•Protection should also increase with increased mobbing:
oExample: a researcher took a colony of black-headed gull, and took a bunch of
chicken eggs and layed it from the outside of the colony to deep in the colony,
where it’s the densest
oThe zones where they layed down the eggs : A-E : by the time you get inside of
the colony, almost a 100% of the time that the crow approaches, it will get
attacked by at least 10 individuals. That’s quite a big attack. And the percent of
succesfull predation by the crow decreases as it goes deep into the colony, and
this is the affect of mobbing and protecting offspring.
•Information center effect
oIf you are in a big colony living with a group of other individuals and it’s very
hard to find food, you can use the information from what other individuals are
doing in the group to help you find food.
oThis is more important for species where food is mobile and hard to find
Ospreys : they skim the surface of water to find fish
The fish comes from a school of fish, which is moving. If you find a school
of fish you do really well, and if you don’t find a school of fish you won’t be
eating that day potentially.
They have babies in rookeries, or large dense aggregations high above the
water ( in rotten trees)
IC hypothesis predicts that individuals who are able to observe their
neighbours catching food should be more successful in eating.
Graph shows (observational study) : the # of individuals that caught a fish
that observed their neighbour returning with a fish.
•Increased capacity to deal with physical challenges in the environment :
oSome species that go through a period of turper that slows down their
metabolism can do better when they are in a cluster
oPenguins cluster themselves in the Antarctic when it is very cold
oThis allows them to maintain their body heat at a higher level than they would
be able to do alone.