Lecture 13

Question 1

Individual Distance:

Answer 1

the minimum distance an animal routinely keeps between itself and other of the same species

Question 2

An individual or group may defend :

Answer 2

1. A large area containing all required resources for survival 2. A point source with a particular resource (nest site) 3. Establish a priority for access to resources.

Question 3

In social or group living birds what is different about territory defending?

Answer 3

a territory is not defended instead a stable dominance hierarchy is maintained by signals. A period of fighting is often needed to establish the hierarchy

Question 4

Agnostic signals:

Answer 4

used in dominance interactions and territory defense

Question 5

How do harris sparrows become more dominant?

Answer 5

Bib size! The ones more black the ones are more dominant. They did an experiment with injection of T and black bib. The ones injected and painted bib did the best. You need the link between appearance and behaviour to rise in status

Question 6

what are 4 benefits of dominance?

Answer 6

1 increased food availability 2 decrease social harassment 3 decreased presation risk 4 increased copulations or reproductive success

Question 7

when is there a peak in stress in birds?

Answer 7

when they are trying to figure out there place in the hierarchy

Question 8

Reproductive skew and example:

Answer 8

matings often higher for a few members of the group. In manakins they do a group display and females would only mate with alpha male. The other do this in hopes the alpha male dies some day and they will become alpha. But long lived so can take long time

Question 9

what is the chickadee and titmice example of benefit of being dominance and body weight?

Answer 9

subordiantes carry more body fat in winter! It makes them less agile and less able to escape predators. If a dominant already has good access to foods it doesnt have to pile on the weight like the subordinates do.

Question 10

can dominance operate between species, not only within species?

Answer 10

Yes! Birds in tropics the large dominant birds will control the ant site and the range of availability drops the smaller the birds are.

Question 11

what are the benefits of group living?

Answer 11

1. cooperative hunting (harris hawks hunting a rabbit) 2. Protection from predators 3. social information (source of food)

Question 12

what are the 2 behavioural strategies in flocks?

Answer 12

1. producers actively search for and find food patches 2. scroungrs dont look for themselves but eat food from patches that others find

Question 13

in the pigeon experiment how many were producers and how many were scroungers?

Answer 13

2:14

Question 14

draw the graph for ideal ratio between producers and scroungers

Answer 14

Question 15

whats an example of being beneficial to be in a group to get information?

Answer 15

starlings left empty patches sooner when foraging with a partner than when foraging alone

Question 16

in flocks what are the 2 categroeis flocks reduce pradation?

Answer 16

1. reduce encounter rate with predators: eans in a larger group there is less a chance the predator will pick you.
2. reduce success of predator attack by vigilance, confusion, and mobbing

Question 17

what is the selfish herd cocnept?

Answer 17

1. stay in group because your individual chances of getting eaten are smaller as part of group than living alone
2. not all position in the heard are equal.

Question 18

the selfish heard concept is only teu of what 3 things are held up?

Answer 18

1. predators only take a few individuals at a time
2. attack rate is independent of group size. say if you joined a group with 100 individuals but attacks came 100x more often there would be no dilution effect

Question 19

american crows drop walnuts to break them open, the upwards flight though todrop is energetically costly and the higher they go the more likely another bird will steal. So how do they adjust?

Answer 19

english walnuts break more easily than black and can be dropped lower, you can also lower by substrate hardness and to minimiza the chance of theft. when the risk exceeds a certain threshold, crows lowered the drop height so they can recover the nut before it is snatched by another birds.

Question 20

what does the graph look like for optimal flock size?

Answer 20

Question 21

Mixed species flocks are common where?

Answer 21

in tropics and in temperate sone during the non breeding season.

Question 22

what is the assumed benefit of mixed species flocks?

Answer 22

is increased predator dtection and foraging efficieny

Question 23

what are the 2 types of colonies?

Answer 23

1. breeding colonies. 13% of bird speces
2. Roosting colonies, outside of the breeding season.

Question 24

why are colonies usually located in inaccessable areas with as few predators as possible?

Answer 24

breeding or roosting measn the birds are spening a large amount of time in 1 area in a potentially vulnerable state. Like swift salivia mud nests on cliff faces and seabirds on remote island or snowy egrets ontop of trees

Question 25

some species of colonial nesting birds have synchronous breeding timing, why?

Answer 25

proposed advantage is swamping the predators with so many chicks they cant eat all of them

Question 26

Ecological correlates of coloniality:

Answer 26

1. resources are either;
   a. )widely sscattered and hard to defend
   b. ) Unpredictable in space and time
2. Nesting sites are insaccesble like cliffs or islands

Question 27

In weaver birds some species are territorial, nesting in pairs and foraging singly but most species are colonial nesters and flocking foragers. what is the reason for differences?

Answer 27

food.

Question 28

Disadvanatge of coloniality

Answer 28

competition:

1. feeding competition. Many animals living in the same area means lots of demand for food
2. Nesting material
3. Nesting site, some sites better than others. Advantageous sites may be highly contested

Question 29

what is the major cost of flocking?

Answer 29

food must be shared

Question 30

how do house sparrows communicate if their is food availability?

Answer 30

giving chirrup. If there is limited food they will not chirrup

Question 31

what are all the disadvantages to colonialtiy?

Answer 31

1. competition
2. predation
3. disease and parasites

Question 32

what cost does it add to the parents by the fact their neighbor may eat their kid?

Answer 32

One parent mist remain at nest to guard. Less time available to forage and may raise fewer young.

Question 33

3 ways disease and parsites are aided by coloniality?

Answer 33

1. proximity to conspecifics facilitates transmission of diseases and parasites
2. Many ectoparasites are species-spcific so the only way to become infested is through close association with other conspecifics.
3. cliff swallows example, weight of chicks from nests with ticks was inversely related to number of ticks. Chicks at fumigated nests had 50% chance of dong better

Question 34

Ectoparasitism in cliff swallows; high potential fitness cost for these colonial nesting birds so why do they stay close together?

Answer 34

natural constraint of cliff sites and food supply is localized

Question 35

Information center hypothesis:

Answer 35

it is advantageous to stay in group because of the increasing foraging efficiency, many sets of eyes can find food quicker than on set remem=bering that coloniality is associated with patchy food resources

Question 36

How did ospreys watch their neighbour?

Answer 36

if they were successful in fishing they would go to the same spot as their neighbour

Question 37

what are the 6 things that must be satisfied to support information center hypothesis?

Answer 37

1. sit fidelity.
2. Differential foraging success.
3. successful birs must be identifiable
4. synchronous departure from colony by leaders and followers
5. Following must take place
6. followers must be tolerated

Question 38

what are the benefits of territory defense?

Answer 38

1. decreased predation (spread out nests)
2. decreased parasitism and disease
3. Food lasts longer
4. Food supply more predictable
5. Increased number of mates
6. Better/safer condition for rearing offspring

Question 39

what are the costs of territory defense?

Answer 39

1. evict a previous owner
2. Maintenance (time and energy)
3. Injury costs of fighting

Question 40

what are the types of territory?

Answer 40

type A: a large defended area in which ass reproductive activitity and feeding occurs. Insectivorous birds, many raptors and passerines, some woodpeckers

Type B: a large defended area in which all reproductive activity occurs, but not the primary source of food. ex. Night hawks

Type C: a small defended area around the nest. Many colonial birds.

Tpe D: An area for pairing or mating only (leks) ex.) manakins

Tpe E: roosting area, personal sleeping space in a cave like oil bird.

Question 41

In type A territories size correlates with what?

Answer 41

with body mass and food type

Question 42

explain the cost to benefit theory for size of territory and draw graph.

Answer 42

The more area you have to cover, the more energy you have to put in. However, the benefits as the territory gets bigger you will get benefits out of it.

Question 43

For sun birds when does it pay to be territorial?

Answer 43

when the nectar is rish and sufficient energy to outweigh defense costs. But if nectar too rich then the bird is swarmed with competitors and spend all time/energy defending