Re: [cayugabirds-l] Eagle Question

[Candace Cornell]

About 60-70% of young osprey and most other hawks perish in their first
year primarily due to starvation, although collisions, electrocutions,
hunting, and other hazards also befall them. Young eagles and hawks have to
learn to hunt for themselves and it is a steep learning curve. Many fail to
develop their hunting skills quickly enough to survive.  Once they get to
full maturity, the odds improve, but there . 90% seems accurate.

Candace

On Wed, Sep 28, 2016 at 7:23 PM, Peter  wrote:

> Howdy folks.
>
> Am reading a very interesting, creative book by Pete Dunne called "The
> Wind MastersThe Lives Of North American Birds of Prey". Dunne takes a
> very creative approach to teach us about these birds...the book reads more
> like a novel!  I highly recommend it but have a question.
>
> In his piece about Bald Eagles, Pete says that, with respect to young
> eagles, more than 90% that fledge in a given season don't survive to
> adulthood, and nearly 60% of these die during their first year. Evidently,
> to quote Dunne, "starvation is a young eagle's greatest adversary"..
>
> I was wondering what anyone thought about his statistics.
>
> Thanks for the feedback.
>
> Pete Saracino
>
>
>
>
>
> --
>
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>
> Please submit your observations to eBird:
> http://ebird.org/content/ebird/
>
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>

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Re: [cayugabirds-l] Eagle Question

[Peter]

Thanks for the responses Kevin and Candace.

I always teach my students that Nature "throws the kitchen sink" at 
organisms in terms of selection pressures; just never realized how 
severe it really is.

And as you imply Kevin - and Pete Dunne also says - while it is 
ultimately bad for the individual organism, it is ultimately good for 
the species as a whole - both the predator AND the prey (in terms on 
honing hunting skills to insure survival or honing evasive skills to 
insure same).

Thanks again. Much appreciated.

Pete Saracino



On 9/28/2016 8:53 PM, Kevin J. McGowan wrote:
>
> Sounds about right. I'd have to check the BNA account tomorrow at work 
> to verify the numbers, but that seems in the ballpark.
>
>
> For medium-sized songbirds, like robins and Red-winged Blackbirds, 70% 
> of nests fail to produce any fledglings, 92% of those fledglings die 
> over the first year, and half of all adults die each year.
>
>
> Larger birds tend to have higher yearly survival, but they take longer 
> to reach maturity, too. For American Crows, roughly just over half of 
> the nests produce fledglings, half of those survive their first year, 
> but most don't breed until they're 4 years old, and it's 15% mortality 
> each year. Bald Eagles don't breed until they're 5 or so, so I would 
> expect numbers something Pete quotes.
>
>
> It's a rough world out there. That's one of the reasons that natural 
> selection is so strong at weeding out "frivolous" behavior.
>
>
> Kevin
>
>
> 
> *From:* bounce-120838092-3493...@list.cornell.edu 
>  on behalf of Peter 
> 
> *Sent:* Wednesday, September 28, 2016 7:23:58 PM
> *To:* CAYUGABIRDS-L; CAYUGABIRDS-L
> *Subject:* [cayugabirds-l] Eagle Question
> Howdy folks.
>
> Am reading a very interesting, creative book by Pete Dunne called "The
> Wind MastersThe Lives Of North American Birds of Prey". Dunne takes
> a very creative approach to teach us about these birds...the book reads
> more like a novel!  I highly recommend it but have a question.
>
> In his piece about Bald Eagles, Pete says that, with respect to young
> eagles, more than 90% that fledge in a given season don't survive to
> adulthood, and nearly 60% of these die during their first year.
> Evidently, to quote Dunne, "starvation is a young eagle's greatest
> adversary"..
>
> I was wondering what anyone thought about his statistics.
>
> Thanks for the feedback.
>
> Pete Saracino
>
>
>
>
>
> --
>
> Cayugabirds-L List Info:
> http://www.NortheastBirding.com/CayugabirdsWELCOME
> http://www.NortheastBirding.com/CayugabirdsRULES
> http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm
>
> ARCHIVES:
> 1) http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html
> 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds
> 3) http://birdingonthe.net/mailinglists/CAYU.html
>
> Please submit your observations to eBird:
> http://ebird.org/content/ebird/
>
> --
>
> No virus found in this message.
> Checked by AVG - www.avg.com 
> Version: 2016.0.7797 / Virus Database: 4656/13105 - Release Date: 09/28/16
>


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Re: [cayugabirds-l] Eagle Question

[Candace Cornell]

About 60-70% of young eagles perish in their first year primarily due to
starvation, although collisions, electrocutions, and other dangers also
befall them. Young eagles have a long adolescence to learning to hunt for
themselves and it is a steep learning curve. Birds that are slow to learn
do not make it. From what I’ve read, 10-20% survive to maturity.­

Candace

On Wed, Sep 28, 2016 at 7:23 PM, Peter  wrote:

> Howdy folks.
>
> Am reading a very interesting, creative book by Pete Dunne called "The
> Wind MastersThe Lives Of North American Birds of Prey". Dunne takes a
> very creative approach to teach us about these birds...the book reads more
> like a novel!  I highly recommend it but have a question.
>
> In his piece about Bald Eagles, Pete says that, with respect to young
> eagles, more than 90% that fledge in a given season don't survive to
> adulthood, and nearly 60% of these die during their first year. Evidently,
> to quote Dunne, "starvation is a young eagle's greatest adversary"..
>
> I was wondering what anyone thought about his statistics.
>
> Thanks for the feedback.
>
> Pete Saracino
>
>
>
>
>
> --
>
> Cayugabirds-L List Info:
> http://www.NortheastBirding.com/CayugabirdsWELCOME
> http://www.NortheastBirding.com/CayugabirdsRULES
> http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm
>
> ARCHIVES:
> 1) http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html
> 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds
> 3) http://birdingonthe.net/mailinglists/CAYU.html
>
> Please submit your observations to eBird:
> http://ebird.org/content/ebird/
>
> --
>

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Re: [cayugabirds-l] Eagle Question

[Kevin J. McGowan]

Sounds about right. I'd have to check the BNA account tomorrow at work to 
verify the numbers, but that seems in the ballpark.


For medium-sized songbirds, like robins and Red-winged Blackbirds, 70% of nests 
fail to produce any fledglings, 92% of those fledglings die over the first 
year, and half of all adults die each year.


Larger birds tend to have higher yearly survival, but they take longer to reach 
maturity, too. For American Crows, roughly just over half of the nests produce 
fledglings, half of those survive their first year, but most don't breed until 
they're 4 years old, and it's 15% mortality each year. Bald Eagles don't breed 
until they're 5 or so, so I would expect numbers something Pete quotes.


It's a rough world out there. That's one of the reasons that natural selection 
is so strong at weeding out "frivolous" behavior.


Kevin


From: bounce-120838092-3493...@list.cornell.edu 
 on behalf of Peter 

Sent: Wednesday, September 28, 2016 7:23:58 PM
To: CAYUGABIRDS-L; CAYUGABIRDS-L
Subject: [cayugabirds-l] Eagle Question

Howdy folks.

Am reading a very interesting, creative book by Pete Dunne called "The
Wind MastersThe Lives Of North American Birds of Prey". Dunne takes
a very creative approach to teach us about these birds...the book reads
more like a novel!  I highly recommend it but have a question.

In his piece about Bald Eagles, Pete says that, with respect to young
eagles, more than 90% that fledge in a given season don't survive to
adulthood, and nearly 60% of these die during their first year.
Evidently, to quote Dunne, "starvation is a young eagle's greatest
adversary"..

I was wondering what anyone thought about his statistics.

Thanks for the feedback.

Pete Saracino





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[cayugabirds-l] Hanshaw Road Cackling Goose

[Brad Walker]

A/The CACKLING GOOSE was present with the Canada Geese in the corn field on
Hanshaw Road adjacent to Bluegrass Lane. The bird appeared at dusk and fed
relatively close to the road before moving to the back. Jay managed to get
some good photos of the bird. I'll check for it again in the morning when I
leave for work.

http://ebird.org/ebird/view/checklist/S31801766

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[cayugabirds-l] Eagle Question

[Peter]

Howdy folks.

Am reading a very interesting, creative book by Pete Dunne called "The 
Wind MastersThe Lives Of North American Birds of Prey". Dunne takes 
a very creative approach to teach us about these birds...the book reads 
more like a novel!  I highly recommend it but have a question.


In his piece about Bald Eagles, Pete says that, with respect to young 
eagles, more than 90% that fledge in a given season don't survive to 
adulthood, and nearly 60% of these die during their first year. 
Evidently, to quote Dunne, "starvation is a young eagle's greatest 
adversary"..


I was wondering what anyone thought about his statistics.

Thanks for the feedback.

Pete Saracino





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[cayugabirds-l] Freese Road Lincoln's Sparrow

[bob mcguire]

There was at least one crisp, clean, and very cooperative LINCOLN’S SPARROW in 
the community gardens plots along Freese Road this morning. It sat, perched up, 
for a good long minute! Also present were the first fall (for me) White-crowned 
Sparrow, one Chipping Sparrow, three Savannah Sparrows, and the usual, numerous 
Song Sparrows. One of the Song Sparrows has been singing its “plastic song” for 
the last couple of days, usually from the NE corner of the veg plots. I’m quite 
sure that it is the same bird. Other birds of interest were a Tennessee 
Warbler, Common Yellowthroat, and an Eastern Phoebe.

After leaving the community gardens I drove down Hanshaw Road. The corn has 
been cut and the field plowed. A moderate-sized flock of Canada Geese has taken 
over to glean whatever kernels were left behind. Close to the road, in the NW 
corner of the field, was a goose that was noticeably smaller than the other 
Canadas. MUCH smaller, with a short bill, which led me to believes it was a 
Cackling Goose. On closer examination, it was identical in appearance to the 
other Canadas - the same pale breast and relatively long neck - leading me to 
conclude that it was a Richardson’s Goose (subspecies of Canada) and not the 
darker and even smaller Cackling Goose. 

Bob McGuire
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