Colonial Breeding Flashcards
1
Q
Is a gregarious lifestyle common among seabirds?
A
- Yes!
- Over 96% of seabird species are colonial
- Occurs in all orders of seabirds
2
Q
Do species that breed in colonies also breed in solitary pairs?
A
No
3
Q
What is a characterization of colonial nesting areas?
A
Absence of mammalian predators (and avian predators)
4
Q
How are colonies typically segregated?
A
Better quality birds are typically segregated from poorer quality birds (in terms of reproductive success)
5
Q
Do colonial seabirds form groups outside of the breeding season?
A
- No
- Very few form dense long-term groups outside of the breeding season
6
Q
What are some theories as to why seabirds breed in colonies?
A
- Shortage of nesting sites
- Defense against predators
- Safety
- Social stimulation
- Information
- Adjustment
- Group foraging
7
Q
Shortage of nesting sites theory
A
- Nesting sites are limited in space so birds must crowd together
8
Q
What are limitations to the shortage of nesting sites theory?
A
- Alternative nesting areas probably exist
- It does not explain why seabirds do not nest in those areas
- Some species are currently spreading to new areas and forming new colonies
9
Q
Defense against predation theory
A
- Large number of prey intimidate or confuse predators
- Reduce effectiveness of predators
- Seabirds have better protection against predators in large groups
10
Q
What are limitations to the defense against predation theory
A
- Most colonies are free or nearly free of predators
- Large predators are not deterred by seabird defenses
- Many seabirds are unable to defend their eggs
11
Q
Theoretical synchrony theory
A
- A more synchronous breeding colony will have more birds breeding than predation requires (more young = less predation)
- A less synchronous colony will have less birds breeding than predation requires (less young = more predation)
12
Q
Safety theory
A
- Birds return to the colony that they were born in
- The presence of young seabirds indicates that a nesting site is safe
13
Q
Social stimulation theory
A
- Highest hatching success occurs among breeding individuals
- Hatchling success is not linked with peak food availability for parents but to social effect within the colony
- Large colonies are expected to be more synchronous
14
Q
What are limitations to the social stimulation theory?
A
- Large colonies are found to be less synchronous
- Local density, not colony size or age composition, are important
15
Q
Information theory
A
- Birds may obtain information and resources of food from behavior of individuals which fed successfully (this is similar to beehive workers)
16
Q
What are limitations to the information theory?
A
- Worker bees are clones and therefore the information theory can be explained by kin selection
- Natural selection suggests it is not advantageous to share information with unrelated individuals
17
Q
Adjustment theory
A
- Social stimulation in colonial breeders is a quicker and more effective adjustment of the breeding system
- Solitary pairs = incapable of breeding
- Breeding in a colony = achieved by display and interaction of a pair AND stimulation from other individuals
18
Q
Group foraging theory?
A
- Group foraging is a selective advantage in colonial breeding
- Easier to form a group by returning to a high density area (colony)
19
Q
What are limitations to the group foraging theory?
A
- Long distance foragers take a long time to return to their colony, form a feeding group, and then return to the feeding area again
20
Q
What are some disadvantages of colonial breeding?
A
- Increased competition for food
- Transfer microbes and parasites
- Build-up of microbes, parasites, in re-used nests
- Intraspecific aggression
- Increased risk of predation
21
Q
Why is colonial breeding still favored over solitary breeding if there are disadvantages?
A
- The benefits outweigh the disadvantages
- Otherwise evolution / natural selection would have gotten rid of it
22
Q
Breeding Phenology
A
Timing of breeding events and factors that influence the timing of breeding events (ex: climate, seasonality, environmental variables etc.)
23
Q
What factors affect breeding phenology?
A
- Temperature
- Food availability
- Experience
- Length of daylight
24
Q
How does food affect breeding periods?
A
- Seabirds breed in time with highest energy availability
25
Climate and breeding phenology
- Polar and sub-polar birds face the biggest energetic constraints caused by climate
- Tropical and sub-tropical birds are less constrained by climate
26
How are polar and sub-polar birds constrained by climate?
- Low temperatures
- Prey is seasonally available
- Short time-period available for nesting
- Birds can tolerate extreme weather conditions but are sensitive to changes in food availability
27
How are tropical and sub-tropical birds less constrained by climate?
- Nest seasonally (food is seasonally available)
- Breeding period is less constrained
28
How is breeding timed around food availability?
Breeding is timed so that birds fledge and learn to forage during periods of high food availability
29
Biennial Breeding
Breeding cycles that last more than a year
30
Can molting and nesting occur at the same time in some bird species?
-No
- There is a high energetic demand for both activities
31
What are some breeding habitat constraints?
- Nesting and foraging habitats are separate
*Seabirds spend years at sea learning how to forge before returning to colonies to breed*
32
What are important factors of breeding habitats?
- Food (proximity to foraging areas)
- Shelter from predators
33
What are some different nest site habitats?
- Cliffs
- Flat ground
- Trees or bushes
- Burrows
- Crevices
- Open ground
34
What are some bird species that nest at the surface?
- Most penguins
- Albatrosses
- Large petals
- Most pelecaniformes
- Most gulls
- Most terns
- Most skuas
35
What are some bird species that nest in burrows?
- Smaller petals
- Some penguins
- Most alcids
- Tropicbirds
36
What are some bird species that nest in trees?
- Frigatebirds
- Red-footed Booby
- Abbott's Booby
- Black Noddy
37
What are the two levels of breeding habitat selection?
1. Colony selection
2. Nest-site selection
38
Colony selection
- Occurs when the colony is first established
- Influenced by biotic and abiotic factors
39
Nest-site selection
Evaluated by comparing specific characteristics at the nest sites with those available within the colony
40
What are some common threats that seabirds face?
- Predation
- Grazers
- Plants
41
Why is predation a threat to seabirds?
- Seabirds evolved in the absence of predators (they do not know how to
- Explorers and tourist bring rats and other predators to seabird colonies
42
What is a big threat to seabirds on Long Island (Jones Beach)
Feral cats
43
What are some direct impacts that humans have on seabirds?
- Illegal harvest of eggs or down
- Harvesting of seabirds for food
- Seabird - fishery interactions
- Tourism
- Research
- Disturbances
44
What are some indirect impacts that humans have on seabirds?
- Introduction of predators
- Habitat destruction
- Wind farms
- Disease
- Contaminants / pollution
- Climate change
45
How can humans influence the habitats of seabirds?
- Beach driving
- Chemical pollution
- Introduction of predators
46
What disease currently has had a global impact on seabird populations
Avian influenza
47
What are seabird reproductive strategies?
Invest in adult survival at the expense of low net reproductive output
48
How do seabird reproductive strategies affect conservation efforts?
- Increases in adult mortality
- Results in low fecundity and low survival
49
What are wind farms and how are they a threat to seabirds?
- Increase wind energy
- Seabirds collide with turbines
- Result in habitat modification and displacement
