Navigation Flashcards
(37 cards)
piloting/ place navigation:
use of familiar reference points
piloting
ability to find a goal by referring to familiar landmarks
What can give sense of location? - example of bee and wasps with their nest - what does it require?
landmarks can give sense of location
- bees and wasps - acorns around burrow/nest -> move acorns and can not find nest
requires use of relationships between stable/ predictable external (visual, olfactory, auditory) cues
Pigeons as model organisms
Lipp et al (2014)
1. how many pigeons?
2. how many GPS tracks?
3. released up to what from loft?
4. where the birds non-experienced or experienced?
5. how many years were they released over and around where?
- 34 pigeons
- 216 GPS tracks
- released up to 50 km from loft
- experienced birds
- released over 3 yrs around Rome
Lipp et al (2014)
what was found?
pigeons follow the road home
bee-line to loft = straight line to loft = quickest way
pigeons did not follow the bee-line, followed roads
Lipp et al (2014)
1. simulated…?
2. what was counted?
3. significant road following in…?
4. cost of detours?
- simulated tracks from all release sites
- count number of times tracks crossed grid squares with roads
- significant road following in 40-50% of tracks
- cost of detours? - pay a price for following the landmarks - longer route
Landmarks - piloting not straightforward over long distances
(Schmidt-Koenig & Walcott 1978)
1. what did they add to this experiment?
2. birds orientated towards?
3. did they reach the loft or not?
- no object vision
- birds orientated towards the loft
- many reached the loft
Landmarks - piloting not straightforward over long distances
1. what do many animals use (including ants)?
2. when are landmarks not ideal?
3. what happens if they can not see landmarks?
- many animals use landmarks AND a compass
- landmarks good if not moving - h/e rivers moving - rainfall changes shape of river
- can see light and dark but not necessarily make out landmarks - not only follow roads when navigating from A to B
Map and compass definitions (Kramer 1953)
compass: sense of direction - need to know where you are to give sense of geographic position
map: sense of geographic position
- compass orientation definition?
- how would you test if animals are following a compass bearing?
- The ability to head in a geographical direction without the use of landmarks
- translocation experiments - move them
Experimental relocation of inexperienced animals cause them to…
…miss the goal by the amount of its displacement
birds migrate from Netherlands (breeding range) to North of France (normal winter range) -> moved to Switzerland and migrated in the same direction as normal but to Spain
use of compass orientation
Blackcap birds
1. what birds are investigated?
2. what was the pattern of direction?
- brown: Germany
white: Hungary
blue: F1 - on compass - brown arrows facing south west, white arrows facing south east; F1, blue arrows facing both south west and south east
Sun compass (Kramer 1951)
1. what is needed to know to use sun compass?
2. what might be unclear if time is not known?
3. what occurs when young pigeons were only allowed to see the morning sun?
4. can experimentally alter the relationship between time and angle to produce?
5. limitations?
6. how can produce predictions?
- need to know time to use sun compass
- would not know whether it was morning or evening and T/F do not know if its East or West
- young pigeons only allowed to see the morning sun lack the ability to use the sun for navigation in the afternoon
4.can experimentally alter the relationship between time and angle to produce predictable deflections over <1.5 - 165 km
- sun not always visible, path alters with location
- can produce predictable errors by shifting internal clocks
Celestial compass (Emlen 1967)
1. what does it require?
2. lots of birds and song birds migrate when, and why?
3. how might animals detect which way is North using this method?
- requires animals to relate the alignments of star patterns to the axis of celestial rotation
- migrate at night - safer, less likely to encounter day time predators, cooler - flight is costly and generates heat but at night the air is cooler, less turbulence - cheaper/ less energy to fly at night; no access to sun compass
- if animals can detect the way the stars rotate around the North star - know which way is North
Celestial compass (Emlen 1967) - classic experiment
1. what is a must see for this compass use by young pigeons?
2. what bird was used, where were they taken and what is the name of the equipment they were put in?
3. what occurred during the study and what did it demonstrate?
4. results?
5. what is this evidence for?
- young birds must see the night sky to use this compass
- indigo buntings (bird) - taken to planetarian, use Emlen funnels
- bird able to see night sky, Emlen funnel has ink at bottom and blotting paper lining funnel - birds jump up and get ink on feet and land on plotting paper as they try to move - demonstrates the way they move
- frequency birds try to jump in that direction was measured - outdoor and artificial (planetarium) were the same direction - when reversed (night sky rotate around different star) direction birds jump to is opposite to outdoor and artificial
- evidence for animals using stars as compass
Magnetic compass - (Guerra 2014)
1. what animal uses sun compass BUT migrate to where when cloudy?
2. magnetic compass trials?
3. how was the study conducted?
4. even when cloudy (no sun) where do the butterflies migrate, and what may this mean?
5. what are lots of animals sensitive to?
6. what can the box change?
- Monarchs use sun compass BUT South when cloudy
- flight simulator surrounded by magnetic coil system, insects responded to inclination
- butterfly tethered to the box -> when flies it record the direction
- migrate South still - suggests another compass being used
- lots of animals are sensitive to magnetic cues
- box can change magnetic field lines
Magnetic compass - Engels et al (2014)
1. what does anthropogenic electromagnetic noise disrupt?
2. where is electromagnetic noise emitted from?
3. what occurred in this experiment?
- anthropogenic electromagnetic noise disrupts magnetic compass orientation in a migratory bird
- electromagnetic noise is emitted everywhere we use electronic devices
- Robins were used to investigate magnetic compass - with presence of anthropogenic electromagnetic noise, direction breaks down; when shielded by magnetic noise, direction is strong
Compass types
1. what is the type of compass system used dependent on?
2. what else do animals use?
3. what does each system incorporate?
4. discrepancy between?
5. animals must know what?
- weather conditions, time of day, and past experience
- animals also use other cues (polarized light, wind, waves…)
- each system incorporates both learnt and innate components
- discrepancy between compasses i.e. magnetic North is different to geographic North - need to know how they relate to each other if switching between compass techniques
- animals must know how compass cues interact
Manx shearwaters (Puffinus puffinus)
1. what did the study entail?
2. what was the result?
3. can compass alone explain ability to return from displacement?
- take birds from West Wales and displace across Atlantic ocean and in Mediterranean
- never fly over land, returned within 14 days (up to 5150 km)
- compass can not explain alone - animals did not know where they were initially - need to find out where they were displaced to , to use compass
Thorup & Holland (2009)
displacement - return to breeding sites after displacement
1. marine species - example
2. terrestrial species - example
- Laysan albatrosses - displacement up to 6630 km from Midway Atoll to the Philippine Islands (returning in 32 days)
- White stork - displacement up to 2269 km from Butyny, Poland to Lydda, Palestine (returning in 19 days)
what is true navigation?
the ability of an animal to return to its original location after displacement to a site in unfamiliar territory, without access to familiar landmarks, goal emanating cues, or information about the displacement route
True navigation
1. map stage
2. compass stage
3. adults and juveniles?
- animals at unfamiliar sites determine position relative to a destination
- animals progress to destination
- adult birds can, juveniles cannot
The map sense
1. bi-co-ordinate map requires?
2. gradients should not intersect where?
3. requires animals to learn what?
- bi-co-ordinate map requires 2 factors to change continuously in space
- gradients should not intersect at an acute angle
- requires animals to learn alignment of environmental gradients within home range and extrapolate these beyond familiar area
The magnetic map sense
what two aspects of the magnetic field do animals respond to?
inclination/ dip angle (varies from 0-90°)
AND
intensity (Varies from 20 µT at the equator to 65 µT at the poles)
