Date post: | 12-Jan-2016 |
Category: |
Documents |
Upload: | ginger-watson |
View: | 216 times |
Download: | 0 times |
Plumageand its
Function in birds
Basic distinction between:
Molt = feather replacement and Plumage = Feather coat
Basic (prebasic molt)- renewed plumage post- breeding
Alternate (prealternate molt)- breeding plumage
Typically replace all feathers after breeding and, often, before onset of migration
Typically partial replacement of feathers in spring
…M
OLT….
Why replace feathers?
Mite damage – can damage an individual's plumage during heavy infestations & result in energy-loss via poor thermoregulation
…or loss of mates if plumage is involved in mate selection
Birds use three general types of pigments:
Melanins: are synthesized in animals. These pigments are typically responsible for the blacks, browns, and less striking colors.
Porphyrins & Carotenoids: are responsible for the reds and yellows and greens. They are only synthesized by plants, and thus must be consumed in the diet.
The plumage of iridescent birds is caused by reflectance from the sun and amplification of certain wavelengths, rather than using pigments.
Great-tailed grackle
Barbules are layered with air bubblesthat create a diffraction/interference pattern to reinforces selectedwavelengths while canceling others
Many birds have plumage characters that reflect UV light
UV
Sunscreen applied
Broods from sunscreen-ed males produce fewer sons
Feather wear, as in this Snow Bunting,which changes from a contrasting black and white in the male to a less contrasting, browner plumage after breeding
What is the function of a bird’s plumage ?
- Stream-lining
- Thermoregulation
- Waterproofing
- Protection
- Camouflage
- Foraging
- Anti-predator behavior
What is the function of a bird’s plumage ?
- Stream-lining
- Thermoregulation
- Waterproofing
- Protection
- Camouflage- Foraging
- Anti-predator behavior
Concealment of the eye
a bc
d e
100%
50%
Distance to border
Det
ect
abili
ty (
%)
What is the function of a bird’s plumage ?
- Stream-lining
- Thermoregulation
- Waterproofing
- Protection
- Camouflage
- Foraging- Anti-predator behavior
American redstart wing-flicking
What is the function of a bird’s plumage ?
- Stream-lining
- Thermoregulation
- Waterproofing
- Protection
- Camouflage
- Foraging
- Anti-predator behavior
Sun bittern “eyespots”
Pygmy owls
What is the function of a bird’s plumage ?
- Stream-lining
- Thermoregulation
- Waterproofing
- Protection
- Camouflage
- Foraging
- Anti-predator behavior
Hooded PitohuiMELRYID BEETLE
Not all “color” need have a function
- Stream-lining
- Thermoregulation
- Waterproofing
- Protection
- Camouflage
- Foraging
- Anti-predator behavior
} Color would have little role inthese functions …except which?
}Color has a behavioral functioni.e., within species interaction
…so does color always have a behavioral function?
- Stream-lining
- Thermoregulation
- Waterproofing
- Protection
- Camouflage
- Foraging
- Anti-predator behavior
} Color would have little role inthese functions …except which?
}Color has a behavioral functioni.e., within species interaction
Structural coloration
What is the function of a bird’s plumage ?
What else ?
COMMUNICATION
- Stream-lining
- Thermoregulation
- Waterproofing
- Protection
- Camouflage
- Foraging/Anti-predator behavior
This male Lyrebirdhas something to
communicate
- Species recognition
- Individual identification
- Social dominance rank (age)
- Fitness (male quality)
- Attract mates
What do birds have to COMMUNICATION ?
Badges of Status
The size of the black bibin several species of sparrows signals dominance rank andeliminates undo fighting between males
“Private”
“Sergeant”
“Captain”
- Species recognition
- Individual identification
- Social dominance rank (age)
- Fitness (male quality)
- Attract mates
What do birds have to COMMUNICATION ?
Paint blackInject testosterone
Both
Lookdominant
Behavedominant
Change instatus
Y N N
N Y NY Y Y
Summary of results from Rohwer and Rohwer (1978) manipulation experiments on subordinate Harris’ Sparrows
Cheating is prevented b/c status is ultimately checked by escalation
If birds BOTH look dominant and act dominantthey can rise in status, whereas acting w/o looking dominant they can’t
BreedingFemale
- Species recognition
- Individual identification
- Social dominance rank (age)
- Fitness (male quality)
- Attract mates
What do birds have to COMMUNICATION ?
Non-breedingFirst Yr Male
BreedingSecond Yr Male
American Redstart
- Species recognition
- Individual identification
- Social dominance rank (age)
- Fitness (male quality)
- Attract mates
What do birds have to COMMUNICATION ?
- Species recognition
- Individual identification
- Social dominance rank (age)
- Fitness (male quality)
- Attract mates
What do birds have to COMMUNICATION ?
Plu
mag
e S
atu
rati
on
(%
)
Plumage Hue
Red-billed Quelea
Northern Cardinal
- Species recognition
- Individual identification
- Social dominance rank (age)
- Fitness (male quality)
- Attract mates
These two types of traits are not limited to (colorful) plumage…what else is there?
Displays
Vocalizations
And in very special cases….bowers