Regional Migration Analysis: 25 August – 1 September 2017

Philadelphia Vireo. Daniel Jauvin/Macaulay Library. eBird S38795447.

Continental Summary

Light to moderate movements were the norm in the West and featured American Wigeon, Northern Pintail, Green-winged Teal, Wilson’s Warbler, Townsend’s Warbler, and Green-tailed Towhee, while moderate to locally heavy flights were common in the East and featured American Golden-Plover, Swainson’s Thrush, Canada Warbler, Nashville Warbler, Bay-breasted Warbler, and Baltimore Oriole. Hurricane Harvey slammed Texas, bringing with it large numbers of Magnificent Frigatebirds and terns.

Curious what birds will move next? Check out our forecast.

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Upper Midwest and Northeast

Moderate to locally heavy movement,s primarily east of the Ohio River Valley, kicked off the weekend. These were followed by similarly intense movements in the Upper Midwest to begin the work week. Gradually these movements spread east, becoming more widespread across the region as the period progressed. By Thursday night moderate to locally heavy flights were apparent from the central Great Lakes east through the Ohio River Valley to the mid Atlantic and southern New England coasts.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Magnolia Warbler 88% 7.3
Tennessee Warbler 86% 5
American Redstart 42% 15.7
Chestnut-sided Warbler 53% 7.5
Blackburnian Warbler 66% 4.2
Common Nighthawk 55% 6.9
Bay-breasted Warbler 109% 1.9
Wilson's Warbler 88% 2.6
Black-throated Green Warbler 62% 4.1
Black-and-white Warbler 40% 10.5
Swainson's Thrush 102% 1.9
Nashville Warbler 64% 3
Blackpoll Warbler 99% 1.5
Least Flycatcher 46% 4.3
American Golden-Plover 77% 1.8
White-breasted Nuthatch 12% 30
Red-eyed Vireo 19% 19.1
Warbling Vireo 37% 6.6
Red-bellied Woodpecker 13% 23
Cape May Warbler 73% 1.8
Blue Jay 8% 46.6
Northern Flicker 14% 20.2
Common Yellowthroat 21% 15.7
Philadelphia Vireo 96% 1
Northern Parula 61% 2.3

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Eastern Kingbird -41% 7.9
Purple Martin -39% 2.8
Indigo Bunting -36% 5.6
Barn Swallow -20% 22.7
Cliff Swallow -37% 1.4
Yellow Warbler -27% 3.7
Red-winged Blackbird -18% 11.9
Yellow-billed Cuckoo -22% 3
Song Sparrow -15% 24.1
Spotted Sandpiper -15% 7.8
Bank Swallow -24% 2.6
Fish Crow -17% 4
Black Tern -30% 0.9
Tree Swallow -11% 13
Sedge Wren -48% 0.4
Blue Grosbeak -21% 2
Baltimore Oriole -9% 9.3
Chipping Sparrow -9% 12.9
Short-billed Dowitcher -16% 3.3
Black-necked Stilt -42% 0.2
Great Black-backed Gull -10% 6.6
Common Grackle -8% 14.2
Swamp Sparrow -22% 1.7

Black Tern. Jane Mann/Macaulay Library. eBird S38800297.

Gulf Coast and Southeast

Hurricane Harvey brought unprecedented and devastating rain, in addition to powerful wind, as it lumbered ashore and then back to the Gulf again before heading north and east over the Mississippi River. Light to moderate movements were the norm in many areas of there Gulf of Mexico region as it came ashore, and its effects were probably farther reaching than they appeared from a bird migration perspective. By Monday night, as the storm moved slowly north and east, moderate and heavy flights followed in its wake over Texas. Some areas of Florida also experienced intense movements. As the system moved farther away from the Gulf, migration intensities stayed more or less constant with moderate to locally heavy flights continuing to the west of the storm and generally more local moderate flights to its east. Note, the species list below includes Hurricane Harvey displaced birds as well as the usual movers.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
American Redstart 54% 7.6
Magnificent Frigatebird 71% 3.3
Black-and-white Warbler 37% 6.3
Northern Parula 28% 8.9
Northern Waterthrush 72% 2.5
Eastern Wood-Pewee 24% 8.7
Hooded Warbler 39% 4
Red-shouldered Hawk 16% 16
Yellow Warbler 21% 8.1
Baltimore Oriole 88% 1.6
Blue-gray Gnatcatcher 13% 21
Canada Warbler 89% 1.3
Bank Swallow 38% 2.8
White-eyed Vireo 15% 12.9
Blue-winged Teal 35% 4.3
Least Flycatcher 59% 1.3
Bald Eagle 25% 3.3
Loggerhead Shrike 15% 6.9
Royal Tern 14% 8.2
Belted Kingfisher 12% 9.7
Black Tern 19% 4.7
Wilson's Warbler 88% 0.7
Sooty Tern 92% 0.8
Yellow-throated Vireo 23% 2.8
Forster's Tern 16% 5.1

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Mississippi Kite -32% 3.8
Indigo Bunting -34% 3.7
Blue Grosbeak -24% 4.8
Black-chinned Hummingbird -29% 2
Upland Sandpiper -50% 0.6
Yellow-billed Cuckoo -23% 4.1
Western Wood-Pewee -80% 0.1
Eastern Towhee -12% 10.9
Western Kingbird -32% 0.9
Chipping Sparrow -19% 3.9
Gull-billed Tern -35% 0.5
Eastern Meadowlark -23% 1.7
Roseate Spoonbill -15% 3.2
American Robin -10% 7.2
Field Sparrow -22% 1.8
White Ibis -6% 12.7
Eastern Bluebird -8% 13.4
Pectoral Sandpiper -15% 4.4
Broad-tailed Hummingbird -64% 0.1
Long-billed Dowitcher -27% 0.7

Swainson’s Thrush. Doris Guimond et Claude Gagnon/Macaulay Library. eBird S38464026.

Great Plains

Scattered light to locally moderate flights gave way to more widespread moderate flights over the first few days of the forecast period. These flights intensified in the southern Plains by Tuesday, but thereafter the region was mostly quiet for the remainder of the period. Note that some of the most intense movements in the southern Plains were associated with the passage to the east of Hurricane Harvey’s remnants.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Wilson's Warbler 101% 8.1
Nashville Warbler 140% 3.4
Warbling Vireo 72% 12.4
American Redstart 72% 7.7
Red-eyed Vireo 45% 13.9
Olive-sided Flycatcher 67% 6.8
Least Flycatcher 54% 8.3
Chestnut-sided Warbler 108% 3.1
Black-and-white Warbler 81% 4.2
Brown Thrasher 44% 10.8
Red-shouldered Hawk 50% 7.3
Roseate Spoonbill 115% 2.5
Ovenbird 93% 2.8
Blue-headed Vireo 117% 1.8
Swainson's Thrush 135% 1.6
Tennessee Warbler 100% 2.2
Baltimore Oriole 22% 17.1
Canada Warbler 99% 2
Downy Woodpecker 15% 24.6
Magnolia Warbler 97% 1.7
Gray Catbird 21% 11
Bald Eagle 31% 7.9
Red-bellied Woodpecker 14% 16.3
Yellow-bellied Flycatcher 88% 1.4

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Forster's Tern -61% 1.4
Purple Martin -71% 1.2
Western Kingbird -61% 2.4
Cliff Swallow -44% 4.2
Black Tern -54% 1.5
Eastern Kingbird -26% 17.4
Wilson's Phalarope -66% 0.7
Sedge Wren -45% 1.7
Indigo Bunting -37% 6
Pectoral Sandpiper -39% 3.1
Chimney Swift -22% 7.2
Lark Bunting -86% 0.1
Song Sparrow -29% 3.2
Mallard -14% 13.1
Barn Swallow -10% 32
Tree Swallow -29% 2.7
Wilson's Snipe -72% 0.3
Western Meadowlark -25% 5.2
White-winged Dove -46% 1
Lark Sparrow -27% 3.3
Upland Sandpiper -42% 1.4
Scissor-tailed Flycatcher -21% 4.7
Least Tern -87% 0.1
Greater Yellowlegs -23% 2.8

Northern Pintail. DigiBirdTrek/Macaulay Library. eBird S38846363.

West

Light and moderate flights were the norm around the region for the period, despite some widely scattered precipitation in the mountainous regions of the West. Some of these flights were more intense, particularly to begin the period in the southern Rockies and to end the period in the northern Rockies and Great Basin.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Wilson's Warbler 25% 13.5
American Wigeon 57% 2.9
Killdeer 13% 20.8
Green-winged Teal 23% 5.3
Orange-crowned Warbler 16% 7.9
Northern Pintail 29% 3.4
Northern Shoveler 18% 5.2
Black Phoebe 9% 18
Mallard 7% 27.6
Song Sparrow 10% 20.9
Gadwall 15% 5
Warbling Vireo 16% 4.9
Cooper's Hawk 11% 7.6
Townsend's Warbler 22% 2.4
Common Yellowthroat 9% 10
Sanderling 18% 1.8
Green-tailed Towhee 18% 2.1

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Cliff Swallow -44% 2.7
Eastern Kingbird -39% 1.8
Western Wood-Pewee -26% 7.7
Rufous Hummingbird -23% 4.9
Tree Swallow -29% 2.5
Pigeon Guillemot -36% 1.3
Bullock's Oriole -31% 1.6
Cassin's Sparrow -76% 0.1
Baird's Sandpiper -27% 2.3
Common Nighthawk -27% 1.6
Northern Rough-winged Swallow -23% 2.6
Black-headed Grosbeak -16% 5.8
Barn Swallow -7% 23.9
Brown-headed Cowbird -21% 3
Turkey Vulture -9% 19.1
Bald Eagle -19% 2.7
Western Kingbird -11% 6.6
Black-bellied Plover -25% 1.5
Red Crossbill -24% 1.5
Mountain Chickadee -10% 7.4
Red-faced Warbler -80% 0

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Farnsworth and Van Doren

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