Introduction to Ornithology - WS

Feather Anatomy

Rachis- cental axis of feather

Vanes, Barbs, Barbules and Hooks are branching structures

What are contour feathers?

Long rachis, barbs and barbules; outer covering, including flight feathers.

What are semiplume feathers?

Soft feathers with a central shaft but loose barbs; found under contour feathers; help with insulation and body shape.

What are down feathers?

Short rachis, no barbules; provide great insulation via air pockets.

What are bristle feathers?

Mostly stiff rachis, few or no barbs; used for protection and detection.

What are filoplume feathers?

Hair-like, long thin rachis, few barbs at tip; have a sensory role, located near contour feathers.

What are down feathers?

The first feathers on young birds that insulate by trapping heat.

What is the function of contour feathers?

They provide body coverage and ornamental plumage.

How do contour feathers achieve waterproofing?

Through barbule interlocking, preen oil, powered down, layering, or hydrophobic microstructures.

Sensory feathers

filoplumes -

sense feather movement/environment

bristles -

protect eyes/mouth

detect prey or objects

What is molt?

The process of shedding old feathers to make way for new ones.

How often does molt occur?

Annually or seasonally.

What is one trigger for molt?

Function change, such as transitioning from down to adult feathers.

What is another trigger for molt?

Feather damage or parasite removal.

What role does breeding season play in molt?

It can trigger changes in plumage for attraction.

How can age be identified in birds like herring gulls?

Through the process of molt.

Why is molt energetically costly?

Feathers make up 25-40% of a bird's dry mass.

What is a consequence of molt in terms of insulation?

Loss of insulation, which can lead to increased metabolism.

How can molt affect a bird's behavior?

It can cause hiding due to vulnerability during the process.

What is preening in birds?

A behavior where birds use their beak to clean and arrange their feathers.

What gland do birds use during preening for quality control?

Uropygial gland

How does preening help birds socially?

It helps with social bonding.

What adaptations assist birds in preening?

Beak shape and pecniate claw

What is one method birds use for plumage care besides preening?

Dust baths

What is 'anting' in birds?

A behavior where birds use ants to help clean their feathers.

What is a continuous plumage pattern?

Linked to age/stage of life

What is a discontinuous plumage pattern?

Not age dependent

What is polychromatism in plumage patterns?

Multi colour morphs in a species

What is sexual dimorphism in plumage?

Male vs female colour differences

How do male birds typically display their plumage?

Bright for displays/dominance

How do female birds typically display their plumage?

Dull for camouflage

What are primary remiges?

Outer wing flight feathers attached to the hand, numbered 9-12, that provide thrust.

What is the function of primary remiges?

They provide thrust.

What are the characteristics of primary remiges?

They are long, narrow, and flexible.

Give an example of birds that have primary remiges.

Falcons and owls.

What are secondary remiges?

Inner wing flight feathers attached to the forearm, numbered 6-40, that provide lift.

What is the function of secondary remiges?

They provide lift.

What are the characteristics of secondary remiges?

They are shorter, broader, and less flexible.

Give an example of birds that have secondary remiges.

Eagles and vultures.

What are rectrices?

Tail feathers that are stiff and used for steering and braking.

What are the two types of variation in social signalling?

Continuous and discontinuous

What is an example of delayed plumage migration?

Bald eagles - immature vs adult

What is one benefit of delayed plumage migration?

Camouflage

What is another benefit of delayed plumage migration?

Mimicry

What is a third benefit of delayed plumage migration?

Avoiding aggression

What is Batesian mimicry?

Harmless mimics harmful species

What is Müllerian mimicry?

Harmful species share warning signals

What is aggressive mimicry?

Predator mimics prey

What is vocal mimicry?

Sound mimicry

What is automimicry?

One body part mimics another

What does age-related plumage indicate in animals?

Maturity, dominance, and mating ability

What social factors can serve as status symbols in animals?

Bright plumage, size, and territory

Why do birds use sound?

Evolutionary crucial for communication to attract: mates, defend territory, warn others, and identify individuals.

What does a spectrogram show?

Frequencies, duration, and intensity of sound, with color indicating loudness.

What does an oscillogram represent?

Air pressure instead of frequency.

What is drumming in bird vocalisations?

A non-vocal sound that is species specific, such as woodpeckers, and is affected by tree type and beak mass.

What is pitch in the context of sound?

Frequency.

What does intensity refer to in sound?

Amplitude.

What does pattern refer to in bird vocalisations?

Rhythm of sound.

How do birds adjust to noisy environments?

By singing louder.

What is one way birds adapt their singing in noisy environments?

By raising pitch.

What behavior do birds exhibit to cope with noise in their environment?

By repeating calls more.

What is an example of a bird that increases pitch near streams?

Dippers.

What happens to sound transmission over distance?

Sound weakens over distance.

Which frequencies are worse for sound transmission over distance?

High frequencies.

What environmental conditions are bad for sound transmission?

Low temperature and high humidity.

What environmental conditions are good for sound transmission?

High temperature and low humidity.

How does foliage affect sound transmission?

Foliage increases attenuation.

What is one effect of degradation on vocal calls?

It creates echoes of distant calls.

What effect does dense vegetation have on sound?

It causes more reverberation.

What is one solution to improve vocal transmission in dense vegetation?

Delay signals.

What is another solution to improve vocal transmission in dense vegetation?

Call in flight.

What is a third solution to improve vocal transmission in dense vegetation?

Sing away from trees.

How does habitat influence bird vocalization in dense forests?

It results in lower pitch and longer notes.

How does habitat influence urban bird vocalization?

It results in higher pitch and longer songs.

What is the duration of songs?

Long

What is the complexity of songs?

Complex

During which season are songs typically produced?

Breeding

Which sex is mostly associated with songs?

Mostly males

What is the purpose of songs?

Mating, territory

What is the duration of calls?

Short

What is the complexity of calls?

Simple

During which season are calls typically produced?

Year-round

Which sex is associated with calls?

Both

What are the purposes of calls?

Alarm, contact, ID, social

What are alarm calls?

Quiet, long, narrow-band calls used to avoid drawing attention.

What are mobbing calls?

Loud, short calls with wide frequencies designed to be local and punchy.

What is the purpose of distress calls?

To attract help or warn others.

How do distress calls differ in healthier individuals?

They are harsher and longer.

What are examples of other types of calls?

Flight calls and begging calls.

What social functions do calls serve?

Aggression, bonding, and courtship.

How does song use relate to territory in birds?

More singing leads to better defense of territory.

What happens to red winged magpies when they are silenced?

They suffer more intrusions.

What is a major sign of ownership for birds?

Singing.

What do birds recognize about themselves?

They recognize themselves.