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Birdaday Field Notes

Migration reference

When do birds migrate? Spring and fall timing by region and bird group

Updated

In the United States, birds migrate north mainly from March to early June and south mainly from mid-August through November, but the peak depends on where you are and which birds you mean. BirdCast, the Cornell Lab of Ornithology's radar migration project, uses March 1–June 15 and August 15–November 30 as its full migration periods. Waterfowl and early sparrows move first in spring, warblers peak in May, and in fall warblers pass in August and September while sparrows, hawks and ducks keep moving into November and December. In spring, the West peaks in late April and the first week of May, and the Northeast and Upper Midwest a few weeks later (Cornell Lab, All About Birds).

Jump to: Timing chart · Peaks by region · A migration year, drawn · Night migration · BirdCast · eBird bar charts · Lights Out

Bird migration timing chart by region and bird group

Dates are what each source states for its own area. Most detail comes from Black Swamp Bird Observatory's timing guides for the Lake Erie shore of northwest Ohio (written by Kenn Kaufman), one of the few places with a group-by-group calendar; other rows add Texas, the Gulf Coast and the West where a source gives them. Your county can differ by weeks.

Bird group Spring Fall Day or night Where the dates apply
Ducks, geese and swans Moving from late February; peak March 16–31; winding down by early May Blue-winged Teal peak in September; most dabbling ducks late September–November; diving ducks late October into early December; Tundra Swans peak in November Often by day Northwest Ohio (BSBO)
Hawks and other raptors From March 1 (Red-shouldered Hawk, Bald Eagle, Turkey Vulture); Broad-winged and Sharp-shinned Hawks and Osprey April 16–30; winding down by early May Broad-winged Hawks mainly in September; Merlins late September–October; Red-tailed Hawks late October–November; Rough-legged Hawks arrive from early November Often by day Northwest Ohio (BSBO)
Sparrows Song Sparrow March 1–15; Fox Sparrow late March to mid-April; White-throated and Swamp Sparrows April 16–30 Main passage late September through October; Fox Sparrow late October–November; American Tree Sparrow arrives in numbers in November Night, like most birds Northwest Ohio (BSBO)
Warblers Texas: Northern Parula and Yellow-throated Warbler early March to mid-April; Magnolia, Blackburnian and Bay-breasted late April to mid-May (TPWD). Ohio: first major wave May 1–10, many species peak May 11–31 (BSBO) First migrants about the first week of August; strongest the first three weeks of September; declining after October 1; Yellow-rumped Warblers into November Night, like most birds Texas (TPWD); northwest Ohio (BSBO)
Hummingbirds Ruby-throated: Gulf Coast late February or early March (Journey North); Texas late March to mid-May (TPWD); northwest Ohio mid-May (BSBO). Allen's Hummingbird heard north of San Francisco as early as January (Audubon) Ruby-throated males may leave by early August and the species is bound for Central America by early fall (Cornell). Rufous Hummingbirds reach parts of Arizona by early July (Audubon) — Eastern US; California coast; Arizona
Shorebirds Pectoral Sandpiper late March; numbers build through May, many species peak May 21–31, some into early June Southbound from late June; juveniles outnumber adults in late August; Dunlin peak October to early November — Northwest Ohio (BSBO); US-wide fall start (Audubon)

"Day or night" follows Cornell's All About Birds: most birds migrate at night, while raptors, waterfowl and swallows sometimes travel by day. A dash means the sources used here don't say.

Peak migration by region

Weather radar counts all night-flying birds together, without species, so these peaks are for nocturnal migration as a whole.

Region Spring peak Fall peak
West Late April and the first week of May Southwest and Mountain West (Arizona, New Mexico, Colorado, Wyoming): earliest in the country, second half of August
Pacific Coast North of San Francisco (Palomarin): no distinct waves; insect-eaters from mid-March, berry and seed eaters from mid-April North-to-south from Seattle to San Francisco; Los Angeles peaks earlier than those cities
Western Texas to the Dakotas Relatively early: a main migration highway —
Texas and the western Gulf Later than the eastern Gulf: most long-distance migrants arrive here Houston about two weeks before Dallas
Southeast Several weeks earlier than areas of long-distance migrants: short-distance migrants winter here Part of a rolling north-to-south wave from the Mississippi to the Appalachians
Northeast and Upper Midwest A few weeks later than the West Massachusetts to Virginia Beach: early October, later than the rest of the East

Spring rows: BirdCast radar analysis (143 radars, 2013–2022) as reported by the Cornell Lab, and Audubon for the Pacific Coast. Fall rows: BirdCast's peak windows for about 1,000 US cities, as mapped by Kate St. John (2025). On that map, the peak lasts 3 to 4.5 weeks once it starts; Pittsburgh's ran September 15–October 11, 2025.

A migration year on Lake Erie, drawn

A migration year on the Lake Erie shore of northwest Ohio, by bird groupA twelve-month timeline with six numbered rows. Light blue bars mark the main spring and fall passage of waterfowl, hawks, sparrows, warblers and Ruby-throated Hummingbirds as described by Black Swamp Bird Observatory for northwest Ohio, with the hummingbird fall bar from the Cornell Lab. Dark blue sections mark stated peaks: waterfowl in the second half of March, warblers in May and the first three weeks of September, sparrows from late September through October. Row 6, in yellow hatching, shows BirdCast's Lights Out periods, March 1 to June 15 and August 15 to November 30.JFMAMJJASOND123456
  1. Ducks, geese and swans: late February to early May, peak March 16–31; fall from September (Blue-winged Teal) into early December (diving ducks).
  2. Hawks: March 1 to early May; fall September (Broad-winged) through November (Red-tailed, Rough-legged).
  3. Sparrows: March 1 to early May; fall main passage late September through October, Fox and American Tree Sparrows into November.
  4. Warblers: from April, peak in May; fall from early August, strongest in the first three weeks of September, Yellow-rumped into November.
  5. Ruby-throated Hummingbird: mid-May in northwest Ohio; fall bar from Cornell's rangewide account (males from early August, gone south by early fall).
  6. BirdCast Lights Out periods: March 1–June 15 and August 15–November 30 (yellow hatching).
Drawn for Birdaday Field Notes from Black Swamp Bird Observatory's spring and fall timing guides for northwest Ohio (rows 1–5), the Cornell Lab's Ruby-throated Hummingbird account (row 5, fall) and BirdCast's Lights Out page (row 6), all cited below. Light blue = main passage; dark blue = a peak the source states. Bar ends approximate phrases such as "late February"; other regions run earlier or later.

Night migration and the big nights

BirdCast says at least 80% of migratory bird species in the US migrate at night. Cornell's All About Birds explains that the air is calmer at night and there are fewer predators about; raptors, waterfowl and swallows are the groups it names as sometimes traveling by day. On one autumn night with good winds, it says, more than a billion birds can be in the air over the United States.

Migration is also pulsed. In a Conservation Biology study of 143 weather radars, Kyle Horton and colleagues (2021) found that most birds (54.3%) move on just 10% of a season's nights. Birds typically fly in clear weather and may drop to the ground when rain starts, so weather fronts can change local activity (Cornell). Departure timing responds to changes in day length, temperature and food supplies, and it can be remarkably steady: Cornell notes that Red-winged Blackbirds reach central New York within the same two-week window each spring.

In the East, spring songbirds come in waves, Audubon explains: short-distance migrants such as Yellow-rumped Warbler and White-throated Sparrow first, then Neotropical migrants from May, then late arrivals such as American Redstart and Swainson's Thrush. Within each wave, males usually arrive ahead of females.

A vast flock of white geese filling a blue sky above a lake, with thousands more birds resting on the water below
Snow Geese, as identified on the Commons file page, moving north at Squaw Creek National Wildlife Refuge in northwest Missouri on February 17, 2013. The file page notes the geese turned back south days later, when a blizzard hit the Great Plains.
Photo: CrunchySkies / CC BY-SA 3.0, via Wikimedia Commons

How to read BirdCast for your area

BirdCast covers the Lower 48 states. Its tools, as Cornell's guide describes them:

  1. Migration forecast: predicted migration for the next three nights. Brighter colors mean more birds; gray marks weather fronts that may disrupt migration. It is a model estimate and is not always right.
  2. Live migration maps: near-real-time radar during spring and fall, updated every 10 minutes through the night, in estimated birds per kilometer. Hovering over a county shows its peak spring and fall migration dates.
  3. Migration dashboard: type your county or state to see the night's total migration traffic, with their average speed, direction and altitude compared with past years. An "expected nocturnal migrants" list draws on local eBird checklists, because radar cannot tell species apart.
  4. Migration alerts: pick the nearest city and confirm your email to be told when a big night is predicted.

Because the dashboard refreshes every 10 minutes, Cornell suggests checking it during the night or in the morning to plan a birding trip.

How to read eBird bar charts for your county

eBird's bar charts show which species turn up when, for any region or hotspot (eBird Help Center):

  1. Open Explore, choose Bar Charts, and enter your county; or use the Bar Charts link on a region or hotspot page.
  2. Read each bar as frequency: the share of complete checklists from that area reporting the species at that time of year. A frequency of 0.4 means the bird is on 40% of complete checklists for that week.
  3. Taller bars mean the bird is more likely to be found. An empty gray box means no reports; a vertical line marks today's date.
  4. Look for where the bars start, swell and fade in spring and fall: that is your local migration window for that species. Click a species' chart icon for a line graph, or "Download Histogram Data" for the numbers.

There is more on checklists and bar charts in eBird for beginners, and arrival-date tips for hummingbirds in when to put out hummingbird feeders.

Lights Out: what to do on big nights

Because most birds migrate at night, lit structures are a hazard, and collisions happen most during spring and fall migration, says the U.S. Fish and Wildlife Service, which puts the number of birds colliding with glass in the US at more than a billion. BirdCast's Lights Out advice for homes and offices:

The sources differ on timing. BirdCast's page says dusk to dawn, from March 1 to June 15 and August 15 to November 30. Cornell's All About Birds suggests 11 p.m. to 6 a.m. and calls February 15 to June 15 the most effective spring period. It also says dimming lights for the busiest three weeks covers the time when half of the migrants pass. The Horton study is more targeted: following forecasts, about 10 nights of action protect half of a season's migrants passing an area (Colorado State University summary). For the glass itself, see window collisions.

Sources