[CT Birds] Cormorants and Eagles

Dennis Varza dennisvz at optonline.net
Tue Feb 23 18:13:30 EST 2010

Hi Folks

I had been thinking about the eagles and cormorants  the other day  
and it occurred to me that this is an example of intra-guild predation.

In Ecology a group of organisms that feed (roughly) on the same  
organisms  and are normally considered competitors are called a  
guild, In this case these are fish eating birds. When one of the  
competitors also starts eating its competitors it distinctly shifts  
the balance of  dominance between the species and affect community  
organization. As I recall the first time I heard about it was a study  
on Scorpions, but it is more general than one would think. Another  
example off the top of my head is Great Horned Owls and Screech Owls.

In this particular case I would expect to see the cormorants changing  
their behavior and distribution after a while as they catch on to the  
danger.  What would be really interesting is to see how this is  
affecting the fish populations.

Dennis Varza

More information about the CTBirds mailing list