Boucher's birding blog: Why elevation makes a difference
Just 400 meters can lead to fascinating differences in species.
Tue, Dec 15, 2009 at 11:13 AM
The helmeted guineafowl (left) and the vulturine guineafowl. (Photo: Timothy Boucher/TNC)
A short distance up or down can make a big difference for birding! On a recent trip to Lewa Conservancy in Kenya — with which The Nature Conservancy works to foster a community conservation movement that is rapidly spreading through northern Kenya — I was surprised at the difference 400 meters in elevation could make in the birds we saw.
Pictured above are two guineafowls — same family, obviously different species — helmeted guineafowl on the left, and vulturine guineafowl on the right. Driving the dozen or so miles that led to the 400-meter elevation change, it occurred to me that we were traveling through an ecological threshold point, and the slightly drier and hotter climate translated to subtle habitat shift from mostly grass and shrub (pictured in the photo on the left) to more scrubby and sparse.
This slight habitat shift led to a consequent fascinating change in bird species — and not just the guineafowls. A lot of species changed — go-away-birds, barbets, mousebirds and flycatchers to name but a few.
Most ecologists understand these zones well, while many birders do not — to their detriment. Recognizing the different zones as applied to your interest (birds, in this case) — and what occurs in between (known as transition zones) — are critical to which species you can find and to maximizing the diversity of species.
And where do you find information about what zones that birds prefer? Simple: most of it is in the field guides you would buy before visiting a new place!
In the text of almost all of them are basic descriptions of which habitats and sometimes even elevations that the birds prefer. From my field guides, I knew that the helmeted would be most common around Lewa (which it was), but to see the vulturine I would need to get lower (and drier). Well, on the one planned field trip, we did go lower (to Il Ingwesi) — to below the important 1,100-meter elevation level, and that’s where we saw that zany bird on the right.
Now, identifying the vulturine guineafowl was easy (clearly it’s visually very different), but sometimes visual differences can be subtle. This is when knowing the habitat can be critical. Sometimes it may not be elevation, it can be simply a different type of forest, or aspect of a valley, or side of a range.
But knowing these habitat clues will make all the difference in your quest to find our feathered friends and learn more about them. As an old ornithologist friend (admittedly a curmudgeon) once said to me (clearly after many questions on my part) — “It’s all in the book! Read it!”
And I have been reading ever since.
-- Text by Timothy Boucher, Cool Green Science Blog