Ornithology 1B Spring 2005 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. The class calendar from last fall is available here.
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May 24
- We finished the book, covering gnatcatchers, thrushes, mockingbirds, starlings, pipits, waxwings, phainopeplas,
warblers, tanagers, sparrows, cardinals, blackbirds, finches and old world sparrows.
- 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.
- 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.
- Selander's findings on the geographic variation in the House Sparrow was discussed as illustrating the relatively
rapid change in populations in the face of various climatic conditions.
- Please preregister after July 1st
if you plan to enroll in the Fall. Click here for
details.
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May 10
- Families: Larks, swallows, chickadees, verdins, bushtits, creepers, nuthatches, wrens, dippers, kinglets.
- 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.
- 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. Note: correct spelling is "neoteny."
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May 3
- Families: Woodpeckers, flycatchers, vireos, and corvids, larks, and swallows.
- 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.
- 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?
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April 26
- Families: hummingbirds, trogons, kingfishers, and woodpeckers.
- 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.
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April 19
- Families: cuckoos, owls, nightjars & swifts.
- Discussed feather ruffling, fluffing, and other mechanisms of thermoregulation.
- Asymmetrical ears in owls enable the birds to accurately locate prey by hearing.
- 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.
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April 12
- Families: alcids, pigeons, parrots.
- Discussed the historical dynamics of the population of Common Murres.
- Discussed the origins and identity of the various parrot populations in San Francisco. More information is
available here.
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April 5
- Families: jacanas, oystercatchers, stilts, sandpipers & gulls.
- Discussed instinctive behavior in terms of "releaser" stimuli in the Oystercatcher where the egg
provides a stimulus to incubate and contrasted that with gulls where the nest itself is the focus of incubation
behavior.
- Discussed plumage maturation and molt in shorebirds..
- Discussed the role of the red spot on the mandible of gulls as part of a complex series of behavioral releasers.
- Outlined molt in the Western Gull pointing out the protracted first prealternate molt.
- The "Morlan Method" gull identification key with full text is here.
Adobe acrobat reader required. An abridged html version is here.
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March 22
- Families: quail, limpkins, coots, cranes & plovers.
- 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.
- A dead Golden-crowned Sparrow was used to demonstrate external bird morphology. The possible dangers of handling
dead birds was discussed in view of West Nile Virus.
- We discussed the possible evolution of distraction displays in shorebirds.
Note: This was the last class for Part A. Please register as soon as possible for Part
B which starts April 5th. You can register online, or mail or fax this registration
form.
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March 15
- Families: vultures, hawks, falcons, guans, grouse.
- The use of thermals in raptors was discussed as was visual acuity in the Golden Eagle.
- 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 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.
- View nesting Peregrines live on the PG&E building in San francisco here.
- Reviewed the general rules of geographic variation
in warm-blooded animals..
- Allen's Rule - an animal's extremities are shorter in colder parts of its range than in warmer parts.
- Bergman's Rule - an animal's body size is smaller in warmer parts of its range than in colder parts.
- Gloger's Rule - dark pigments increase in warm and humid habitats.
- We discussed the evolution of leks using the Sage Grouse as an example. Advantages and disadvantages of this
breeding strategy were discussed.
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March 8
- Families: herons, storks and flamingos, ibises, waterfowl.
- Discussed molt and morphology using a sunning Great Blue Heron as an example.
- 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.
- Eclipse plumage in ducks is actually equivalent to basic plumage.
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March 1
- Families: pelicans, anhingas and cormorants.
- Discussed the local decline in breeding Brown Pelicans as related to egg-shell thinning from DDT.
- 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.
- Discussed breeding success as correlated with age in cormorants.
February 22
- Families: albatrosses, and shearwaters, storm-petrels, frigatebirds, tropicbirds, & boobies.
- 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.
- Discussed post-breeding dispersal & vagrancy in boobies and other colonial waterbirds.
February 8
- Discussed binoculars and optics.
- Some good sites that deal with optics for birding:
- Families: Loons, grebes and albatrosses.
- Discussed polymorphism and the distinction between polymorphism and other types of plumage variation.
- The biological species
concept was reviewed and the situation with Clark's and Western grebes was used as an example. Positive assortative
mating prevents gene flow between the populations.
February 8
- We start at 7pm sharp with your observations and questions.
- The biological species
concept was reviewed.
- 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.
- Families: Loons.
- Assignment - 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.