Author Archives: corvidresearch

Salutations lovely blog followers!  This is just a quick note to explain my absence over the last couple of months, and invite you to see what it’s all been for.

For whatever reason (ambition, insanity, desire to please, capability, or the combinations therein) I took on a little more than I could chew this quarter.  Teaching, taking courses, taking my qualifying exams, submitting a paper and, as a cherry on top, taking my general exam (i.e the dissertation proposal).  I love my blog, and you folks and the aspects of crows that I can share with you are constantly on my mind.  At the end of the day though, my priority is my graduate work and sometimes the blog needs to take a backseat.

I do not tell you this in the hopes you’ll understand, I tell you this because I already know you understand.  But I also know you follow the blog because you are passionate about crows and to that end, I want to invite you to see the presentation of my dissertation proposal this Monday, Dec 5th.

While this talk is intended to impress my faculty committee enough that they approve me as a PhD candidate, it is given to a room of largely first year students, and is therefore designed to be inclusive of all backgrounds and knowledge levels.  Crucially, this seminar is also open to the entire community, so you won’t find any awkwardness strolling in as a member of the public and not as a UW student.  I hope to see you there!

For a map to Kane Hall click here.

Provided the forecast for possibly historic weather conditions, people all over the PNW are preparing themselves for heavy rain, wind, and the falling trees, debris and power outages that may follow as a result.  For many (though sadly not all) people, these preparations may be as simple as a trip to the grocery store and a commitment to stay within the safety of their homes for the weekend.  But what becomes of our wildlife?  How might they weather the predicted 60mph winds and stay warm enough to survive such conditions?

Despite their delicate reputation, birds are well adapted to survive even intense weather.  This is perhaps unremarkable, given that survival is really the name of the game and that stochastic weather conditions are an inevitable part of an animal’s life. To prepare for such weather events, some research suggests that birds and other animals are sensitive to the pressure drops that anticipate severe weather and increase their food intake as a result¹. Since foraging may be altered or inhibited during bad weather, this kind of preparation goes a long way to keep birds sated.  For this reason, making sure feeders are kept stocked or offering high nutrition items such as bird friendly corn bread is the best way you can aid your feathered companions in advance of a storm.

Precisely what a bird does during the height of the storm comes down largely to its life history, such as whether it is a cavity nester and rooster, and whether it’s migratory or residential. For cavity nesting and roosting species such as woodpeckers and chickadees, natural and artificial cavities like bird houses can make good retreats.  Birds that do not already make use of cavities such as crows or hummingbirds, however, will find refuge in the dense vegetation of conifer trees or shrubs.  While the exteriors of trees and shrubs may take a beating, their interior microhabitats can be substantially drier, warmer, and more stable, providing a suitable space for birds to wait out the worst of a storm in safety. Migratory birds on the other hand can simply fly around areas of heavy wind.  As a last resort they may even take shelter in some odd places, like a public restroom.

Even if the crows are getting blown around a bit, their hold on a perch is at little risk of giving way.  Since crows are passerines (aka perching birds), their feet lock around a perch at rest, meaning that rather than taking energy to hold on, it actually takes effort to let go.  This keeps them well secured even in windy conditions.  Lastly, their feathers keep them  protected from the rain and cold temperatures that may accompany a bad storm.  Although crows will articulate their feathers for certain kinds of behavioral displays, puffing their feathers also traps insulating air and with it, heat.

 

So if you find yourself worried about what may become of your crow neighbors over the weekend, take comfort that there is little to worry about.  These animals are adapted to sense and prepare for bad weather, find locations that offer safety, and have the physiology to withstand the kind of weather that makes us want to stay in bed.

Literature cited

“There’s not a raven alive that wouldn’t eat that,” my colleague exclaimed as we finished spreading out the tuna.  It was a beautiful carcass.  Big, glistening head, bones and guts spread out over the asphalt, perfect bait to lure the ravens we were attempting to band.  As I wiped the blood off my shoes, I could hear the beating of raven wings above my head. Surely when we returned in a few hours it would be gone. Twenty four hours later it smelled considerably worse but was otherwise unchanged.  The ravens had inspected our offering and evidently rejected it. Where had we gone wrong?

There are many possibilities, but a likely explanation is that our set-up was simply too unusual in its setting.  Perhaps if we had been working on the coast or at a dumpster, the carcass wouldn’t have seemed so out of place.  Here, however, high above a freshwater lake our bait was probably not something these birds had ever encountered.  Seeing such a strange carcass likely drove our ravens off to a more conventional and trusted source of food.

Contrast this with the behavior of an urban crow, and this level of cautiousness on behalf of our forest ravens might seem strange.  For example, watching a crow root seemingly recklessly through your garbage might give the impression that they worry little about new things.  In fact, corvids are notoriously neophobic¹ (fearful of new objects) in contrast to many other bird species.  This may seem at odds with an urban corvid’s lifestyle. After all, the urban environment is constantly presenting them with new objects, many of which contain edible food.  An unnecessary fear could therefore be a costly inhibition to exploiting worthy food sources.  On the other hand, too little indiscretion could expose them to predators, poisons or other dangers.   So how do urban crows deal with this paradox and how might they compare with their rural counterparts?

A study by Alison Greggor et al.², recently published in Animal Behaviour set out to address this question.  To do so, they presented 5 corvid species (including jays, rooks, crows, magpies and jackdaws) and 7 urban dwelling non-corvids species (including blackbirds, finches, tits, robins, pigeons, etc.) in both urban and rural settings  with a novel object placed near a familiar food source.  The novel object was either a) natural objects, b) familiar pieces of litter or c) strange new object made to look unlike any animal or food packaging. Neophobia was measured by changes in latency to the food after the object was placed near it.

They found that, in contrast to non-corvid species, corvids were more wary to approach food near any of the three novel objects, adding support to their neophobic reputation. Interestingly, there was no difference between urban and rural corvid’s willingness to approach the completely new object (object c).  Urban crows were however, faster to approach food near familiar litter (object b) than their rural counterparts.  They interpret these findings to suggest that urban living fosters context specific, rather than generalized reductions in neophobia.  This balance may best keep corvids out of trouble with respect to entirely new things while still allowing them to exploit items that look similar to other known anthropogenic food sources.

I guess next time we’ll stick with trail mix and old sandwiches to entice our wary ravens!

Literature cited

1. R. Greenberg, C. Mettke-Hofmann (2001) Ecological aspects of neophobia and neophilia in birds.  Current Ornithology 16: 119–178
2. Greggor, A., Clayton, N., Fulford, A., and Thorton, A. (2016).  Street smart: faster approach toward litter in urban areas by highly neophobic corvids and less fearful birds.  Animal Behaviour 117: 123-133.  doi:10.1016/j.anbehav.2016.03.029

Pinching a peanut shell between my fingers, I pulled my hand out of my pocket and laid the nut on the concrete between us.  GO cocked her head, catching the light on her left cheek and reflecting the deep blues that hid among her inky black feathers.  “Please don’t die before I graduate,” I whispered.  GO stared back at me a moment before galloping forward for her treat and making off.

Try as I might, I couldn’t will her to understand my foreign tongue anymore than I could will her body to keep working indefinitely.  Today it finally stopped.  Today I say goodbye to my companion.

For those that follow my blog regularly, you’re probably familiar with GO.  Even if you’ve never seen mentions of her, you see her face every time you visit my site; she’s the bird staring back at you from my site’s banner. I first met GO while searching for banded birds to use as subjects in my early funeral experiments.  Her name actually comes from her band combo: Green/Red/Metal x Green/Orange.

The location of her and her mate’s territory was ideal, and soon I was regularly feeding her as apart of the initial conditioning phase of the experiment.  Like most campus birds, she readily took to feeding and soon enough I could hear the soft rattling of her bands as soon as I approached the food site each day.  After the funeral event though, GO and her mate aggressively avoided the food and I wrapped up the experiment assuming that, like many of my other data points, she would be anxious to never have to see me or my ‘scary’ accomplice ever again.  But a few months later, while waiting for the bus I heard the familiar rattle of her bands and turned to see her looking expectantly down at me from a branch.  I offered her a peanut and she took it without pause.  I never went to the bus stop without a few peanuts in my pocket after that.  It’s been four years since then.

During the darkest days of writing my last publication I might have visited her 2 or 3 times a day, desperate for someone to shake me out of my writer’s block or my frustration with myself. Hearing her wing beats was like taking a Xanax; it was calming and reminded me why I was working 15 hours a day juggling field work and authorship duties.  I adored her, I wanted to know and understand everything I could about her, and I wanted to be part of the community that was using science to enhance people’s appreciation for corvids.  She wanted peanuts.  I don’t think her side of things was any more complicated than that but that’s never cheapened the relationship for me.   She wasn’t a pet or a human friend dressed in corvid clothing.  She was a wild crow, and it was wondering about how she existed in that wild, urban space that most inspired my work.  Still, I had always hoped GO would somehow be spared from the one thing I wonder about the most: death.

For all the advances our team has made about the function of crow funerals we know almost nothing about what the birds are really thinking.  Like most other social animals, they do a great variety of things which makes getting at what they are thinking or feeling very difficult.  GO and her mate had presumably been together many years.  It’s hard for me to imagine this is lost on him, but I can’t say for sure.  All I know with certainty is how I feel about her loss and I know the thought of silence in place of the soft rattle of her bands or the whoosh of her wing beats as I approach our spot makes my heart ache.

GO was at least 16 when she died. In that time she successfully raised many broods, contributed to two scientific publications, and undoubtedly befriended more people than just me. She embodied everything we love about crows: their deft skill at thriving among us, their bold demand of our time and attention, and the way they engender our curiosity and admiration.  She was my data, inspiration, stress relief, and eager companion.  I will never forget what this bird meant to me.  Miss you already my lovely ladybird.

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For the most part, crows come in the same general size, shape and color, but every once in a while individuals will deviate from this template in eye catching ways. These deviations can manifest as missing or elongated beaks, color abnormalities such as white plumage, or jarring metamorphoses into rudderless, flying orbs. 

Tailless crows are fairly uncommon; in a typical year I’ll maybe spot a couple afflicted individuals. Although feather loss and replacement is a normal part of a crow’s annual cycle, crows don’t shed their tail feathers simultaneously so we can’t blame molting season for this odd appearance. Instead, a tailless crows most often indicates that the bird recently escaped a predator or other kind of threat. 

Similar to some lizards, many bird species can drop their tails defensively as a last resort to avoid being injured or killed. In fact, tail feathers require less force to detach in contrast to other feathers on a bird’s body. In addition, the force required to remove tail feathers decreases with how vulnerable a species is to predation.¹ Tail feathers can also be broken, rather than completely lost. Although that might sound painful, unlike a bird’s beak which is full of nerve endings, mature feathers are dead structures like hair or fingernails. While a bird surely feels and avoids the sensation, it’s not painful. 

Tails are crucial to most birds not only for their visual appeal but also because they allow birds to steer and maneuver in flight. Without one a crow can still fly and land, but they’re not nearly as agile in the air and you’ll notice their take offs and landings are a bit awkward. Fortunately, the tail will eventually grow back though just how quickly is contingent on what happened to the feathers themselves. If the feathers were pulled out, so long as the follicles weren’t damaged they will begin to regrow immediately. If, on the other hand, the feathers were broken rather than pulled out, the crow will need to wait until its annual summer molt to replace them. 

For crows fortunate enough to be brought into a wildlife care facilities, there’s also a secret second option to correcting a broken flight feather: imping. Although little known outside of rehab or falconry circles, imping is an age-old technique dating back to at least the 1240’s when it was mentioned in The Art of Falconry by the Holy Roman Emperor, Frederick II. The procedure involves trimming the broken feather to about one inch above the skin and then inserting a thin piece of wire, fiberglass, or wood (called the imping needle) into the empty feather shaft. A matching donor feather is then affixed to the exposed portion of the imping needle. Picture sheathing a double sided samurai sword, where the sword is the imping needing and the sheaths are the imbedded, trimmed feather shaft and the donor feather respectively. Historically, rust was used as a bonding agent but today vet safe epoxies are the standard adhesive. 

So the next time you see a tailless crow go ahead and give it a few extra treats. It’s not in any pain, but it’s been through something fierce. And to quite literally add insult to injury, it looks absolutely ridiculous.

Literature cited

1. Moller, A.P., Nielsen, J.T., Erritzoe, J.  (2006).  Losing the last feather: feather loss as an antipredator adaptation in birds.  Behavioral Ecology 17: 1046-1056