Ornithology 1B Spring 2007 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

• We finished the book, covering: babblers, chickadees, verdins, bushtits, creepers, nuthatches, wrens, dippers, kinglets, gnatcatchers, thrushes. mockingbirds, starlings, pipits, waxwings, phainopeplas, warblers, tanagers, sparrows, cardinals, blackbirds, finches and old world sparrows.
• 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.
• 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 if you plan to enroll in the Fall. Click here for details.

• Families: woodpeckers, flycatchers, shrikes, vireos, 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 "cryptic 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?
• We postulated that the Horned Lark was a relatively recent immigrant to North America which has not had time to diversify into multiple species.

  There is no class next week. The final class will be Tuesday, May 22.

• Families: owls, nightjars, swifts, 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.
• Families: , flycatchers, shrikes, vireos, corvids, larks, swallows, and babblers.
• Trogons were used to highlight a discussion on the ethics of song playback in birding.
• Niche partitioning in tropical kingfishers illustrated Gause'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.

  Click here for alternate routes to the Briones field trip. Click here for revised directions.

• Families: pigeons, parrots, cuckoos & owls
• 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.
• Discussed feather ruffling, fluffing, and other mechanisms of thermoregulation.
• Asymmetrical ears in owls enable the birds to accurately locate prey by hearing.

• Families: gulls & alcids.
• 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 preformative molt.
• The "Morlan Method" gull identification key with full text is here. Adobe acrobat reader required. An abridged html version is here.
• Discussed the historical dynamics of the population of Common Murres.
• We discussed the nature and evolutionary implications of sexual size dimorphism in hawks and other raptors. One explanation is related to the long incubation by female owls.

• Families: plovers, jacanas, oystercatchers, stilts & sandpipers.
• We discussed the possible evolution of distraction displays in shorebirds. 
• 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.

• Families: vultures, hawks, falcons, limpkins, coots, and cranes.
• 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..
• 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 in San francisco here.
• Reviewed the general rules of geographic variation in warm-blooded animals..
  1. Allen's Rule - an animal's extremities are shorter in colder parts of its range than in warmer parts.
  2. Bergman's Rule - an animal's body size is smaller in warmer parts of its range than in colder parts.
  3. Gloger's Rule - dark pigments increase in warm and humid habitats.

There is no class next week because of Spring Break. Class resumes Tuesday, April 10.

• Families: herons, storks and flamingos, ibises, and vultures.
• 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.

This was the last class of the quarter. Please click here to register for part B. Course numbers, dates and descriptions are here.

• Families: pelicans, anhingas, cormorants and herons.
• Reviewed 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).
• Click here for a diagram showing the annual cycle of breeding, molt, and migration of the Anhinga in North America. Thick lines indicate peak activity; thin lines, off-peak. Daigram taken from the Birds of North America account (Frederick, P. C., and D. Siegel-Causey. 2000. Anhinga (Anhinga anhinga). In The Birds of North America, No. 522 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.)
• Discussed breeding success as correlated with age in cormorants.
• Niche partitioning in cormorants illustrated Gause's Law of Competitive Exclusion.
• Discussed molt and morphology using a sunning Great Blue Heron as an example.

• The "Morlan Method" gull identification key with full text is here. Adobe acrobat reader required. An abridged html version is here.
• Families: storm-petrels, frigatebirds, tropicbirds, boobies and pelicans.
• Discussed post-breeding dispersal & vagrancy in boobies and other colonial waterbirds.
• Discussed the local decline in breeding Brown Pelicans as related to egg-shell thinning from DDT.
• A dead White-crowned Sparrow was used to demonstrate external bird morphology. The possible dangers of handling dead birds was discussed in view of West Nile Virus.

• Families: quail, grebes, albatrosses and shearwaters.
• 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.
• 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.
• Reviewed the general rules of geographic variation in warm-blooded animals..
  1. Allen's Rule - an animal's extremities are shorter in colder parts of its range than in warmer parts.
  2. Bergman's Rule - an animal's body size is smaller in warmer parts of its range than in colder parts.
  3. Gloger's Rule - dark pigments increase in warm and humid habitats.

• Families: waterfowl, guans, grouse and quail.
• Eclipse plumage in ducks is actually equivalent to alternate plumage.
• 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 evolution of leks using the Sage Grouse as an example. Advantages and disadvantages of this breeding strategy were discussed.  
• 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 binoculars and optics.
• Some good sites that deal with optics for birding:
  • Better View Desired
  • Cornell
  • Optics for Birding
  • Eagle Optics
  • Laura's Optics Guide
• Reviewed external bird topography.
• Families: Loons.
• 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).

• 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. Herons are "Semi-altricial 1".
• World Diversity - Click here.
• Bring binoculars to class next week, for optics discussion.
• Assignment - Memorize the parts of a bird on pages 10-12 of the National Geographic Guide (5th edition) and bring your questions to class.