Chapter 18: Population Dynamics

Question 0

What can cause dramatic fluctuations in bird populations?

Answer 0

Hunter

Unpredictable climate change

Major storms

Question 1

What is so legendary about the Short-Tailed Albatross?

Answer 1

Hunters and volcanos reduced it’s population to the point of near extinction.

Six pairs actually remained and restored the species.

Question 2

Texas quail populations are declining or increasing?

Answer 2

Declining due to widespread habitat degradation.

Question 3

what happened when Common Starling was introduced to Central Park?

Answer 3

multiplied from 120 birds to 200 million

Question 4

benefits of short generation times?

Answer 4

• Accelerates rates of population growth

- promotes colonization, speciation, diversity

Question 5

what is the reproductive rate of large bodies species?

Answer 5

10-30%

Question 6

what is the reproductive rate of small-bodied species?

Answer 6

50-100%

Question 7

define and explain the S-Shaped growth pattern

Answer 7

• sigmoid

- growth begins slow then accelerates then tapers off

Question 8

Why does S shapes growth taper off?

Answer 8

• Negative feedback that lowers reproduction and survival

- carrying capacity

Question 9

Define environmental carrying capacity

Answer 9

a population’s growth rate slows as availability of resources falls below the need for resources

Question 10

values for per capital replacement, R that are greater than 1 indicates…?

lesser than 1…?

Answer 10

greater than 1: growing population

lesser than 1: declining population

Question 11

what does Local Recruitment of a local population include?

Answer 11

1) number if young produced in the breeding season that survive
2) young that have immigrated from elsewhere

Question 12

in reference to population size, define “limitation”

Answer 12

any ceiling on population growth

habitat, food, climate, resources, predation, availability of nest holes

Question 13

in reference to population growth, define “regulation”

Answer 13

refers to effects of population density on the population size

Question 14

as population density increases what decreases ?

Answer 14

• mean clutch size
• number of fledglings
• parental success due to increased predation
• quality & availability of resources

Question 15

what type of trees do great tits prefer over pine?

Answer 15

oak and beech

Question 16

deforestation favors which species?

Answer 16

It favors open country species over those that rely on large timber

Question 17

where do Eurasian Blackcaps and Dunnocks tend to live?

Answer 17

undergrowth of forests

Question 18

how do white-tailed deer harm certain bird populations?

Answer 18

they destroy the forest undergrowth that many bird populations usually dwell in.

Question 19

why are tropical natural habitats important to preserve?

Answer 19

many migratory species converge into dense populations to winter in these lands

Question 20

what is the main food of many seabirds?

Answer 20

anchovies

Question 21

define “irruption”

Answer 21

mass evacuation of bird populations

ex: snowy owl in 1945

Question 22

on what types of birds do predators serve as a limitation on population growth?

Answer 22

• island birds
• ducks
• game birds (since we have removed many of the top predators that preyed on mid-sized predators which are now free to kill birds)

Question 23

exposure to parasites has caused birds to…

Answer 23

• invest more into immunity
• lose energy required for reproduction
• become more mate biased
• —-favor plumage quality and display endurance

Question 24

what currently is parasitizing Darwin’s Galapagos finches?

Answer 24

blowflies which feed on the nestlings blood and burrow deep into their bodies and brains.

average finch had 23 maggots

Question 25

how do abundant species overcome declines in local populations?

Answer 25

by recruiting young birds from other populations.

Question 26

the best documented example of a decline in population due to bacterial disease is with what?

Answer 26

North American house finches with conjunctivitis from Mycoplasma gallisepticum

Question 27

epizootic refers to what?

Answer 27

a new disease that exceeds expectations in an animal population

Question 28

Explain the three stages of available habitats.

Answer 28

1) primary habitats fill up.
2) surplus birds move to suboptimal habitats and wait for vacancies in primaries.
3) floaters live singly on home ranges that overlap breeding pairs

Question 29

what does the presence of floater birds in a population indicate?

Answer 29

that the breeding population is limited by the habitat

Question 30

Recall the procedure when a vacancy arises in a suboptimal habitat.

Answer 30

the most dominant and sexually appropriate floater bird quickly seeks to replace the vacant bird by trying to mate with the remaining bird on the suboptimal or primary territory.

if the old bird returns, the floater is demoted again. ex: Rufous-collared Sparrow.

Question 31

how is dispersal related to population density?

Answer 31

the greater the population density, the greater the dispersal length of the population. (they travel further for territories)