Category Archives: Crows and humans

15,000 crows

I had imagined it like a beckoning flood.  A small sputter of water followed with increasing force until a great river finally makes its way.  Rather than water though, the flood I was trying to envision was the ascent of 12-15,000 crows to their nightly roost in Bothell, Washington.

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Witnessing it in person, I found that my water analogy was not entirely accurate.  Rather than being a steady stream with a predictable course, their arrival ebbed and flowed, sometimes leaving the sky lonely with only its fading grey light while other times exploding into seemingly endless black clouds.  They arrived from all cardinal directions, colliding into a mass that could be deafening at close range.  Although the movement of the flock as a whole was more restrained, individually they showed off with spontaneous dived and barrel-rolls.  Soon the light receded completely, and all I could sense was the cacophony of so many crows settling into the willow trees they would call their beds for the evening.

Time lapse of Bothell crow roost I took with my GoPro in December of 2016.  Music by Andy McKeen.

Since that first experience, I have visited the Bothell roost many times, each as awe inspiring as the time before.  This behavior isn’t unique to my region, however.  Cities and rural areas all over the world call themselves home to the upwards of thousands, even hundreds of thousands of crows that may seek their refuge when darkness falls.  Even in the greater Seattle area, Bothell is only one of two roughly equally sized roosts.  This kind of mass sleepover, known as communal roosting, isn’t unique to crows, but it certainly captures our attention in ways most other birds don’t.  So what exactly are the characteristics and functions of roosts?

For all species of corvid, roosts are places where anywhere from a small handful to hundreds of thousands of individuals may converge to spend the night together.  Though roosting occurs year round, it peaks in winter, when territorial pairs are free from the eggs or nestlings that demand all-night attention.  They may occur in wildlands, but more typically occur in cities, where sequestration of heat is higher than in surrounding areas.  Here in Bothell, the roost converges in a wetland outside of the University of Washington’s Bothell campus, but in other areas they may take over the rafters of abandoned buildings or trees dotted within a business district.

Historically Danville, IL hosted North America’s largest roost, a whopping 325,000 birds but I do not know if they remain the contemporary record holder.  The midwest is particularly primed to host such large numbers because many thousands of crows head there during winter from their too cold territories in Canada and because appropriate roosting locations are few and far between.

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Prior, or just after roosting crows attend “staging” or “pre/post-roost” areas where they gather in the trees or on the ground by the hundreds or thousands.  Since these staging areas often occur on asphalt or turf where there’s little food or water, their function continues to elude scientists though social or anti-predator implications seem likely.1 A new UW research study is attempting to parse why crows are so vocal during the staging period and what they might be trying to communicate.  Perhaps their findings will shed some much needed light on these events. 

Corvids get different things out of roost itself depending on the species or possibly even the region they live.  For example, for ravens roosts act, in part, as mobile information centers.2  A raven knowledgeable of a food bonanza such as a moose carcass will display to other ravens at first light, and recruit others to the food.  Rather than being a sign of food altruism, this kind of recruitment is often the only way a lone raven can gain access to a large carcass.  Finding and gaining access to an animal carcass is challenging both because its arrival is unpredictable but also because it’s intensely guarded by the pair whose territory happened to claim the animal’s life.  Overpowering a pair takes a small army, so by recruiting other birds, rather than giving up food in the name of helping others, the lone raven actually gains access to a resource it would have otherwise been boxed out of.

American crows on the other hand do not have this need because urban waste and invertebrate filled yards are so easy to come by.  For crows, roosts act in large part as predator protection.  The odds of successfully fleeing an incoming owl are much better when there are thousands of you, rather than just you and your mate.  They may serve other purposes as well though including socialization, mate finding, and thermoregulation.  Lastly, while there isn’t strong evidence of information sharing among crows it would be arrogant to claim we know it doesn’t occur.

How roosts are organized remains largely mysterious.  For example some evidence shows that ravens that come from the same food bonanzas also sleep near each other in a roost,2 whereas other work done on crows suggested that group cohesion is low at roosts.3  Still, other research suggests that while group cohesion from the territory is low,  it’s high leaving the staging area.  So perhaps there is deep rhyme and reason for who they sleep with, it just hasn’t been captured by the questions we’ve so far asked.  One thing is for certain though; the one place you don’t want to be is low in the trees with others above you.  There would be no escaping the white shower raining down throughout the night.

Even the people who share the UW’s campus are sensitive to this reality.  In perfect synchrony with the incoming cloud of birds, the umbrellas bloom like moonflowers.  Here in Seattle, people seem willing to take such measures to coexist with the birds (though I’m sure there are many who only do so only by rule of law).  In other areas though the cultural attitude or resulting damage makes such cohabitation difficult, even deadly.  In the most extreme case, 328,000 crows were killed in 1940 when the city of Rockford, IL elected to dispose of a local roost with dynamite.4  Today, crows are protected under the migratory bird treaty act and cities are usually required to take more creative, non-lethal approaches including noise and light deterrents.

City living doesn’t always lend itself to witnessing the kind of mass animal movements we fawn over when they appear in Planet Earth footage, but that doesn’t mean they are devoid of such spectacles.  The mass micro-migration of thousands of crows is an awe inspiring event,  grand in both scale and the mysteries it contains.  Any corvid or birdwatcher would be remiss to ignore such an opportunity and I encourage everyone to get outside, head to your roost, and watch the magic unfold.

Literature cited

  1. Moore JE, and Switzer PV. (1998).  Preroost aggregations in the American crow, corvus brachyrhyncos.  Canadian Journal or Zoology.  76: 508-512.
  2. Wright J, Stone RE, and Brown N. (2003).  Communal roosts as structured information centers in the raven, Corvus corax. Animal Ecology 72: 1003-1014.  DOI: 10.1046/j.1365-2656.2003.00771.x
  3. Donald F. Caccamise, Lisa M. Reed, Jerzy Romanowski and Philip C. Stouffer
    (1997). Roosting Behavior and Group Territoriality in American Crows. The Auk 114: 628-637
  4. Marzluff, J.M. and Angel, T. 2005. In the company of crows and ravens.  Yale University Press

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Filed under Birding, Crow behavior, crow conflicts, Crow curiosities, Crow life history, Crows and humans

Gifts for crow lovers

With the holiday season upon us, many people find themselves tasked with finding thoughtful gifts for their loved ones.  Although birds are seemingly so universally adored that finding bird themed gifts is no trouble, if it’s specific species you’re after, the challenge can be more immense.  Fortunately for crow lovers, there are lots of options to choose from if you know where to look.  Since you’re looking here, rest easy that half the battle is now over.  So sit back, enjoy, and feel free to add your own suggestions in the comments.

    1. Jewelry and apparel
    2. Art
    3. Books and education
    4. Kids
    5. Conservation


    Jewelry and apparel

    Sometimes you want to wear your passions on your sleeve, literally.  Fortunately online marketplaces like Etsy makes this more than possible.  A quick search of “crow t-shirt” reveals hundreds of options for any aesthetic.  Personally, I like to stick with shirts featuring original art.  Here are some of my top Etsy picks:

    Coyotees Maine

    Elusive Catfishery
    Maison Hydre
    Kathy Morton Stanion

    Outside of Etsy the apparel options can be harder to find but they are out there.  Charlie Harper for example, has an awesome screen printed tee that any crow lover will adore.

    For jewelry you can turn, once again, to Etsy but there are other options too.  June Hunter, who I also recommend elsewhere on this list, has a great collection of corvid themed jewelry.  The bonus here is that I can personally attest to the care and passion June has for these birds, so finding something in her shop will not only deem you an awesome gift-finder among your crow friends, but you’ll be supporting the work of someone who is themselves an ardent lover of crows.  Your local art galleries can also be great places to find amazing crow themed jewelry.  A favorite among my own collection was sourced from the Mary Lou Zeek gallery in Salem, Oregon.


    Art

    I can’t stress enough here that your city’s art galleries and boutiques can be great places to find local, handmade, and even one of a kind items.  Many people (including artists) love crows, which is good news for your brick and mortar shopping prospects.  Please, spend your money locally as much as possible.  That said, here are some online shopping options that support talented artists:

    From prints, to wall art, to totes and calendars, June Hunter has you covered.  Her Vancouver based studio celebrates the beauty of urban wildlife, with a special emphasis on crows.

    If ever I find myself with a great deal of disposable money, purchasing one of Jason Tennant’s astounding wood carvings will be among my top priorities.  Seriously, they’re unbelievable.  And wouldn’t luck have it, ravens are a fairly regular subject of his work.

    If it’s illustrations and painting you’re after, Etsy is once again a great resource. From acrylic to watercolor, there’s something for everyone.  Hey, even if you want something more out of the box like stained glass, you’re bound to find something.

    Perhaps the person you are shopping for already has walls covered in corvid paraphernalia and you need to get a little more creative with housewares.  Laura Zindel will help you outfit their shelves and table tops with gorgeous ceramics.  I own a set of plates and can attest to their beauty and durability.


    Books and Education

    There are so many excellent books on the topic of corvids that covering them really requires its own post. Fortunately, that post already exists, so I’ll simply direct you to it here.

  1. Books aren’t the only way, however, to give the gift of knowledge. Back in 2010, PBS first aired their NATURE documentary, A Murder of Crowswhich showcases a number of great studies and anecdotes, including the facial recognition work conducted by John Marzluff. Although you can stream the video for free, $18 is a small price to pay for being able to watch it whenever you please, and showing PBS some love.
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    For the ultimate crow education however, you should consider registering your loved one for the North Cascades Institute’s corvid class that’s offered the last weekend in June and is taught by John Marzluff and myself.  It’s a two day class complete with lovely and TAG approved accommodations, great food, beautiful scenery, and more information about corvids than you can possibly retain.  We often see nearly every species of corvid found in Washington, including ravens, crows, magpies, Clark’s nutcrackers, Steller’s jays and grey jays.  Registration for this year won’t open until January or February, but who doesn’t like an IOU for a gift?  It is worth noting the class fills up quickly once registration is open so make sure to stay on the ball.

  2. Kids

    I firmly believe that the indoctrination of crow love into kids should begin early; immediately if possible.  Fortunately, Etsy has your back with onesies, night lights, and probably whatever else your imagination can cook up.  For stuffies, local children’s stores or nature stores often carry raven or crow themed plush toys including this awesome raven puppet.

    There’s no shortage of corvid books aimed at kids either.
    10 roudy ravens by Susan Ewing is a counting book great for early readers.
    Lila and the crow by Gabrielle Grimard tells the story of a little girl who learns the beauty of being different from her neighborhood crow.
    Clever crow by Cynthia De felice uses rhyme to tell the story of a young girl trying to outwit a mischievous crow that is stealing trinkets from her mother.  Obviously the biology isn’t a highlight here, but the reviews are otherwise great.
    If accurate biology is what you’re after, Crow smarts by Pamela Turner promises to introduce children (and adults!) to the astounding minds of crows.
    For a children’s book that is more for adults than kids, consider Aldous Huxley’s The Crows of Pealblossom.  Considering that crows and snakes are both often on the receiving end of misguided public vitriol, I’m not a fan that the crows’ triumph comes at the  expense of the snake’s grisly end.  While the snake’s fate may not be appropriate for sensitive children, any adults that share a love of crows and Huxley’s other works will surely be delighted.


    Conservation

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    Perhaps your family tradition is that gifts should give back, or you recognize that your recipient would be happier knowing money was spent towards helping crows.  The Alalā, or Hawaiian crow, is one of the most endangered animals on the planet. Since 2002, they have been considered extinct in the wild.  Thanks to captive breeding efforts by the Alalā project, which is a partnership between San Diego Zoo Global and the Hawaiʻi Division of Forestry and Wildlife, and the US Fish and Wildlife Service, eleven individuals were just released into the forests of the Big Island.  These kinds of captive breeding and reintroduction programs are the only hope for these birds, but they are expensive.  By donating not only can you directly help their cause, but you can demonstrate public interest in keeping this species alive.  Currently, there is no way to donate money online but you can do so the old fashion way.  Make checks payable to San Diego Zoo Global and put in the memo line that the money is to be directed to the the Hawaiian crow project.  I called San Diego Zoo Global to confirm that money can be allocated to the Alalā project specifically.  Mail checks to: P.O. Box 120271 San Diego, CA 92112.

    With these suggestions in mind, I wish you the best in your search for the perfect gift for the crow lover in your life. Happy hunting and please feel free to mention your own gift suggestions in the comments section.

 

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Filed under Crows and humans, Just for fun

Saving the rarest crow

It can be hard to imagine crows as anything but ubiquitous.  During winter across the country, dusk marks the time where some cities see their skies turn black with thousands, even hundreds of thousands of American crows converging to roost.  These crows have taken nearly all that people have thrown at them: deforestation, mass waste, and the urban sprawl that simplifies previously complex ecosystems, and uses it to their advantage.  Not all species of crow have thrived in the Anthropocene, however.

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Thousands of gather accumulate in the skies above UW’s Bothell campus in the winter

Far from being icons of the ultimate adapters some species of crow represent some of the most endangered animals in the world.  Among those, the ‘Alalā or Hawaiian crow, is arguably one of the rarest birds on earth. Once locally abundant in the forests and woodlands of Hawaii’s Big Island, their decline began in the 1890’s following persecution by coffee and fruit farmers1.  Back in September, 2015 there remained only 114, all living  exclusively in captivity giving them the unenviable title of ‘extinct in the wild’.  How can one species thrive with such zeal while another holds on by a thread?

Island species are generally more specialized and therefore more sensitive to human induced changes.  In fact proportionally, islands host a higher number of endangered or extinct species than continental areas2.  In Hawaii alone, 77 different species of endemic birds have gone extinct since the arrival of the Polynesians 2,000 years ago4, all largely for similar reasons: habitat destruction and invasive species.

Unlike their generalist, continental counterparts, the ‘Alalā is more specialized to feed on understory fruits and nuts and in fact were key seed distributors for many of Hawaii’s native plants.  Island living also fostered a similar behavior seen in only one other species of crow: tool use.  Like the New Caledonian crow, the ‘Alalā is a dexterous tool user, though the two species are only distantly related.  Scientists believe this example of convergent evolution is fostered by aspects typical of islands, namely low predation and low competition for embedded food5.

Unfortunately, limited distributions and higher specialization also meant their population was more fragile than that of continental crows.  Logging, agricultural development, loss of native pollinators, and alterations by non-native ungulates challenged both food acquisition and breeding habitat.  Introduced diseases such as avian pox, malaria and the Toxoplasma gondii parasite carried by cats further weakened an already ailing population6,7. Invasive predators including rats, mongoose and cats consumed eggs, nestlings and fledglings.  Finally, humans continued their tradition of persecution, particularly feral pig hunters who would shoot the birds before they could alarm call and scare off their prey2.

Together, these threats set into motion a decline in population we failed to recover despite some increases in research and management starting in the 1970’s.  The last known wild egg was laid in 1996, and the last wild pair was seen in 20022,3.  Some people did recognize the urgency of their decline prior to 2002, however, and a captive breeding population was started successfully rearing over 90 birds8.  Although such a small number of breeders may raise red flags with respect to inbreeding and genetic depression, this is rarely as big of an issue as is commonly perceived.  Unfortunately, light management and depredation by the also endangered Hawaiian hawk (‘io), decimated the released population and reintroduction efforts were halted in 1999 until a larger captive population and better management strategy could be devised.

Since that time, the ‘Alalā Restoration Project (collaboration between the State of Hawaii, the U.S. Fish and Wildlife Service, and San Diego Zoo Global) has spearheaded captive breeding programs on Maui and the Big Island culminating in a population of over 100 birds.  An important part of these captive breeding programs is the use of puppets, which help prevent habituation to humans9.  In addition, intensive management operations have taken place to ready their prospective home at the Pu‘u Maka‘ala Natural Area Reserve including the removal of invasive/feral animals, erecting exclosure fencing, and constructing a sort of half-way house to help ease the birds into life in the wild.  These efforts have not been without setbacks, however.  Back in June, 2015 two miles of protective fencing was cut down by vandals, though their motivations remain unknown.

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A human dressed as an ‘Alala feeds captive reared nestlings. Photo c/o San Diego Zoo Global

Finally, after so much work, the end of 2016 marked the first time researchers and managers agreed the elements were in place for a reintroduction effort.  On December 14th, five male birds were released onto the reserve, marking the first time the ‘Alalā set claw into the wild since 2002.  Sadly, within weeks all but two had died. Two were killed by the native Hawaiian hawk or ‘lo, and the third was killed by “natural circumstances” which, I’m guessing, is related to a heavy storm that occurred shortly after their release.  As a protective measure, the remaining two were recaptured until the results from the necropsies are obtained.

While clearly disheartening, early hiccups in a release effort like this are not unusual and conservationists and biologists are not losing hope that success is still possible.  Part of ensuring such success, however, is undoubtedly public support particularly with respect to maintaining the strength of the Endangered Species Act and support of the ‘Alalā Restoration Project.  The perception that all crows are alike or that generous populations of American crows means protections for other corvus species is unwarranted or redundant will be a disaster for these rare birds.  So make your voice heard when funding for conversations efforts come under fire, and share your passion for endangered corvus species with friends and family.  The fate of the world’s rarest crow quite literally depends on it.

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Two newly released ‘Alalas peer around their new surrounding in the Pu’u Maka’ala Natural Area Reserve.  Photo c/o the San Diego Zoo Global 

Literature cited

  1. https://www.fws.gov/pacificislands/fauna/alala.html
  2. Faike, E. 2006. Wild voices in captivity: the date of the ‘Alala. Birding 38: 64-67.
  3. Banko, P. C.; Burgett, J.; Conry, P. J.; David, R.; Derrickson, S.; Fitzpatrick, J.;
  4. National Research Council (US) Committee on Scientific Issues in the Endangered Species Act. Science and the Endangered Species Act. Washington (DC): National Academies Press (US); 1995. 2, Species Extinctions. Available from: https://www.ncbi.nlm.nih.gov/books/NBK232371/
  5. Rutz C, Klump BC, Komarczyk L, Leighton R, Kramer J, Wischnewski S, Sugasawa S, Morrissey MB, James R, St Clair JJH, Switzer RA, and Masuda BM. (2016).

    Discovery of species-wide tool use in the Hawaiian crow.  Nature 537: 403-407 doi:10.1038/nature19103

  6. Maxfield, B. 1998. Wild ‘Alala population suffers major setback. ‘Elepaio 58: 51.
  7. Liebermann, A.; Nelson, J. T.; Simmons, P.; Unger, K.; Vitousek, P. M. 2003. Draft revised recovery plan for the Alala (Corvus Hawaiiensis. US Fish and Wildlife Service, Portland, OR, USA.
  8. Lieberman, A. C., Kuehler, C. M. 2009. Captive propagation. In: Pratt, T. K.; Atkinson, C. T.; Banko, P. C.; Jacobi, J. D.; Woodworth, B. L. (ed.), Conservation Biology of Hawaiian Forest Birds: Implications for Island Avifauna, pp. 448-469. Yale University Press, New Haven.
  9. Valutis LL, and Marzluff JM. (1999).  The appropriateness of puppet-rearing birds for reintroduction.  Conservation Biology 13: 584-591

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Filed under Conservation, Corvid diversity, Corvid health, crow conflicts, Crows and humans, Ecosystem

5 reasons to leave baby crows alone 

Those blue eyes, that awkward gate, their seemingly constant precariousness, they’re all calling to you to intervene. Here are 5 reasons second guessing that instinct might be in the bird’s best interest.

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1) The vast majority don’t need your help. It’s totally normal for baby crows to be on the ground and flightless as long as they’re covered with feathers and appear otherwise alert and mobile. Even nestling crows are usually on the ground on purpose. Not because they are ready, but because their parents have intentionally rejected them for one reason or another. They will die and that’s ok. Part of coexisting with wildlife is giving them the agency to be wild. The story is different of course for species where the survival of individuals may mean the difference between population survival and extinction, especially because these situation are almost always driven by human activity.

2) It’s hard to tell when they’re stressed.  Recently, I saw a video on Facebook of a Steller’s jay fledgling in the care of a very well intentioned good samaritan.  She was giving it gentle strokes with her fingertips, each touch resulting in the young bird turning its head towards its back and opening its mouth.  The comment thread filled with ooo’s and awww’s and general comments of encouragement or gratitude for her actions.  For me it was like watching an alien attempt to care for a human child, the child recoiling and screaming while its caretakers congratulated themselves on how kind they were being.  Having handled baby corvids before, I know what that kind of posturing means, it means “I’m scared and stressed.”  To an untrained eye though, it may not look much different than the kind of gaping that means ‘feed me.’  Being stressed to death is a reality for young, or even adult animals, so any handling best be done by experts whenever possible.

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3) It’s illegal to rehab crows without a license. You can provide temporary care until you can get them to a licensed facility, but do not attempt to rehab them on your own.  Mistakes like the one I just described are a prime example of why the law seeks to protect animals by ensuring they are only raised or rehabilitated by experts.  For more information on how to handle them until you can get them to a facility visit my previous post.

4) Imprinted crows do not survive well in the wild.  Even if baby crows are receptive to being treated like a pet, doing so is both a legal violation and I would argue a violation of their right to be a wild animal with a healthy fear of people.  Of all my daydreams, at the top of the list is having a wild but imprinted crow that follows me around.  I even have a name picked out.  This fantasy of mine will forever remain just that, however, because it’s too dangerous to allow a crow to become that comfortable with people.  All it would take is one cranky neighbor with a pellet gun and it would be over.  Not to mention being imprinted on people, instead of crows, denies them access to skills and relationships with other crows that will help them survive into adulthood.

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Killing them with kindness is a real risk.

5) It may do more harm than good.  The conventional wisdom suggests “well, worse case scenario is I try and rehab this baby crow and it dies, which it would have done anyway so really, nothing’s been lost.”  The more we study death in social animals the more we are beginning to realize there may be a cost to prematurely removing ailing or dead animals from their groupmates, however.  Being able to interact with their dead may serve an important role for social animals, and denying them this opportunity may have serious implications in their ability to process that death.  So be thoughtful about how slim the chance of survival is.  It might be that the kindest, most responsible action is no action at all.

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Filed under Corvid health, Crow behavior, Crow curiosities, Crow life history, Crows and humans, Uncategorized

Everything you want to know about crow nests

Spring marks one of my favorite times of year.  Cherry blossoms abound, the rain smell sweet and the birds get busy putting their carpentry skills to good use. Starting early March, the silhouettes of crows with bill loads of timber or wads of soft material dot the skies as they shuttle back and forth to their nest tree. Like a townhouse development, these construction projects are over in the blink of an eye and soon, their bill loads of twigs will be replaced by food for their mate and, eventually, their insatiable young. Spotting these nests is both a great way to observe and engage with your local crow family and avoid unpleasant conflicts with protective crow parents.  With a little knowledge and a bit of practice, tracking down your resident crow nest will become one of your favorite spring traditions in no time.

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Nest construction and site selection

Nest construction begins in early March and will continue (as nests fail) through about June. It takes 1-2 weeks to finish a nest after which the female will lay a clutch of 2-6 eggs. Unlike similarly sized squirrel nests (aka: dreys) which are made of leaves, crow nests are made mostly of pencil-width twigs. A new nest is usually about 1.5 ft across and 8-10 in deep.  After the bulk of construction is complete, they’ll line the cup of the nest with soft materials like grass, tree bark, moss, flowers, paper or fur. Once we saw a crow ripping out the hair of an outdoor manakin, no doubt to use as lining material.

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A crow gathers moss off the branches of a big leaf maple to use as lining material.  


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This bird toyed with this branch for a few minutes before rejecting it and letting it fall to the ground.  


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A sidewalk littered with twigs is good evidence that the nearby deciduous tree is a favorite among the local crows to pull branches from.  I’ve only once seen a crow try and retrieve a branch it dropped, so these are all rejects.  

 

Crows will nest in an astounding array of places, from the eaves of skyscrapers to the crooks of well concealed tree limbs. They can tower in the sky or be almost within reach. Most commonly, I see them built close to the trunk in the top third of Doug fir trees, but this is, of course, specific to the PNW.  Both partners participate in nest construction. Helpers will aid to some degree but most of the work is left to the parents.

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Differences among corvids

Crow, jay and raven nests are similar in shape and material but differ in overall size in accordance with the size of the bird. The main standout are magpies,  which build incredible domed-shaped nests the size of a large beach ball.  The nests require so much material, they can take as much as 40 days to build.  Japanese jungle crows are another species of note, as they have a (relatively) new and problematic habit of building nests out of wire hangers and causing massive blackouts.

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A Jungle crow nest in urban Japan. Photo: Götz


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The magpie’s nest is the big clump in the middle of the tree.

Reuse

The life of a typical nest is only about 9 weeks (1-2 weeks of building, 6 days of laying, 20 days of incubating and 4 weeks of nestlings) though they are hardy structures and can remain intact in a tree for years.  After the young fledge, the crows will not return to the nest.  Crows will only use a nest once, and generally only fledge one brood a year. They will, however, build on top of an old nest particularly in areas where nest trees are especially sparse like downtown Seattle. This also appears to be more common in the Midwest.

Avoiding conflicts

Most breeding related dive bombs occur as the result of a person being too close to a fledgling, but some crows get feisty around their nest too. Crows in areas where they are less persecuted (like cities) tend to be more aggressive than their rural counterparts. If you know where a nest is and can avoid it, do so and save everyone the aggravation. Otherwise carry an umbrella or paint eyes on the back of a hat. Crows rarely attack from the front so having eyes on the back of your head can be an effective deterrent!

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Putting all this together to actually find nests, is one of the most rewarding moments an urban naturalist or crow enthusiast can have.  Be warned though: crows are wary of potential predators (including people) spying on them and they have a few tricks for throwing you off, so don’t be surprised if a nest location you were certain of turns out to have been a ruse!

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Can you spot the nest? 

Have more questions? Let me know in the comments!

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Filed under Birding, Breeding, Crow behavior, Crow life history, Crows and humans

Crow curiosities: Do crows collect shiny objects?

The notion that corvids, especially magpies, have a special affinity for shiny object has been around for more than a century.  In fact to refer to someone as a magpie is to describe them as someone who ‘compulsively collects or hoards small objects’.   This idea is so old hat that it can feel a bit frivolous to even wonder if it’s true.  The trouble with this bit of corvid whimsy, however, is that when we do investigate it, and scientists have, we find there’s no empirical evidence to support it.

'Crow Collects' by Cori Lee Marvin.

‘Crow Collects’ by Cori Lee Marvin.

For instance, one study1 presented both captive and free-living magpies piles of blue or shiny silver screws, rings, and pieces of tin foil near piles of food to which they had been previously habituated.  They found that, rather than thieving and subsequently caching the gleaming objects, the birds were actually more nervous to take food than they had been previously.  In the 64 conducted tests, only two instances of contact between a bird and an object were recorded.

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Experimental set-up for magpie study.

Cornell crow expert Kevin McGowen, elaborates on this general conclusion, suggesting that perhaps the origin of this folklore is pet crows who are attracted to the objects of obvious value to their owner like coins, keys or jewelry.  Speaking personally as someone who has spent countless hours observing hundreds of individual crows in the field, I can also attest to the fact I have never witnessed anything resembling this behavior.  So there you have it, corvids do not, according to the best empirical evidence, show an attraction to, or are otherwise known to collect shiny objects.

And yet…

And yet I still hear anecdotes about this behavior that peak my curiosity.  For instance, once or twice a year I’ll see a headline about crows thieving shiny stones at the expense of bereft family members.  In Jewish culture, it’s tradition to leave a small stone atop a gravestone, as a way to honor the deceased and indicate that they’ve been visited.  For whatever reason, particularly across Ireland, these stones occasionally go for joy rides in the mouths of crows.  In Omagh, Patsy Kerlin who mounts headstones in his town’s graveyard recently told a local reporter that “It seems to be only the black shiny ones they take and a lot of them go missing.”  Even in my own neck of the woods at the University of Washington one of the gardeners at the Urban Horticulture Center regaled John Marzluff and I with his story of how the crows regularly steal the shiny metal placards that identify the center’s plants.

In science, we often like to say “the plural of anecdote is not data”.  This is unequivocally true.  But just because they’re not data doesn’t mean they’re meaningless either.  I’m inclined to believe there’s more to these stories than random chance and I think they are worth exploring.  Perhaps these stories emerge out of confirmation bias, meaning people tend to report theft with respect to shiny things more often because they’re looking to confirm a suspicion they already had about crows.  If so, it would be yet another fascinating example of the extent to which corvids have infiltrated our culture.  Or perhaps this is the work of curious juveniles as has been suggested by my crow colleague Dr. Jennifer Cambell-Smith.  If so, teasing out any evidence of discrimination or bias juveniles are using when selecting objects to explore could give us insight into how they learn about the world, or how our garbage is modifying that behavior.  Or perhaps crows do like to carry off with glossy objects, but for textural, rather than visual reasons.  At least some corvid species swallow small stones to aid in digestion and these stones are most often partially smoothed2.  These ‘grit stones’, however, are considerably smaller (on average only 2.9 mm) than I imagine grave stones are, so perhaps this behavior is evidence of poor grit stone selection among naive birds.

Or maybe it’s none of the above, we simply cannot say.  Which, for me, is exactly why I find these anecdotes so interesting.  While we can rule out that this behavior isn’t a manifestation of corvids’ love for ‘bling’, we can’t exactly explain this behavior either.   It’s yet another item on the shelf along with thieving golf balls and wiper blades where we can’t do much more than offer an educated guess.  So while I’m quick to clarify that crows are not attracted to shiny objects, I’m not dismissive of these anecdotes either.  My friend and colleague David Craig likes to say that every bird has a story, and citizen science is part of sharing that story.  In my book, the story of corvids and their light fingered behavior seems an ideal project for the crow minded bird nerd.

  1.  Shepard, T. V, Lea, S. E. G., and Hempel de Ibarra, N.  2014.  Thieving magpie’?  No evidence for attraction to shiny objects.  Animal Cognition 18: 393-397.
  2. Gionfriddo, J.P., and Best, L. B. 1996.  Grit-use patterns in North American birds: The influence of diet, body size and gender.  The Wilson Bulletin 108: 685-696

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Filed under Corvid mythology, Crow behavior, crow conflicts, Crow curiosities, Crow life history, Crows and humans, In the news

Why the crow is black and other mythology

Since humans began telling stories and writing them down, they’ve told stories about crows and other corvids.  This should come as no surprise considering corvids are found in nearly every corner of the world and are as connected to us now as they were centennials ago.  Whether they are sharing (or thieving) the food we grow, consuming the soft tissues of our dead, or delighting us with their company, corvids have infiltrated the most intimate parts of our lives. They walk the earth cloaked in black, and yet persist with the light of life even we perish through disease or famine.  It is this juxtaposition that I think made our human ancestors look upon those glossy feather and conclude they must have some greater tie to creation than their other avian kin.  Be it India, Rome, the Middle East or the New World, they’ve been written into the oldest stories explaining how the facts of the world came to fruition.  With that in mind, let’s break from answering questions with the rigors of science this week and embrace the explanations offered by our ancestors.

Photo: American Museum of Natural History

Photo: American Museum of Natural History


Why the crow is black (According the the Greeks/Romans)

Apollo, the son of the most powerful greek God Zeus, had an important, albeit tumultuous relationship with crows.  The greek word for crow, corone, comes from the name of Apollo’s mistress, Coronis.  According to the version of this story told by Appolodorus, although Coronis and Apollo had been lovers, she left him to marry a mortal, Ischys.  The crow, then white, brought news of the marriage to Apollo who became so incensed he burned the bird’s feathers and then burned Coronis to death.  In other versions Coronis is herself turned into the black crow and it’s possible the Greeks saw a mated pair of crows as a representation of the forbidden love between Coronis and Ischys.   This may be one of the earliest stories of a woman marrying below her class for love.

Apollo

 

Why the crow is black (According to Muslims)

Muhammad, born sometime around 570 CE, is considered to be the founder of Islam and the last profit sent to earth by God, according to the Islamic faith.   A popular legend depicts a time Muhammed was hiding from his enemies in a cave.  A crow, then white, spotted him and cried “Ghar, Ghar!” (cave, cave!) to his seekers.  They did not comprehend the crow’s cries, however, and Muhammad escaped.  He turned the crow black for the betrayal and cursed him to only utter one phrase for the rest of time;  “Ghar, Ghar!”


Why the crow is hoarse (According to Greek/Romans).  

Apollo sent a raven to gather water for a feast but the raven was distracted by an unripened fig tree.  Determined to obtain the figs, the raven waited until the tree ripened, ate his fill, and then captured a watersnake to bring back to Apollo.  The watersnake, the raven explained, was the reason he was late and unable to collect the requested water, but Apollo saw through the lie.  As punishment, Apollo declared the raven could never again drink from the stream until the figs ripened.  Since the raven must now wait, his voice is hoarse from thirst.


Why owls and crows fight  (According to Hindus)

According to the great animal epic, the Panchatantra, the birds had come together to elect a king and choose his earthly appearance.  They had elected the owl and were beginning to organize his lavish coronation, when the crow arrived.  The crow laughed at their decision, protesting that the owl was too ugly, his features without tenderness, and his nature without pity.  Furthermore, Garuda, the eagle mounted Vishnu was already their king and to take another was a sin that could result in severe punishment by the Gods.  The others, scared by the crow’s warning left in agreement.  Being nocturnal, the owl had slept through all this but now awoke to find his coronation canceled due to the crow’s persuasive words.  They have fought ever since.

Hindu

 

Why we die (According to the Haida Natives)  

Ravens have a significant role in the creations legends of many different Native American tribes.  According to the Haida tribe of the Queen Charlotte Islands, Greater Raven was the creator that first called earth into being on the endless sea.  He then made humans out of both rock and leaf.  The people of rock were (as I can well imagine) more difficult to shape and were never finished.  The people of leaf, on the other hand, were quickly completed and ready to roam the land.  The raven instructed them that, like the leaf, they must eventually fall and rot back into the earth and thus death entered the world.

NA

 

Why the sky is full of light (According to the Tsimshian Natives)

Greater Raven, as mentioned above, eventually gave dominion of the world to his sister’s son, Lesser Raven, who it was said was as robust as stone and would live forever.  Unlike Greater Raven, Lesser Raven was both a trickster and had a voracious appetite.  To satisfy his hunger, Lesser Raven filled the earth with food, but feared he would be unable to find it, as at that time the earth was still dark.  Seeking a solution, Raven flew through a hole in the sky where he found another world much like our own.  When he saw the daughter of the Chief of Heaven collecting water he transformed into a needle and floated into her vessel.  When she drank the water and the needle, Lesser Raven impregnated her and was later reborn as her son.  The infant charmed the Chief and his wife and was granted permission to play with the box containing the light of day.  Suddenly, Raven took his original form and flew back to earth through the hole in the sky, taking the box with him.  Later, he broke the box out of anger and filled the sky with the sun, moon and stars.

Map showing tribal delineations for NW coastal tribes including the Haida and the Tsimshian

Map showing tribal delineations for NW coastal tribes including the Haida and the Tsimshian

 

Why we bury our dead (According to Judaism)

According to the Yalkut Shimoni, an aggadic compilation of the Hebrew bible written in the 13th century, after Adam and Eve’s son Abel died, they did not know what to do with the body.  Seeing their distress, a raven killed one of his companions to show the grieving couple how to dig a hole and bury the body. To thank the raven for his kindness, God feeds baby ravens until their feathers turn black after which their parents take over.

***

Thus, be it the color of ravens or the intimate mysteries of human death, crows have offered a canvas on which early peoples the world over painted their explanations of life.   My thanks to Borgia Sax and his terrific book, Crow, which was the factual source and inspiration for this post.

 

 

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Filed under Corvid mythology, Crows and humans