Ornithology Final Exam

Lectures 19-24, does not include families and orders

What is Circadian Rhythm?

The daily activity cycles 24 hours long

With the circadian rhythm, what does a bird’s typical day look like?

• 1—6: Sleep

• 6—11: Sing/Feed

• 11—13: Rest

• 13—17: Sing/Feed

• 17—24: Sleep

What is Circannual Rhythms?

Activity cycles 12 months long

What are two common annual cycles?

• “Typical” Migrant Passerine

• Typical Resident

What does the “Typical” Migrant Passerine annual cycle look like?

Winter → Molt → Migration → Breeding → Molt → Migration → Winter

What does the Typical Resident annual cycle look like?

• Jan—July to Aug: Breeding

• Mid July—Mid Sept: Molt

• Mid Sept—December: Winter

What is entrainment?

The use of environmental cues to fine-tune circadian rhythms

What is the Innate Internal Clock?

A mechanism for keeping an approximately 24-hour cycle without external cues

What is Zeitgeber?

“Time giver,” A cue used by animals to set circadian rhythm (light)

Photosensititve period

Period when exposure to light stimulates physiological changes in birds

Photoperiod

Most common zeitgeber for circannual cycle

What is the zeitgeber for the Red-billed Quelea?

Rainfall

What is the zeitgeber for the Pinyon Jay?

Pinyon cones

Global warming is causing what evolutionary responses in a few species?

• Earlier spring migration

• Earlier first egg date

Calls

Brief sounds with a relatively simple acoustical structure. These are year-round and both sexes do it

Songs

More complex sounds than calls, generally composed of 5 or more notes separated by pauses. These are only made by males during breeding season

Syrinx

Avian voice box that is functionally equivalent to a human larynx

Identify the structures

How is sound produced in the avian vocal apparatus?

• Vibrations of the membrane

• Forcing air through passageway

What is dual sound source theory? What bird was this tested with?

Birds have independent control of the right and left sides of the syrinx. Tested with Wood Thrush by cutting nerves on one side of the syrinx then the next side.

What are the functions of songs?

• Signaling social status in male-male competition

• Attracting females during mate choice

Song might be an honest signal of

• Stamina

• Brain structure

• Cellular respiration

Dawn chorus

Heightened volume of bird song at dawn

Dawn song is hypothesized to signal what?

Male quality, only males in the best condition can wake up and sing for an hour before foraging

Repertoire size

Number of distinct songs that are sung by an individual

Mimicry

Using the songs of other birds or other sound sources as part of the song

Territory

An area of exclusive resource use defended by one or a small group of individuals

Home range

An area habitually used by a bird—not exclusive

What are the types of territories?

• Breeding

  • Type A — All-purpose territory

  • Type B — Mating and nesting but no feeding

  • Type C — Mating only (leks)

  • Type D — Small nesting territory

• Non-breeding territories

  • Feeding territories

Factors that determine territoriality

• Food density

• Nest site availability

• Predation pressure

Determinants of Dominance

• Size and physical attributes

• Age and experience

• Home court advantage

• Motivation

What is a status signal in terms of dominance?

A morphological trait that reliably indicates resource holding potential

What is delayed plumage maturation?

Not attaining definitive (adult) plumage until after the first potential breeding season —> Subadult Plumage

Two types of nest

• Cup nests

• Cavity nests

What are two types of cavity nester?

• Excavators

• Non-excavators

Typical types of nest construction

• Sticks only

• Mud only

• Sticks and mud

• Sticks and Saliva

What are 2 general strategies to clutch size?

• Fixed clutch size

• Variable clutch size

What determines clutch ability?

• Parental ability

• Risk of loss

Incubation

Keeping eggs warm with parental body heat

What bird is the only bird that does not incubate it’s eggs?

Brush Turkeys — use heat of rotting vegetation to warm eggs

Brood patch

Bare patch on the breast that becomes fluid-filled

Two adaptations for hatching

• Hatching muscles (on back of the neck in nestlings)

• Egg tooth

What are two developmental strategies?

• Precocial development

• Altricial development

Precocial development

Development primarily inside the egg

Altricial development

Development primarily outside the egg

Synchronous hatching

All chicks hatch at once

Asynchronous hatching

Chicks hatch on different days

Precocial young must hatch synchronously. T/F

true

Brood reduction

Letting the youngest/weakest chicks starve if food is limited

Brood parasitism

Laying eggs in other bird’s nests

2 forms of brood parasitism

• Facultative brood parasites

• Obligate brood parasites

Facultative brood parasites

Are capable of building a nest and raising young, but sometimes brood parasite

Obligate brood parasite

Incapable of building nest or raising young. Must parasitize another species

Cooperative breeding

More than 2 birds of the same species provide care in rearing the young from one nest

Helpers

birds other than the core breeding pair that help raise offspring

Resident

Species present throughout the year

Wintering species

Species present only during non-breeding season

Breeding migrant

Species present only during breeding season

Transient migrant

Species that breed to the north and winter to the south. Present only during migration

Invasive species

Species present because they were introduced by humans

Neotropical Migrants

Species that breed primarily in the temperate or subarctic regions of the New World and winter in tropical or subtropical regions

What are reasons for the decline of neotropical migrants?

• Direct persecution

• Habitat fragmentation

• Habitat loss

Direct persecution

Killing of birds by people or pets

Predator control

Widespread outdated belief that all predator birds were bad

Negative effects of increased edge (due to fragmentation) is

• Increased cowbird parasitism

• Increased predation

Species-based management

Focus on the most critically endangered species

Ecosystem-based management

Focus on preserving ecosystems

Census

A complete enumeration of a population

Survey

a tally of a portion of the population

Standardization

Strict guidelines for how/where/when to conduct a survey

Plot counts

Tallying all birds within a designated plot within a specified period of time

Point counts

A quick tally of birds detected from a pre-determined fixed point. Generally the best way to survey birds.

What type of survey is the Christmas Bird Count?

Plot count

What type of survey is the Breeding Bird Survey?

Point count

What birds are best surveyed by the Breeding Bird Survey?

• Upland birds

• Birds that breed in populated parts of the U.S. and Canada

What birds are poorly surveyed by the Breeding Bird Survey?

• Boreal Forest and Arctic breeders

• Waterbirds

Detectability

The probability that a bird species will be detected if individuals of that species are present during a survey

Occupancy Modeling

Predicting the habitats needed (occupied) by birds.

What bird was the 1st bird in North America driven to extinction by Europeans?

Great Auk

What was the reason for the Great Auk’s extinction?

Direct persecution

What was the most abundant bird ever recorded?

Passenger Pigeon

What was the reason for the extinction of the Eskimo Curlew?

Direct persecution

What were the reasons that the Heath Hen went extinct?

• Major food source for Native Americans and European settlers

• Last population remaining died on Martha’s Vineyard due to a fire

The Carolina Parakeets were hunted because

They were an agricultural pest

Reasons for the extinction of Carolina Parakeets

• Direct persecution

• European Honeybees

Reason for the Dusky Seaside Sparrow extinction

Habitat loss (Cape Canaveral)