Connection Between Fall Weather and Bird Migrations

Does fall weather impact bird migrations? Millersville’s Weather Information Center Director, Kyle Elliott, provides an updated fall weather outlook, and Dr. Aaron Haines, professor of conservation biology, explains the connections between bird migration and fall weather patterns.

“Overall, temperatures should be warmer than normal this fall and precipitation near average,” says Elliott. “Early-season cold shots will be few and far between, with the worst of winter delayed until later in January and February.”

Haines believes there are some general trends that suggest fall weather impacts bird migration patterns. “Fall migration is related to the passage of cold fronts,” says Haines. “Migrations are heavier in northerly winds, falling temperatures, shortly after the passage of a cold front. The efficiency of downwind flight is enhanced by the facts that average winds blow roughly in the migratory directions of the birds and that the birds show behavioral selection in terms of the wind directions and synoptic weather situations in which they initiate migration.”

Hains explains that synoptic weather situations are weather conditions that occur over a large area for the same time period. Thus, birds will opportunistically use cold fronts and winds coming down from the north to help in their southward migrations.

Haines’ professional research interests involve identifying more effective approaches to implement on-the-ground conservation strategies to benefit species of conservation concern.

Haines has studied birds for the past 20 years and believes his calling is to preserve wild places and wild things for the betterment of human society.

“The fall season is so dynamic for birds because of migration activity,” says Haines. “During the fall, we still see our breeding birds leaving at the beginning of the fall on their way south. We can also see birds that breed north of us and are just passing through on their way south. These birds we only see during the migration season. Lastly, we also begin to see birds that breed north of us but will stay and spend the winter in Pennsylvania.”

“This is why the fall season is such an exciting time for bird watchers,” says Haines. “The diversity and richness of different bird species in a place like Pennsylvania is maximized during the migration seasons. We see more bird migrations during the fall because there are more young birds migrating after the breeding season.”

Recently, Haines was part of a group project that modeled migration pathways for birds using multiple datasets including human counts and observations, satellite tracking, and radar.

A resource suggested by Haines is Birdcast which provides real-time predictions of bird migrations: when they migrate, where they migrate, and how far they will fly.

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