Migration Calendar
When each species peaks at Loess Bluffs National Wildlife Refuge — the effort-robust answer to "when should I drive up" — built live from 3 seasons of USFWS survey records.
Peak timing by species
| Species | Peaks | Present | Typical peak |
|---|---|---|---|
| Mallard | late Nov | Sep–Mar | ~123,646 |
| Northern pintail | late Nov | Sep–Mar | ~60,280 |
| Green-winged teal | mid-Nov | Sep–Dec | ~120,705 |
| Canada goose | early Feb | Sep–Dec | ~9,762 |
| Greater white-fronted goose | late Nov | Oct–Dec | ~49,930 |
| Snow goose | late Feb | Oct–Mar | ~1,359,770 |
| Trumpeter swan | early Jan | Oct–Mar | ~4,199 |
| Bald eagle | early Dec | Nov–Feb | ~703 |
| Tundra swan | late Nov | Nov–Mar | ~11 |
Read the peak first — that's when a species is present in force, and it holds up regardless of how often surveys ran. The dabblers (mallard, pintail, teal) arrive in September on photoperiod and peak by November. Snow geese trace in by October but don't mass until the February push — the gap between first arrival and the spectacle is the whole story. Bald eagles follow the freeze.
"Present" marks the first and last surveys that recorded each species. True arrival likely precedes it, since birds pass between the refuge's irregular surveys — so treat those edges as when the refuge noticed a species, not when it truly arrived or left.