Bird Migration and Navigation Patterns

Migration

Regular population movements based on time and geography.

Irruptions

Irregular movements in certain bird species.

Arctic Tern

Migrates 17,000 km annually between poles.

Blackpoll Warbler

Nonstop flight from New England to Lesser Antilles.

Long-distance migration

Movement between temperate and tropical zones.

Short-distance migration

Movement within tropical or temperate zones.

Altitudinal migration

Seasonal movement up and down mountains.

Nearctic/Neotropical system

Migration system with 200 species, 5 billion individuals.

Trans-gulf Migration

Migratory path of Whimbrel across 600 miles.

Loop migration

Circular migratory route tracked by satellite data.

Swainson's Thrush

Migrates primarily to Central America.

Black-and-white Warbler

Migrates to Central America and Caribbean.

Seasonal timing of migration

Predictable migration timing, usually ± 1 week.

Resource availability

Primary factor influencing migratory behavior.

Temperature

Secondary factor affecting migration patterns.

Evolution of migration

Adaptation to exploit seasonal resources and avoid scarcity.

Boreal owls

Exhibit irruptive movements in North America.

Evening Grosbeak

Example of an irruptive bird species.

Blue Grouse

Breeds at high altitudes, winters in forests.

Phylogenetic tree study

Mapped migration evolution of Neotropical-Nearctic birds.

Fecundity trade-off

Survivorship versus reproductive output in migration evolution.

Zugunruhe

Migratory restlessness before migration starts.

Neuroendocrine system

Regulates migration in response to photoperiod changes.

Hyperphagia

Intense feeding before migration to build fat reserves.

Fat deposition

Accumulation of fat to support migration.

Blackpoll Warblers

Nearly double weight from 11g to 21g pre-migration.

Flight range

Distance birds can travel based on fat reserves.

Fat reserves

40% of body weight in small landbirds.

Fat burning rate

1% of body weight per hour of flight.

Stopover ecology

Refueling stops during migration for food and fat.

Critical stopover sites

Essential for conservation of migratory species.

Bar-headed Goose

Bird with highest known migratory route (28,000 ft).

Flight altitude

Typical heights: shorebirds 6,500-13,000 ft, landbirds <2,600 ft.

Flight speed

Waterfowl and shorebirds 30-50 mph; landbirds 20-30 mph.

Diurnal migrants

Birds that feed during the day while migrating.

Nocturnal migrants

Birds that feed during the day at stopovers.

Weather impact

Departure times influenced by weather conditions.

Spring migration

Birds move northward behind warm fronts.

Fall migration

Birds move southward behind cold fronts.

Homing ability

Ability to return to original nesting site.

Migratory navigation

Instinctual ability to find wintering and breeding grounds.

Odor navigation

Some birds use smell for locating nests.

Landscape features

Birds use prominent features for navigation.

Sun compass

Uses sun's position for navigation, time-compensated.

Star compass

Birds navigate using constellations, may not need time compensation.

Geomagnetic compass

Birds sense Earth's magnetic fields for orientation.

Territory

A fixed area defended continuously by individuals.

Defense behaviors

Actions to discourage rivals from entering territory.

Intraspecific territoriality

Defense against individuals of the same species.

Interspecific territoriality

Defense against individuals of different species.

Feeding territories

Areas defended primarily for foraging resources.

Nesting territories

Areas defended primarily for breeding purposes.

All-purpose territories

Areas defended for multiple resource types.

Territory size

Varies with species' body mass and resource density.

Northern Cardinal territory size

1 ha for a body mass of 45 g.

Red-tailed Hawk territory size

230 ha for a body mass of 1030 g.

Territoriality benefits

Effective when defensible resources are present.

Territoriality costs

Includes time, energy, and predator exposure.

Behavioral components of defense

Includes song, patrolling, displays, and attacks.

Flocking behavior

Group behavior for foraging or roosting.

Benefits of flocking

Improved foraging efficiency and predator defense.

Costs of flocking

Includes competition and disease transmission.

Cooperative hunting

Intentional group foraging to enhance success.

Beater effect

Unintentional group behavior improving resource location.

Information exchange

Communication about resource locations among individuals.

Guanay Cormorant behavior

Forms rafts to indicate food patch locations.

Raft adjustment

Position changes based on returning cormorants' direction.

Flocking

Group behavior providing safety from predators.

Predator confusion

Disorienting predators through group movement.

Interior positions

Safer positions within a flock.

Many eyes effect

Increased vigilance through multiple observers.

Sentinels

Individuals taking turns watching for predators.

Alarm calls

Vocal signals warning conspecifics of predators.

Predator-specific alarm calls

Distinct calls for different predator types.

Altruistic behaviors

Actions benefiting others at personal cost.

Mobbing behavior

Cooperative aggression against predators by groups.

Beater effect

Increased foraging efficiency in mixed-species flocks.

Core species

Key species maintaining mixed-species flock cohesion.

Social mimicry

Imitating others to enhance group unity.

Dominance hierarchies

Social ranking established through aggressive encounters.

Pecking orders

Another term for dominance hierarchies.

Agonistic behavior

Behavior related to conflict and competition.

Dominance factors

Body size, sex, age, and genetics influence dominance.

Higher fitness

Increased reproductive success and resource access.

Color badges

Visual signals indicating dominance in birds.

Huddling

Group behavior for warmth and protection.

Allopreening

Mutual grooming to strengthen social bonds.

Personal space

Maintaining distance to reduce aggression.

Mixed-species flocks

Flocks consisting of different bird species.