BIO205 Lecture 6
- Lecture 6: How do populations change?
- Marking can have its problems
o We want to get a measure of their size
o It’s not a new idea that banding affects animal behaviour
o Putting leg bands for finches (different colour leg bands)
Red bands are way more attractive than any other bands and finches with red
bands got more mates
- Banding impacted penguins
o Banded penguins died more often than unbanded
o After 4 years of using bands, the penguin is not that much difference between
- Banding had a variety of effects
o Cascade of consequences
o Lost sufficient of foraging
o Because of warmer weather, the birds need to be out longer to get food and especially
more time is needed for penguins with bands
o So that means less time to breed or have successful breeding
o Then the population growth rate decreases
- But – how did they do the experiment?
o How do you go about comparing the unbanded and banded in this study?
Mark them differently?
Injected a tiny device (32 mm) into the penguin and then hid a wire in the
ground which scans when the penguin crossed over it
It’s not a external banner and it did not introduce any problems to the penguins
Decades of paper have to be reanalyzed because they assumed that banding did
not affect the penguins
- How do populations change over time?
- Picture of a beach and water
o Strangest place on the globe
o Sand dune in the middle of the ocean
o Population of 5 people (people who are studying it)
o Population of 400 sable ponies
- Grey seal population on Sable Island is increasing
o In the 60s and 70s, they used flipper tags
Didn’t tag every pup born on the island