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Forecast and Analysis

Regional Migration Forecast: 28 August – 4 September 2015

Andrew Farnsworth The Cornell Lab Aug 28, 2015

Common Yellowthroat, ©Ryan Schain

Continental Summary

Generally unfavorable migration conditions prevail in the West this week, with those pulses of movements that occur featuring Green Heron, Least Sandpiper, Short-billed Dowitcher, Pacific-slope Flycatcher, Common Yellowthroat, and Clay-colored Sparrow, while the East sees a return to more summer like conditions until more favorable conditions and associated moderate flights of Common Nighthawk, Ruby-throated Hummingbird, Red-eyed Vireo, Blue-winged Warbler, Blackburnian Warbler, and Chipping Sparrow come after the middle of the week.

Wondering what was on the move this past week? Check out our regional migration analysis!

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!

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

Marginal conditions remaining as a high pressure center arrives bring light to moderate flights on Friday night along the coast. But these flights are followed by a period of generally unfavorable and summer like conditions in most areas away from New England until the middle and end of the period. While New England sees a return to moderate and locally heavy flights on Sunday night, light movements prevail across the rest of the region. Wednesday and Thursday see a return of more favorable northerly flow in an increasing number of locations, spawning moderate to heavy flights from Wednesday through the end of the period. One interesting feature of note is what is now Erika – this storm may become a hurricane as it approaches the southeastern US and move into to this region as a dissociated tropical depression. BirdCast will monitor this system’s evolution and its potential to bring tropical waifs to the region.

Scarlet Tanager, ©Ian Davies

Species on the Move

Beginning to Arrive What is this?

Species Begin Arrival Rapid Influx Peak Rapid Depart
Northern Flicker **** 28-Aug 9-Sep 26-Sep 13-Oct 30-Oct
House Wren *** 28-Aug 4-Sep 15-Sep 7-Oct 23-Oct
Gray Catbird *** 28-Aug 6-Sep 17-Sep 9-Oct 24-Oct
Gray-cheeked Thrush ** 29-Aug 8-Sep 23-Sep 8-Oct 19-Oct
Northern Pintail ** 1-Sep 3-Oct 31-Oct 20-Nov 11-Dec
Sedge Wren * 1-Sep 20-Sep 5-Oct 24-Oct 1-Nov
Marsh Wren ** 1-Sep 20-Sep 5-Oct 24-Oct –
Lapland Longspur * 3-Sep 15-Sep 10-Nov – –
Great Cormorant * 3-Sep 12-Nov After Dec 31 – –
Eastern Phoebe *** 4-Sep 16-Sep 30-Sep 20-Oct 3-Nov
Palm Warbler *** 4-Sep 18-Sep 5-Oct 22-Oct 4-Nov

Arriving

Species Begin Arrival Rapid Influx Peak Rapid Depart
Sora * 12-Aug 28-Aug 21-Sep 16-Oct 30-Oct
Black-and-white Warbler *** 10-Aug 28-Aug 13-Sep 2-Oct 14-Oct
Yellow-throated Warbler * 19-Aug 29-Aug 12-Sep 30-Sep 12-Oct
Wood Thrush ** 23-Aug 30-Aug 11-Sep 28-Sep 15-Oct
Tennessee Warbler *** 16-Aug 30-Aug 16-Sep 4-Oct 18-Oct
Red-headed Woodpecker * 22-Aug 1-Sep 13-Sep 2-Oct 14-Oct
Magnolia Warbler *** 20-Aug 1-Sep 17-Sep 3-Oct 15-Oct
Bald Eagle * Before July 1 2-Sep 6-Nov – –
Sabine's Gull * 22-Aug 2-Sep 16-Sep 1-Oct 10-Oct
Bay-breasted Warbler *** 22-Aug 2-Sep 16-Sep 2-Oct 13-Oct
Scarlet Tanager *** 23-Aug 2-Sep 15-Sep 3-Oct 15-Oct
Philadelphia Vireo *** 22-Aug 3-Sep 17-Sep 2-Oct 12-Oct
Common Yellowthroat *** 25-Aug 3-Sep 18-Sep 9-Oct 24-Oct
Summer Tanager * 25-Aug 3-Sep 16-Sep 3-Oct 15-Oct
Merlin ** 19-Aug 4-Sep 28-Sep 26-Oct 16-Nov
House Wren ** 28-Aug 4-Sep 15-Sep 7-Oct 23-Oct
Swainson's Thrush *** 24-Aug 4-Sep 19-Sep 5-Oct 16-Oct
Cape May Warbler ** 22-Aug 4-Sep 19-Sep 5-Oct 17-Oct

Peaking

Species Begin Arrival Rapid Influx Peak Rapid Depart
Red Knot * – Before July 1 28-Aug 15-Sep 28-Sep
Ruby-throated Hummingbird *** 30-Jul 14-Aug 28-Aug 21-Sep 5-Oct
Blue-winged Warbler ** 1-Aug 13-Aug 28-Aug 14-Sep 27-Sep
Eastern Wood-Pewee *** 5-Aug 16-Aug 29-Aug 22-Sep 9-Oct
Baird's Sandpiper ** 6-Aug 17-Aug 30-Aug 15-Sep 25-Sep
Eastern Whip-poor-will * 16-Aug 21-Aug 30-Aug 19-Sep 2-Oct
Olive-sided Flycatcher * 4-Aug 16-Aug 30-Aug 15-Sep 27-Sep
Canada Warbler ** 5-Aug 16-Aug 30-Aug 15-Sep 26-Sep
Common Nighthawk *** 7-Aug 17-Aug 31-Aug 14-Sep 25-Sep
Kentucky Warbler * 15-Aug 21-Aug 31-Aug 17-Sep 29-Sep
Bobolink ** 5-Aug 16-Aug 31-Aug 19-Sep 15-Oct
Sanderling ** – Before July 1 1-Sep 23-Sep 6-Oct
Mourning Warbler * 4-Aug 15-Aug 1-Sep 21-Sep 7-Oct
Buff-breasted Sandpiper * 10-Aug 20-Aug 3-Sep 17-Sep 28-Sep
Least Flycatcher ** 7-Aug 18-Aug 3-Sep 22-Sep 5-Oct
Warbling Vireo *** 13-Aug 21-Aug 3-Sep 19-Sep 30-Sep

Departing

Species Begin Arrival Rapid Influx Peak Rapid Depart
Bank Swallow *** – Before July 1 1-Aug 28-Aug 15-Sep
Clapper Rail * – Before July 1 1-Aug 28-Aug 29-Oct
Upland Sandpiper * 26-Jul 1-Aug 11-Aug 29-Aug 12-Sep
Ruddy Turnstone ** Before July 1 25-Jul 12-Aug 29-Aug 17-Sep
Cliff Swallow ** – – Before July 1 29-Aug 18-Sep
Tree Swallow *** – – Before July 1 30-Aug 10-Nov
Barn Swallow *** Before July 1 22-Jul 4-Aug 30-Aug 16-Sep
American Oystercatcher * – Before July 1 29-Jul 30-Aug 25-Sep
Blue Grosbeak * Before July 1 18-Jul 5-Aug 31-Aug 17-Oct
Roseate Tern * – Before July 1 20-Jul 1-Sep 23-Sep
Black-bellied Plover * 20-Jul 1-Aug 20-Aug 3-Sep 1-Dec

Gulf Coast and Southeast

Generally unsettled and unfavorable conditions prevail in the region during this forecast period, pending the passage of Erika in the middle of the week. Warm temperatures and southerly flow will keep flights light to locally moderate. Once Erika arrives and makes landfall, and its circulation begins to influence more significantly regional weather patterns, increasingly moderate to locally heavy flights are likely (this is typical during and after the arrival of such a system). By Wednesday and Thursday nights areas near and west of the Mississippi River valley will experience the best movements of the week.

Brown Thrasher, ©Ian Davies

Beginning to Arrive What is this?

Species Begin Arrival Rapid Influx Peak Rapid Depart
Broad-winged Hawk ** 28-Aug 9-Sep 25-Sep 13-Oct 1-Nov
Veery *** 28-Aug 7-Sep 21-Sep 5-Oct 16-Oct
American Redstart ****! 29-Aug 11-Sep 28-Sep 16-Oct 30-Oct
Sora * 29-Aug 10-Sep 18-Dec – –
Nashville Warbler *** 30-Aug 13-Sep 4-Oct 26-Oct 15-Nov
Cape May Warbler ** 31-Aug 12-Sep 29-Sep 16-Oct 31-Oct
Scarlet Tanager *** 31-Aug 12-Sep 27-Sep 15-Oct 28-Oct
Tennessee Warbler *** 31-Aug 15-Sep 3-Oct 22-Oct 5-Nov
American Avocet * 1-Sep 20-Oct 5-Nov 24-Nov 8-Dec
Blue-headed Vireo * 1-Sep 18-Oct 18-Dec After Dec 31 –
Magnolia Warbler *** 1-Sep 14-Sep 1-Oct 19-Oct 1-Nov
Clay-colored Sparrow ** 2-Sep 15-Sep 4-Oct 21-Oct 4-Nov
Common Yellowthroat *** 2-Sep 16-Sep 5-Oct 23-Oct 6-Nov
Sharp-shinned Hawk ** 2-Sep 17-Sep 28-Oct 12-Nov 22-Nov
Brown Thrasher *** 3-Sep 18-Sep 5-Oct 24-Oct 7-Nov
Merlin *** 3-Sep 17-Sep 11-Oct 1-Nov 18-Nov
Swainson's Thrush *** 3-Sep 14-Sep 29-Sep 15-Oct 27-Oct
Wood Thrush ** 3-Sep 16-Sep 2-Oct 19-Oct 31-Oct

Arriving

Species Begin Arrival Rapid Influx Peak Rapid Depart
Worm-eating Warbler * 9-Aug 29-Aug 15-Sep 4-Oct 17-Oct
Baltimore Oriole *** 18-Aug 30-Aug 14-Sep 30-Sep 10-Oct
Least Flycatcher ** 15-Aug 30-Aug 14-Sep 1-Oct 13-Oct
Ruby-throated Hummingbird *** 26-Jul 30-Aug 13-Sep 5-Oct 20-Oct
Yellow-throated Vireo ** 16-Aug 30-Aug 15-Sep 3-Oct 17-Oct
Chuck-will's-widow * 15-Aug 31-Aug 17-Sep 6-Oct 20-Oct
Summer Tanager *** 19-Aug 31-Aug 15-Sep 4-Oct 19-Oct
Yellow-bellied Flycatcher * 15-Aug 31-Aug 15-Sep 3-Oct 15-Oct
Acadian Flycatcher ** 20-Aug 1-Sep 16-Sep 5-Oct 18-Oct
Blue-winged Warbler * 19-Aug 1-Sep 17-Sep 4-Oct 16-Oct
Eastern Wood-Pewee *** 16-Aug 1-Sep 19-Sep 12-Oct 29-Oct
Hooded Warbler ** 3-Aug 3-Sep 20-Sep 11-Oct 27-Oct
Northern Parula *** 7-Aug 3-Sep 23-Sep 17-Oct 2-Nov
Northern Waterthrush *** 19-Aug 3-Sep 19-Sep 7-Oct 21-Oct
Warbling Vireo * 23-Aug 3-Sep 17-Sep 3-Oct 14-Oct
White-eyed Vireo *** 19-Aug 3-Sep 20-Sep 11-Oct 30-Oct
Bobolink * 21-Aug 4-Sep 21-Sep 9-Oct 23-Oct
Red-headed Woodpecker ** 24-Aug 4-Sep 18-Sep 6-Oct 11-Nov
Wilson's Warbler *** 23-Aug 4-Sep 19-Sep 4-Oct 14-Oct

Peaking

Species Begin Arrival Rapid Influx Peak Rapid Depart
Cerulean Warbler * 1-Aug 13-Aug 28-Aug 14-Sep 26-Sep
Common Nighthawk ** 10-Aug 18-Aug 28-Aug 19-Sep 4-Oct
Prothonotary Warbler * 2-Aug 11-Aug 28-Aug 23-Sep 9-Oct
Bell's Vireo * 8-Aug 18-Aug 29-Aug 23-Sep 10-Oct
Buff-breasted Sandpiper * 31-Jul 14-Aug 30-Aug 17-Sep 30-Sep
Bank Swallow ** 6-Aug 17-Aug 1-Sep 16-Sep 28-Sep
Brown-crested Flycatcher * 16-Aug 23-Aug 1-Sep 20-Sep 2-Oct
Cave Swallow * – – 1-Sep 26-Sep 26-Nov
Great Crested Flycatcher *** 11-Aug 20-Aug 1-Sep 20-Sep 5-Oct
Western Sandpiper * Before July 1 11-Jul 1-Sep 20-Sep 2-Oct
Bullock's Oriole * 13-Aug 21-Aug 2-Sep 18-Sep 30-Sep
Dickcissel * 10-Aug 19-Aug 2-Sep 24-Sep 16-Oct
Kentucky Warbler * 4-Aug 15-Aug 2-Sep 24-Sep 9-Oct
Alder Flycatcher * 4-Aug 17-Aug 3-Sep 20-Sep 4-Oct

Departing

Species Begin Arrival Rapid Influx Peak Rapid Depart
Mississippi Kite *** – – 8-Aug 28-Aug 12-Sep
Black Skimmer ** – Before July 1 6-Aug 4-Sep 18-Sep

Great Plains

Southerly flow and warmer temperatures overspreading the region will keep migration unseasonably quiet during this coming week. Light movements will be the norm, with locally moderate movements occurring when conditions allow. Not until Thursday does the hint of change appear, with favorable conditions in the Dakotas spawning moderate to heavy flights there.

Palm Warbler, ©Ian Davies

Species on the Move

Beginning to Arrive What is this?

Species Begin Arrival Rapid Influx Peak Rapid Depart
Broad-winged Hawk * 28-Aug 7-Sep 20-Sep 7-Oct 19-Oct
Summer Tanager ** 28-Aug 6-Sep 18-Sep 5-Oct 17-Oct
Northern Flicker **** 30-Aug 13-Sep 7-Oct 26-Oct 5-Nov
Pied-billed Grebe *** 30-Aug 12-Sep 31-Oct 20-Nov 6-Dec
Palm Warbler ** 31-Aug 11-Sep 27-Sep 13-Oct 25-Oct
Sharp-shinned Hawk *** 31-Aug 25-Sep 10-Oct – –
Common Yellowthroat NA 1-Sep 15-Sep 25-Sep 9-Oct 14-Oct
Franklin's Gull *** 1-Sep 16-Sep 13-Oct 10-Nov 25-Nov
Indigo Bunting ** 1-Sep 15-Sep 1-Oct 10-Oct 21-Oct
Orange-crowned Warbler ****! 3-Sep 17-Sep 3-Oct 21-Oct 2-Nov

Arriving

Species Begin Arrival Rapid Influx Peak Rapid Depart
White-eyed Vireo * 19-Aug 28-Aug 10-Sep 29-Sep 11-Oct
Brown Thrasher *** 19-Aug 30-Aug 11-Sep 30-Sep 12-Oct
Gray Catbird *** 18-Aug 30-Aug 11-Sep 1-Oct 14-Oct
Swainson's Thrush *** 18-Aug 30-Aug 13-Sep 29-Sep 10-Oct
Black-throated Green Warbler * 17-Aug 1-Sep 19-Sep 7-Oct 22-Oct
Blue-headed Vireo *** 19-Aug 1-Sep 18-Sep 5-Oct 18-Oct
House Wren ** 25-Aug 1-Sep 10-Sep 3-Oct 19-Oct
Cooper's Hawk ** 8-Aug 2-Sep 25-Sep 20-Oct 10-Nov
American Golden-Plover * 6-Aug 3-Sep 27-Sep 23-Oct 19-Nov
Clay-colored Sparrow *** 20-Aug 3-Sep 24-Sep 16-Oct 31-Oct

Peaking

Species Begin Arrival Rapid Influx Peak Rapid Depart
Common Nighthawk *** – – 28-Aug 22-Sep 8-Oct
Ruby-throated Hummingbird *** Before July 1 29-Jul 28-Aug 21-Sep 8-Oct
Blackburnian Warbler * 3-Aug 15-Aug 30-Aug 15-Sep 27-Sep
Canada Warbler * 6-Aug 17-Aug 30-Aug 14-Sep 24-Sep
Northern Waterthrush ** 7-Aug 17-Aug 31-Aug 15-Sep 25-Sep
Red-eyed Vireo *** 11-Aug 19-Aug 31-Aug 19-Sep 2-Oct
Chipping Sparrow *** – – 1-Sep 31-Oct 14-Nov
Common Tern * – – 1-Sep 7-Oct 1-Nov
Yellow-bellied Flycatcher * 6-Aug 17-Aug 1-Sep 17-Sep 28-Sep
Olive-sided Flycatcher *** 9-Aug 19-Aug 2-Sep 18-Sep 29-Sep
Yellow-throated Vireo ** 11-Aug 20-Aug 2-Sep 20-Sep 2-Oct
American Redstart *** 10-Aug 20-Aug 3-Sep 20-Sep 2-Oct
Least Flycatcher *** 8-Aug 19-Aug 3-Sep 20-Sep 3-Oct
Mourning Warbler * 10-Aug 20-Aug 3-Sep 18-Sep 29-Sep
Black-and-white Warbler *** 10-Aug 20-Aug 4-Sep 20-Sep 3-Oct
Ovenbird ** 10-Aug 20-Aug 4-Sep 20-Sep 2-Oct
Rose-breasted Grosbeak ** 12-Aug 22-Aug 4-Sep 25-Sep 10-Oct
Yellow-breasted Chat * 20-Aug 26-Aug 4-Sep 24-Sep 8-Oct

Departing

Species Begin Arrival Rapid Influx Peak Rapid Depart
Prothonotary Warbler * – – Before July 1 30-Aug 24-Sep
Cliff Swallow *** – – Before July 1 2-Sep 25-Sep
Short-billed Dowitcher * Before July 1 6-Jul 7-Aug 2-Sep 4-Oct
Tree Swallow ** – – Before July 1 4-Sep 8-Nov

West

Aside from marginally favorable conditions in intermountain and desert locales on Monday to Wednesday nights that carry locally moderate flights, much of the early part of the forecast period is dominated by unfavorable winds and warm temperatures. By Wednesday night, areas from the Pacific Northwest through the northern Rockies will experience more typically fall like conditions, and moderate flights are likely in these areas. By Thursday night, these conditions expand to cover much of the northern portion of the West, and moderate migration so too will be more widespread.

Lincoln’s Sparrow, ©Ian Davies

Species on the Move

Beginning to Arrive What is this?

Species Begin Arrival Rapid Influx Peak Rapid Depart
Merlin * 29-Aug 13-Sep 22-Dec – –
American Pipit *** 30-Aug 14-Sep 7-Nov – –
Eared Grebe *** 30-Aug 29-Sep 9-Nov 29-Nov 11-Dec
Lincoln's Sparrow *** 30-Aug 13-Sep 5-Oct 22-Oct 8-Nov
Say's Phoebe *** 30-Aug 13-Sep 1-Oct – –
Yellow-rumped Warbler *** 2-Sep 26-Sep 17-Oct 29-Oct 8-Nov
American Wigeon *** 3-Sep 19-Oct 20-Nov 4-Dec 16-Dec
White-crowned Sparrow **** 4-Sep 20-Sep 14-Oct 26-Oct 6-Nov

Arriving

Species Begin Arrival Rapid Influx Peak Rapid Depart
Clay-colored Sparrow * 14-Aug 28-Aug 17-Sep 6-Oct 2-Nov
Pacific-slope Flycatcher ** 19-Aug 28-Aug 12-Sep 4-Oct 20-Oct
Common Yellowthroat *** 17-Aug 29-Aug 16-Sep 9-Oct 28-Oct
Savannah Sparrow *** 13-Aug 29-Aug 27-Sep 21-Oct 9-Nov
Pomarine Jaeger * 20-Jul 30-Aug 25-Sep 22-Oct 14-Nov
Townsend's Warbler *** 12-Aug 30-Aug 30-Sep 27-Oct 10-Nov
Vesper Sparrow ** 17-Aug 30-Aug 15-Sep 3-Oct 17-Oct
Common Tern * 19-Aug 1-Sep 16-Sep 3-Oct 16-Oct
Green-tailed Towhee * 21-Aug 1-Sep 14-Sep 1-Oct 12-Oct
Pectoral Sandpiper ** 17-Aug 1-Sep 20-Sep 11-Oct 28-Oct
Orange-crowned Warbler *** 12-Aug 2-Sep 22-Sep 12-Oct 29-Oct
Turkey Vulture *** 23-Aug 3-Sep 14-Sep 6-Oct 19-Oct
Parasitic Jaeger * 21-Aug 4-Sep 20-Sep 8-Oct 22-Oct
Sabine's Gull * 15-Aug 4-Sep 21-Sep 6-Oct 17-Oct

Peaking

Species Begin Arrival Rapid Influx Peak Rapid Depart
Least Sandpiper *** Before July 1 15-Jul 28-Aug 13-Sep 25-Sep
Short-billed Dowitcher * Before July 1 4-Jul 28-Aug 13-Sep 24-Sep
Baird's Sandpiper ** 30-Jul 13-Aug 29-Aug 15-Sep 29-Sep
Sage Thrasher * – – 29-Aug 24-Sep 20-Oct
Western Sandpiper *** Before July 1 8-Jul 29-Aug 15-Sep 6-Oct
Greater Yellowlegs ** Before July 1 10-Jul 30-Aug 14-Sep 11-Dec
Green Heron * – Before July 1 30-Aug 23-Sep 18-Oct
American Avocet * – Before July 1 31-Aug 28-Sep 20-Oct
Stilt Sandpiper * Before July 1 17-Jul 31-Aug 15-Sep 27-Sep
American White Pelican * Before July 1 17-Aug 1-Sep 26-Sep 11-Dec
Red-necked Phalarope *** 2-Aug 16-Aug 1-Sep 19-Sep 5-Oct
Yellow-headed Blackbird ** 12-Aug 21-Aug 2-Sep 24-Sep 11-Oct
Franklin's Gull * Before July 1 1-Jul 3-Sep 3-Oct 1-Nov
Willow Flycatcher *** 9-Aug 20-Aug 3-Sep 23-Sep 7-Oct
MacGillivray's Warbler *** 8-Aug 19-Aug 4-Sep 23-Sep 7-Oct
Nashville Warbler ** 2-Aug 16-Aug 4-Sep 23-Sep 12-Oct
Northern Waterthrush * 9-Aug 20-Aug 4-Sep 19-Sep 3-Oct

Departing

Species Begin Arrival Rapid Influx Peak Rapid Depart
Yellow-billed Cuckoo * – Before July 1 28-Jul 28-Aug 19-Sep
Upland Sandpiper * 26-Jul 2-Aug 14-Aug 29-Aug 10-Sep
Common Nighthawk ** – – 4-Aug 1-Sep 22-Sep
Black-headed Grosbeak *** – – Before July 1 2-Sep 30-Sep
Eastern Kingbird ** 24-Jul 1-Aug 11-Aug 2-Sep 16-Sep
Grace's Warbler * Before July 1 22-Jul 4-Aug 2-Sep 20-Sep
Broad-tailed Hummingbird *** – Before July 1 28-Jul 3-Sep 26-Sep
Calliope Hummingbird * – Before July 1 27-Jul 3-Sep 23-Sep

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Farnsworth and Van Doren

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