Avian Biology Exam 4

How do birds meet temporary high demands for energy (molt, migration, egg production)?

Hyperphagia- rapid feeding

What are the stages of foraging and consumption?

• Search and recognition

• Capture and extraction

• Preparation and ingestion

• Pulveration and digestion

What is optimal foraging theory?

A model of foraging behavior with the goal of maximizing energy gain + minimizing energy acquisition

What is the ideal prey?

Gives maximum energy and requires the least amount of time and energy to obtain

Geophagy

The consumption of soil, clay or sand (to aquire sodium)

How do shorebirds reduce interspecific competition?

They have varying anatomy that allows them to use different niches

What are two types of interspecific competition?

• Exploitation: One species is better at getting a resource

• Interference: One species prevents another from getting a resource

What affects variation in beak size and shape?

• Foraging

• Body size

• Food

• Thermoregulation

• Singing

How does foraging strategies influence wing shape?

• Some wings are more pointed and better for fast gliding and quickly changing direction

• Some wings are more rounded, allowing for fast takeoffs and tight maneuvering (e.g. through trees)

What is unique about crossbills?

• They have crossed beaks that specialize in removing seeds from certain conifer (pinecone) plants

• Some beaks are curved to the left and some to the right

• Crossbills and conifers coevolved

What is special about hummingbird feeding?

• Hummingbirds have hair-like lamella that allow them to soak up/trap nectar

What is special about flamingo foraging?

• Flamingos feed upside down to filter out animals and plants through special lamellae beak structures

What does mate preference lead to?

The evolution of:

• Ornamentation

• Behavioral displays

• Coercive mating (e.g. forced mating)

What mating systems are there?

• Monogamy: One male and one female (may not be genetically monogamous)

• Polygyny- One male with multiple females

• Polyandry- One female with multiple males

What are the trade-offe of extra-pair mating?

• Benefits of extra-pair:

  • More helpers

  • More parental care

• Costs of extra-pair:

  • Main male feeds less with more extra-pair young

  • Helpers allow females to have time for more extra-pair breeding

Same-sex pair bonds

• Occurs in albatrosses

• There is less successful incubation, but more successful raising of young

What tupes of polygyny are there?

• Female defense- Males defend females but not habitats

• Resource defense- Males defend resources used by females

• Lek

  • Classic- Many males at one location

  • Exploded- Males are more spread out

What is a lek?

a mating ground where multiple male animals of a species gather to display to attract and compete for females

What are the benefits of polyandry?

• Fertility assurance- If a male is infertile, there is a chance of another that isn’t

• More parental care

What is sequential polyandry?

a mating system where a female mates with multiple males, one after another, rather than simultaneously (Wilson’s phalarope, females have male-like plumage)

What is sound?

• Waves if moving air molecules

• Frequency- frequency of vibrations (kHz)

• Amplitude- loudness, measured in decibels

How are bird vocalizations visualized?

• Spectrogram (bw or color)

• Oscillogram (pressure/ volume only)

Mnemonics

Memory strategies used to remember bird songs

What is a song?

• Loud and complex

• Used for mate attraction and territory defense

What is a call?

• Shorter and simpler

• Used for more than territory and mate attraction

What are common call types?

• Contact call- for flock cohesion

• Flight calls- for migratory flock cohesion

• Food calls- to attract mates/offspring/conspecifics to a food source

• Begging calls- Used to call a parent for feeding

• Alarm calls- To alert others of a danger

• Mobbing calls- To attract others to a danger

What is found in typical song structures?

• Song bout- Song sung in rapid succession

• Song- divided into phrases, separated by long gaps

• Phrase- Combination of notes

• Note- A continuous trace on a spectrogram

• Trills- rapid repeats it short elements

What are some examples of non-vocal bird sounds?

• Drumming- woodpecker

• Feathers hitting

• Tools

What are examples of species where females sing more than males?

• Streak-backed Orioles

• Stripe-headed sparrow

Oscines

Songbirds, show vocal learning

Suboscines

Do not learn song (innate)

When do birds mostly learn song?

The sensitive period

What are the developmental stages of song?

• subsong

• Plastic song

• Crystallized song

What are species that learn songs throughout their whole lives?

Open-ended learners (e.g. mimicks)

Are dialects more common in oscines or suboscines?

Oscines- They can learn songs that may vary geographically (songs may be incomplete as they are learned/spread)

Why do dialects change over time?

• Mistakes in learning

• Immigration

• Local noise selecting for best transmission

What is the primary sound producing organ in birds?

• The strinx

• Oscines/songbirds can control both sides

What other areas are invilved in song production (the song control system)?

• Nerve cells

• Neural pathways

• The vocal tract

When do birds breed?

Right before the best nestling food is prevalent. To raise healthy chicks

Ehat do birds use to time their breeding?

• The photoperiod (Daylight)

• Plant/ insect abundance

• Rainfall

What functions do nests serve?

• Keep eggs contained

• Protecting eggs from predation

• Insulation of eggs

• Attracting mates

• Strengthening pair bond when buliding

• Roosting site

• Deter predators-termite nests

What types of nests are there?

• Globe

• Dombed

• Cup

  • Statant

  • Pensile

  • Adherant

• Scrape

• Burrow

• Cavity

• Mound

• Platform

• Pendant

Did cup nests or domed nests evolve first?

Dombed nests (cup nests evolved from them)

What are possible consequences of laying eggs?

• Nests and eggs can be easily identified

What are eggs made of?

• Air cell

• Outer/inner membrane

• Vitelline membrane

• Yolk

• Albumen (whites)

• Chalazae

• Shell

What are the benefits/functions of eggs?

• Promote flight

• Promote bi-parental care

• Possibility for abandonment

What are yolk rings?

The yolk is in rings, darker when feeding (day) lighter at night

How are eggs made?

• Chorioalantonic membrane- The chorion and the allantosis fuse during embryo development

• Allantois- collects waste

• Chorion- similar to placenta, surrounds the yolk sac amnion and allantois

What is the function of the chorioallantoic membrane?

Similar to lungs, allowing gas exchange with shell pores

What affects the size of eggs?

• Body mass

• Lage clutches = smaller eggs

• Precocial eggs are larger than altrucial

What is the difference between precocial and altricial?

• Precocial- pre developed

• Altricial- Underdeveloped

Clutch

A complete set of eggs laid in an uninterrupted series

What influences clutch size?

• Food availability

• Young independence

• Larger clutches in cold environments

• Less predation

• Early nests are larger

• Older females

Determinate layer

Lays a fixed number of eggs (no egg replacement)

Indeterminate layer

Lays eggs until clutch size is present (replaces eggs)

What is the goal of incubation

Maintaining a constant temperature

Favorite bird + 3 facts

European robin- The first wild bird I ever held (very cute)

• Sing year round and are often residential (non migratory) in europe

• Follow gardeners to get access to insects

• European robins are not closely related to american robins, but rather flycatchers

What hormonal changes initiate incubation?

Prgesterone, LH are low

Prolactin is high