Project Update: Looking ahead

Andrew Farnsworth The Cornell Lab Aug 11, 2017

Next Friday, BirdCast begins its official Fall 2017 season of weekly forecast and analysis reports. But like last week, we are posting a pre-flight forecast before the flights soon to come! Additionally, we will be introducing new members of Team BirdCast, some new visualizations, and of course discussions of any interesting patterns we see (or hear).

Olive-sided Flycatcher. Miriam Baril/Macaulay Library. eBird S38576396.

Marginal migration conditions that begin the week will gradually give way to more favorable conditions for light to moderate flights in many areas of the West, while the East will experience pulses of moderate flights in the central Mississippi River Valley, the northern Great Plains, and much of the Northeast during the first half of the period.

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

A frontal passage brings favorable migration conditions to the Great Lakes and Ohio River Valley over the weekend, where locally moderate to isolated heavy flights will occur. These migration conditions generally deteriorate with a return warm and moist conditions, keep most flights local and generally light to moderate. New England and the northern Appalachians experience a pulse of moderate flights by mid week, as northerly and northwesterly flow bring new arrivals. Note in particular the favorable conditions for birds to take flight over the ocean in coastal New England, suggesting birders should avail themselves of coastal viewing points to observe morning flight.

Top Movers


Species Increase from Last Week % of Checklists Reporting
Lesser Yellowlegs 23% 8.6
American Redstart 26% 6
Baltimore Oriole 22% 8.8
Chimney Swift 13% 19.1
Black-bellied Plover 46% 2.9
Caspian Tern 20% 6.4
Ruby-throated Hummingbird 11% 22
Cooper's Hawk 24% 4
Semipalmated Plover 13% 8.9
Ring-billed Gull 9% 19.5
Greater Yellowlegs 17% 6.5
Black-and-white Warbler 24% 3.7
Blue-gray Gnatcatcher 11% 9.5
Olive-sided Flycatcher 102% 0.3
Eastern Wood-Pewee 7% 18.8
American Golden-Plover 294% 0.1
Semipalmated Sandpiper 11% 9.5
Red-shouldered Hawk 19% 2.8
Least Sandpiper 9% 11.3
Wood Duck 8% 13
Wilson's Phalarope 45% 0.5
Blue-winged Teal 17% 1.6
Pectoral Sandpiper 14% 4.9

Gulf Coast and Southeast

Aside from a local pulse of moderate flights in the lower Mississippi River Valley and another in the central and southern Appalachians in the first half of the period, the region will generally experience conditions that are unfavorable for migration and see isolated light to moderate flights. Note, however, an interesting forecast for Friday in the coastal Southeastern US, where a frontal boundary pushes off the coast, slowly, with favorable flight conditions over the Atlantic; birders along the immediate coast should watch for local concentrations of birds (shorebirds and passerines) that may encounter unfavorable conditions over water and make brief stopovers along the coast.

Wilson’s Phalarope. Suzanne Zuckerman/Macaulay Library. eBird S38487756.

Top Movers


Species Increase from Last Week % of Checklists Reporting
Yellow Warbler 57% 3.2
Pectoral Sandpiper 19% 5.8
Rufous Hummingbird 85% 0.7
Belted Kingfisher 13% 7.6
Black-throated Sparrow 61% 0.9
Ruby-throated Hummingbird 7% 19.4
Olive-sided Flycatcher 216% 0.2
Semipalmated Plover 9% 5.5
Red-headed Woodpecker 10% 4
Yellow-throated Vireo 17% 1.8
Red-shouldered Hawk 3% 11.6

Great Plains

Locally moderate flights begin and end the period, particularly in the northern and central Plains, where favorable conditions for migration, though short-lived, will spawn such flights. The remainder of the period will see most areas of the region experience unfavorable conditions, including areas of precipitation. Birders in these areas should watch closely, particularly in wetlands, for concentrations of shorebirds. This will be especially true in the southern Plains from Monday through Wednesday.

Northern Waterthrush. Tom Forwood, Jr./Macaulay Library. eBird S38578255.

Top Movers


Species Increase from Last Week % of Checklists Reporting
Olive-sided Flycatcher 394% 1.4
Northern Harrier 62% 6
Swainson's Hawk 60% 6.2
Forster's Tern 53% 5
Loggerhead Shrike 56% 3.6
Rose-breasted Grosbeak 104% 1.8
Great Egret 18% 15.5
Bullock's Oriole 122% 1.5
Ruby-throated Hummingbird 18% 14
Eastern Wood-Pewee 21% 10.8
Eastern Towhee 34% 3.7
Least Flycatcher 59% 2.6
Wood Thrush 101% 1.3
Cooper's Hawk 22% 5.3
American Kestrel 18% 9.7
Bald Eagle 29% 4
Common Raven 207% 0.6
Lark Bunting 47% 2.9
Pied-billed Grebe 18% 6.1
American Golden-Plover 666% 0.2
Western Grebe 69% 1.5
Northern Waterthrush 471% 0.2


Locally favorable migration conditions come to the Pacific Northwest and portions of the northern Rockies to begin the period, and light to moderate flights will be apparent where these conditions occur. Wednesday night will see the greatest extents of nocturnal flights, with reasonably widespread  light to moderate flights.

Red-necked Phalarope. Petra Clayton/Macaulay Library. eBird S38449548.

Top Movers


Species Increase from Last Week % of Checklists Reporting
Baird's Sandpiper 90% 3.3
Red-necked Phalarope 108% 2.8
Least Sandpiper 36% 10.3
Wilson's Warbler 38% 5.4
Greater Yellowlegs 34% 8.5
Lesser Yellowlegs 48% 4.3
Western Sandpiper 32% 9.3
Northern Shoveler 51% 2.7
Green-winged Teal 47% 2.1
Northern Harrier 24% 3.5
Belted Kingfisher 12% 8.1
Yellow Warbler 14% 10.9
Turkey Vulture 8% 20.6
Cinnamon Teal 18% 4
Black-throated Gray Warbler 24% 2.7
Northern Pintail 36% 1.2
Pied-billed Grebe 12% 8
Orange-crowned Warbler 15% 4.5
American Coot 10% 9.4
Green Heron 14% 4.7
Nashville Warbler 31% 1.2
Ring-billed Gull 11% 6.5


Farnsworth and Van Doren