Chapter 4: Part 3

Question 1

Aposematic Coloration (plumage)

Answer 1

• rare
• Feathers contain high concentrations of a deadly alkaloid neurotoxin called homobatrachotoxin (similar to that of poison dart frogs)
• Produced by ingesting Chloresine beetles (Melyridae), which produce this toxin to defend themselves against predation

Question 2

Cryptic Coloration

Answer 2

• change plumage seasonally for camouflage
• many various birds, more common

Question 3

Disruptive Coloration

Answer 3

• bands visually separate the outline of its head from that of its body
• breaks up shape of bird from a distance, helps with predator

Question 4

Countershading

Answer 4

• a darker dorsal surface and a lighter ventral surface compensates for the effect of body shadows and conceal the outline of the body
• contrast increases with the intensity of illumination from above
• think penguin!

Question 5

Signal Patches

Answer 5

• used during the breeding season
• think male Red-winged Blackbird

Question 6

Sexual Dimorphism

Answer 6

• in songbird type species, oftentimes male can be more brightly colored than the female
• they can have all round or seasonal coloration (or changes
  -seasonal changes of plumage can leave the male looking like their female counterparts

(example: american goldfinch, males have alternate plumage in breeding, and basic plumage that is similar to females in nonbreeding)

Question 7

Describe an exception to sexual dimorphism

Answer 7

• Wilson’s phalarope
• In contrast to the norm, the Phalarope female is polyandrous and hasbright plumage and displays for the males. Testosteronecauses the bright coloration in all birds, regardless of which sex is wearing it.

Question 8

Delayed Plumage Maturation

Answer 8

• delay of official coloration in a male or female bird until after the first potential breeding season
• can vary from dull to brightly colored

Question 9

Describe a prebasic molt

Answer 9

Stages:

• Natal plumage&raquo_space; PREJUVENAL MOLT&raquo_space; Juvenal Plumage&raquo_space; 1st PREBASIC MOLT&raquo_space; Basic Plumage
• continues cycle in adulthood through prebasic molt for basic plumage

Example: bluejay, cedar waxwing

Question 10

Describe prealternate molt

Answer 10

• Similar stages to prebasic:
• Natal plumage&raquo_space; PREJUVENAL MOLT&raquo_space; Juvenal Plumage&raquo_space; 1st PREBASIC MOLT&raquo_space; Basic Plumage
• But in adulthood, the birds have a PREALTERNATE MOLT&raquo_space; Alternate plumage&raquo_space; Prebasic molt&raquo_space; back to basic plumage
• alternate molts can happen during breeding season

Example: American Goldfinch

Question 11

Eclipse Plumage

Answer 11

• Makes: simultaneous molt of all of their flight feathers after breeding, rendering them flightless for several weeks

Males acquire the same camouflage as the females, a useful protection while they cannot fly

Question 12

Describe how molting happens

Answer 12

• Molt of primary and secondary flight feathers proceeds in a stereotyped spatial pattern across the wing
• During active molt, the distribution of worn, actively growing, and newly replaced feathers provides evidence about the molting pattern
• replaces from inwards near secondaries out