[CT Birds] Bald Eagles vrs Great Cormorants

Boletebill boletebill at yahoo.com
Mon Feb 22 21:04:51 EST 2010

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.
Bill Yule
Lyme, CT

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


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