avian bio exam 3

What sex chromosomes do female and male birds have?

Females have ZW sex chromosomes and males have ZZ.

What sex chromosomes do female and male mammals have?

Males have XY and females have XX chromosomes

Male hormones increased during mating period

Testosterone, produced in the leydig cells of the testes. Belong to the androgen group. Involved in courtship, territory defense, and mating/gamete protection.

Female hormone increased during mating period

Estrogen and progesterone, produced in the follicles of ovaries. Belong to the Estrogen and Progestogen steroid groups. Involved in nesting behavior, and mating/gamete protection.

What are the main reasons for bird population declines?

• Habitat loss

• Habitat fragmentation

• Introduced predators

• Exploitation

• Chemicals

• Pollutants

• Diseases

• Climate change

• Stochastic fluctuation

What are the genetic consequences of small population sizes and inbreeding?

• Loss of genetic diversity

• Inbreeding depression

• Genetic drift

• Increased risk of extinction

How are consequences of inbreeding and small population size caused genetically?

• Increased Homozygosity, loss of heterozygosity

• Allele fixation

• Less effective population size

• Linkage disequilibrium

What is inbreeding depression?

Reduced fitness of offspring of closely related parents.

What is the extinction vortex?

The combined effects (inbreeding, drift, low adaptability) can push small populations into a vortex, where as the population shrinks, genetic issues worsen, and a negative spiral is created.

Why does the extinction vortex affect small populations?

Small populations are vulnerable due to their low genetic complexity.

What happens during an extinction vortex?

• Small population

• Inbreeding + genetic drift

• Loss of genetic variability

• Decreased individual fitness

• Decreased fecundity + survival

• Decreased effective population size

• Extinction

How can populations escape the population vortex?

• Identify and remove major threats

• Increasing genetic variation and reducing inbreeding

What are some bird conservation success stories?

• Wood duck- minimized hunting

• California condor- lead poison treatment

• Florida scrub-Jay- prescribed burning

• Several island species- predator removal and habitat restoration

What can we do to improve conservation?

• Education

• Collect data: citizen science

• Consumer choices

• Advocate for policy change

• Support conservation

• Plant native plants in yard

Why are native plants so important for healthy bird populations?

• Species diversity

• More native insect/fruit/seeds

• Shelter

How many birds are killed by cats each year in the USA?

1.3 - 3.9 billion birds

What are the major causes of direct mortality of birds?

• Cat predation

• Collisions (windows, cars, powerlines)

• Habitat loss

• Pesticides

What anatomy traits do most birds have in common?

• Rigid beak

• Long neck

• Two wings

• Partially fused vertebrae

• Strong hind legs

• Short tail

How do common traits of birds help with flight?

• Bones- rigid for stability

• Body- lightweight for efficient flight

• Internal systems- efficient

What are the benefits of pneumatic bones?

• Lightweight

• Allows carrying of heavy eggs

• Incubation and non-crushing of eggs

What are the benefits of a bird’s skeletal system?

• Fusion provides stability

• Limited joints on wings

What’s the furcula?

• The wishbone

• It acts as an elastic spring during flight

What is the thoracic vertebrae?

• Fuses to and supports ribs

• Supports breathing

What is the synsacrum?

• Near the pelvis, fused vertebrae and pelvis

• Allows for stability during landing

Fused skull bones

• Allows for damage prevention to woodpeckers

What is the benefit of having a long neck?

Allows for easy turning of the head (almost fully around)

What is rhphoteca?

Keritinized soft nerve tissue on beak

What is cranial kinesis?

Movement of both the upper maxilla and lower mandible

What is rhinchokinesis?

Elastic zones of beak. Used for probing and grabbing slippery prey.

What does the hypid apparatus do?

Wraps tongue around head to protect brains of woodpeckers & allow for extended tongues (hummingbirds)

What bones are primary feathers attached to?

The birds hand: metacarpals and phalanges

What bones are secondary feathers attached to?

The birds forearm: ulna

What is the alula attached to?

The thumb: first digit

What are unicare processes?

Hook shaped bones, allow for breathing

What is the carina?

The keel of the sternum. Where flight muscles attach, larger in stronger fliers

How do birds fly? What muscles are used?

Pectoralis- pulls wings down (strongest and largest muscle)

Supracoracoideus- pulls wings up

Why is the avian respiratory system effective?

• Gas exchange is counter current

• There is unidirectional air flow

What is the urogenital system?

The urinary and reproductive system. Both use the cloaca

How are eggs produced by birds?

• Ovary contains ova

• Ova develops in follicles

• Eggs can be fertilized in the infidibulum of the oviduct

• Ovum breaks out of follicle and travels to the oviduct (egg whites are added)

• At the shell gland of uterus- shell is added

What is homeostasis?

Maintenance of constant physiological conditions in the body

Why are salt and water balances linked?

Electrolytes in salt allow for osmosis, which moves water through the body

What are salt glands?

Glands that excrete excess salt out of the beak of birds. Can allow for drinking salt water

How do birds excrete waste and retain water?

Uric acid is excreted by birds and reptiles. It saves water but requires mire energy to make. The kidney removes nitrogenous waste

What are avian kidneys made of?

• Nephrons (both types are found in birds)

• Mammalian nephrons- save more water via loop of henle

• Reptilian nephrons- simpler no loop of henle

What affects heat balance of birds?

• Birds are endothermic homeotherms- they use energy to maintain body heat (39-43 C)

• Conductive heat loss/gain with objects and fluids

• Heat loss/ gain with Sun radiation

• Evaporative heat loss- loss of heat via water evaporation

How do birds cope with cold temperatures?

• Metabolic heat production

• Acclimation

• Huddling

• Regional heterothermy (cold feet)

• Temporal heterothermy- low body temp. (Torpor)

How do birds cope with hot temperatures?

• Evaporative cooling

  • Panting

  • Gular fluttering

  • Urinating on legs

• Bringing water to nests with wet feathers

• Can tolerate slight higher temperatures

• Find shade

• Lower metabolic rate

• Lower water flux

What is basal metabolic rate?

The resting state of birds. Birds have higher basal mbr than mammals

What type of vision do birds have?

Wide field vision, narrow binocular area

What photoreceptors do birds have?

• Rods- allow for night vision (150)

• Cones- color sensitive (birds have 4, humans have 3) can see UV light

What are the 4 types of cones?

• UV

• Urine/feces

• UV coating on berries

What are the differences between bird hearing and human hearing?

• Birds hear similar frequencies, but can hear many lower frequencies

How do owls hear mice so well?

They have ear openings that catch sound and direct it to their ears

Olfactory System

Birds have small olfactory bulbs

Seabirds locate food by smell

Other birds can recognize conspecifics

What is the field metabolic rate of birds?

The actual typical metabolic rate of active birds

What is optimal foraging theory?

How animals balance energy gain from food, and the time and energy required to get the food

How do you calculate optimal foraging theory?

If low energy and handling time outweigh high energy per high handling and search time