Birds Zoology
Class Aves
• Wings• Feathers• No teeth• Flexible long neck• Scales on legs• Bones with air spaces• Endothermic• Four chambered heart• Multiple air sacs for
respiration
WHAT BODY PARTS DOES A BIRD HAVE TO HELP IT FLY?
EVERYTHING!
EVERY body system in a bird is modified in some way to help it fly!
MODIFICATIONS ofSKELETAL SYSTEM
Bones = hollow/air sacs extend into bones to make them LESS DENSE = fused to make them STURDY
FURCULA – stabilizes shoulders during flight
STERNUM- attaches flight muscles
PYGOSTYLE- support for tail
Adaptations for Flight
• Honey combed bones– Air cavities– Less weight– Internal “struts” for
strength
Image modified from:http://www.biology.eku.edu/RITCHISO/554notes1.html
FURCULA – “wishbone” or fused clavicles to provide sturdier, stronger skeleton for flightPYGOSTYLE – fused vertebrae to provide balance during flightSTERNUM—large sternum to support chest muscles used for flight
FUSED BONES = Sturdy
MODIFICATIONS ofINTEGUMENTARY SYSTEM
• Feathers- (light weight & sturdy)
provide lift & protect against heat loss
• Preen gland keeps feathers “fly-able”• Streamline body to decrease air/wind
resistance
Image from: http://www2.thny.bbc.co.uk/education/darwin/exfiles/archaeopteryx.htm
ARCHAEOPTERYX First bird Fossil image from:
http://www.ucmp.berkeley.edu/diapsids/birds/archaeopteryx.html
Archeopteryx
• Reptile characteristics– Teeth– Boney tail– Fingers with claws
• Bird characteristics– Feathers– Furcula
MODIFICATIONS ofCIRCULATORY SYSTEM
Heart large for body size-pumps more blood
Closed 2 loop system- most efficient/faster
Complete septum/4 chamber heart- keeps Low/High oxygen blood totally separated
Rapid heart rate- delivers more oxygen/faster
HEART
Heart = 1 ½ to 2 times larger than in equal size mammal
Heart rate much faster to move more blood
HOW FAST IS THAT?A human heart beats ~ 60-90 times/min
A resting hummingbird’s heart beats 250 times/min. Or 1200 beats per minute (BPM) when feeding.
http://www.deskpicture.com/DPs/Nature/Animals/hummingbird.jpg
SINUS VENOSUS & CONUS ARTERIOSUS ARE GONE
• Main vein returning to heart = VENA CAVA
• Main artery to body = AORTA• Main artery to lungs = PULMONARY
http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_anatomy.html
MODIFICATIONS ofENDOCRINE SYSTEM
ENDOTHERMIC METABOLISM-
provides maximum energy for extended activity (flying)
BURNING more GLUCOSE faster… is where the heat comes from!
Image from:http://www.rit.edu/~vertzo/Pigeon/PigeonPages/Home.html
Oil makes feathers waterproofPreening straightens feathers and re-hooks barbules
PREEN GLAND
… to eat like a bird
means to eat very little
BUT… Birds EAT A LOT
http://www.harrybliss.com/store/images/eat_like_a_bird.jpg
Most birds eat half their weight in food every day. That's like a 100-pound person eating 50 pounds of food in a day. And some young birds eat more than their weight in food every day!
MODIFICATIONS ofDIGESTIVE SYSTEM
• Fast efficient digestive system fuels endothermic metabolism for more energy for extended activity
• CROP- stores next batch so food always moving through
• 2 part stomach (Crop/Gizzard)- so food moves through faster
• COLIC CAECA- help break down plants
• LONG SMALL INTESTINE-absorbs lots of nutrients
• SHORT LARGE INTESTINE- Absorbs less water / feces not stored… out of body as it is made so weigh less
Digestive System
• Crop– Storage
• Proventriculus– Enzymes
• Gizzard– Grind food
• Cloaca– Waste– Reproduction
CROP
No digestion happens hereStores and moistens food waiting to be digestedAllows food to move faster/next batch is waiting
Image by Riedell/VanderWal©2005
CROP MILK
COLUMBIFORMES- crop makes nutritious fluid called CROP MILK for babies
http://www.joanbramsch.com/images/feeding.jpg
SMALL INTESTINE (Duodenum & Ileum)
LARGE INTESTINE
isn’t very large!
Absorbs less water back from feces
(Water is HEAVY!)
EXITS through CLOACA
MODIFICATIONS ofRESPIRATORY SYSTEM
• SUPER EFFICIENT RESPIRATORY SYSTEM gets the most oxygen possible
• Extra AIR SACS (posterior and anterior) allow oxygen in lungs on both the INHALE AND EXHALE
• Air sacs extending into bones makes skeleton less dense
• Alveoli increase surface area for more gas
exchange
Respiratory System
• Seven to Nine air sacs– Connect to lungs and
centers of bones– Cools the bird
• Fresh air always moving– No dead ends as in
mammals
• Each wing beat moves air– Never run out of air
Air Circulation
• An inhale will move oxygen / air in through the trachea and some air will move to the posterior air sacs while air that was in lungs moves to the anterior air sacs
• On the exhale, the air that was in anterior air sacs moves back out of body while the air in posterior air sacs move to the lungs
• This is a constant and continuous flow of air through respiratory system, not an “in, then out” system like ours
Multiple air sacs
Air sacs increase buoyancy and all one way oxygen flow for more efficient gas exchange
MODIFICATIONS ofEXCRETORY SYSTEM
Excrete nitrogen waste as URIC ACID- so uses less water to dilute
No URINARY BLADDER- so urine (water) not stored… less weight
MODIFICATIONS ofREPRODUCTIVE
SYSTEM• Female has only ONE OVARY & OVIDUCT
on left side … less weight
• OVIPARITY- lay eggs OUTSIDE of body … less weight
• REPRODUCTIVE ORGANS-enlarge during breeding season/shrink rest of time
INTERNAL FERTILIZATION
http://people.eku.edu/ritchisong/avianreproduction.html
http://www.usgs.nau.edu/swwf/images/WIFL%20nest%20with%20eggs%20-%20MD.jpg
OVIPAROUSLay amniotic eggs
DIRECT DEVELOPMENT2 KINDS OF BABIES
ALTRICIAL = HELPLESS
hatch without feathers, eyes closed, can’t walk, parents must feed every 20 min
Ex: songbirds,
pigeons, raptors
http://www.kathyskritters.com/tales/robins/images/baby_robins_5-13.jpg
DIRECT DEVELOPMENT 2 KINDS OF BABIES
PRECOCIAL – MORE INDEPENDENT
hatch with fuzzy down, can follow parent and feed itself soon after hatching
EX: Ducks and geese
http://cowpi.com/journal/2004/06/the_dangers_of_leadership.html
Chicks
• Altricial– No feathers– Cannot walk or see– Cannot feed
themselves
Precocial– Down feathers– Can walk and see– Can feed themselves
MODIFICATIONS ofNERVOUS SYSTEM
• Large brain for body size = “smarter”• Bigger CEREBRUM for more complex
behaviors problem solving; learning; navigation;
• Bigger CEREBELLUM- for muscle coordination• Bigger OPTIC LOBES for better vision; 3D & Color• Concentration of iron in brain to act as compass
EYESBIG for size of head See in COLOR
Eyes on front of face- gives depth perception Seen in predators
Eyes on sides of head-Gives wide range of vision Seen in prey
Kestral Image from:http://www.biology.eku.edu/RITCHISO/birdbrain2.html
Order Passeriformes
• Perching foot• Songbirds• 5000 species• Mocking bird• Thrushes• Swallows• Magpie • Crow• Starling• Jays
Hummingbirds
• Fly up, down, left, right, backwards and upside down
• Wings beat 50 -200 times per second
• Heart rate =600 bpm• Eat 2/3 body weight
each day• Nectar, pollen &
insects
Order Psittaciformes
• Thick tongue• Hinged and movable
upper beak• Bright colors• Parrots• Parakeets
Migration
• Migration to find food and reproduce
• Sissor-tailed flycatchar
• Migates to Central and South America in October
• Returns in April