[CT Birds] Bald Eagles vrs Great Cormorants

Boletebill boletebill at yahoo.com
Tue Feb 23 12:45:01 EST 2010


Thanks Glen for your observation
 
This is really interesting. For years we've seen Bald Eagles diving on great Cormorants when they surface holding a large fish to swallow. I always assumed when I saw an eagle dive on a GC in the water that the eagle was trying to make the Cormorant give up a captured fish.  I don't assume this any more.
 
So it would appear that those water-logged feathers that allow Cormorants to dive deeper than other birds have their drawbacks...like a slow take-off after fishing...and BE's have tuned in to that drawback.
 
Bill Yule

"For those who hunger after the earthly excrescences called mushrooms."

--- On Tue, 2/23/10, Glenn Williams <gswilliams9 at yahoo.com> wrote:


From: Glenn Williams <gswilliams9 at yahoo.com>
Subject: Re: [CT Birds] Bald Eagles vrs Great Cormorants
To: ctbirds at lists.ctbirding.org, "Boletebill" <boletebill at yahoo.com>
Date: Tuesday, February 23, 2010, 12:20 PM


Bill,

This past week while birding the Connecticu River from Eli Ferry Road to Gillette's Castle, my family and I watched a sub-adult Bald Eagle attempt to take a Great Cormorant on the water and later two sub-adults doing the same thing at a location further north.

Glenn Williams
Mystic

--- On Mon, 2/22/10, Boletebill <boletebill at yahoo.com> wrote:

> From: Boletebill <boletebill at yahoo.com>
> Subject: [CT Birds] Bald Eagles vrs Great Cormorants
> To: ctbirds at lists.ctbirding.org
> Date: Monday, February 22, 2010, 9:04 PM
> This is not a sighting report but an
> observation.
>  
> As I reported Friday Great Cormorants turned up on the
> lower CT River in visible numbers suddenly after an almost
> total absence earlier.  This weekend 30-40 GC's were in
> their usual haunts between Essex and Deep River.
>  
> Greg had made reference to GC predation by Bald Eagles in
> Maine so I looked into that report and the article was
> highly publicized and sensationalized but it looked as if
> there was something significant going on there. It seems as
> if BE's are flying out to offshore breeding colonies of GC's
> and preying on chicks.  What struck me the most about this
> report was the quote by the interviewed biologist that
> described the eagles as "THESE YOUNG EAGLES" are like
> "thugs", etc. He seemed to be making a point that they were
> not ADULT eagles but sub-adult eagles. This description
> struck a memory chord in me about an two incidents from last
> year and something I saw this week.
>  
> Since Wednesday there's been a cohort... (I'm not sure this
> is the right term but it sounds more professional that
> "gang")...there's been a cohort of 6 or 7 sub-adult BE's on
> the river between Hamburg Cove in Lyme and North Cove in
> Essex.  They all hang out together and have been giving
> great performances and interactions for the tour boats. On
> Thursday and Friday there was still ice on North Cove and at
> one point 5 of these birds were on the ice together eating a
> large dark bird. I couldn't see what the bird was but it
> brought me back to last year when there was a similar cohort
> of 4 sub-adult BE's and twice, that is two separate
> occasions, we saw all 4 sub-adult BE's eating an adult GC on
> an ice floe. Clearly one or more of these young eagles had
> killed the GC dragged it on the ice and ALL 4 were feeding
> on it. This happened not once but twice. This has led me to
> ponder whether or not there are records of co-operative
> hunting among sub-adult BE's?
>  Could it be that these "gangs" of young eagles, like
> "thugs" in the words of the Maine biologist, are working
> together to take down GC's?  I've never heard of anything
> like this.  I've heard of this with Harris Hawks but not
> with Bald Eagles. Fascinating stuff though.
>  
> I'd be interested if anyone has any ideas about this
> possibility.
>  
> Thanks.
> Bill Yule
> Lyme, CT
>  
>  
>  
> 
> "For those who hunger after the earthly excrescences called
> mushrooms."
> 
> 
>       
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