I just returned from the first of a 7-class ornithology class given by CCSF (City College of San Francisco), and it promises to be a very informative and interesting class. Joe Morlan, the instructor, has been teaching this class for the past 30 years and is clearly extremely knowledgable about the subject.
This class focusses more on the biology, taxonomy, and study of birds, rather than just field identification (although Joe teaches two classes in that as well); although I have a lot to learn about identification, I have even more to learn about the underlying science of classification, breeding, habitat, and so on.
Tonight he talked mostly about:
– what makes a bird a bird: being a feathered vertebrate.
– The first known bird: archaeopterix. Debatable if it actually flew (although, unlike flightless modern birds, it had asymmetrical primary feathers, it also lacked a keeled breastbone, which all modern flighted birds have (it serves as an attachment point for the wing muscles)), and if it did, if it flapped on the ground in a hopping-type motion, or climbed trees and glided down in search of prey.
– feather types: Vane/contour, Filo plume, Down, Semi-plume, Vane w/aftershaft. Not that I’d really given it a lot of thought, but I learned that feathers are blood-less by the time we see them, although they are vascularized while they grow – once they shed their sheath, the attachment to the bone tapers and cuts off the blood supply, then hollows out. I also didn’t know that the barbs of feathers (the parts that fork off of the rachis (plume) consist of barbules that work rather like a zipper to mesh together or come apart as conditions dictate.
– young-raising strategies: Altricial vs. Precocial. The former type have much smaller eggs and shorter incubations, but the chicks are born naked, blind and helpless and require constant care & feeding by both parents (sometimes just the father), while the Precocial have larger clutches of larger eggs, which require much more energy of the mother during the laying, since they hatch nearly fledged. Another interesting point is that altricial birds nest in trees while precocial birds nest on the ground. This didn’t make sense to me until we learned that precocial birds cannot fly when they fledge, while altricial birds can (and must, since they’re in trees when they leave the nest!).
– DNA hybridization: a process whereby the DNA from two birds are heated until the double helixes break into a single helix, then are cooled to result in a double helix containing both birds strands. This hybrid double helix is again heated and the temperature at which each pair bond breaks is recorded. The higher the temperature required to break the bond, the closer affinity the two species have (for that particular pair)
– the Loon family: they “loon” (dip their heads underwater to look for food), have solid bones, and are fairly “primitive” in that their genus evolved a long time ago.
Alas, it looks like I am going to have to buy yet another field guide, as the text for this class is the National Geographic Field Guide to North American Birds. Fifth edition (I have the 4th, and they’ve rearranged things considerably between the two editions – d’oh!).
I’m looking forward to the next 6 lectures (which have accompanying slide shows during at least part of them), as well as the weekend field trips, as I haven’t done nearly enough birding with groups, which of course is a much faster way to learn than birding along as I usually do.