Tuesday, April 13, 2010

Crows and Ravens: The Corvids and their odd behavior

Why were crows harassing theowlbox, Harassing our dear Molly and McGee? Well, it's a long time tradition. Corvids harass and even sometimes kill hawks, owls, falcons. There are different theories as to why.

There has been a lot of great research on crows and ravens. Their intelligence is astonishing and their behaviors are often not turning out to be what we used to think. For example, people used to think that crows and ravens attacked predators in their territories just to harass them but now it's been discovered that there is much more to it. Believe it or not, many times when you see corvids harassing a predator, the corvid is actually assessing the relative aggressiveness of the predators in their neighborhood, so as to decide whether or not it would be advisable to try to steal the prey of that predator! Who knew that crows were doing profiling to see how safe they'd be stealing from a predator!

They may have been interested in stealing the "food in the pantry", since they steal from predators. They follow predators to see if they kill something and leave any tasty scraps. And they steal from the lair of a predator if possible.

We all do that, don't we? We size each other up to see not whether or not we can get away with stealing from each other (hopefully!), but to try to figure out what we can expect from someone. Is the person especially hostile and aggressive? Then we are especially careful not to upset them. If they seem really relaxed and nice, we may be less on guard.

Same goes for crows. But how do they find out how bad it's going to be when they go after the coyote's kill or try to steal bits of carcass from a hawk's nest? By harassing them ahead of time in a less volatile situation to profile their personalities.

Before scientists were willing to acknowledge that predators HAD different personalities, they could not have seen what was right in front of them, but those days are long gone.

Crows and ravens have amazing intelligence and even MAKE and use tools. Yes, make.

There's one experiment, now famous, where scientists put a test tube in a cage with a treat at the bottom where the raven could not reach it. Then the scientists put a hooked wire and a straight wire in the cage as well. Of course they did not allow the ravens to watch each other solve the problem. Ok, so in comes the first raven. He hardly needs to even look the situation over. He grabs the hooked wire and pulls out the treat. WOW!

So they put another treat in the tube and let another raven in (this bird did not see the first one). But what the scientists hadn't realized is that the first guy flew out holding the hooked wire. The second raven looks over the situation, grabs the straight wire, and without hesitating, bent it to make a hooked end, then pulled out the treat.

And that's just the beginning!

A great book on all of this, quite readable, is "The Mind of the Raven" by Berndt Heinrich. He also had a great horned owlet that he raised for two years while he was living in a very rural area where he could let the owl come and go as it pleased and learn to hunt. When the owl was 2 years old, he (the owl) went wild.

So why do crows mob owls and hawks? Some literature says it's to drive them away from their nests. To me that doesn't explain it thoroughly enough because they seek out the hawks and owls... Are they trying to eliminate the hunters ahead of time? Are they killing their enemies before the enemies can kill them? But owls don't usually go after crows' nests.

I haven't done the research on this. If someone HAS or wants to find the research, please put the info in the comment section. In the meantime, I can only speculate. Hey, I'm a barn owl person, not a corvid expert.

I will put "The Mind of the Raven" on my stack o' urgent books to read again!

I CAN tell you that those of you who witnessed the attack, that you've seen the owl nono's which are so hard to describe and which are really something to see! They mean, "I'm going to rip your face off!" It's the darn cutest way to say, "I'm going to rip your face off" that I've personally ever seen.

-Stacey

7 comments:

annmartina said...

A few nights ago we observed a barred owl just off the walking trail. There is a pair in the area. There was a Cooper's hawk sitting in a tree about 100 yards away. The hawk flew away when we came onto the trail but came back again after a few minutes. He seemed like he was keeping an eye on the owl. The owl seemed to be noticing him too, but to a lesser degree. Like corvids, would hawks and owls size each other up?

Ter-o-fla said...

I actually love watching crows; they are about the only wild animals near enough to watch regularly. (well, I recently discovered a mouse under the front step!)

I had not known about the crows harassing the owls. Fascinating creatures, all of them!!

Thank you again for telling us all so many interesting things, Stacey!

-t-

Charlotte said...

FASCINATING information, Stacey. LOVED this piece. For weeks I've been incredibly focused on the INside of that nesting box. Your writing continues to fill out more and more of the wonder and beauty in the boundless and awe inspiring tapestry of nature. I am humbled that we are a valued part of your process.
with gratitude
charlotte loomis

suzie2 said...

I really enjoyed reading about crows and ravens here this evening. I see them everywhere pretty much every day and have come to enjoy their calls.
A few years ago, I was working alone in my classroom at school and I heard the most enormous commotion outside. I went to see what was happening. A crow was lying on the ground near another classroom and was obviously dying.
An entire community of other crows had formed around it and were making a huge ruckus. I do not know what happened to the dying crow or that what I was watching was "grief"-it seemed to be. Needless to say they stole my heart with what appeared to be their concerns. I got our custodian to help by getting a towel and a box and he called for help, but the crow did die before any help could get there...just in case anyone wonders.

I wasn't at The Owl Box when the crow attack happened. I would have loved to have seen Molly and her no-no behavior.
When she went on her first flight out this evening, she left with some of the most impressive hisses I have heard yet. I can not imagine anything wanting to bother her after that!
I enjoy reading your blog almost as much as I enjoyed reading your book...it's great!!

suzie2 said...

I really enjoyed reading about crows and ravens here this evening. I see them everywhere pretty much every day and have come to enjoy their calls.
A few years ago, I was working alone in my classroom at school and I heard the most enormous commotion outside. I went to see what was happening. A crow was lying on the ground near another classroom and was obviously dying.
An entire community of other crows had formed around it and were making a huge ruckus. I do not know what happened to the dying crow or that what I was watching was "grief"-it seemed to be. Needless to say they stole my heart with what appeared to be their concerns. I got our custodian to help by getting a towel and a box and he called for help, but the crow did die before any help could get there...just in case anyone wonders.

I wasn't at The Owl Box when the crow attack happened. I would have loved to have seen Molly and her no-no behavior.
When she went on her first flight out this evening, she left with some of the most impressive hisses I have heard yet. I can not imagine anything wanting to bother her after that!
I enjoy reading your blog almost as much as I enjoyed reading your book...it's great!!

Janet said...

Last week I watched a juvenile Great Horned Owl in a cluster of cottonwood trees across from my home. He showed up every evening, sometimes hooting, most times silent. It was a thrill! On the weekend, I heard a ruckus outside in the afternoon and I ran out to see four ravens (or perhaps they were crows). They were flying around in the cottonwood trees making lots of noise. They stayed about 24 hours, continued to make noise and fly around, and then they left. I haven't seen the owl since then, and I'm trying to figure out why the corvids came suddenly, make a racket and then left. I hope they didn't hurt the sweet owl!

Rion Alvey said...

I was in a deer blind this morning watching a beautiful hardwood bottom with a deep, water run off gulley at the bottom. I could hear crows going nuts chasing a hawk or an owl. I've witnessed that many many times. But this time I realized that the crows were getting closer and then I saw them mob attacking something that was in the gulley. I could not see what had there attention but they were deffinetly attacking what ever it was.

After a few minutes they were quite...then they startws again and I could see a large barred owl flying up the gulley with crows after it. It landed and was trying to get under the overhanging edge to get away but they were all over him. I jumped out of the blind and walked towards them. The crows flew away and the owl flew up into a branch making a strange mewing noise almost like a scared kitten.

It eventually flew off and in about 30 minutes I heard the crows again....It was a very interesting morning.