Bird Numbers

To: "John Leonard" <>,
Subject: Bird Numbers
From: Ronald Orenstein <>
Date: Sun, 27 May 2001 20:36:26 -0400
At 11:28 PM 27/05/01 +0000, John Leonard wrote:
At the risk of seriously gripping off large numbers of people I could relate how on a recent birding tour of Costa Rica we spent one morning on a forest trail and saw 45 - 50 spp (with the aid of tapes and a very knowledgeable leader), the next day we spent the same amount of time on the same trail, saw very few of the birds we had seen the day before, but saw another 35 - 40 spp!

If you or birding in a rainforest, I am not the least surprised. My one experience of Costa Rica was as a student on a two-month field course run by the Organization for Tropical Studies back in 1971. During that time, we spent two weeks in the rain forest of the Osa Peninsula. I plotted a graph of the bird species I recorded during that time to see how long it would take to level off -- that is, to reach a point at which I was no longer adding new species to my list for the area. In over two weeks, it never did!

Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court
Mississauga, Ontario, Canada L5L 3W2          
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