Forecast and Analysis

Regional Migration Analysis: 1-8 September 2017

Andrew Farnsworth The Cornell Lab Sep 08, 2017

Blackpoll Warbler. Frank King/Macaulay Library. eBird S39030232.

Continental Summary

Light to locally heavy flights, particularly in the first half of the period, occurred in the West and featured Common Loon, Black-bellied Plover, Say’s Phoebe, Swainson’s Thrush, White-crowned Sparrow, and Lincoln’s Sparrow, while numerous moderate to heavy flights featuring Gray-cheeked Thrush, Swainson’s Thrush, Blackpoll Warbler, Tennessee Warbler, Orange-crowned Warbler, Wilson’s Warbler, and Lincoln’s Sparrow were the norm across the East following the passages of a significant frontal boundary.

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Quick Links to Regions

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BirdCast West Region

Upper Midwest and Northeast

A disturbance passing at the beginning of the period left a complex distribution of light to heavy flights across the region. But a more organized frontal passage on Monday brought favorable migration conditions in its wake, first to the Upper Midwest where moderate to heavy flights followed. As this front pushed to the east on Tuesday, the distribution of these flights shifted into the Ohio River valley and were apparent in many areas to the west of the Appalachians. By Wednesday and Thursday as the front pushed to the coast, widespread moderate and locally heavy flights continued in some areas west of the Appalachians, mostly on Wednesday night; additional local moderate and heavy flights were scattered to the east of the Appalachians in the coastal plain as well, including flights occurring in precipitation associated with the boundary of the front in New England on Wednesday night and then along the immediate coast on Thursday night.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Swainson's Thrush 179% 6.9
Blackpoll Warbler 151% 5
Magnolia Warbler 61% 13.7
Palm Warbler 247% 2.5
Nashville Warbler 70% 5.8
Bay-breasted Warbler 97% 4.6
Tennessee Warbler 60% 8.4
Northern Parula 65% 4.7
American Redstart 26% 20.6
Gray-cheeked Thrush 465% 1
Black-throated Green Warbler 48% 6.9
Philadelphia Vireo 91% 2.1
Cape May Warbler 62% 3.7
Warbling Vireo 31% 8.9
Canada Goose 16% 29.5
Wilson's Warbler 38% 3.7
White-eyed Vireo 40% 3.4
Black-throated Blue Warbler 51% 2.8
Common Yellowthroat 14% 18.3
Red-bellied Woodpecker 11% 25.5
Golden-winged Warbler 67% 1.6
Blue Jay 7% 49.9
Scarlet Tanager 30% 3.7
Lincoln's Sparrow 136% 0.5
Merlin 36% 2.7

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Eastern Kingbird -54% 3.8
Baltimore Oriole -50% 4.3
Least Sandpiper -32% 7.6
Barn Swallow -26% 17.2
Spotted Sandpiper -28% 5.4
Semipalmated Sandpiper -23% 7.9
Solitary Sandpiper -28% 3.6
Bank Swallow -47% 1.4
Semipalmated Plover -19% 8
Common Grackle -17% 11.6
Mourning Dove -10% 43
Baird's Sandpiper -49% 1
Killdeer -13% 14.8
Lesser Yellowlegs -16% 8.2
Yellow-billed Cuckoo -35% 1.9
Pectoral Sandpiper -22% 4.1
Purple Martin -32% 2.1
Canada Warbler -32% 2.3
Field Sparrow -25% 3.6
Brown-headed Cowbird -25% 2.9
Chipping Sparrow -11% 11.4
Red-winged Blackbird -11% 10.9
Stilt Sandpiper -27% 2.4
Blue-gray Gnatcatcher -13% 9.2
Green Heron -12% 8.8

Baltimore Oriole. James Rieman/Macaulay Library. eBird S38987384.

Gulf Coast and Southeast

Scattered moderate flights were the norm for the first half of the period, as birds moved in marginal migration conditions in advance of an approaching frontal boundary. When this boundary advanced into the region on Wednesday, moderate and heavy flights occurred. These were primarily in northern and central Texas on Tuesday night, followed by more extensive flights from Texas through southern Appalachia and the Florida Panhandle on Wednesday night. By Thursday night the intensity and extent  of these flights moderated, with primarily moderate to locally heavy flights in coastal areas, the southern Appalachians, in the Carolinas.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
White-eyed Vireo 38% 18.5
Baltimore Oriole 131% 4.1
Blue-winged Teal 57% 7.5
Eastern Phoebe 38% 11.9
Wilson's Warbler 164% 2.9
Blue Jay 21% 47.9
Summer Tanager 38% 9.4
Tennessee Warbler 232% 1.4
Common Yellowthroat 59% 4.5
Magnolia Warbler 140% 1.3
Chimney Swift 22% 14.9
Brown Thrasher 25% 9
Northern Flicker 38% 5.1
Yellow-throated Vireo 41% 4.2
Scissor-tailed Flycatcher 32% 5.7
Yellow-breasted Chat 75% 1.6
Northern Shoveler 59% 1.8
Belted Kingfisher 20% 12.5
Blue-gray Gnatcatcher 17% 25.1
American Crow 14% 33.8
Pine Warbler 23% 8.1
Northern Mockingbird 13% 36.2

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Magnificent Frigatebird -79% 0.5
Purple Martin -47% 2.4
Least Tern -50% 1.6
Mississippi Kite -39% 2.4
Laughing Gull -16% 11.6
Black Tern -28% 3.1
Wilson's Plover -39% 0.9
Osprey -11% 12.5
Black Skimmer -19% 2.6
Tricolored Heron -13% 7.5
Neotropic Cormorant -22% 2.1
Anhinga -12% 7.8
White Ibis -11% 11.5
Eastern Kingbird -13% 6.6
Say's Phoebe -76% 0.1
Willet -13% 5.6
Sanderling -13% 4.8
Cattle Egret -11% 7

Orange-crowned Warbler. Nick Saunders/Macaulay Library. eBird S39013337.

Great Plains

Moderate to locally heavy flights gradually spread from the north across the Plains for the first half of the period, reaching their greatest extent on Tuesday. By Tuesday night, most of the action was occurring in the southern Plains, where moderate to locally heavy flights occurred while more northern locations saw mostly light movements. As less favorable wind conditions spread through the region, and the effects of the earlier passage of the frontal boundary faded, Wednesday and Thursday nights saw markedly lower migration traffic across the entire region.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Orange-crowned Warbler 467% 5.6
Lincoln's Sparrow 315% 4.5
Swainson's Thrush 169% 5.5
Nashville Warbler 121% 6.9
Pied-billed Grebe 66% 11.2
Franklin's Gull 74% 10.2
Tufted Titmouse 57% 14
Yellow-rumped Warbler 286% 3
Clay-colored Sparrow 104% 5.2
House Wren 52% 14
Osprey 140% 4.1
Philadelphia Vireo 163% 2.9
Hairy Woodpecker 53% 11.8
Blue-headed Vireo 111% 4.2
Canada Goose 40% 24.6
White-throated Sparrow 258% 2
Yellow Warbler 39% 13.9
Purple Finch 210% 2
White-breasted Nuthatch 32% 19.8
Northern Parula 90% 3.6
Blackpoll Warbler 190% 1.8
Cedar Waxwing 38% 11.9
Pine Siskin 74% 3.6
American Wigeon 199% 1.8
Northern Flicker 30% 17.4

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Mississippi Kite -62% 4.7
Baltimore Oriole -43% 8.3
Bald Eagle -50% 3.3
Northern Mockingbird -44% 6.1
Dickcissel -49% 2.2
Eastern Kingbird -32% 11.9
Bank Swallow -52% 1.8
Eastern Meadowlark -46% 1.8
Spotted Sandpiper -34% 3.5
Barn Swallow -17% 27.3
Cliff Swallow -34% 3.5
Green Heron -33% 3.2
Grasshopper Sparrow -90% 0.1
Yellow-headed Blackbird -34% 2.7
Black Tern -47% 1.1
Field Sparrow -29% 3.1
American Avocet -30% 3
Brown-headed Cowbird -25% 3.6
Red-winged Blackbird -14% 11.5
White-winged Dove -42% 0.8
Blue Grosbeak -36% 1.6
Snowy Egret -21% 5.4
Sedge Wren -39% 1.3

Lincoln’s Sparrow. Good Smith/Macaulay Library. eBird S39037644.

West

The region experienced light to moderate flights in many areas to kickoff the weekend, particularly in the vicinity of the Rockies where intensities were higher. These flights continued through the beginning of the work week, but a disturbance moving through the region and associated scattered precipitation slowed and stopped migration traffic. This was particularly true in the western half of the region, although the entirety of the West saw significantly lower migration intensities in flights during the second half of the period. Some locally more intense flights persisted to the end of the work week, for example in the Central Valley of California.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
White-crowned Sparrow 45% 10.1
Lincoln's Sparrow 89% 3.1
Orange-crowned Warbler 31% 11
Northern Mockingbird 36% 9.2
Savannah Sparrow 36% 8.3
Western Tanager 29% 11.6
Black Phoebe 23% 21.8
Say's Phoebe 38% 5.8
Common Yellowthroat 23% 12.5
Wilson's Warbler 22% 16.3
Swainson's Thrush 37% 3
Song Sparrow 19% 24.7
Common Loon 57% 1.8
House Wren 21% 12.9
Brown Pelican 28% 7.3
Warbling Vireo 27% 6.7
Black-bellied Plover 38% 2.7
Ruby-crowned Kinglet 37% 2.5
Belted Kingfisher 18% 12.5
Marbled Godwit 27% 3.7
Willow Flycatcher 24% 3.7

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Eastern Kingbird -47% 1
Common Nighthawk -45% 0.9
Red-necked Phalarope -30% 1.9
Lesser Yellowlegs -18% 3.3
Rufous Hummingbird -14% 4.7
Northern Rough-winged Swallow -21% 2.2
Black-headed Grosbeak -13% 5.4
Mountain Chickadee -10% 7.2
Brown Creeper -14% 3.9
Swainson's Hawk -12% 3.9
Purple Martin -21% 1.2
Osprey -7% 9.1
Bullock's Oriole -20% 1.3
Cliff Swallow -14% 2.6
Violet-green Swallow -12% 3.8
Olive-sided Flycatcher -17% 1.5
Barn Swallow -3% 23.1
American White Pelican -11% 4.2
Ash-throated Flycatcher -22% 0.8
Western Kingbird -7% 6

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Farnsworth and Van Doren

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