Ornithology 1B Spring 2003 Calendar
If you miss a class, please check this page and study the listed topics in your field guide or in "The
Birder's Handbook" by Ehrlich et al. ( Fireside, 1988). Many of the essays and species accounts from that
book are available online. I also recommend visiting field
trip sites on your own if you can't make the actual trips.
May 20
- We finished the book, covering starlings, pipits, waxwings, phainopeplas, warblers, tanagers, sparrows, cardinals,
blackbirds, finches and old world sparrows..
- The invasion of the European Starling in North America and its consequence to native species was discussed.
The success of the American introduction while the native European population is declining may be caused by the
small genetic sample size of the original introduced population.
- Flocking behavior in the Cedar Waxwing can be linked to its food requirements which are unreliable as it is
an obligate frugivore.
- The relationship of the Brown-headed Cowbird and its hosts was discussed. Recent increases in cowbird numbers
in California can be traced to clearing of the land for cattle. California's native species are less able to cope
with parasitism than their Eastern counterparts because they have not had time to evolve protective mechanisms.
- Please preregister after July 1, if you plan to enroll in the Fall. Click here for details.
May 6
- We covered verdins, bushtits, creepers, nuthatches, wrens, dippers, gnatcatchers, thrushes, and mockingbirds.
- Dissussed morphology using a Western Tanager specimen.
- Causes of social plasticity in the Bushtit were discussed.
- Niche partitioning in the nuthatches of the San Francisco Bay area is based mostly on geography with White-breasted
in the interior, Pygmy on the coast and Red-breasted in the mountains. But in the Sierra, these three coexist by
partitioning the resources within the same tree. Pygmy on the outer branches and cones, White-breasted on the main
trunks and Red-breasted on the larger limbs.
- Wrens are diverse in North and South America, but only one species is found in Eurasia. We hypothesized that
the Winter Wren may be a fairly recent arrival to Eurasia from North America. We also suggested that polygeny,
rather than predator avoidance, may be reasons for the evolution of multiple nest building in wrens.
- Geographic variation in the American Dipper was used to illustrate neoteny (retention of juvenile characters
into adulthood) as an evolutionary mechanism.
- Gloger's rule of geographic variation can be seen in the race "caurinus" of the American Robin.
A very dark form from the Pacific Northwest which winters in small numbers in California.
- Mockingbirds sing to attract females. Those with larger repertoires are more successful at breeding.
- There is no class next week. The final class will be May 20.
April 29
- We covered shrikes, vireos, corvids, and larks, wrentits and chickadees.
- Shrike diversity in North America is less than in Eurasia. The Loggerhead Shrike is probably an evolutionary
offshoot of the Northern Shrike after the latter species invaded North America prior to recent glaciations.
- The ability of a raven to seemingly count up to six was discussed in terms of the dangers in methodology of
measuring intelligence.
- The Horned Lark illustrated the differences in diversity of larks in North America vs. Eurasia. Why are there
many species of larks in Eurasia and only one in North America? We postulated that the Horned Lark was a relatively
recent immigrant to North America which has not had time to diversify into multiple species.
- Geographic variation in the Chestnut-backed Chickadee has given rise to three isolated populations which are
named as subspecies. The dividing lines are areas of unsuitable habitat, "Cristo's Line" between Petaluma
and Bodega Bay and the Golden Gate are boundaries to gene flow between these subspecies.
April 22
- We completed hummingbirds, trogons, kingfishers, woodpeckers and flycatchers.
- Mechanisms for backwards flight in the hummingbird were explained.
- The correct mixture for a hummingbird feeder is 1 part sugar to 4 parts water.
- Trogons were used to highlight a discussion on the ethics of song playback in birding.
- Niche partitioning in tropical kingfishers illustrated Gauss's Law of Competitive Exclusion.
- We discussed the nature of the hybrid zone between two races of Northern Flicker and the possible evolutionary
basis for the divergence of the two races. The vicariance model was compared with the Founder Principal. Geographic
isolation caused by past ice-ages was suggested as a mechanism for the evolutionary independence of the two lineages.
The different wing colors may be a consequence of genetic drift rather than natural selection.
- Male mimicry in juvenile woodpeckers was assigned as a topic for further research.
- The Western Flycatcher has recently been split into the Pacific-coast Flycatcher and the Cordilleran Flycatcher.
These are examples of "sibling species," i.e. biological species which do not differ morphologically.
April 8
- We completed cuckoos, owls, nightjars, and swifts.
- Discussed feather ruffling, fluffing, and other mechanisms of thermoregulation.
- We discussed the nature and evolutionary implications of sexual size dimorphism in owls and other raptors.
One explanation is related to the long incubation by female owls.
- Hibernation in the Common Poorwill was discussed.
- There is no class next week because of Spring Break. Class resumes April 22.
April 1
- We covered gulls, alcids, pigeons, parrots, and cuckoos.
- Discussed the origins and identity of the various parrot populations in San Francisco. More information is
available here.
- We outlined the evolution of egg mimicry in the Common Cuckoo.
March 27
- We have enough students to continue as scheduled this quarter. Thank you for your support!
March 25
- We reviewed the biological species concept and mechanisms of allopatric speciation.
- We completed stilts, sandpipers and began gulls.
- We discussed the general rules of geographic variation. Body size increases and extremity length decreases
in response to colder climates (Bergman's Rule and Allen's Rule). Pigment saturation increases in moist climates
(Gloger's Rule). These rules apply to all warm-blooded vertebrates and are believed to be thermoregulatory adaptations.
- We focused on instinctive behaviors in gulls and stages of plumage maturation and molt.
March 18
- We completed quail, limpkins, coots, cranes, plovers, jacanas, and oystercatchers.
- The decline of California Quail in Golden Gate Park was correlated to increases in feral cat colonies in the
park. For information on the American Bird Conservancy's "Cats Indoors!" program, click here.
- Discussed regulation of animal numbers a la Malthus and Lack. It's the carrying capacity of the environment
that ultimately determines population levels.
- We discussed the possible evolution of distraction displays in shorebirds.
- We discussed rooftop nesting in the Killdeer.
- This was the last class for Part A. Please register for Part B next week.
March 11
- Families: hawks, falcons, guans and grouse.
- The use of thermals in raptors was discusses as was visual acuity in the Golden Eagle.
- We discussed the success of the Peregrine Recovery Program and causes of the species decline. We outlined the
causes and consequences of eggshell thinning in the Peregrine Falcon noting that the banning of DDT has not resulted
in significant increases in shell thickness.
- We discussed the general rules of geographic variation. Body size increases and extremity length decreases
in response to colder climates (Bergman's Rule and Allen's Rule). Pigment saturation increases in moist climates
(Gloger's Rule). These rules apply to all warm-blooded vertebrates and are believed to be thermoregulatory adaptations.
- We discussed the evolution of leks using the Sage Grouse as an example. Advantages and disadvantages of this
breeding strategy were discussed.
March 4
- Families: Storks, flamingos, ibises,http://www.abcbirds.org/cats/ waterfowl, and vultures.
- Storks are actually related to Vultures; we discussed water levels and water quality in relation to breeding
success or failure in the Wood Stork.
- Most North American sightings of flamingos are escapes. Filter feeding.
- White-faced Ibis decline as a breeding bird in the Central Valley impacted by water management practices.
- We speculated that the apparent increase in the Turkey Vultures in the East may be related to increases in
forest habitat, rather than global warming or increases in road-kill.
February 25
- Families: boobies, pelicans, anhingas, cormorants, and herons.
- Discussed vagrancy in boobies and other birds.
- Discussed the local decline in breeding Brown Pelicans as related to egg-shell thinning from DDT.
- Discussed molt in Anhingas.
- Discussed breeding success as correlated with age in cormorants.
- Dissussed molt and morphology using a sunning Great Blue Heron as an example.
- Discussed molt and plumage terminology. Natal down, juvenal, basic, alternate plumages. Prebasic, prealternate
molts. Prebasic molts are complete; prealternate molts are partial. Basic plumage = winter; alternate plumage =
summer (usually). Eclipse plumage in ducks is the same as basic plumage.
February 18
- Families: Grebes, albatrosses, shearwaters, storm-petrels, frigatebirds, and tropicbirds.
- Dynamic soaring and Bernoulli's Principle,
how birds fly and soar. Dynamic
soaring in the albatross was demonstrated.
- Discussed polymorphism in the Northern Fulmar and the distinction between polymorphism and other types of plumage
variation.
- The biological species
concept was described and the situation with Clark's and Western grebes was used as an example. Positive assortative
mating prevents gene flow between the populations.
February 11
- Discussed binoculars and optics.
- Some good sites that deal with optics for birding:
- Discussed size illusion.
- Families: Loons.
February 4
- We start at 7pm sharp with your observations and questions.
- Theme of class- What are the factors contributing to avian diversity in the face of Natural Selection?
- Definition of "bird" - Feathered vertebrate. Five major vertebrate classes.
- Types of feathers - Vane, contour, down, semiplume,
filoplume, aftershaft.
- Parts of a feather - Shaft or rachis, barbs, barbules.
- Earliest Bird - Archaeopteryx
- Could it fly?
- Breeding strategies
- Altricial, Precocial. Energetic costs and benefits of each strategy.
- World Diversity - Click here.
- The biological species
concept was described.
- Assignments - Memorize the parts of a bird on pages 10-11 of National Geographic Guide and bring your questions
to class.
- Bring binoculars to class next week, for optics discussion.