Rare, very rare and other classification...

[David Bridge]

--- On Sun, 14 Mar 1999 00:21:31 -0700  Robin Leech <robinl at CONNECT.AB.CA>
wrote:
>
>I am afraid that, for most species, the concept of rare is not real.  In
>fact, it is meaningless.  It is really our ability to find the creature or
>plant.  Often it is the ability of the collector to "suss out" the critters
>(or plants).
>
>Now, there are some rare species, but not as many as our egos would like to
>think that there are.
>
------------------------------

Maybe there are more factors to this concept ...

1. The true population or abundance of a animal or plant.
2. "Our" understanding of its biology, ecology, etc.
3. An individuals ability to put this knowledge to work in the field.

I suspect that "our" understanding is often lacking for many species.
If you only have a few records in museums, what do we really know about
its biology ?  In support of Robin (above) does "rare" = lack of knowledge?

In birds there are some species were the world population is 200 individuals
or less.  In 1976, the Chatham Island Robin population was seven birds all on
one small rocky island.  Could we say that this is a rare bird ?
(It numbers have increased some since then.)

Some bird books now use a system I find more useful, than common, rare, etc.

Hard to miss             = "found on nearly every field trip"
Should see               = "found on 3 out of 4 trips"
May see                  = "found on 1 out of 4 trips"
Lucky to find            = "found on 1 out of 10 trips, or less"
How lucky can you get    = "occur at infrequent intervals"

yours, David Bridge
David at simsc.si.edu