Movements and Migration
Modified:
2023-11-07 11:30AM CST
Introduction
- Looking at:
- movement in the local environment
- endogenous compass orientation
- true navigation
Movement in Local Environment
- Relationship of animal and environment
- Ranges from hardly any movement from natal area to migrations of thousands of miles (see below)
- Animals that stay with natal environment or family group for long periods
- Animals that leave the natal environment or family group quickly
Migration
- Definition: any pattern of animal movement
- Questions
- Why?
- Change in environments (a given, btw)
- practically speaking there is no such thing as a constant environment, all of the following vary:
- weather
- temperature
- seasons
- one might argue that the deep ocean is as close to a constant environment as possible
- Track beneficial changes in environment
- Migrating animals look to optimize:
- food sources
- temperatures
- habitats
- How?
- Planned migration
- Animals track local conditions and respond
- Wildebeest track rain using visual and auditory
cues
- Wildebeest Migration
- Seasonal migration
- Animals anticipate regular environmental changes
- Regular environmental changes include:
- seasons,
- changing daylight length,
- biologically correlated changes
(leaves falling, vegetation loss)
- insect species abundance or decline (prey)
- Requirements
- Accurate environmental cue
- Compass sense, MagR gene
- found in pigeons (see below) and monarch butterflies, salmon, sea turtles, newts, lobsters, bees, dolphins, and bacteria
- gene orients to magnetic fields
- use sun and stars as directional cue
- How animals sense magnetism (read, on test)
- Hormones often involved in migration
- decline in sex hormones may trigger migration
- More Examples
- Monarch Butterflies
- Shortening daylight is likely cue
- Need to avoid cold is another factor
- Not learned (one generation migrates)
- Fewer migrants of late because of pesticides and lack of milkweed
- Lemmings
- Passenger Pigeon
- Extinct species that once migrated seasonaly in
large numbers in North America
- Martha, the last passenger pigeon
- American Bison (buffalo)
- Nearly driven to extinction
- Migration was seasonal in North American
midcontinent
- American Bison FAQ
- Arctic Tern
- Migrates seasonally from Arctic to Antarctic
- Arctic Tern 25,000 miles per year (from pole to pole)
- Blackpoll Warbler Migration Route
- Another long distance migrant
- Gray Whale
- Migrates from Bering Sea to Baja California
seasonally
- Insect migration
- Large biomass (3,200 tons over Southern England alone)
- Radar used to spot them
- Human migration
- Post-Columbian explosion (post 1492)
- Before Columbus
- Europeans lived in Europe
- Asians lived in Asia
- Native Americans lived in N. and S. America
- After Columbus
- Much voluntary and involuntary migration
- Forced vs voluntary
- Wars
- World War II
- United States
- FYI, I'm a product of that forced migration. My father was drafted into the US Army and eventually was stationed in Cairo, where he met my mother. They had two children, my brother and I.
- Another example was a woman from South Dakota who moved to Washington, DC to work in the war effort. There she met a man from New York drafted into the US Army. They married before he shipped out to European Theatre and Patton's Third Army. He survived and had a family of three children.
- There are millions of stories similar to these.
- Europe
- Some 15 million Germans and other refugees forcibly moved following World War II
- Ethnic cleansing
- Trail of Tears
- Thousands of Native Americans forcibly moved from Eastern United States to lands in the west
- 2020 Supreme Court Ruling
- McGirt v. Oklahoma (2020) affirmed that much of Oklahoma remains Native American territory and is excluded from Oklahoma law.
- Economic
- United States: The Great Migration (1916-1970)
- Caused by:
- Jim Crow Laws following end of Reconstruction
- Violence against African-Americans
- Destinations
- New York City
- Chicago
- Philadelphia
- Detroit
- The passage of the 1964 Civil Rights Act marked the end of the Great Migration
- History of ancient human migration (video, watch, pay attention to years)
Homing
- Three Possibilities
- Memorize local landmarks
- Digger Wasps
- Tinbergen's research
- Philanthus triangulum
- Dig nests on the beach
- Lay eggs and provision the eggs with immobile (but alive)
- A symbiotic relationship with bacteria protects the larva
- Find more prey (bees) (hard for humans to find, btw)
- Picture
and Animation, (slow link, be patient)
- Click on link "Home location by digger wasps" on that page
- Another picture
- Wasps learn local landmarks
- Home site is recognizable at a distance
- Salmon migration
- One-time return to natal stream
- Salmon imprint (learn with brief exposure) the odor of their native stream
- Use earth's magnetic field
- Use chemical cues to find natal stream
- Mate, die
- Whoosh tube
- Device helps salmon stranded at dams continue to migrate upstream
- Internal map sense
- Pigeon navigation
- True navigation
- Time corrected solar compass
- Used when sun is out
- If researchers artificially alter pigeon's daily light cycle (called "clock shifting") pigeons will alter their routes
- Magnetic sense
- Used when overcast
- Brass, Magnets, and Helmholtz Coils
- Brass is non magnetic and is used as a control for the weight of the magnet or Helmholtz coil
- Magnets attached to the head overcome the Earth's natural magnetism
- Helmholtz coils are small electromagnets that overcome the Earth's natural magnetism
- Picture Magnetic Effects notice how magnets cause faulty navigation only when pigeons released on cloudy days
- Olfaction
- Used when overcast
- Controversy
- Article attempts to resolve competing data about role of olfaction in pigeon navigation (test question)
- Low frequency infrasound
- Infrasound: sound frequencies less than 20 Hz
- Pigeons can detect infrasounds as low a 0.05 Hz
- Pigeon navigation using infrasound (includes sound samples, fyi)
- Research began when Concorde jet's sonic boom caused loss of 60,000 pigeons in cross Channel race
- Cornell University birds often lost their way when released from particular towers
- Sound shadow was the problem
- Whales and elephants also use low frequency sounds to communicate
- The US Navy uses very low frequency sounds (3 to 30 kHz)to communicate with its submarines while submerged at shallow depths
- Use landmarks
- SAU Water Tower would be an example of a prominent local landmark
- Roads: birds of all kinds have been shown to follow highways as landmarks
- Learning
- Young pigeons are less able to navigate
- Indicates they are learning all of their potential navigation cues as they mature
- Humans
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