WILD 3580 1st Edition Lecture 34Outline of Last Lecture I. Why do birds sing?II. Learning to sing III. Non-vocal sounds Outline of Current Lecture I. MigrationCurrent LectureI. Migration- Periodic two way movement o Bird migration North and south movements from winter to summer Some birds do shorter migrations in east to west Mostly waterfowl, birds of prey, ect. - Neotropical migrants- birds breed in North America and migrate to the south in the winter Most birds migrate at night o Why? Disadvantages 1. High mortality 2. High energetic cost 3. Loss of territory Advantages1. Avoid times of food shortage 2. Avoid extreme climates 3. Reduced competition a. Interspecific (with other species) for nesting space b. Intraspecific factors within the species o How? Migration is cued by photoperiod (day length)- Predictable and reliable - Hormonal/physiological response These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Hyperphagia- increased rate of feeding - Preparing for migration through energy preserves Zugunruhe- nocturnal migratory restlessness The proper distance and direction is innate - Innate ability is modified by experience How do they find their way?- Direction- finding mechanisms1. Sun compass- some animals can determine direction by the position of the sun 2. Celestial navigation- navigate through starsa. Research by Stephen Emlen using Indigo Buntings b. Cue on constellations near the North Star 3. Magnetic field orientation – geomagnetism 4. Visual cues- ex. Water courses, mountain ranges a. More learned than innate 5. Smell- not as much of a component in
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