Forecast and Analysis

Regional Migration Forecast: 18-25 August 2017

Andrew Farnsworth The Cornell Lab Aug 18, 2017

Red-eyed Vireo. Yves Dugré/Macaulay Library. eBird S38576118.

Continental Summary

Conditions in the West are favorable for light to moderate migration featuring Green-winged Teal, Northern Shoveler, Red-tailed Hawk, Least Sandpiper, Red-necked Phalarope, Yellow Warbler, and MacGillivray’s Warbler in the first half of the forecast period, while moderate to heavy flights of Wood Duck, Lesser Yellowlegs, Least Sandpiper, Ruby-throated Hummingbird, Great Crested Flycatcher, Yellow Warbler, and Baltimore Oriole will follow the passage of a frontal system through the East late in the period. Also, do not forget to go birding and submit your complete checklists during the eclipse on Monday 21 August!

Arrows show wind speed and direction (arrow points in the direction to which wind is blowing) 100 m above ground level. Areas with southerly winds are colored red; northerly winds colored blue. Accumulated precipitation (in 6 hour intervals) is green, outlined by white. Broadly speaking, areas of the map in blue will experience conditions that are favorable for migration, and areas where blue and green (and red and blue) intersect and overlap may experience migrant concentrations and fallouts as migrants interact with precipitation.

We use data collected by eBird users help make more accurate forecasts. If you enjoy the predictions contained in these posts, please consider submitting your own bird sightings to eBird to even further improve the content. Every observation counts, whether it be a single bird at a feeder in your backyard, or an entire day spent in a national park. To get started with eBird, head on over to the site!

Please note that photographs and other digital media showing birds come from the Macaulay Library, which receives credit along with the photographer/observer in the media caption as part of a new initiative that allows public contribution, access and use of natural history media.

Need a review of our definitions for regions, species on the move, and migration amounts? Please visit this link.

Quick Links to Regions

Upper Midwest and NortheastBirdCast Upper Midwest and Northeast Region Gulf Coast and SoutheastBirdCast Upper Southeast Region
Great Plainsbirdcast_plains West
BirdCast West Region

Upper Midwest and Northeast

Pockets of favorable migration conditions will allow for locally moderate flights over the weekend and early work week. This will be particularly true for portions of the Great Lakes, Ohio River Valley, and eventually New England, respectively. A major change arrives by Wednesday, as a more intense frontal boundary passes through the Great Lakes and brings highly favorable conditions for birds to migrate. Moderate to heavy flights will follow in the wake of the frontal passage, first in the western Great Lakes on Wednesday, then into the Ohio River Valley, northern Appalachians, and coastal plain by Thursday. These conditions persist through the end of the week, with Thursday and Friday seeing their greatest extents and the most widespread moderate and locally heavy flights.

Magnolia Warbler. Wendy Hogan/Macaulay Library. eBird S38549420.

Species on the Move

Beginning Arrivals What is this?

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Blue-winged Teal *** 8/2 8/19 9/7 10/22 11/5
Northern Harrier ** 8/2 10/9 10/21 11/2 11/13
Cooper's Hawk *** 8/2 9/7 10/11 10/28 11/8
Bald Eagle ** 8/2 9/5 9/17 9/26 10/1
Peregrine Falcon * 8/2 9/23 10/4 10/17 10/28
Northern Waterthrush ** 8/2 8/31 9/10 9/24 10/9
Black-and-white Warbler *** 8/2 8/29 9/13 9/30 10/11
Bobolink ** 8/2 8/19 9/2 9/16 10/19
Northern Shoveler ** 8/9 10/12 11/8 After Nov 30 -
Red Knot * 8/11 8/19 8/28 9/10 9/22
Least Flycatcher *** 8/11 8/21 9/3 9/21 10/4
Sora * 8/12 8/21 9/24 10/12 10/25
Baird's Sandpiper *** 8/12 8/20 8/30 9/10 9/19
Red-breasted Nuthatch ** 8/12 9/4 10/2 10/17 After Nov 30
Blackburnian Warbler *** 8/12 8/23 9/8 9/26 10/7
Green-winged Teal ** 8/13 10/11 10/24 After Nov 30 -
Western Sandpiper * 8/13 8/19 8/28 9/9 9/20
Common Nighthawk *** 8/13 8/20 8/29 9/8 9/15
Yellow-bellied Flycatcher * 8/13 8/24 9/6 9/20 9/30
Chestnut-sided Warbler *** 8/14 8/26 9/9 9/25 10/6
Great Crested Flycatcher ** 8/15 8/21 8/27 9/14 9/24
Red-eyed Vireo *** 8/15 8/24 9/7 9/28 10/11
Ovenbird *** 8/15 8/29 9/12 9/30 10/12
American Golden-Plover ** 8/16 8/26 9/9 9/22 10/16
Buff-breasted Sandpiper *** 8/16 8/23 9/3 9/14 9/22
Tennessee Warbler *** 8/17 8/29 9/15 10/4 10/19
Golden-winged Warbler * 8/18 8/28 9/8 9/20 9/29
Warbling Vireo *** 8/19 8/27 9/5 9/17 9/25
Veery *** 8/19 8/28 9/7 9/19 9/28
American Redstart ****! 8/20 8/31 9/12 9/26 10/8
Magnolia Warbler ****! 8/20 9/1 9/16 10/2 10/13
Yellow-throated Vireo *** 8/21 8/29 9/9 9/22 10/2
Wood Thrush ** 8/22 8/28 9/12 10/1 10/12
Wilson's Warbler *** 8/22 8/31 9/11 9/23 10/2
Red-headed Woodpecker * 8/23 9/1 9/11 9/27 10/13
White-eyed Vireo *** 8/23 8/31 9/10 9/23 10/3
Blue Jay ****! 8/23 9/8 9/28 10/30 11/26
Nashville Warbler *** 8/23 9/3 9/20 10/10 10/22
Hooded Warbler * 8/23 8/31 9/10 9/24 10/5
Black-throated Blue Warbler *** 8/23 9/2 9/25 10/14 10/23
Pine Warbler *** 8/23 9/4 9/21 10/12 10/26
Common Yellowthroat *** 8/24 9/2 9/17 10/9 10/23
Black-throated Green Warbler *** 8/24 9/7 9/21 10/6 10/17
Scarlet Tanager *** 8/24 9/3 9/15 10/1 10/12
Cape May Warbler *** 8/25 9/4 9/18 10/2 10/15
Red-shouldered Hawk ** 8/26 9/5 9/21 11/10 11/19
Merlin *** 8/26 9/4 9/20 10/26 11/6
Bay-breasted Warbler *** 8/26 9/4 9/15 9/28 10/8

Peaking Arrivals

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Wood Duck ** - 8/2 8/21 11/2 11/22
Greater Yellowlegs ** - 8/2 8/20 11/11 After Nov 30
Lesser Yellowlegs *** - 8/2 8/19 9/5 9/24
Sanderling * - 8/2 9/2 9/22 10/4
Least Sandpiper *** - 8/2 8/19 9/8 9/22
White-rumped Sandpiper * - 8/2 8/27 9/15 9/22
Caspian Tern ** - 8/2 8/20 9/12 10/22
Ruby-throated Hummingbird *** - 8/2 8/31 9/21 10/3
Belted Kingfisher ** - 8/2 9/19 10/16 10/29
Blue-winged Warbler ** - 8/2 8/28 9/15 9/26
Prairie Warbler * - 8/2 9/10 9/25 10/7
Baltimore Oriole *** - 8/2 8/20 9/3 9/13
Royal Tern * - 8/2 8/21 11/8 After Nov 30
Semipalmated Sandpiper ** 8/2 8/7 8/20 9/6 9/20
Blue-gray Gnatcatcher ** 8/2 8/12 8/26 9/15 9/27
Black Tern * 8/7 8/16 8/25 9/7 9/18
Pectoral Sandpiper * 8/11 8/17 8/23 9/7 11/13
Stilt Sandpiper * 8/12 8/18 8/26 9/8 9/18
Olive-sided Flycatcher * 8/2 8/18 8/30 9/12 9/25
Eastern Wood-Pewee *** 8/7 8/18 8/29 9/24 10/9
Canada Warbler *** 8/2 8/18 8/29 9/11 9/24
Blue-winged Teal ** 8/2 8/19 9/7 10/22 11/5
Red Knot * 8/11 8/19 8/28 9/10 9/22
Western Sandpiper * 8/13 8/19 8/28 9/9 9/20
Bobolink ** 8/2 8/19 9/2 9/16 10/19
Baird's Sandpiper ** 8/12 8/20 8/30 9/10 9/19
Common Nighthawk *** 8/13 8/20 8/29 9/8 9/15
Sora * 8/12 8/21 9/24 10/12 10/25
Least Flycatcher ** 8/11 8/21 9/3 9/21 10/4
Great Crested Flycatcher * 8/15 8/21 8/27 9/14 9/24
Buff-breasted Sandpiper ** 8/16 8/23 9/3 9/14 9/22
Blackburnian Warbler ** 8/12 8/23 9/8 9/26 10/7
Yellow-bellied Flycatcher * 8/13 8/24 9/6 9/20 9/30
Red-eyed Vireo *** 8/15 8/24 9/7 9/28 10/11
American Golden-Plover ** 8/16 8/26 9/9 9/22 10/16
Chestnut-sided Warbler *** 8/14 8/26 9/9 9/25 10/6

Beginning Departures

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Glossy Ibis * - - Before Aug 1 8/23 9/24
Killdeer *** - - Before Aug 1 10/25 11/24
Spotted Sandpiper *** - - Before Aug 1 9/3 9/18
Whimbrel * - - Before Aug 1 9/19 10/3
Least Tern ** - - Before Aug 1 8/22 9/6
Common Tern ** - - Before Aug 1 8/24 9/30
Northern Rough-winged Swallow ** - - Before Aug 1 8/25 10/25
Purple Martin *** - - Before Aug 1 8/22 9/7
Cliff Swallow * - - Before Aug 1 8/29 9/17
Blue Grosbeak * - - Before Aug 1 8/31 10/17
Orchard Oriole ** - - Before Aug 1 8/21 9/6
American Oystercatcher * - 8/2 8/4 8/23 9/26
Bank Swallow ** - 8/2 8/5 8/28 9/12
Yellow-crowned Night-Heron * - 8/2 8/6 10/10 10/28
Piping Plover * - 8/2 8/6 8/22 9/1
Yellow-billed Cuckoo * - 8/2 8/6 9/28 10/12
Little Blue Heron * - 8/2 8/9 8/25 10/24
Black-crowned Night-Heron * - 8/2 8/9 8/25 10/27
Eastern Kingbird *** - 8/2 8/9 8/26 9/7
Tree Swallow *** - 8/2 8/9 10/25 11/6
Barn Swallow *** - 8/2 8/9 8/28 9/13
Ruddy Turnstone * - 8/2 8/10 9/2 9/25
Snowy Egret ** - 8/2 8/11 10/17 10/31
Willet ** - 8/2 8/11 8/28 9/14
Green Heron *** - 8/2 8/12 9/16 10/5
Great Egret *** - 8/2 8/13 10/22 11/5
Solitary Sandpiper *** - 8/2 8/13 9/11 9/30
Laughing Gull ** - 8/2 8/14 After Nov 30 -
Great Blue Heron *** - 8/2 8/15 10/20 After Nov 30
Osprey *** - 8/2 8/15 10/19 11/4
Forster's Tern * - 8/2 8/16 9/26 After Nov 30
Short-billed Dowitcher *** 8/2 8/11 8/17 9/4 9/14
Cedar Waxwing *** - 8/2 8/17 9/25 After Nov 30
Black-bellied Plover ** - 8/2 8/18 8/27 After Nov 30
Semipalmated Plover *** - 8/2 8/18 9/11 9/28
Chimney Swift *** 8/9 8/14 8/18 10/11 10/20
Lesser Yellowlegs *** - 8/2 8/19 9/5 9/24
Least Sandpiper *** - 8/2 8/19 9/8 9/22
Greater Yellowlegs ** - 8/2 8/20 11/11 After Nov 30
Semipalmated Sandpiper *** 8/2 8/7 8/20 9/6 9/20
Caspian Tern ** - 8/2 8/20 9/12 10/22
Baltimore Oriole *** - 8/2 8/20 9/3 9/13
Wood Duck ** - 8/2 8/21 11/2 11/22
Royal Tern * - 8/2 8/21 11/8 After Nov 30
Pectoral Sandpiper ** 8/11 8/17 8/23 9/7 11/13
Black Tern ** 8/7 8/16 8/25 9/7 9/18
Stilt Sandpiper ** 8/12 8/18 8/26 9/8 9/18
Blue-gray Gnatcatcher *** 8/2 8/12 8/26 9/15 9/27

Ending Departures

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Willow Flycatcher *** - - Before Aug 1 8/3 8/21
Black Skimmer * - - Before Aug 1 8/3 10/28
Yellow Warbler *** - - Before Aug 1 8/10 9/24
Orchard Oriole * - - Before Aug 1 8/21 9/6
Piping Plover * - 8/2 8/6 8/22 9/1
Least Tern ** - - Before Aug 1 8/22 9/6
Purple Martin *** - - Before Aug 1 8/22 9/7
Glossy Ibis * - - Before Aug 1 8/23 9/24
American Oystercatcher * - 8/2 8/4 8/23 9/26
Common Tern *** - - Before Aug 1 8/24 9/30
Little Blue Heron * - 8/2 8/9 8/25 10/24
Black-crowned Night-Heron * - 8/2 8/9 8/25 10/27
Northern Rough-winged Swallow ** - - Before Aug 1 8/25 10/25
Eastern Kingbird *** - 8/2 8/9 8/26 9/7

Gulf Coast and Southeast

Local light to moderate flights will be associated with pockets of favorable migration conditions early in the forecast period. But even these pockets of conditions will disappear by early in the work week in advance of an approaching frontal boundary. Wednesday night will see the first hints of a change, with the frontal boundary pushing south and east into portions of the region. Here, locally moderate to heavy flights will occur. By Thursday night favorable migration conditions associated with the frontal boundary passage will bring more widespread moderate to locally heavy flights to many areas east of Texas and north of Florida. Note that several areas of precipitation associated with the passage of the frontal boundary are worth watching for concentrations of migrants, and migrants fly into the area of disturbed weather particularly in the Florida Panhandle and portions of the Low Country on Thursday night and Friday morning.

Blue-gray Gnatcatcher. Daniel Irons/Macaulay Library. eBird S38658763.

Beginning Arrivals What is this?

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Great Blue Heron *** 8/2 11/5 11/16 After Nov 30 -
Cooper's Hawk ** 8/2 9/21 10/17 After Nov 30 -
American Avocet * 8/2 10/22 11/7 After Nov 30 -
Baird's Sandpiper * 8/2 8/19 8/30 9/17 9/28
Yellow-bellied Flycatcher * 8/2 9/4 9/16 10/1 10/11
Least Flycatcher ** 8/2 9/2 9/12 9/24 10/5
Cave Swallow * 8/2 8/28 9/4 9/16 11/21
Blue-gray Gnatcatcher *** 8/2 8/29 9/12 9/26 10/15
Yellow-throated Warbler ** 8/2 9/3 9/25 10/20 11/4
Prairie Warbler ** 8/2 9/7 9/22 10/14 11/3
Blue-winged Teal *** 8/8 8/26 11/8 11/29 After Nov 30
Hooded Warbler ** 8/8 8/20 9/20 10/5 10/29
Worm-eating Warbler ** 8/11 8/23 9/16 10/1 10/10
Northern Parula *** 8/11 9/2 9/19 10/24 11/4
Ruby-throated Hummingbird *** 8/13 8/29 9/13 10/4 10/19
Belted Kingfisher *** 8/13 9/18 10/22 After Nov 30 -
Bank Swallow *** 8/14 8/21 8/31 9/12 9/22
Great Crested Flycatcher *** 8/15 8/23 9/2 9/19 10/1
Northern Waterthrush *** 8/15 9/7 9/20 10/3 10/13
Pine Warbler *** 8/15 9/1 10/9 10/26 11/3
Yellow-throated Vireo *** 8/17 8/31 9/15 9/30 10/13
Canada Warbler ** 8/17 8/27 9/8 9/22 10/4
Yellow-breasted Chat ** 8/17 8/25 9/7 9/23 10/7
Buff-breasted Sandpiper * 8/18 8/27 9/4 9/17 9/25
Eastern Wood-Pewee *** 8/19 9/1 9/17 10/17 11/2
Red-eyed Vireo *** 8/20 9/3 9/17 10/8 10/24
Common Nighthawk ** 8/21 8/27 9/3 9/16 9/24
Acadian Flycatcher ** 8/21 9/1 9/15 10/2 10/16
White-eyed Vireo *** 8/21 9/2 9/19 10/13 10/28
Blue-winged Warbler ** 8/21 9/2 9/15 9/29 10/10
Mourning Warbler ** 8/21 8/30 9/11 9/22 10/2
Summer Tanager *** 8/21 9/1 9/15 10/1 10/18
Dickcissel * 8/21 8/29 9/5 9/20 10/25
Bobolink ** 8/21 9/2 9/20 10/13 10/26
Red-headed Woodpecker ** 8/22 9/4 9/18 10/26 11/5
Black-and-white Warbler *** 8/22 9/5 9/22 10/25 11/5
Chimney Swift *** 8/23 9/5 9/21 10/11 10/22
Chestnut-sided Warbler *** 8/23 9/6 9/22 10/9 10/23
Ovenbird *** 8/26 9/11 9/25 10/25 11/5
Blackburnian Warbler *** 8/26 9/5 9/18 10/3 10/28
Baltimore Oriole *** 8/26 9/2 9/12 9/23 10/1

Peaking Arrivals

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Swainson's Hawk * - 8/2 10/2 10/16 10/28
Black-bellied Plover * - 8/2 10/31 After Nov 30 -
Semipalmated Plover ** - 8/2 8/20 9/17 9/27
Piping Plover * - 8/2 8/20 After Nov 30 -
Upland Sandpiper ** - 8/2 8/19 9/11 9/24
Sanderling * - 8/2 8/19 9/3 9/16
Least Sandpiper ** - 8/2 8/25 9/15 After Nov 30
Short-billed Dowitcher * - 8/2 8/22 9/6 9/21
Wilson's Phalarope * - 8/2 8/23 9/14 10/2
Caspian Tern * - 8/2 11/7 After Nov 30 -
Olive-sided Flycatcher * - 8/2 9/6 9/24 10/4
Yellow Warbler *** - 8/2 9/8 9/30 10/13
Black Tern ** 8/2 8/6 8/24 9/10 9/26
Semipalmated Sandpiper * 8/2 8/13 8/26 9/14 9/28
Kentucky Warbler * 8/2 8/13 9/4 9/25 10/6
Prothonotary Warbler * 8/2 8/15 8/29 9/24 10/6
Solitary Sandpiper * 8/13 8/16 8/20 9/11 9/23
Western Sandpiper * 8/2 8/17 8/31 9/15 After Nov 30
Baird's Sandpiper * 8/2 8/19 8/30 9/17 9/28
Hooded Warbler ** 8/8 8/20 9/20 10/5 10/29
Bank Swallow ** 8/14 8/21 8/31 9/12 9/22
Great Crested Flycatcher *** 8/15 8/23 9/2 9/19 10/1
Worm-eating Warbler ** 8/11 8/23 9/16 10/1 10/10
Yellow-breasted Chat ** 8/17 8/25 9/7 9/23 10/7
Blue-winged Teal * 8/8 8/26 11/8 11/29 After Nov 30

Beginning Departures

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Cattle Egret ** - - Before Aug 1 10/3 10/18
Green Heron *** - - Before Aug 1 9/18 10/8
Yellow-crowned Night-Heron * - - Before Aug 1 10/8 10/23
Least Tern ** - - Before Aug 1 9/3 9/17
Black-chinned Hummingbird * - - Before Aug 1 9/21 10/10
Eastern Kingbird *** - - Before Aug 1 9/22 10/5
Cliff Swallow ** - - Before Aug 1 9/14 10/18
Blue Grosbeak ** - - Before Aug 1 8/24 10/28
Orchard Oriole * - - Before Aug 1 9/14 9/30
Gray Kingbird * - - Before Aug 1 9/17 10/11
Mississippi Kite *** - 8/2 8/10 8/29 9/8
Barn Swallow *** - 8/2 8/10 9/9 11/14
Louisiana Waterthrush * - 8/2 8/13 9/6 9/30
Wilson's Plover * - 8/2 8/14 9/3 9/23
Stilt Sandpiper * - 8/2 8/14 9/17 9/27
Black Skimmer ** - 8/2 8/14 8/30 9/11
Pectoral Sandpiper * - 8/2 8/16 9/19 9/30
Sandwich Tern * - 8/2 8/16 8/27 After Nov 30
Ruddy Turnstone ** - 8/2 8/17 8/28 9/7
Spotted Sandpiper *** - 8/2 8/18 9/10 9/22
Common Tern * - 8/2 8/18 9/30 11/10
Upland Sandpiper ** - 8/2 8/19 9/11 9/24
Sanderling * - 8/2 8/19 9/3 9/16
Semipalmated Plover ** - 8/2 8/20 9/17 9/27
Piping Plover * - 8/2 8/20 After Nov 30 -
Solitary Sandpiper ** 8/13 8/16 8/20 9/11 9/23
Short-billed Dowitcher * - 8/2 8/22 9/6 9/21
Wilson's Phalarope * - 8/2 8/23 9/14 10/2
Black Tern *** 8/2 8/6 8/24 9/10 9/26
Least Sandpiper *** - 8/2 8/25 9/15 After Nov 30
Semipalmated Sandpiper ** 8/2 8/13 8/26 9/14 9/28

Ending Departures

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Swallow-tailed Kite ** - - Before Aug 1 8/3 8/27
Purple Martin *** - - Before Aug 1 8/3 9/10
Western Kingbird ** - - Before Aug 1 8/14 9/8
Blue Grosbeak ** - - Before Aug 1 8/24 10/28

Great Plains

Locally light to moderate flights will pepper the region, particularly the northern and central Plains, during the first half of the period. But a significant and noticeable change comes on Tuesday night, when a frontal passage ushers in cooler and more northerly flow of winds. With these changes will come moderate to heavy flights, first in the northern and central Plains on Tuesday night, then in more southerly areas on Wednesday night. By the end of the forecast period, favorable conditions have mostly moved farther east than the Plains, but some areas of the region will still experience light to moderate flights, in particular close to the Mississippi River Valley. Birders should watch for concentrations of shorebirds and landbirds in areas where the frontal boundary and its precipitation interact with the northerly winds in their wake.

Ruby-throated Hummingbird. Jack and Shirley Foreman/Macaulay Library. eBird S38590304.

Species on the Move

Beginning Arrivals What is this?

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
American White Pelican ** 8/2 9/8 10/18 After Nov 30 -
Turkey Vulture *** 8/2 9/4 9/27 10/16 10/25
Cooper's Hawk *** 8/2 9/5 9/24 10/24 11/8
Red-shouldered Hawk * 8/2 9/7 9/29 10/28 11/25
Sanderling * 8/2 8/20 9/6 10/7 10/26
Wilson's Snipe * 8/2 10/3 10/18 11/3 11/16
Red-necked Phalarope * 8/2 8/22 9/7 9/29 10/15
Caspian Tern * 8/2 8/31 9/11 9/26 10/9
Peregrine Falcon * 8/2 9/13 9/24 10/9 10/23
Least Flycatcher *** 8/2 8/20 9/4 9/20 10/2
Great Crested Flycatcher * 8/2 8/25 8/30 9/16 9/25
Red-eyed Vireo *** 8/2 8/20 9/1 9/20 10/2
Gray Catbird *** 8/2 9/4 9/13 10/1 10/13
Western Meadowlark ** 8/2 9/9 10/15 10/29 11/7
Purple Finch * 8/2 10/27 After Nov 30 - -
American Redstart *** 8/10 8/24 9/5 9/19 9/28
Black-and-white Warbler *** 8/11 8/23 9/5 9/21 10/2
Chestnut-sided Warbler ** 8/11 8/21 9/3 9/18 10/1
American Golden-Plover * 8/12 9/22 9/30 10/12 11/16
Northern Waterthrush ** 8/12 8/19 8/29 9/8 9/17
Mourning Warbler ** 8/12 8/20 9/1 9/13 9/27
Stilt Sandpiper *** 8/13 8/19 8/27 9/8 9/16
Olive-sided Flycatcher *** 8/13 8/23 9/3 9/16 9/24
Ovenbird *** 8/13 8/22 9/4 9/18 10/5
Bell's Vireo ** 8/14 8/19 8/26 9/9 9/19
Common Nighthawk *** 8/15 8/21 8/29 10/1 10/10
Buff-breasted Sandpiper ** 8/16 8/21 8/29 9/10 9/18
Say's Phoebe * 8/16 8/28 9/7 9/26 10/8
Magnolia Warbler ** 8/16 8/27 9/9 9/23 10/3
Philadelphia Vireo ** 8/18 8/31 9/13 9/27 10/6
Merlin * 8/19 9/6 10/24 11/8 11/24
Yellow-breasted Chat * 8/19 8/26 9/5 9/20 9/30
Warbling Vireo *** 8/20 8/28 9/6 9/19 9/27
Black-throated Green Warbler * 8/20 9/2 9/22 10/13 10/28
Clay-colored Sparrow *** 8/20 9/3 9/24 10/16 10/30
Semipalmated Plover * 8/22 8/25 8/29 9/15 9/23
White-eyed Vireo ** 8/24 9/1 9/12 9/27 10/8
Yellow-throated Vireo ** 8/24 8/31 9/8 9/19 9/27
Swainson's Thrush *** 8/24 9/1 9/11 9/22 10/1
Blue-headed Vireo *** 8/25 9/2 9/16 9/28 10/24
House Wren *** 8/25 9/1 9/11 10/6 10/20
Brown Thrasher *** 8/26 9/4 9/14 9/29 10/9
Northern Parula *** 8/26 9/2 9/12 9/24 10/5

Peaking Arrivals

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Wood Duck *** - 8/2 8/20 10/28 After Nov 30
Great Egret * - 8/2 9/13 10/20 11/11
Snowy Egret * - 8/2 8/20 10/5 10/26
Black-crowned Night-Heron * - 8/2 8/27 9/27 10/28
White-faced Ibis * - 8/2 9/1 10/2 10/30
Swainson's Hawk ** - 8/2 9/11 10/14 10/22
Sora * - 8/2 9/27 10/20 11/4
Black-bellied Plover ** - 8/2 8/21 9/1 11/21
Greater Yellowlegs * - 8/2 10/27 11/16 After Nov 30
Lesser Yellowlegs * - 8/2 8/20 9/13 11/8
Forster's Tern * - 8/2 8/20 9/10 10/19
Ruby-throated Hummingbird *** - 8/2 8/31 9/22 10/5
Red-headed Woodpecker ** - 8/2 8/29 9/23 10/13
Eastern Wood-Pewee ** - 8/2 8/20 9/21 10/5
Bank Swallow * - 8/2 8/19 9/10 9/26
Blue-gray Gnatcatcher * - 8/2 8/30 9/20 10/1
Yellow Warbler *** - 8/2 8/29 9/18 9/27
Least Sandpiper * 8/2 8/6 8/25 9/14 9/24
Snowy Plover * 8/2 8/9 8/23 9/8 9/19
Tennessee Warbler ** 8/2 8/9 9/9 10/3 10/23
Blue-winged Teal *** 8/2 8/10 9/13 10/24 11/10
Little Blue Heron * 8/2 8/11 8/21 9/8 10/7
Rose-breasted Grosbeak * 8/2 8/12 9/2 9/29 10/12
Semipalmated Sandpiper * 8/2 8/13 8/20 9/9 9/23
Mississippi Kite * 8/9 8/14 8/20 9/7 9/20
Black-necked Stilt * 8/2 8/15 8/24 9/7 9/18
Canada Warbler * 8/2 8/16 8/31 9/14 9/25
Wilson's Phalarope * 8/12 8/17 8/23 9/12 9/25
Baltimore Oriole *** 8/7 8/17 8/26 9/8 9/18
Western Wood-Pewee * 8/12 8/18 8/25 9/11 9/23
Stilt Sandpiper ** 8/13 8/19 8/27 9/8 9/16
Bell's Vireo ** 8/14 8/19 8/26 9/9 9/19
Northern Waterthrush ** 8/12 8/19 8/29 9/8 9/17
Sanderling * 8/2 8/20 9/6 10/7 10/26
Least Flycatcher *** 8/2 8/20 9/4 9/20 10/2
Red-eyed Vireo *** 8/2 8/20 9/1 9/20 10/2
Mourning Warbler ** 8/12 8/20 9/1 9/13 9/27
Buff-breasted Sandpiper * 8/16 8/21 8/29 9/10 9/18
Common Nighthawk *** 8/15 8/21 8/29 10/1 10/10
Chestnut-sided Warbler * 8/11 8/21 9/3 9/18 10/1
Red-necked Phalarope * 8/2 8/22 9/7 9/29 10/15
Ovenbird ** 8/13 8/22 9/4 9/18 10/5
Olive-sided Flycatcher *** 8/13 8/23 9/3 9/16 9/24
Black-and-white Warbler *** 8/11 8/23 9/5 9/21 10/2
American Redstart *** 8/10 8/24 9/5 9/19 9/28
Semipalmated Plover * 8/22 8/25 8/29 9/15 9/23
Great Crested Flycatcher * 8/2 8/25 8/30 9/16 9/25
Yellow-breasted Chat * 8/19 8/26 9/5 9/20 9/30

Beginning Departures

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Cattle Egret * - - Before Aug 1 10/1 11/2
Killdeer *** - - Before Aug 1 11/4 After Nov 30
Spotted Sandpiper *** - - Before Aug 1 9/9 9/29
Willet * - - Before Aug 1 8/26 9/29
Upland Sandpiper *** - - Before Aug 1 8/25 9/17
Baird's Sandpiper ** - - Before Aug 1 9/10 9/21
Pectoral Sandpiper ** - - Before Aug 1 9/2 10/23
Least Tern * - - Before Aug 1 8/22 9/15
Black Tern ** - - Before Aug 1 9/12 9/30
Northern Rough-winged Swallow ** - - Before Aug 1 10/7 10/23
Purple Martin *** - - Before Aug 1 8/23 9/6
Tree Swallow ** - - Before Aug 1 9/9 11/1
Cliff Swallow *** - - Before Aug 1 8/31 9/22
Lark Sparrow *** - - Before Aug 1 9/13 9/26
Bobolink * - - Before Aug 1 9/4 10/2
Blue Grosbeak *** - 8/2 8/9 8/23 9/3
Yellow-headed Blackbird * - 8/2 8/9 9/27 10/8
Lark Bunting ** - 8/2 8/11 9/17 9/24
Eastern Kingbird *** - 8/2 8/13 9/4 9/21
Solitary Sandpiper ** 8/2 8/7 8/15 9/10 9/26
Marbled Godwit * - 8/2 8/15 9/10 10/2
Chimney Swift *** - 8/2 8/15 10/11 10/20
Green Heron *** - 8/2 8/17 9/22 10/9
Mourning Dove *** - 8/2 8/17 10/4 10/25
Bank Swallow *** - 8/2 8/19 9/10 9/26
Wood Duck ** - 8/2 8/20 10/28 After Nov 30
Snowy Egret ** - 8/2 8/20 10/5 10/26
Mississippi Kite *** 8/9 8/14 8/20 9/7 9/20
Lesser Yellowlegs ** - 8/2 8/20 9/13 11/8
Semipalmated Sandpiper *** 8/2 8/13 8/20 9/9 9/23
Forster's Tern ** - 8/2 8/20 9/10 10/19
Eastern Wood-Pewee *** - 8/2 8/20 9/21 10/5
Little Blue Heron ** 8/2 8/11 8/21 9/8 10/7
Black-bellied Plover * - 8/2 8/21 9/1 11/21
Snowy Plover * 8/2 8/9 8/23 9/8 9/19
Wilson's Phalarope ** 8/12 8/17 8/23 9/12 9/25
Black-necked Stilt * 8/2 8/15 8/24 9/7 9/18
Least Sandpiper *** 8/2 8/6 8/25 9/14 9/24
Western Wood-Pewee * 8/12 8/18 8/25 9/11 9/23
Bell's Vireo *** 8/14 8/19 8/26 9/9 9/19
Baltimore Oriole *** 8/7 8/17 8/26 9/8 9/18

Ending Departures

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Western Kingbird *** - - Before Aug 1 8/3 9/15
Dickcissel *** - - Before Aug 1 8/4 9/1
Orchard Oriole *** - - Before Aug 1 8/15 9/18
Yellow-crowned Night-Heron * - - Before Aug 1 8/17 10/10
Yellow-billed Cuckoo *** - - Before Aug 1 8/17 10/2
Least Tern * - - Before Aug 1 8/22 9/15
Purple Martin *** - - Before Aug 1 8/23 9/6
Blue Grosbeak *** - 8/2 8/9 8/23 9/3
Upland Sandpiper *** - - Before Aug 1 8/25 9/17
Willet * - - Before Aug 1 8/26 9/29

West

Light to moderate movements will be the norm in the northern half of the region during the first half of the forecast period. This will be especially true for portions of the northern Rockies, where densities of migrants may be higher on Sunday and Monday nights. Tuesday and Wednesday see changes in the region, with generally less favorable conditions becoming widespread and flights diminishing to locally light intensities. This pattern continues to end the period, although some areas along the Pacific Coast will experience more favorable conditions locally. In these areas, light to moderate flights are likely, particularly on Wednesday and Thursday nights.

MacGillivray’s Warbler. Oscar Wilhelm/Macaulay Library. eBird S38479773.

Species on the Move

Beginning Arrivals What is this?

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Canada Goose ** 8/2 11/4 After Nov 30 - -
Green-winged Teal *** 8/2 8/20 11/17 After Nov 30 -
Pied-billed Grebe ** 8/2 10/19 11/11 After Nov 30 -
Sooty Shearwater * 8/2 9/5 9/15 9/29 10/8
Cooper's Hawk ** 8/2 9/7 10/1 10/24 11/11
California Gull * 8/2 10/22 11/7 After Nov 30 -
Elegant Tern * 8/2 8/21 9/7 After Nov 30 -
Cassin's Vireo * 8/2 8/29 9/8 9/20 9/29
Gray Catbird * 8/2 8/25 9/2 9/17 9/26
Wilson's Warbler *** 8/2 8/27 9/8 9/24 10/9
Brewer's Sparrow ** 8/2 8/29 9/9 9/24 10/5
Savannah Sparrow *** 8/2 9/3 9/23 10/24 11/2
Northern Shoveler *** 8/6 8/20 11/20 After Nov 30 -
Yellow-headed Blackbird * 8/6 8/22 9/2 9/23 10/11
Red-tailed Hawk *** 8/7 9/10 After Nov 30 - -
Pink-footed Shearwater * 8/8 8/27 9/14 10/25 11/7
Red-necked Phalarope *** 8/8 8/20 9/1 9/16 10/9
Ring-billed Gull ** 8/10 11/7 11/22 After Nov 30 -
Northern Pintail *** 8/12 8/20 11/19 After Nov 30 -
Townsend's Warbler *** 8/13 8/30 10/2 10/22 11/6
Turkey Vulture *** 8/14 9/9 9/17 10/5 10/17
Willow Flycatcher ** 8/14 8/26 9/5 9/19 9/29
Pacific-slope Flycatcher ** 8/14 8/25 9/12 10/3 10/17
American Avocet * 8/15 8/21 8/30 9/30 After Nov 30
Heermann's Gull * 8/15 9/14 9/21 10/2 After Nov 30
Black-necked Stilt * 8/16 8/20 8/27 9/26 10/6
Pectoral Sandpiper ** 8/16 8/25 9/20 10/9 10/24
Black Phoebe *** 8/16 9/9 11/17 After Nov 30 -
Northern Harrier ** 8/17 11/8 11/20 After Nov 30 -
Red-shouldered Hawk ** 8/17 9/12 10/3 After Nov 30 -
Clay-colored Sparrow * 8/17 8/28 9/14 10/18 11/6
Orange-crowned Warbler *** 8/18 9/1 9/18 10/15 10/27
Common Yellowthroat *** 8/18 8/30 9/15 10/5 10/27
Sora * 8/21 9/1 9/13 9/23 After Nov 30
Warbling Vireo *** 8/21 8/29 9/9 9/22 10/9
Marsh Wren * 8/21 9/20 10/29 After Nov 30 -
Swainson's Thrush ** 8/22 8/29 9/10 9/25 10/7
Sharp-shinned Hawk ** 8/23 9/10 10/19 11/11 After Nov 30
Olive-sided Flycatcher * 8/23 8/26 8/29 9/17 9/28
House Wren *** 8/23 8/31 9/9 9/21 10/26
Western Tanager *** 8/23 8/30 9/8 9/21 10/3
Brewer's Blackbird *** 8/23 9/11 9/27 10/20 After Nov 30
Common Tern * 8/24 9/6 9/17 10/1 10/11
Hammond's Flycatcher * 8/24 8/31 9/8 9/19 9/26
Vesper Sparrow ** 8/24 9/2 9/13 9/27 10/15
Red-winged Blackbird *** 8/25 9/12 10/10 10/27 After Nov 30
Red-necked Grebe * 8/26 10/20 11/3 11/13 11/20
Parasitic Jaeger * 8/26 9/6 9/19 10/1 10/29

Peaking Arrivals

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Blue-winged Teal * - 8/2 9/22 10/23 11/3
Common Merganser * - 8/2 9/23 9/28 9/30
Osprey ** - 8/2 8/25 9/16 10/2
Franklin's Gull * - 8/2 8/31 10/3 11/5
Belted Kingfisher ** - 8/2 10/22 After Nov 30 -
Red-breasted Nuthatch ** - 8/2 9/7 10/19 10/30
Blue-gray Gnatcatcher * - 8/2 9/10 9/22 10/3
Sage Thrasher * - 8/2 8/31 9/20 10/13
Nashville Warbler ** - 8/2 9/5 9/19 9/29
MacGillivray's Warbler *** - 8/2 9/5 9/21 10/2
Yellow Warbler *** - 8/2 9/8 10/2 10/21
Black-throated Gray Warbler * - 8/2 10/4 10/19 10/29
Hermit Warbler * - 8/2 8/19 9/3 10/23
Chipping Sparrow ** - 8/2 9/8 10/18 11/2
Semipalmated Sandpiper * 8/2 8/9 8/20 9/5 9/15
Barn Swallow ** 8/2 8/9 8/23 9/17 10/12
Green Heron * 8/2 8/10 8/28 9/23 10/17
White-faced Ibis * 8/2 8/12 8/27 9/26 10/13
Cinnamon Teal * 8/2 8/13 9/2 9/27 10/13
American White Pelican * 8/2 8/13 9/2 9/27 10/19
Solitary Sandpiper * 8/2 8/13 8/26 9/9 9/22
Killdeer *** 8/2 8/14 9/7 10/3 11/3
Least Sandpiper *** 8/2 8/14 8/25 9/6 9/16
Western Sandpiper *** 8/2 8/14 8/25 9/6 10/5
Mourning Dove * 8/9 8/14 8/19 9/21 10/8
Virginia's Warbler * 8/2 8/14 8/28 9/16 10/1
Lesser Yellowlegs ** 8/2 8/15 8/25 9/6 10/7
Semipalmated Plover ** 8/9 8/17 8/26 9/8 9/20
Wandering Tattler * 8/10 8/17 8/26 10/2 10/10
Marbled Godwit * 8/9 8/17 8/28 9/29 After Nov 30
Black Turnstone * 8/6 8/17 9/21 10/2 After Nov 30
Sanderling * 8/2 8/17 9/8 9/26 10/6
Baird's Sandpiper ** 8/3 8/17 8/27 9/8 9/20
Greater Yellowlegs ** 8/11 8/18 8/28 After Nov 30 -
Short-billed Dowitcher ** 8/10 8/18 8/26 9/6 9/13
Northern Shoveler *** 8/6 8/20 11/20 After Nov 30 -
Northern Pintail ** 8/12 8/20 11/19 After Nov 30 -
Green-winged Teal ** 8/2 8/20 11/17 After Nov 30 -
Black-necked Stilt * 8/16 8/20 8/27 9/26 10/6
Red-necked Phalarope *** 8/8 8/20 9/1 9/16 10/9
American Avocet * 8/15 8/21 8/30 9/30 After Nov 30
Elegant Tern * 8/2 8/21 9/7 After Nov 30 -
Yellow-headed Blackbird * 8/6 8/22 9/2 9/23 10/11
Pectoral Sandpiper ** 8/16 8/25 9/20 10/9 10/24
Pacific-slope Flycatcher ** 8/14 8/25 9/12 10/3 10/17
Gray Catbird * 8/2 8/25 9/2 9/17 9/26
Olive-sided Flycatcher * 8/23 8/26 8/29 9/17 9/28
Willow Flycatcher ** 8/14 8/26 9/5 9/19 9/29

Beginning Departures

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Snowy Plover * - - Before Aug 1 9/11 10/1
Whimbrel * - - Before Aug 1 9/29 10/13
Wilson's Phalarope ** - - Before Aug 1 9/8 9/27
Pigeon Guillemot * - - Before Aug 1 8/27 9/8
Caspian Tern ** - - Before Aug 1 9/7 9/27
Black Tern * - - Before Aug 1 9/22 10/4
White-winged Dove *** - - Before Aug 1 9/3 9/15
Common Nighthawk * - - Before Aug 1 9/2 9/24
Black-chinned Hummingbird *** - - Before Aug 1 9/14 10/3
Broad-tailed Hummingbird ** - - Before Aug 1 9/1 9/26
Rufous Hummingbird *** - - Before Aug 1 9/7 9/24
Calliope Hummingbird * - - Before Aug 1 9/5 9/24
Western Kingbird *** - - Before Aug 1 9/4 9/24
Bell's Vireo * - - Before Aug 1 9/28 10/11
Northern Rough-winged Swallow ** - - Before Aug 1 9/10 9/25
Purple Martin * - - Before Aug 1 9/4 9/20
Black-headed Grosbeak *** - - Before Aug 1 9/14 9/28
Blue Grosbeak ** - - Before Aug 1 9/16 10/9
Bullock's Oriole ** - - Before Aug 1 9/2 9/14
Sulphur-bellied Flycatcher * - - Before Aug 1 8/20 8/31
Western Wood-Pewee *** - 8/2 8/10 9/20 9/30
Eastern Kingbird ** - 8/2 8/14 8/30 9/10
Lazuli Bunting ** - 8/2 8/14 9/21 10/2
Lark Sparrow ** - 8/2 8/15 9/20 9/30
Bank Swallow * - 8/2 8/17 9/11 9/25
Lark Bunting * - 8/2 8/17 9/17 9/26
Swainson's Hawk ** - 8/2 8/18 9/28 10/12
Spotted Sandpiper *** - 8/2 8/18 9/17 10/3
Mourning Dove *** 8/9 8/14 8/19 9/21 10/8
Hermit Warbler * - 8/2 8/19 9/3 10/23
Semipalmated Sandpiper * 8/2 8/9 8/20 9/5 9/15
Barn Swallow *** 8/2 8/9 8/23 9/17 10/12
Osprey ** - 8/2 8/25 9/16 10/2
Lesser Yellowlegs ** 8/2 8/15 8/25 9/6 10/7
Least Sandpiper *** 8/2 8/14 8/25 9/6 9/16
Western Sandpiper *** 8/2 8/14 8/25 9/6 10/5
Semipalmated Plover *** 8/9 8/17 8/26 9/8 9/20
Solitary Sandpiper ** 8/2 8/13 8/26 9/9 9/22
Wandering Tattler * 8/10 8/17 8/26 10/2 10/10
Short-billed Dowitcher ** 8/10 8/18 8/26 9/6 9/13

Ending Departures

Species Noticeability Migrants Begin Arriving Rapid Migrant Influx Peak Rapid Migrant Departure Last Migrants Depart
Ash-throated Flycatcher ** - - Before Aug 1 8/3 8/26
Tree Swallow *** - - Before Aug 1 8/3 9/17
Violet-green Swallow *** - - Before Aug 1 8/3 10/23
Yellow-breasted Chat * - - Before Aug 1 8/3 9/25
Hooded Oriole ** - - Before Aug 1 8/3 9/22
Broad-billed Hummingbird * - - Before Aug 1 8/7 9/16
Cliff Swallow *** - - Before Aug 1 8/11 9/14
Sulphur-bellied Flycatcher * - - Before Aug 1 8/20 8/31

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Farnsworth and Van Doren

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