please, have mercy, it’s been over 15 minutes since I was last fed.

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MAYBE I’VE ALREADY DIED AND NOW I’M A GHOST IS THAT WHY YOU AREN’T LISTING TO ME???

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I’m sorry.  I’m just hangry.  I love you.

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Cheers to yet another beautiful crow.  Goodbye for now!

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Filed under Birding, Crow curiosities, Just for fun

RAVENous for crow eggs 

Given their similarities, it might surprise folks to see crows occasionally harassing and chasing ravens. After all, birds of a feather right? Not in this case.  Rather than being in cahoots, the relationship between crows and ravens is most often competitive, though it can also be predatory.

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A raven barrel rolls to scold an attacking crow.

Such is the case in a recent video shared with me by a reader, Ty Lieberman.  To the dismay of him and his colleagues, a crow nest they had been observing outside their Los Angeles office window was partially dismantled, and at least one egg taken by what they believed was a pair of crows.   Concerned for the survival of the nest, Ty reached out for my interpretation.  Based on his initial description, I wondered if maybe he had witnessed egg transport, something I knew had been observed in black-billed magpies and pinon jays.1  Previous accounts of these species included descriptions of eggs being taken, and then returned to the nest, as well as eggs being deposited into the nests of neighbors, both of which are utterly fascinating behaviors and probably warrant their own post.

To date, however, there are no accounts of crows engaging in this behavior, though there is one documented observation of a nestling being deposited into a nest from which it did not originate.2  Again, utterly fascinating, but not helpful here.

Later, a more detailed account from Ty made mention of the size of the intruding birds, which quickly led me to the story’s true explanation.  Shortly after my ‘ah ha’ moment, to the dismay of he and his colleagues the nest raiders returned, and this time were caught on video by one of Ty’s colleagues (who you can follow on twitter, @namnam).  Rather than being crows, these literal homewreckers were common ravens.

Instead of being something out of the ordinary, Ty had witnessed a typical breeding season interaction between crows and ravens.  It’s no wonder then, that crows can be so hostilie when ravens enter their territory. 

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Crows (top) mobbing a raven (bottom) in Kent, WA

Eggs of all kinds are one of the most power-packed meals in the animal kingdom, so it’s no surprise ravens would take advantage of crow nests when they find them.  Around this same time back in 2015, a black bear made a similarly memorable meal out of a raven nest, reminding us that for corvids of all kinds, it’s a constant fight between being predator or prey.

Literature cited

  1.  Trost CH and CL Webb. 1986. Egg moving by two species of corvid. Animal Behaviour 34: 294-295.
  2. Schaefer JM and Dinsmore JJ.  1992.  Movement of a nestling between American crow nests.  The Wilson Bulletin 104: 185-187

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Filed under Birding, Breeding, Crow behavior, Raven behavior

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!

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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.

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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.”

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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.

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Pied crow, photo c/o Frank Vassen

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

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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.

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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.

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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,

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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!

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Filed under Birding, Corvid trivia, Crow curiosities, 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).

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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

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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.

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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

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

Are you playing #CrowOrNo yet?

Crows, ravens, magpies, even blackbirds or other non-corvid species can be tricky to distinguish from one another if you’re a beginning or even experienced birder given the right angle or blurry photo.  While some of it is a matter of learning key field markers, a big part of effectively learning to distinguish these species is an eye for the subtle differences in portion or appearance that comes with practice.  I believe learning these skills is not only fun, but makes us more informed corvid lovers and birders.

To that aim, I’ve started a weekly #CrowOrNo “quiz” on my Instagram (@swiftcrow) and Twitter (@kswift_crow) accounts.  Every Wednesday at 11:30 AM PST, I’ll post one photo and it’s up to you to decide whether or not it’s really a crow.  At the end of the day I’ll share the answer and any tips or tricks that would have helped to discern the true species.  Play, share, or simply spectate.  Whatever you’re comfortable with is fine for me, as long as you’re enjoying the process and learning more about these wonderful animals!  Check out the photos below for examples from past weeks.  I hope to see you there!

Oh, and have photos you think would make good fodder for the game?  Send them my way!

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Filed under Birding, Corvid trivia, Just for fun

New research on the cause of the AKD outbreak

Since the nineties, Avian Keratin Disorder has been an increasingly common disorder among Alaskan and PNW crows, chickadees (~17% of northwest crows1, ~6% of black-capped chickadees2) and a handful of other species, that causes gross deformities of the beak such as elongation, curvature or crossing.  I’ve written previously about the details of this disease before, but at that time there was little progress in determining the underlying source of the outbreak.  While AKD can be caused by a variety of things, at the scale it’s being observed now scientists questioned if there was a more consistent underlying factor.  Since AKD can cause discomfort or even death (primarily through the inability to feed or preen) understanding what might be the source of this outbreak has clear management and conservation implications.

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An AKD-afflicted American crow in Seattle, WA.

Among the initial suspects were environmental contaminants such as heavy metals, organic pesticides, and toxic environmental pollutants like PCBs, PCDDs, and PCDFs.   Blood work done on afflicted Northwestern crows, however, showed no significant difference in the 30 blood elements tested compared to unaffected adults or juveniles3.  Fortunately, new research may finally be shedding light on what’s going on.

Disease can be an easy thing to rule out if you know what you’re looking for, but new to science pathogens can evade traditional diagnostic techniques.  To account for this, a team of USGS and university scientists conducted a sequencing study comparing pooled RNA of healthy and AKD positive chickadees, crows and nuthatches in attempt to identify a candidate pathogen2.  Their work appears to have paid off, revealing evidence for a new picornavirus (a family of viruses previously known to science) they are calling poecivirus.  Whereas 100% of AKD-affected birds (23 subjects) tested positive only 22% of the 9 control individuals did.

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Alaskan black-capped chickadee with severe AKD. Photo c/o Martin Renner

Given these small sample sizes, it’s too early to throw our hands up in complete relief of having identified the cause of the AKD outbreak, especially since there’s still much to be done in understanding the potential relationship of this new virus to the environment.  Nevertheless, these findings offer some insight and hope that scientists are on the right track.  With more dedicated work we may soon have a much better understanding of this novel pathogen, its link to AKD, and management options moving forward.

Literature cited

1.  Van Hemert C, & Handel CM. 2010.  Beak deformities in Northwestern crows: Evidence of a multispecies epizootic.  The Auk 127: 746-751.  doi: http://dx.doi.org/10.1525/auk.2010.10132

2. Zylberberg M, Van Hemert C, Dumbacher JP, Handel CM, Tihan T, and DeRisi JL. 2016. Novel picornhttps://wordpress.com/post/corvidresearch.wordpress.com/3363avirus associated with Avian Keratin Disorder in Alaskan birds.  mBio 7 doi: 10.7589/2015-10-287

3. Van Hemert C, Handel C. 2016.  Elements in whole blood of Northwestern crows (Corvus caurinus) in Alaska USA: No evidence for an association with beak deformities.   Journal of Wildlife Diseases 52:713-718 doi: http://dx.doi.org/10.7589/2015-10-287

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Filed under Birding, Corvid health, Crow curiosities, Crow disease, Crow life history, Ecosystem, Uncategorized

15 of the prettiest corvids from around the world

When most Americans think of corvids, the color palette that probably comes to mind is black, grey, blue, white and iridescent.  Together, these colors have certainly assembled a handsome collection of birds, but there’s an awful lot more pigments in the corvid family than that.  Even among those colors, some of the more topical corvids exploit them in dazzling ways.  Unlike American or New Caledonian crows though, these birds have not gotten their fair share of the corvid limelight and it’s time we change that.  The following is a sample of just some of the corvid diversity more folks should know about.  If you really want to have a little extra fun, ignore the scientific names and see if there are any birds you would group together in the same genus (reminder: Family>Genus>Species).  Then you can go back and look at the first part of the scientific name to see if you were right!

These photos were primarily sourced from some of the generous and talented photographers that can be found on Flickr.  Please click on their names to see more of their great work.

1. Common green magpie (Cissa chinensis).  Found in parts of India, China and Indonesia.  A flocking corvid often found low in the canopy where they can be very difficult to spot among the vegetation.  According to the International  Union on the Conservation of Nature (IUCN) their populations are considers stable and of least concern.

2. Taiwan Magpie (Urocissa caerulea).  Endemic to Taiwan, these are flocking corvids that feed mostly from tree canopies.  Their populations are stable.

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Photo c/o Dave Irving

3. Lidth’s jay (Garrulus lidthi).  The only jay endemic to Japanese islands of Amami-oshima and Tokunoshima.  In the fall they can gather in groups as large as 100 birds where they feed mainly on acorns.  Habitat loss and predation have this bird listed as declining and vulnerable.

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Photo c/o Mark Curley

4. Unicolor jay (Aphelocoma unicolor).  Ranges intermittently from western Mexico to El Salvador and may have as many as 5 subspecies! They are considered of least concern, though populations are declining.

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Photo c/o Maynor Ovando

5. Green jay (Cyanocorax yncas). These jays can be found from southern Texas throughout central America and as far south as Peru.  Although they are a solitary breeder, they are very social in the non-breeding season.  Populations are increasing and they are considered of least concern.

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Photo c/o Wade Strickland

6. Spotted nutcracker (Nucifraga caryocatactes).  Native across Europe and Asia, theses birds are monogamous and generally hang out only with their mate.  Like the unicolor jay they are considered of least concern but trends point towards decline.

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Photo c/o Dave Irving 

7. Ceylon magpie (aka Sri Lanka blue magpie; Urocissa ornata).  Another Sri Lankan endemic.  These birds can be seen in pairs or small flocks where they noisy work the tree canopy.  They are considered vulnerable and declining.

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Photo c/o Dave Irving 

8. Black-throated magpie jay (Calocitta colliei).  This bird is limited to northwest Mexico where it can be found in open woodlands chatting loudly and waiving their tails.  They are common and populations are stable.

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Photo c/o Ahmed Eldaly

9. Turquoise jay (Cyanolyca turcosa).  Can be found in the humid forests of Ecuador, north Peru, and south Columbia.  Overall this species is poorly documented.  Right now it is considered a least concern species but it’s possible that’s due to lack of data.

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Photo c/o Dave Irving

10. Rufous treepie (Dendrocitta vagabunda).  Found across India and southeast Asia.  These birds are generally wary of people but have been known to enter houses to look for geckos.  Would love to find one in my house!  Populations are stable and they are considered least concern.

11.  Gold-billed magpie (Urocissa flavirostris).  Endemic to Taiwan, these birds keep their tails erect when on the ground, possibly to prevent the feathers from being damaged. Populations are stable and they are considered of least concern.

12. Bornean green magpie (Cissa jefferyi).  Found only in Indonesia and Malaysia, these birds look (and act) similarly to the common green magpie.  Relatively little is known about this species as they are hard to access high in the mountain forests.  It’s listed as of least concern.

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13. Eurasian jay (Garrulus glandarius) Found throughout Europe, Asia and Northern Africa.  This bird is common to most birders outside of North and South America.  Although these birds remain with their mates for extended periods they do not keep much contact throughout most of the year. Eurasian jays are in no danger of global population decline.

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Photo c/o Simon Forster

14. Azure-winged magpie (Cyanopica cyana).  Native across Asia and as far north as Mongolia and southern Siberia*. They form small family parties during the breeding season but amass into large groups during the nonbreeding season.  Populations are increasing and they are of least concern.

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Photo c/o Crotach

15. Finally we have, literally, the beautiful jay (Cyanolyca pulchra). Found only in the Andes of Columbia and north Ecuador.  They can be found alone or in pairs but are not believed to interact in large social groups.  Little known about reproduction, social behavior or predators.  Populations are declining and near threatened.

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Photo c/o Andrew Spencer

Did you pick out a favorite bird?  Let me know in the comments and I’ll try to dedicate a post to it!

Literature cited

*A previous version of this post incorrectly stated that the Azure-winged magpie spread as far west as Spain and Portugal.  Although this was true at the time the reference guide used to write the post was written, since 2002 these western birds have been splint into their own species called the Iberian magpie1.

1Fok KW, Wade CM, Parkin DT (2002). “Inferring the phylogeny of disjunct populations of the azure-winged magpie Cyanopica cyanus from mitochondrial control region sequences.”. Proc. Roy. Soc. B Biol. Sci. 269 (1501): 1671–1678.doi:10.1098/rspb.2002.2057.

All other species descriptions were based on: Madge, S. and Burn, H. 1999.  Crows and jays.  Princeton, New Jersey: Princeton University Press 1999.

 

 

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Filed under Birding, Diversity