Bird Unit - FNR 240 Unit 3

Nocturnal migrants

Songbirds (passerines)

Why birds migrate at night

Cooler air, less predation, calmer winds

Radar used to study migration

NEXRAD weather radar

What radar detects in migration

Density, direction, timing of birds

Migration pulses

Most birds move on few nights

Percent of migration on 10% of nights

About 54%

Nocturnal flight calls

Short calls made during night migration

Purpose of flight calls

Orientation and cohesion

How flight calls are studied

Acoustic monitoring

Night navigation cues

Stars, magnetic field, polarized light

Phototaxis

Attraction to artificial light

Why light pollution is dangerous

Disorients birds and causes collisions

Best conservation action during migration

Turn off unnecessary lights at night

Critical migration seasons

Spring and fall

Aeroconservation

Protection of wildlife in aerial habitats

Near-term ecological forecasting

Predicting movement to guide conservation

Dynamic conservation strategy

Action only on high-migration nights

Fixed window strategy

Action during historical time periods

Which strategy is more efficient

Dynamic forecasting

Major threats to migrating birds

Buildings, light pollution, wind turbines

Why forecasting reduces mortality

Targets action when birds are present