Ornithology exam 4 material

Circannual rhythms

activity cycles 12 months long

Circadian rythm

daily activity cycle 24 hours long

Entrainment

using environmental cues to fine-tune circadian rhythms

free-running circadian rhythms

activity patterns that drift from 24 hr cycles

Innate internal clock

mechanism for keeping approximately 24 hr cycle without external cues

Zeitgeber

An entrainer, a cue used by animals to set circadian rhythm

photoperiod

most common Zeitgeber

photosensitive period

period when exposure to light stimulates physiological changes in birds

North American

the photo-period is the most common zeitgeber for ______ ______ birds

earlier

global warming is causing spring migration and first egg date to occur _____?

calls

brief sounds with relatively simple acoustical structure. Year-round, both sexes.

Songs

more complex sounds, generally composed of 5 or more notes separated by pauses. Breeding season only, males only.

syrinx

avian voice box, functional equivalent of a human larynx

internal tympaniform membrane

this membrane vibrates to produce sound

interclavicular air sac

air is forced through this passageway to produce sound

sonograph

plot of frequency across time

do

birds do or do not have independent control over left and right sides of syrinx?

learn

birds ______ songs

hear

birds must be able to ______ conspecifics (other birds) to learn their song

self

birds must be able to hear ____ sing during subsong period

song learning period

Chick/fledglings learn their songs during this period

Subsong period

Fall juveniles practicing during this period

quiet

Winter juveniles are _____

normal

spring adults sing a _____ song

Brown-headed cowbird

this is the only songbird that has an innate song template, born with a song in their head

Signaling status and attracting females

function of a song

non-vocal

drumming, wing snaps, and tail-whistles are examples of ______ sounds

mimicry

using the songs of other birds or other sound sources as part of 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

breeding and non-breeding

2 broad types of territories

type A

all purpose territory used for breeding (mating and nesting) but also foraging site for parents and young

type B

territory used for breeding (mating and nesting) but not feeding

type C

mating territory only - Leks

type D

"territory" of defending one's nest, not a true territory

feeding territories

non-breeding territory associated with food only

Food density

factor determining whether feeding territories exist

predation

Clumping nests can be beneficial or detrimental depending on _______ pressure

increases

For forest birds, increasing nest density _______ predation risk

decreases

For colonial sea birds, increasing nest density ______ predation risk

Dominance hierarchies

pecking order

linear

most dominance hierarchies are _____

dominance

size, physical characteristics, age, experience, home court advantage, and motivation all determine _________

more

bigger, stronger, older = ____ dominant

less

smaller, weaker, younger = ____ dominant

Status signal

a morphological trait that shows it's ability to win fights (resource holding potential)

Delayed plumage maturation

not attaining definitive (adult) plumage until after the first potential breeding season, called subadult plumage

bright plumage

According to Dr. Hill's study on Black-headed Grosbeaks, territorial birds responded with more aggression to subadult birds with bright or drab plumage?

site residency

territory owners almost always defeat invaders, aka home-court advantage

Parental ability and risk of loss

These two factors determine clutch size

increases

Increased parental experience, condition, and quality of mate ______ clutch size

decreases

Increased predators and weather stochasticity ______ clutch size

endothermic

are birds endothermic or exothermic

incubation

keeping eggs warm with parental body heat

Brush turkeys

These birds do not incubate, rather they use rotting vegetation to warm eggs

Brood patch

bare patch on the breast of birds that becomes fluid-filled and acts like a warm pillow for transferring heat

females

In most birds, who incubates the eggs?

Hatching muscle

muscle at back of neck only present on nestlings

egg tooth

small projection at tip of bill present at time of hatch

precocial development

development primarily inside the egg (duck), born with feathers, can move, feed themselves

altricial development

development primarily outside the egg (songbirds), born naked, immobile, can't feed themselves

Synchronous hatching

all chicks hatch at once, seen with precocial birds

asynchronous hatching

chicks hatch on different days, seen with altricial birds

synchronously

precocial young must hatch _______

Brood reduction

letting the youngest/weakest chicks starve if food is limited

Siblicide

killing siblings, a form of brood reduction

Facultative

brood parasitism when birds are capable of building a nest/parenting but will take the chance to put an egg in another birds nest.

Obligate

brood parasitism when birds incapable of building a nest and raising their own young

wood duck

facultative brood parasite example

brown-headed cowbird

obligate brood parasite example

Rejecter species

sometimes recognize cowbird eggs and reject them

accepter species

almost never recognize cowbird eggs, are very vulnerable to parasitism

Cooperative breeding

2 or more 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

nestling

young bird still in nest

fledgling

young bird outside of nest but get fed/helped by parents

fledging

act of leaving the nest

altricial

do altricial or precocial birds grow faster

resident

species present throughout the year

Wintering

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

neotropical migrants

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

Invasive species

species present because they were introduced by humans

fragmentation and loss

Neotropical migrants decline due to direct persecution, and habitat _____ and ____

Direct persecution

killing of birds by people or pets

market hunting

mass killing of birds for meat and plume for sale

predator control

widespread belief that all predator birds were bad

forest fragmentation

breaking large blocks of forest into smaller pieces with unsuitable habitat between

edge

Forest fragmentation increases _____ effects

cowbird parasitism and predation

Negative edge effects include...

Source populations

populations that produce a surplus of offspring, more offspring than needed to support population

sink populations

populations that do not produce enough offspring to maintain population

species-based

This approach to bird conservation focuses on the most critically endangered species

ecosystem-based

this approach to bird conservation focuses on preserving ecosystems

Silent Spring

Rachel Carson book

Bald eagles

This species bounced back after DDT was banned

Kirtland's Warbler

This highly specialized species relies on fire climax communities and is susceptible to cowbird parasitism. It became more abundant after management changes and was removed from the endangered species list in 2019.

Census

a complete enumeration of population

Survey

A tally of a portion of the population