Journal - MacArthur Paper

Question 1

What are congeneric species? [1]

Answer 1

Organisms that are of the same genus, but a different species.

Question 2

What is the common name for Dendroica castanea? [1]

Answer 2

Bay-breasted warbler.

Question 3

What is the common name for Dendroica fusca?

Answer 3

Blackburnian

Question 4

What is the common name for Dendroica virens

Answer 4

Black-throated green

Question 5

What is the common name for Dendroica coronate?

Answer 5

Myrtle

Question 6

What is the common name for Dendroica tigrine?

Answer 6

Cape May warbler.

Question 7

What two types of population control exist?

Answer 7

Density dependant

Density independent

Question 8

Give three examples of density independent population events. [3]

Answer 8

Natural disasters.
Storms
Predation
Disease

Question 9

Give two examples of density dependant population events. [2]

Answer 9

Food shortages.

Nesting holes.

Question 10

When does coexistence occur?

Answer 10

Coexistence can occur when intraspecific competition surpasses interspecific competition.

Question 11

Why may immigration/emigration allow coexistence?

Answer 11

As if one species would normally be wiped by another due to competition, moving out the area will prevent competition enough to let it sustain its numbers.

Question 12

What’s the issue with studying limiting factors?

Answer 12

It’s hard to know what actually is a limiting factor, since need to isolate it pretty well.

Question 13

How did MacKenzie - 1946 - artificially investigate limiting factors?

Answer 13

He added nest boxes to the ‘Forests of Dean’, led to pied flycatcher numbers increasing.

Question 14

How did Breckeridge - 1956 - show least flycatchers were more abundant in open woods?

Answer 14

He basically just compared two woods, though it’s hard since need to consider ALL the limiting factors.

Question 15

What was the four main points of MacArthur’s paper?

Answer 15

1 Showing density dependant events were important in population control.

Question 16

How did MacArthur show density dependant differences?

Answer 16

He gathered data on Myrtle, Black-throated green and Blackburnian and seen an increase typically followed a decrease in population size.

Basically he calculated the cycles of independent events needed to match the effects of density dependant effects.

Question 17

What did Kendeigh, 1947 establish about bird species abundance with an outbreak of spruce budworm?

Answer 17

Populations of some warbler species increased, shown it was a limiting factor for those species.

Question 18

What treezones did Cape May warblers like?

Answer 18

Upper tree zones and a bit outer.

Question 19

What treezones do Myrtle occupy

Answer 19

Lower side of tree zones.

Question 20

What treezones do Black-throated green occupy?

Answer 20

Nearer the middle of the treezones.

Question 21

What treezones do Blackburnian occupy?

Answer 21

The outer side of tree zones.

Question 22

What treezones do Bay-breasted warblers occupy?

Answer 22

The middle of the tree zones.

Question 23

How did they measure bird habits/flight land time.

Answer 23

They counted seconds until the bird was lost from sight.

They recorded the total number of flights, so mean interval between uses of wing could be computed.

Question 24

What’s the difference between Hawking and Hovering in birdy flight?

Answer 24

Hawking is distinguished as moving prey is sought, while hovering aims for stationary prey.

Question 25

Which species hovers the most?

Answer 25

Black-throated green.

Question 26

What data was gathered about Cape May Warbler?

Answer 26

#1 Fed among flowers, has semitubular tongue.
#2 Unusula breeding timing.
#3 Hawks often, vertical move.
#4 Loves the top of trees

Question 27

What data was gathered about the Bay-breasted Warbler?

Answer 27

#1 Uses rapid peering in hunting, lots of radial movements.
#2 Very rarely hovers.

Question 28

What three reasons may species differ in food they eat?

Answer 28

1 They feed in different places and time.

Question 29

Does bill size differ between birds?

Answer 29

The Cape May warbler has the most noticeable difference, rest are relatively similar.

Question 30

What did McAtee 1932 try prove using 80k bird stomachs?

Answer 30

He tried to disprove mimicry, assuming insects in stomach was proportional to availability.

These differences were most easily explained by feeding area, though overall results inconclusive.

Question 31

Why would Coleoptera be eaten more by Blackburnian?

Answer 31

Perhaps they are more present in inner parts of the tree.

Question 32

What did Cheshire, 1954 show about territoriality?

Answer 32

They shown territory size can be fixed and if compression occurs it only does so during high densities, acting as a stabiliser for co-existence.

Question 33

Was there a recorded activity difference?

Answer 33

Not for the most part, but Cape May nested a bit earlier,

Perhaps insect peak abundance differed…

Question 34

Why is it unlikely behavioural characteristics must be nearly independent of specific environments?

Answer 34

As all five species migrate to similar environments.

Question 35

Do Myrtles hop?

Answer 35

Yes they do.