The Dominican Republic Apr 12—20, 2008
Posted by David Ascanio
David Ascanio
David Ascanio, a Venezuelan birder and naturalist, has spent the last 25 years guiding birding tours throughout his native country, Trinidad and Tobago, Suriname, Guyana,&n...Related Trips
Island biogeography has been a fascinating topic among naturalists and scientists for decades. Terms like geographic isolation, ice age, tectonic plates, and elevation are indeed forces that shaped what we see today in Hispaniolan avifauna: an incredible number of endemic bird species. From the beginning of our tour we were exposed to endemic birds, from the conspicuous Palmchat (endemic family!) to the diminutive todies. In fact, it seemed like there was a chance for a new endemic species every day.
During our trip we learned that some of those endemic birds were incredibly common and widespread (i.e. Hispaniolan Woodpecker), while others were quite restricted to some type of habitat or elevation (i.e. La Selle Thrush). Furthermore, some of the widespread species were locally common (i.e. Hispaniolan Parakeet), while others were scarce and difficult to see (i.e. Bay-breasted Cuckoo). The study of the phenomena of abundance and richness of species in isolated regions is a relatively fresh topic, so there is always the possibility of finding something new or peculiar-such as the Gray Heron on our list.
A term to bear in mind when birding on islands is niche. In areas where there is high richness of species, such as Amazonas, Orinoco, or the Andes, you're likely to find small niches for many species, as they must specialize in order to survive. But when referring to islands, you can find one species occupying several habitat types, thus having an ample niche. Good examples were the Palmchat and Red-legged Thrush, both occurring in forested and unforested areas.
One last comment regarding the dynamic of islands. While visiting the Dominican Republic, we witnessed a snapshot of the process of evolution. Here, changes occur at a faster pace, and forces threatening species are more destructive than those on the continent. This may explain why so many species are facing the threat of extinction.
I hope you found our trip educational and enjoyable!