Transcript Lecture - Birds

What Group Best Fits The Bird You Want To
Identify?
Waterfowl & Marshland Birds
Perching & Tree-clinging
See Visual
Types and
Silhouette
Comparison
Loons, Grebes, Pelicans &
Cormorants, Bitterns,
Herons, & Ibises, Swans,
Geese, & Ducks,
Shorebirds, Gulls & Terns,
Rails, Coots & Cranes,
Kingfishers
Predatory Birds
Cuckoos,
Woodpeckers,
Swifts &
Hummingbirds
See Visual Types
and
Silhouette
Comparison
Hawks, Falcons, &
Eagles,
Owls, Vultures
Song Birds
See Visual Types and
Silhouette Comparison
Upland Ground Birds
See Visual Types and
Silhouette Comparison
Grouse, Quails,
Pheasants, &
Turkeys,
Pigeons &
Doves,
Goatsuckers &
Nighthawks
Tyrant Flycatchers, Larks, Swallows, Corvids ,
Chickadees, Nuthatches & Creepers, Wrens &
Dippers, Kinglets & Gnatcatchers, Thrushes,
Thrashers, Pipits, Waxwings, Shrikes, Starlings,
Vireos, Warblers, Tanagers, Sparrows, Grosbeaks,
Icterids, Fringillids
American Goldfinch
(Carduelis tristis)
Spotted Towhee
(Pipilo maculatus)
American Robin
(Turdus migratorius)
Northern Harrier
(Circus cyaneus)
Red-tailed Hawk
(Buteo jamaicensis)
Tree Swallow
(Tachycineta bicolor)
Northern Roughwinged Swallow
(Stelgidopteryx
serripennis)
Barn Swallow
(Hirundo rustica)
Brewer’s Cowbird
(Euphagus cyanocephalus)
Red-winged Blackbird
(Agelaius phoeniceus)
Osprey
(Pandion haliaetus)
Turkey Vulture
(Cathartes aura)
Western Scrub-Jay
(Aphelocoma californica)
Yellow Warbler
(Dendroica petechia)
Belted Kingfisher
(Ceryle alcyon)
Double-crested Cormorant
(Phalacrocorax auritus)
Wood Duck
(Aix sponsa)
Mallard
(Anas platyrhynchos)
Black-capped Chickadee
(Poecile atricapillus)
Northern Flicker
(Colaptes auratus)
European Starling
(Sturnus vulgaris)
Reptiles
Cladogram of Tetrapods:
Amniotes
Sauropsids (“reptile-like appearance” - Greek)
Diapsids (“two arches” - Greek)
Lepidosaurs
Archosaurs
Squamates
“Ruling Reptile”
Group includes dinosaurs
(Read chapter 16 (VL) to
your hearts content…)
Birds
Birds: (~ 30 orders; ~ 193 families; ~ 9700 species)
Evolution:
• First appearance in fossil record = Jurassic
Archaeopteryx:
The Original Link Between Birds and Reptiles
Class: Aves
Reptilian Features:
1) Non-keratinized snout
• Teeth present
2) Trunk vertebrae not fused
3) Neck attaches to skull from rear
4) Long tail with free vertebrae
Believed evolved
From theropods
(velociraptor)
Most likely capable
of sustained flight
~ 1.5 km / 40 kph
5) Ankle / wrist bones free
Avian Features:
1) Feathers
2) Opposable big toe (hallux)
3) Furcula (wishbone) present
Birds
Mastery of flight opened a world of ecological opportunities…
Avian Anatomical Adaptations for Flight:
1) Streamlined body:
Reduced resistance
when moving through
air…
vs.
2) Feathers:
• Similar to reptilian scales (beta-keratin – present in birds / reptiles)
• Retain scales on non-feathered parts
• Dead structures; damage repair = replacement
• Specialized pockets of epidermal / dermal cells (follicles)
 Feathers appear in fossil record long before flight (e.g., Caudipteryx)
• Hypotheses: 1) Insulation to retain heat (not endothermic…)
2) Social interactions (e.g., reproduction)
3) Shading / insulation for eggs
• Current Functions of Feathers:
???
Birds
Avian Anatomical Adaptations for Flight:
2) Feathers:
A) Contour Feathers (flight feathers – vaned…)
• Long central shaft (rachis)
• Broad vane with numerous barbs
• Barbules hook barbs together
• Calamus (quill) anchors feather in follicle (skin)
• Mobile – individual muscles control each feather
• Stream-lined; decreases drag
• Asymmetrical & curved (independent airfoils)
B) Filoplumes (Provide sensory information)
• Long rachis with few barbs at end
C) Down Feathers (Insulation)
• Lack central shaft; barbs from feather base
• lack barbules; barbs move freely
2000 – 4000 feathers
(~ 15% BW)
Feather Tracts:
Feather attachments
grouped in dense
concentrations
Birds
Avian Anatomical Adaptations for Flight:
2) Feathers:
• Range from drab to colorful…
A) Biochrome Pigments
• Melanins = earth tones (e.g., grays / blacks / browns)
• Resist feather wear (e.g., black wing tips resist fraying)
• Resist bacterial degradation (wet climate = dark color)
• Absorb energy (thermoregulation / feather drying)
• Carotenoids = vibrant colors (e.g., bright yellows / oranges / reds)
• Derived from diet (honest signaling…)
• Porphyrins = vibrant colors (e.g., bright brown / green / magenta)
• Chemically related to hemoglobin
B) Structural Colors
• Result from physical alteration of light (e.g., iridescences)
Can occur
together…
• Nanometer-scale structuring in feather:
1) Air bubbles = White (unpigmented feathers)
2) Melanin granules (melanosomes) = iridescence
 High UV reflectance (birds capable of detecting UV light!)
Yellow-thigh Parrot
Budgie
Birds
Avian Anatomical Adaptations for Flight:
2) Feathers:
• Feather care important…
• Uropygial (Preen) Gland:
• Located at base of rump
• Secrete rich oil (waxes / fatty acids / fat / water)
• Preserves feather moistness / flexibility
• Cleans / waterproofs feathers
• Regulates bacterial / fungal growth
• Repel would-be predators (foul-smelling)
• Birds go through series of feather coats in lifetime
• Molt: Replacement of entire plumage (= feather coat)
Juvenile

Adult
Non-breeding
• Seasonal display
• replace feather wear
• parasite infestations

Breeding
Birds
Avian Anatomical Adaptations for Flight:
3) Bones:
A) Pneumatic: (air-filled; reinforced with internal struts (= trabeculae)
• Reduced weight (but see diving birds…)
B) Number reduction: (weight)
• No teeth
• Carpal / tarsal bone reduction
• Digits lost
C) Fusion: (strength / stability)
• Thoracic vertebrae fused (platform)
• Synsacrum (pelvic support)
• Pygostyle (tail feather support)
• Furculum (wishbone – “spring”)
• Carpometacarpus / Tarsometatarsus
D) Additional Modifications
• Keeled sternum (muscle attachment)
• Enlarged humerus (major force…)
Uncinate
Processes
Birds
Avian Anatomical Adaptations for Flight:
4) Muscles:
• Muscle reduction
• Jaws – power not necessary (food swallowed whole / in chunks)
• Legs – rigid skeleton provides support; perching only major requirement
• Muscle centralized on proximal portion of limb (center of gravity)
• Flight muscles
• Size increase; location near center of gravity
• Both up-stroke (supracoracoideus) and down-stroke
originate on keel
5) Forelimbs Modified as Wings:
Airfoils to
generate
lift…
(pectoralis)
muscles
Passive Flight
Flight:
(requires little energy…)
Active Flight
(requires lots of energy…)
Parachuting
(drop with little control)
Gliding
(membranes =  lift)
Soaring
(utilize wind currents)
Evolution of Active Flight:
“Arborealists”
“From the Tree Down” Theory of Flight:
• Early ancestors tree climbers – jumped from tree to tree
• Selective pressure favored increased distance / lift
(ornithologists)
Gliding  Weak Flapping  Full Airborne Flapping
“From the Ground Up” Theory of Flight:
• Early ancestors fast bipedal runners – “wings” lightened load
• Flapping evolved to provide additional forward propulsion
• Early ancestors used “wings” to snare insects
• Flapping evolved to assist horizontal jumps for prey
• Early ancestors used wings to run up steep slopes
• Wing Assisted Incline Running
“Cursorialists”
(paleontologists)
Birds
Flight:
1% of energy expended
per mile covered (versus mouse)
Cost / Benefit of Flying:
Costs:
• Energetically costly (short-term)
• Limits range of body size
Birds =  variation than other verts.
Benefits:
•  cost / unit distance
• Exploitation of new resources
• Escape from predators
64,000x vs. 50,000,000x
Metabolic / Energetic Requirements for Flight:
Bird’s core temperature higher than
similar sized mammal
• Reduction in Weight (= reduce cost of flight)
• Visceral organs small but efficient; pneumatic skeleton
• High Metabolic Rate ( ability to sustain muscle activity)
• Endothermy: Core temp. sustained by heat released from metabolic processes
• Advantages:
1) Faster response time for brain / muscles
2) Activity levels maintained in cold environments
• Disadvantage:  caloric intake required
Birds
Flight:
Required Modifications for Endothermy:
1) Cardiovascular System
• Larger, more muscular heart
•  blood flow /  blood pressure
• Separation of O2-rich / O2-poor blood
•  hemoglobin concentration in blood
2) Respiratory System
•  exchange surface / unit lung volume
• Unidirectional air flow (no mixing of fresh / stale air)
•  blood flow to lungs
3) Insulation (= feathers)
Birds
Mechanics of Wing Design:
• Two types of contour feathers present on wing:
1) Primaries: Located on hand; provide thrust
2) Secondary: Located on back of arm; provide lift
• Force produced as air passes wing:
During upstroke, air passes between
flight feathers = cost reduction…
1) Lift = Vertical force equal to or greater than weight of bird
A) Cambered Airfoil
• Upward curvature of wing; tapers toward back
Bernoulli
principle
• Ventral = High pressure; Dorsal = Low pressure
•  camber allows for flight at slower speeds
B) Angle of Attack
• Leading edge of wing tilted;  pressure dorsally
• Stalling angle = airflow separates from wing (~ 15º)
• Alula
“Bastard wing”
• Reduce drag by improving air flow
over wing (= steeper angle of attacks)
Birds
Flight:
Mechanics of Wing Design:
• Force produced as air passes wing:
2) Drag = Component opposing forward movement; created by turbulent air flow
• Highest at tips of wings
• Reduce effect = 1) Taper wing
2) Lengthen wing
• Aspect ratio = measures amount of wing drag produced, relative to lift
Ratio = wing span / wing width
Low Aspect Ratio = Wide, short wings (higher drag)
High Aspect Ratio = long, narrow wings (lower drag)
• Wing Loading: (Ratio = body mass / wing surface area)
• Correlates to size – body mass  faster than surface area as body size 
• Low Wing Loading = more maneuverable;  power needed to sustain flight
• High Wing Loading = less maneuverable; often soaring birds
Birds
Major Structural Wing Types:
Elliptical
High Speed
Dynamic Soaring
High Lift
(short & rounded)
(Taper to point)
(Long & narrow)
(Long & broad)
Examples:
Sparrow
Robin
Pigeon
Swallow
Duck
Falcon
albatross
shearwater
petrel
eagle
vulture
raven
Camber
High
Low
Very low
High
Alula
Large
Absent
Absent
Large
Speed
Slow
Fast
Fast
Slow – Mod.
Acceleration
Fast
Slow
Slow
Fast
Maneuverability
High
Moderate
Very Low
High
Endurance
Low
High
Very High
Moderate
Aspect Ratio
Low (3 – 6)
Moderate (5 – 9)
Very high (9 – 18)
Low (small birds)
High (large birds)
Moderate - High
Characteristic
Wing Loading
Low (small birds)
Moderate (6 – 7)
Moderate
(can pick up weight)
Birds
Reproduction:
• Utilize colors, postures, and vocalizations for species, sex, and individual
identification
• Bird Song: Complex array of notes, often with frequency modulation
• Often male specific and during breeding season
• Learned behavior; “window” of opportunity during development
• Species specific; regional dialects relatively common
• Function:
1) Attract mates
2) Repel rivals
• Visual displays often associated with song:
• ♀♀ select males based on visual characteristics :
• Good nutritional status
• Low parasite loads
“truth in advertising…”
• Predator avoidance
♀♀ prefer ♂♂ with longer
tails and more eye spots
Offspring grew faster;
 survival rates
• Better quality mate
Birds
• Increased heterozygosity
Reproduction:
• “hedging” your bets
• Birds exhibit two broad categories of mating systems:
1) Monogamy: Pair bond between single male and female (~ 90% of bird species)
• Both parents required to raise young (e.g., food acquisition)
• Resource distribution (even – control impossible…)
• Skewed sex ratio (partner becomes prized “resource”)
 MONOGAMY does not necessarily mean FIDELITY
• Extra-pair copulation common
2) Polygamy: Individuals mate with > one partner during single breeding season
• Polygyny = Single ♂ – multiple ♀♀; Polyandry = Single ♀ / many ♂♂
Lek:
Aggregation of
many males
Resource defense
polygyny
Male dominance
polygyny
Resource defense
polyandry
Birds
Reproduction:
• All birds are oviparous
Why?
Constraints based on flight
• Most likely ancestral reproductive mode
• No pressure to evolve vivipary (e.g. endothermy
= incubated eggs always warm)
• Genetic sex determination
• Heterogametic chromosomes – ♀♀ = WZ / ♂♂ = ZZ
• Nests protects eggs from physical stresses and predation:
Egg Incubation
~ 33 – 37 ºC
Shallow depression
(e.g., Killdeer)
Megapodes bury eggs
Brood Patch
Colonial Nesting
Protection in numbers
Feathers lost;
Blood vessels proliferate
Stimulated by prolactin
Elaborate structure
(e.g., osprey)
Birds
Reproduction:
• Clutch size variable:
1) Trade-off Hypotheses: Driving force is maximization of lifetime reproductive success
• Physical strain on females / exposure to predation during food collection
2) Predation Hypotheses: Driving force is minimization of nest detection by predators
• More eggs / young =  detection (sound / smell / trips to nest / etc.)
3) Seasonality Hypotheses: Driving force is food availability during breeding season
• More eggs / young =  food reserves /  competition
• Young at differing levels of development at hatching:
Precocial
Semiprecocial
Altricial
High yolk
Moderate yolk
Low yolk
Down present
Down present
Down Absent
Eyes open
Eyes open
Eyes closed
Mobile
Semi-mobile
Not mobile
Self-feeding
Not self-feeding
Not self-feeding
Ducks
Hawks
Incubation may last
from 10 – 80 days
Altricial < Precocial
Growth Rates:
Altricial > Precocial
Infanticide
Passerines
Birds
Ducks: (~ 35 species in North America)
Shared Characteristics:
1) 3 front toes completely webbed
2) Penis present in males
3) Bill typically flattened / blunt-tipped
Characteristic
Dabbling Ducks
Examples
Northern Shoveler
American Widgeon
Cinnamon Teal
Legs
Relatively long;
centered under body
Feet
Smaller
Diving Ducks
Sea Ducks
Redhead
Canvasback
Lesser Scaup
Bufflehead
Eider
Merganser
Short but strong;
set far back on body
Short but strong;
set far back on body
Larger; long outer toes
Larger; long outer toes
Feeding
Dip head underwater;
skim surface with bill
Dive from surface;
wings pressed to body
Dive from surface;
wings open (steer / paddle)
Diet
Invertebrates;
aquatic vegetation
Invertebrates
Invertebrates;
fish (rare)
Wings
Big, broad wings;
lower wing loading
Smaller wings;
higher wing load
Smaller wings;
higher wing load
Flight
More maneuverable;
can fly slow
Less maneuverable;
need room to take off
Less maneuverable;
need room to take off
Habitat
Shallow edges of lake;
surface in deeper areas
Center of lake;
deeper water
Marine coastlines;
fast, clear streams
Birds
Ducks: (~ 35 species in North America)
Duck Life Histories:
Mating Behavior:
• Initiated late fall / early winter (wintering grounds / migration)
• Skewed sex ratio – many ♂; fewer ♀
• Form monogamous pair bond (seasonal)
Tufted Duck – head raise
• Males attract females via:
1) Visual Displays:
• Coloration (♂s more colorful than ♀s)
• Most elaborate in dabblers
Ruddy Duck – tail raise
2) Vocal Displays (primarily dabblers)
• Dabblers have louder, deeper voices
Dabbler Specialty:
Iridescent speculum on wing
Lift wing to display speculum
Birds
Ducks: (~ 35 species in North America)
Duck Life Histories:
Nesting Characteristics:
• Location of Nest:
• Dabblers = Ground
• Divers = Emergent / Floating vegetation
Mallard
• Sea = Tree cavities
• Age at 1st reproduction:
• Dabblers / Divers = 1 year
• Sea = 2-3 years
Brood parasitism
does occur…
• # of Eggs in Nest:
• Dabblers / Divers = 8 – 12 eggs
• Sea = < 8 eggs (space issues in cavity)
Incubation:
Scaup
• Females only (20 – 30 days)
• Pair bond only lasts until eggs are laid
Parental Care:
• Females: 2 – 6 weeks; guard from predators
Merganser
Birds
Ducks: (~ 35 species in North America)
Duck Life Histories:
Seasonal Migration Patterns:
• Benefit = Net increase in lifetime reproductive output
• Spring – Summer:
Reduce Cost…
• Breed at high latitudes (e.g., Canada / Alaska; long days = increased foraging)
•  insect population for young
• Fall – Winter:
• Fly south to avoid physical stresses of extreme cold / lack of food
• Costs = 1)  death rate for young
2)  food acquisition for energy to travel
3) Restricted stops (fewer wetlands to choose from)
4 major N-S flyways in North America
10%
50%
25%
10%
(Ducks heading to Alaska…)
• Fly at night; usually < 1000 ft.
• Variety of orientation methods:
• Sun / star compasses
• Magnetic field