Ornithology 1B Fall 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. The class calendar from last spring is available here.

• We finished the book, covering wrentits, chickadees, verdins, bushtits, creepers, nuthatches, wrens, dippers, 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.
• Please preregister if you plan to enroll in the Spring. Click here for details.

• Families: trogons, kingfishers, woodpeckers, flycatchers, vireos, corvids, and larks.
• 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.
• 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.

• Families: owls, nightjars, swifts, and hummingbirds.
• 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.
• Mechanisms for backwards flight in the hummingbird were explained.
• The correct mixture for a hummingbird feeder is 1 part sugar to 4 parts water.

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November 18

• Families: 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.
• Discussed feather ruffling, fluffing, and other mechanisms of thermoregulation.

• 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 protracted first prealternate molt.
• Discussed the historical dynamics of the population of Common Murres.
• Spent considerable time looking at feather tracts and physical characters of a recently dead Cooper's Hawk.

• Families: jacanas, oystercatchers, stilts, sandpipers and gulls.
• The wing-spur of the jacana was discussed. Ornithologists distinguish between "wing-claws" such as found on Archaeopteryx and "spurs." Spurs are used in combat and differ in structure from claws. Spurs are on the radial side of the carpus. Spur-winged Goose, Spur-winged Plover, Black-necked Screamer, and Sheathbill all have carpal spurs. Digital wing-claws persist into adulthood in the Secretary-bird, Black-necked Screamer, three species of finfoots and are found on the juveniles of the Hoatzin and a few other species.
• 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: Falcons, cranes and plovers.
• 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 possible evolution of distraction displays in shorebirds. 

• Families: vultures, hawks, guans, grouse, quail, limpkins and coots. (Falcons went missing)
• The use of thermals in raptors was discusses as was visual acuity in the Golden Eagle.
• 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 regulation of animal numbers a la Malthus and Lack. It's the carrying capacity of the environment that ultimately determines population levels.
• Note: This was the last class for Part A. Please register for Part B as soon as possible.

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

• Families: cormorants, herons & storks.
• Discussed "Birding" magazine and "North American Birds" published by the American Birding Association.
• Discussed bird anatomy using a dead Fox Sparrow as an example.
• Discussed breeding success as correlated with age in cormorants.
• 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.

• Discussed geographic variation in the Fox Sparrow and the subspecies concept.
• Families: frigatebirds, tropicbirds, boobies, pelicans and anhingas.
• 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 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.

• Families: Grebes, albatrosses, shearwaters, storm-petrels.
• 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.
• Discussed size illusion.

• Discussed binoculars and optics.
• Some good sites that deal with optics for birding:
  • Better View Desired: http://betterviewdesired.com/
  • Optics for Birding: http://www.optics4birding.com/
  • New Jersey Audubon: http://www.njaudubon.org/NatureNotes/Optics.html
  • Eagle Optics: http://www.eagleoptics.com/
• Families: Loons.

• 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.