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Author Topic:   Corvid ecologists
RAZD
Member (Idle past 1487 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 1 of 29 (777917)
02-12-2016 8:32 AM


Interesting news on corvid (crow, jay, raven, nutcracker) behavior and the forests they tend.
Corvids could save forests from the effects of climate change
Crows, jays, and nutcrackers have co-evolved with trees for good reason.
quote:
A raven with a large seed, about to bury it in a field.
(Callum Hoare)
To you, crows and jays might be noisy, obnoxious birds who eat garbage. But for large-seeded trees like pines, hickories, oaks, and chestnuts, they could be life-saving heroes. That's because these birds can actually relocate forests that are threatened by changing climates and habitat loss.
In a new paper published in ornithology journal The Condor, a group of US scientists describe how corvids' unique food-gathering strategies have transformed forests around the world. Now, environmental scientists are actively using the animals as part of their reforestation strategies.
Scatter-hoarding
Corvids, a family of birds that includes crows, ravens, jays, magpies, and nutcrackers, are called scatter-hoarders. They roam large territories to scavenge seeds, fruit, and even meat, storing as many morsels as possible to eat later. That's the "hoard" part. But they don't have one giant stash full of loot the way squirrels do. Instead, they hide each treat in a separate place, occasionally moving it around to prevent other animals from finding it. That's the "scatter" part. Corvids are incredibly intelligent, with excellent visual memory, and scrub jays can remember up to 200 different cache locations at any given time.
Over millennia of evolution, this arrangement has become mutually beneficial. Many large-seeded trees have co-evolved with corvids, developing seeds that contain lots of carbohydrates so the birds fill up faster. As a result, corvids are less likely to gobble up seeds on the spotthey'll be sated and may even fly tens of kilometers to hide the seeds.
Forest builders
Just look how many seeds this jackdaw
has jammed into its beak. Pretty impressive.
(John Haslam )
Corvid appetites have even helped to improve the fitness of pine and oak forests. The birds carefully select their seeds, often examining them visually and shaking them in their shells to determine whether they've been infested by fungus or arthropods. Though the birds are thinking only of what will be tastiest for them, the result is that the seeds that get scatter-hoarded tend to be the healthiest ones. Combine the corvids' pickiness with their predilection for flying great distances to hide their food, and you wind up with new patches of forest, planted by corvids, whose trees are both healthy and genetically diverse. Even better, many corvids prefer to cache their seeds in recently burned or disturbed landscapes, which are the most in need of reforestation.
Corvids have unwittingly become a key part of a virtuous cycle. By planting seeds, they lay the groundwork for entire ecosystems. Many plants thrive in the shade offered by trees like oaks and pines, and animals flock to the area as well. Finally, forest floors are excellent carbon sinks. Scatter-hoarding corvids are, in fact, guardians of the forestor, as the researchers put it, geoengineers.
Human and corvid geoengineers team up
Playful behavior could give clues about why they’re so smart.
In our era of climate change and agricultural expansion, trees are threatened by one basic fact. They can't move. If a habitat gets too wet or too hot, or humans decide to build a farm in the forest, the trees are doomed to die in place. That's why the scatter-hoarding corvid is so important to the life cycles of forests. Some corvids can carry dozens of seeds at a time, up to 50 kilometers away from their sources. Given that the trees and birds prefer the same kind of habitats, scientists believe that corvids might slowly bring forests with them to the right kinds of habitats as the old ones become inhospitable over time.
So once we understand this behavior we can work with it, provide seeds and let the corvids plant them, saving on labor and benefiting the existing ecological process.
This gives me hope that some of the impending doom of global climate change can be ameliorated.
Enjoy

we are limited in our ability to understand
by our ability to understand
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Replies to this message:
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 Message 22 by kjsimons, posted 02-19-2016 3:57 PM RAZD has replied

  
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Message 2 of 29 (777918)
02-12-2016 9:08 AM


Thread Moved from Proposed New Topics Forum
Thread moved here from the Proposed New Topics forum.

  
Blue Jay
Member (Idle past 2779 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 3 of 29 (777923)
02-12-2016 11:14 AM
Reply to: Message 1 by RAZD
02-12-2016 8:32 AM


There's a reason behind my screen handle, and it's not because my actual name is "Jay" (it's not). The blue jay has been my favorite bird since I was a teenager. It's always seemed like an incredibly iconic bird, and it's apparent ability to adapt to both rural and urban areas without being a destructive pest feels sort of like a symbol of conservation, like a small triumph of nature in an urbanized world (I would have preferred to say that in a less cheesy way, however).
Anyway, blue jays have apparently been expanding the northern portion of their range for quite some time now. They apparently weren't seen consistently in the Pacific Northwest until just the past couple of decades. I doubt they're going to "save the forests from the effects of climate change," but they might be able to help the forests migrate as climate change alters habitat suitability (provided the changes don't happen too quickly for them to keep up).

-Blue Jay, Ph.D.*
*Yeah, it's real
Darwin loves you.

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 Message 1 by RAZD, posted 02-12-2016 8:32 AM RAZD has seen this message but not replied

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 Message 4 by Faith, posted 02-12-2016 11:27 AM Blue Jay has replied

  
Faith 
Suspended Member (Idle past 1526 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 4 of 29 (777925)
02-12-2016 11:27 AM
Reply to: Message 3 by Blue Jay
02-12-2016 11:14 AM


I thought this was probably meant to be a nondebate thread since it got put in links and information.
But I'd like to respond to your comment about blue jays that it's hard to like a bird that will bully out all the little birds from the feeder, the chickadees and the finches, the huge raucous bird straddling the thing until it's eaten all the seed or knocked it all to the ground.
Second point I wanted to write when RAZD first put up the subject is that the evolution scenario is of course completely assumed, there is no reason whatever to think the behavior of these birds "evolved" to favor forests. However, microevolution must be involved if their behavior does in fact favor them., -- correction, no, no evolution of any sort, just the natural habits of the birds favoring the spreading of forests. Nice little fact of life, courtesy of the God who made them. Just have to make this comment because believers in evolution always assume it's the explanation for everything without the slightest evidence in any particular case.
Edited by Faith, : No reason given.
Edited by Faith, : No reason given.
Edited by Faith, : No reason given.

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 Message 8 by Blue Jay, posted 02-12-2016 2:26 PM Faith has replied

  
RAZD
Member (Idle past 1487 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 5 of 29 (777928)
02-12-2016 11:51 AM
Reply to: Message 4 by Faith
02-12-2016 11:27 AM


But I'd like to respond to your comment about blue jays that it's hard to like a bird that will bully out all the little birds, the chickadees and the finches, from the feeder, the huge raucous bird straddling the thing until it's eaten or knocked all the seed to the ground.
And that's why I have 3 types of feeders, the tall cylinders with small perches that suit the little birds, purple finches, chickadees, goldfinches and the like, plus flat open feeders for birds like bluejays, cardinals and morning doves, and then suet for nuthatches, sapsuckers and woodpeckers.
The "problem" birds I have are (1) starlings that mob the other birds and try to empty all my feeders in a day, and (2) european house "sparrows" (actually weaver finches) that overwhelm the feeders and drive the shyer birds away, again with large numbers in their flocks. Both these birds are not native introduced species that have spread across the continent. They also steal cavity nests from bluebirds and swifts and the like.
Second point I wanted to write when RAZD first put up the subject is that the evolution scenario is of course completely assumed, there is no reason whatever to think the behavior of these birds "evolved" to favor forests. However microevolution must be involved if their behavior does in fact favor them. Just have to make this comment because believers in evolution always assume it's the explanation for everything without the slightest evidence in any particular case.
Actually it is an evidence based hypothesis that has been and is currently being tested. Corvids are not the only vectors that the trees use, as squirrels and other animals also spread seeds. Bears that raid squirrel hoards also plant seeds along with a dose of fertilizer ...
But the corvids take the seeds the furthest distance, and thus are a much larger vector for spreading the trees to new areas.
This isn't some much an evolution issue, as it an ecological one -- the interaction of species in habitats and how the behavior of one affects the behavior of the others, and the balance of the whole ecology.
So sit back and marvel at the quiet spread of forests by tireless workers while we argue about what needs to be done.
Nature will survive global climate change, the question is what species will survive, which species will change, which will perish, and which one of them will we be.
Enjoy

we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

This message is a reply to:
 Message 4 by Faith, posted 02-12-2016 11:27 AM Faith has replied

Replies to this message:
 Message 6 by Faith, posted 02-12-2016 12:02 PM RAZD has replied
 Message 10 by PaulK, posted 02-12-2016 3:28 PM RAZD has replied
 Message 13 by caffeine, posted 02-16-2016 3:14 PM RAZD has replied

  
Faith 
Suspended Member (Idle past 1526 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 6 of 29 (777929)
02-12-2016 12:02 PM
Reply to: Message 5 by RAZD
02-12-2016 11:51 AM


I don't live where I could have bird feeders but that sounds like a good solution. I rented a room in a friend's house some years ago, and she had one feeder by the window next to the table where we could eat and watch the birds. The feeder was shaped like a gazebo the blue jay could straddle. She obviously needed more feeders.
But the corvids take the seeds the furthest distance, and thus are a much larger vector for spreading the trees to new areas.
This isn't some much an evolution issue, as it an ecological one -- the interaction of species in habitats and how the behavior of one affects the behavior of the others, and the balance of the whole ecology.
That I can appreciate. Evolution isn't necessary to any of that.
Edited by Faith, : No reason given.
Edited by Faith, : No reason given.

This message is a reply to:
 Message 5 by RAZD, posted 02-12-2016 11:51 AM RAZD has replied

Replies to this message:
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RAZD
Member (Idle past 1487 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 7 of 29 (777935)
02-12-2016 1:06 PM
Reply to: Message 6 by Faith
02-12-2016 12:02 PM


I don't live where I could have bird feeders but that sounds like a good solution.
There are several types of stick-on window feeders:
Put low on an upper window frame you can open the lower one to fill it, or two windows side by side work.
A friend of mine has one with a stool inside for the cat ...
Enjoy

we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

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Replies to this message:
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Blue Jay
Member (Idle past 2779 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 8 of 29 (777940)
02-12-2016 2:26 PM
Reply to: Message 4 by Faith
02-12-2016 11:27 AM


Hi, Faith.
Faith writes:
I thought this was probably meant to be a nondebate thread since it got put in links and information.
Meh.
Faith writes:
But I'd like to respond to your comment about blue jays that it's hard to like a bird that will bully out all the little birds from the feeder, the chickadees and the finches, the huge raucous bird straddling the thing until it's eaten all the seed or knocked it all to the ground.
The "pecking order" at bird feeders has been reported a lot: it tends to vary a lot depending on where you live. Blue jays actually aren't all that high in the pecking order. At my home, they're regularly bullied by grackles and even cardinals. They're also more inclined to forage on the ground beneath the feeder than on the feeder itself; so if you scatter seeds beneath the feeder or have a feeder that tends to spill a lot, the blue jays might spend more time on the ground.
Corvids are also interesting because of their intelligence. They're some of the most intelligent birds, so they have diverse habits, they're adaptable, and they can be quite nasty (though that reputation is largely exaggerated). In those ways, they kind of remind me of humans.
The birds I really despise are starlings and house sparrows, because they were intentionally brought here from Europe by people. Back in the late 1800's and early 1900's, people thought introducing new species into an area was good for the wild lands because it "enriched" the environment. In my purist conservation mindset, blue jays, grackles and cardinals have a right to be here, and I love it when native birds can kick the non-native birds' -----.

-Blue Jay, Ph.D.*
*Yeah, it's real
Darwin loves you.

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 Message 4 by Faith, posted 02-12-2016 11:27 AM Faith has replied

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Faith 
Suspended Member (Idle past 1526 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 9 of 29 (777942)
02-12-2016 3:09 PM
Reply to: Message 8 by Blue Jay
02-12-2016 2:26 PM


We have a plague of starlings here too. Not familiar with the house sparrow and its problems.

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PaulK
Member
Posts: 17838
Joined: 01-10-2003
Member Rating: 4.1


Message 10 of 29 (777943)
02-12-2016 3:28 PM
Reply to: Message 5 by RAZD
02-12-2016 11:51 AM


quote:
The "problem" birds I have are (1) starlings that mob the other birds and try to empty all my feeders in a day, and (2) european house "sparrows" (actually weaver finches)
House sparrows are real sparrows (genus passer). Next you will be saying that Erithacus rubecula isn't a "real" robin!

This message is a reply to:
 Message 5 by RAZD, posted 02-12-2016 11:51 AM RAZD has replied

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Blue Jay
Member (Idle past 2779 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


(2)
Message 11 of 29 (777946)
02-12-2016 4:52 PM
Reply to: Message 10 by PaulK
02-12-2016 3:28 PM


There's only one "real" Robin:

-Blue Jay, Ph.D.*
*Yeah, it's real
Darwin loves you.

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14174dm
Member (Idle past 1191 days)
Posts: 161
From: Cincinnati OH
Joined: 10-12-2015


(1)
Message 12 of 29 (778053)
02-15-2016 12:12 PM
Reply to: Message 7 by RAZD
02-12-2016 1:06 PM


check where hulls go
I put a feeder on the railing of my third floor apartment balcony.
After a couple days the second floor balcony (including chairs and table) was covered with the bits of seed hull.
I moved the feeder.

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caffeine
Member (Idle past 1106 days)
Posts: 1800
From: Prague, Czech Republic
Joined: 10-22-2008


Message 13 of 29 (778097)
02-16-2016 3:14 PM
Reply to: Message 5 by RAZD
02-12-2016 11:51 AM


(2) european house "sparrows" (actually weaver finches) that overwhelm the feeders and drive the shyer birds away, again with large numbers in their flocks.
I think you've got muddled. Sparrow weavers are African birds closely related neither to sparrows nor to the birds you call sparrows in America.

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Faith 
Suspended Member (Idle past 1526 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


(1)
Message 14 of 29 (778104)
02-16-2016 4:07 PM


I have no bird in this fight as it were but I got curious. According to Google, RAZD is right, the house sparrow is really the weaver finch:
*Controlling House Sparrows. The English sparrow, commonly referred to as the house sparrow, is a species introduced into the United States in the mid 1800s. Brought over to this continent from England, this non-native bird is not actually a sparrow but a Weaver Finch, a sub-species of the more familiar Finch family.

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caffeine
Member (Idle past 1106 days)
Posts: 1800
From: Prague, Czech Republic
Joined: 10-22-2008


(1)
Message 15 of 29 (778106)
02-16-2016 4:25 PM
Reply to: Message 14 by Faith
02-16-2016 4:07 PM


*Controlling House Sparrows. The English sparrow, commonly referred to as the house sparrow, is a species introduced into the United States in the mid 1800s. Brought over to this continent from England, this non-native bird is not actually a sparrow but a Weaver Finch, a sub-species of the more familiar Finch family.
Well now I'm confused. I think we need some Latin names here for clarity.
The 'English sparrow' I thought RAZD was discussing (ie. the bird called a house sparrow in England), is Passer domesticus:
This is not a member of the finch family (Fringillidae) but of the sparrow family (Passeridae). This bird is common all over the US having been introduced from Europe.
By 'weaver finch' I understood the Ploceidae or weavers, which include birds known as 'sparrow weavers' such as Plocepasser mahali:
.
What, then, is this bird that is known as a house sparrow, English sparrow or weaver finch, but which is neither what the English would call a house sparrow nor a weaver?

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