During which months is bird strike risk highest due to migration?

7-5-1. Migratory Bird Activity
a. Bird strike risk increases because of bird migration during the months of March through April, and August
through November.
b. 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.
c. Considered the greatest potential hazard to aircraft because of their size, abundance, or habit of flying in
dense flocks are gulls, waterfowl, vultures, hawks, owls, egrets, blackbirds, and starlings. Four major migratory
flyways exist in the U.S. The Atlantic flyway parallels the Atlantic Coast. The Mississippi Flyway stretches from
Canada through the Great Lakes and follows the Mississippi River. The Central Flyway represents a broad area
east of the Rockies, stretching from Canada through Central America. The Pacific Flyway follows the west coast
and overflies major parts of Washington, Oregon, and California. There are also numerous smaller flyways which
cross these major north-south migratory routes.