Morten Bjergstrøm wrote:

............................
"Researchers think that the reason why chiles are pungent is an
evolutionary depelopment to keep mammals from eating the chiles because
mammals digestion system destroys the seeds. Capsaicin doesn't has the
same influence on birds whose digestion system doesn't destroy the
seeds. The seeds therefore passes unhindered and the birds are
spreading the seeds widely securing the survival of the chile plants."
http://miljokemi.dk/chili/chilikemi.php?language=uk


Thanks to all who gave a reply. I guess this is the most reasonable
answer to my mind.
There are many fruits that attract mammals and their seeds survive the
trip through the digestive system. Maybe pepper seeds can't survive if
eaten by a mammal and so developed this alternate plan. My first thought
was that there are so many birds that are seed eaters that they must
be able to digest seeds very well. If not, we wouldn't be attracting
many birds to our winter bird feeders.
On the other hand, when birds eat fruits such as Strawberries, I do
believe the seeds survive. I've never seen a bird eat a pepper but I
assume in their native habitat, there are birds that eat them.

Steve