Your point is well taken, but I am not
sure if I fully agree with you. When organizing my article I have divided
the phenomenon of sentinel behaviour into different
At one level there are examples of birds being
vigilant irrespective of the needs of others in the group or others in
surrounding area (unrelated species). In these instances,
individuals could be exploiting the vigilance of others and
"cheating" can occur (explained in the article). On the other end of
the continuum there are the cooperative breeding species that exhibit
a variety of cooperative behaviors including coordinated sentry duty.
This type of behaviour is what I was referring too in my previous post asking
for examples. In these species, kin selection and/or social status within
the group seem to play a role in the evolution of coordinated sentinel
However in the article, I will not even
attempt to resolve the type of controversial issues that you raise. My
goal is to present the facts and suggest ways that ibirders can go about
observing this very interesting set of behaviours. As I mentioned in an
earlier e-mail exchange with you, I see no harm in speculating about why birds
behave the way that they do ... for the fun of it. I thoroughly enjoy
watching and interpreting behavior. In fact, I no longer keep species
lists unless I have witness notable behaviors in the process.
Thanks for your input ... you help keep
me honest. It will be a awhile before I get around to writing the
nocturnal singing article ... would you care to write it (grin)?