Movements and Migration
Modified:
2025-08-25 1:41 PM CDST
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
- 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 (Scroll down)
- 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
(video)
- 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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