Thread by @corvidresearch

If you’re looking for #COVID19 information might I recommend:

@heysciencesam
@aetiology
@mlipsitch
@florian_krammer
@HelenBranswell

If you’re looking for #CORVID19 information, I, a corvid scientist, am happy to oblige. Here’s 5 things we learned about corvids in 2019:

1) Townsend et al. taught us that eating McDonalds burgers gives crows higher cholesterol.

This may not seem surprising but very few studies have actually evaluated how eating trash affects the health of urban birds. What was surprising though is that it wasn’t a bad thing.

It was revealed that a high cholesterol diet resulted in study birds (i.e. those given a McDonalds burger everyday) having a higher body condition relative to control birds.

scholar.google.com/scholar?hl=en&…

Maybe a study over their lifetime would reveal ill effects, but it’s also possible they just don’t live long enough for their diets to catch up with them.

You can read more here: corvidresearch.blog/2019/08/26/dum…

2) Adriaense et al. taught us that common ravens show emotion contagion, a feature many believe is the basis of empathy.

pnas.org/lookup/doi/10.…

To do this, they set up a judgement bias paradigm which is where you set a precedent of either a positive or negative experience and then see if that previous experience influences how you later respond to an ambiguous one.

You know how you’d be excited if you found a wrapped box on your kitchen table? That’s judgement bias from years of nice things coming from wrapped gifts. You don’t know what’s in this one, but you’re predisposed to be excited.

To do this with ravens, they basically manipulated a model raven such that they expressed either positive or negative reactions in response to high or low quality food in a box. An observer bird watched, only they were limited to the model’s reaction, not what caused it.

Then they showed the observer birds an ambiguous stimulus (an unfamiliar box). The ones that had watched another raven act positively were interested in exploring their box. The others...not so much.

Since taking on the emotional states of others is basically what we are doing when our friend’s bummer day makes us sad, this is no small news in the animal behavior world. Though there is still so much more to explore!

3) Nahid et al. taught us that house crows are capable of laying “immaculate blue eggs”.

tandfonline.com/doi/abs/10.108…

Eggs are really cool. Did you know there are only two types of pigments that control the vast array of egg colors that exist? Protoporphyrin makes brownish colors and biliverdin makes blue/green hues.

📸 FRANS LANTING/MINT IMAGES/SCIENCE SOURCE

House crows, like all Corvus species, usually make a blueish/greenish eggs with brown spots but an account from 1889 told of an immaculate blue egg like a robin’s.

📸 Kevin McGowen

After not finding one of these “immaculate” eggs for nearly 100 years though, a 1976 paper asserted that such a claim was either the result of a “rare freak” egg or a case of misidentification.

To the relief that Hume 1889 claim however, the authors of the current study found that a whopping 6% of the house crows in the Bangladesh study produced immaculate eggs. 📸 from study

They speculated that it may be a way to curtail becoming the victim of nest parasitism, which is when one bird lays its eggs in the nest of another, but they were unable to find support for this idea.

Take home message: if you ever see an immaculate blue crow or raven egg, TELL ME, it’s a rare thing and a big deal.

4) My colleagues Loma Pendergraft and John Marzluff taught us that crow communication is still confusing as hell.

Have you ever noticed how when you toss crows food they often vocalize? Yeah so had Loma. And he wanted to know why. Are they calling in friends? Saying keep away?

But to his frustration and surprise, no super clear trends emerged aside from a slight change in call type, despite all the ways he tried to approach what feels like a simple question. You can read a more in depth synopsis here: corvidresearch.blog/2019/03/14/cro…

5) Lastly, Poddubnaya et al. taught us that common magpies (Eurasian magpies) may be key seed dispersers of acorns in agroforestry system. esajournals.onlinelibrary.wiley.com/doi/full/10.10…

This is a super important finding because while magpies are probably pretty popular among most people reading this, a lot of folks see no value in these birds. This study demonstrates that they could be crucial providers of an ecosystem service by helping forests regenerate.

So far from just being noisy nuisances, these birds are an active part of curtailing land degradation and combating climate change. WAY TO GO #CORVIDS.

Want to know more about corvids in 2019 & beyond? Follow for more.

Want to get back to the more pressing science of the day & learn about #COVID19? Check out the latest episode of @Ologies w/ @alieward. Enjoy the coRvids & don’t forget to #WashYourHands

alieward.com/ologies