ENR 5.6 — Bird Migration and Areas with Sensitive Fauna
1. BIRD MIGRATION
Bird strike risk increases because of bird migration during the months of March through April and August through November.
The altitudes of migrating birds vary with winds aloft, weather fronts, terrain elevations, cloud conditions, and other environmental variables. While over 90 percent of the reported bird strikes occur at or below 3,000 feet AGL, strikes at higher altitudes are common during migration. Ducks and geese are frequently observed up to 7,000 feet AGL, and pilots are cautioned to minimize en route flying at lower altitudes during migration.
2. Reducing Bird Strike Risks
The most serious strikes are those involving ingestion into an engine (turboprop and turbine jet engines) or windshield strikes. These strikes can result in emergency situations requiring prompt action by the pilot.
Engine ingestions may result in sudden loss of power or engine failure. Review engine-out procedures, especially when operating from airports with known bird hazards or when operating near high bird concentrations.
Windshield strikes have resulted in pilots experiencing confusion, disorientation, loss of communications, and aircraft control problems. Pilots are encouraged to review their emergency procedures before flying in these areas.
When encountering birds en route, climb to avoid collision because birds in flocks generally distribute themselves downward, with lead birds being at the highest altitude.
Avoid overflight of known areas of bird concentration and flying at low altitudes during bird migration. Charted wildlife refuges and other natural areas contain unusually high local concentrations of birds, which may create a hazard to aircraft.
3. Reporting Bird and Other Wildlife Activities
If you observe birds or other animals on or near the runway, request airport management to disperse the wildlife before taking off. Also, contact the tower regarding large flocks of birds and report the:
- Geographic location
- Bird type (geese, ducks, gulls, etc.)
- Approximate numbers
- Altitude
- Direction of bird flight path
4. Pilot Advisories on Bird and Other Wildlife Hazards
Many airports advise pilots of other wildlife hazards caused by large animals on the runway through the Chart Supplement and the NOTAM system.