Regional Migration Analysis: 5-19 May 2017

Acadian Flycatcher. Tyler Flicker/Macaulay Library. eBird S36894510.

Continental Summary

BirdCast regional analyses return after our global big day absence! Widespread light and moderate to locally heavy flights characterized the first days of this long forecast period in the West and featured Willow Flycatcher, Dusky Flycatcher, Western Wood-Pewee, Swainson’s Thrush, MacGillivray’s Warbler, Yellow Warbler, and Black-headed Grosbeak, while  moderate to very heavy flights occurred in the latter two thirds of the two-week period in the East, first in the Plains and then farther to the coasts, featuring Alder Flycatcher, Yellow-bellied Flycatcher, Philadelphia Vireo, Bay-breasted Warbler, Magnolia Warbler, Canada Warbler, and Wilson’s Warbler.

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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 strong frontal passage in the first days of the period kept most migrants on the ground away from the Upper Midwest, where locally moderate to heavy flights persisted. These flights intensified in the days that followed, building into the Ohio River valley by 8-9 May. These flights never became widespread across the region, as another frontal passage kept birds on the ground in precipitation as it passed 10-12 May. However, some locally intense flights continued around the region during this passage, in particular in coastal and Great Lakes locations. The passage of this strong low pressure system through the Northeast kept a set of primarily unfavorable and marginal migration condition in place there, while the remainder of the region experienced moderate to heavy flights through 15-16 May. It was not until 16-17 May that more extensive intense movements reached areas of the coast and New England. By the end of the period, locally moderate and isolated heavy flights were scattered across the region as more marginal conditions with precipitation filled into many areas of the region.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Magnolia Warbler 1062% 16.4
Eastern Wood-Pewee 1449% 13.7
Chestnut-sided Warbler 691% 16.6
Least Flycatcher 670% 12
Blackburnian Warbler 750% 10.7
American Redstart 203% 29.6
Tennessee Warbler 695% 10
Wilson's Warbler 21894% 7.1
Red-eyed Vireo 185% 26.1
Bay-breasted Warbler 2329% 6.3
Swainson's Thrush 251% 13
Canada Warbler 8689% 4.8
Indigo Bunting 148% 18.4
Scarlet Tanager 166% 19.5
Nashville Warbler 190% 14.2
Philadelphia Vireo 3337% 2.1
Ruby-throated Hummingbird 189% 12.6
Great Crested Flycatcher 127% 24.1
Acadian Flycatcher 406% 4
Rose-breasted Grosbeak 109% 26.6
Common Yellowthroat 99% 38.9
Warbling Vireo 109% 23.2
Blackpoll Warbler 284% 9.3

Decreasing

Species Decrease from Last Week % of Checklists Reporting
White-throated Sparrow -59% 12.9
Greater Yellowlegs -59% 2.7
Blue-winged Teal -61% 2.3
Ruby-crowned Kinglet -46% 8.3
Solitary Sandpiper -53% 3.6
Lesser Yellowlegs -57% 2.7
Bufflehead -83% 0.5
Yellow-rumped Warbler -26% 23.6
Swamp Sparrow -30% 7.3
Tufted Titmouse -15% 29.9
Palm Warbler -28% 8.9
Hermit Thrush -40% 2.8
Northern Shoveler -56% 1.2
Belted Kingfisher -27% 6.4
Carolina Wren -18% 15.9
Purple Finch -37% 3
Sharp-shinned Hawk -53% 0.9
Dark-eyed Junco -50% 2
Lesser Scaup -74% 0.4
Eastern Towhee -16% 17.2
Pectoral Sandpiper -56% 0.7
Louisiana Waterthrush -33% 2.7
Osprey -21% 8.4
American Coot -41% 1.9
Horned Grebe -77% 0.2

Yellow-bellied Flycatcher. Sandy Aubol/Macaulay Library. eBird S36948706.

Gulf Coast and Southeast

Moderate to heavy flights dominated the migration scene for the first 5-6 nights of the period, in particular to the west of the Mississippi River. A frontal passage around 12-13 May quieted these flights, and generally slowed movements across the region. This frontal passage was intense and extensive, muting trans-Gulf flights for the days that followed in the central Gulf of Mexico region in particular. This was perhaps most noticeable in the distribution of nocturnal flights from 14-19 May, for example the lower magnitude flights in portions of the central and eastern Gulf states. By the end of the period, most of the action, which was represented by moderate intensity flights, was in Texas and Peninsular Florida.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Yellow-billed Cuckoo 65% 13.2
Acadian Flycatcher 61% 6.4
Red-headed Woodpecker 41% 6.2
Canada Warbler 68% 2.7
Eastern Wood-Pewee 19% 12.3
Spotted Sandpiper 16% 8.9
White-rumped Sandpiper 26% 2.6
Yellow-bellied Flycatcher 73% 0.6
Green Heron 6% 11.8
Little Blue Heron 6% 10
Olive-sided Flycatcher 24% 0.8
Prothonotary Warbler 10% 4.9
Black Skimmer 11% 2.5

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Rose-breasted Grosbeak -87% 1.7
Baltimore Oriole -90% 1
Nashville Warbler -98% 0.1
Tennessee Warbler -84% 1.2
Black-and-white Warbler -62% 4.9
Palm Warbler -90% 0.4
Scarlet Tanager -60% 4
Gray Catbird -51% 9.4
Yellow-rumped Warbler -84% 1.1
Lincoln's Sparrow -96% 0.1
Lesser Yellowlegs -64% 2
Ovenbird -54% 3.5
Bay-breasted Warbler -73% 1.1
Northern Waterthrush -61% 2
Black-throated Green Warbler -55% 3.3
Laughing Gull -35% 10.7
Savannah Sparrow -77% 0.7
White-crowned Sparrow -93% 0.1
Blue-winged Teal -57% 2.5
White-throated Sparrow -87% 0.3
Ruby-crowned Kinglet -96% 0.1
Willet -50% 3
Long-billed Dowitcher -77% 0.5

Philadelphia Vireo. David McQuade/Macaulay Library. eBird S36833439.

Great Plains

A series of moderate to heavy flights from 5-8 May kicked off this period, with the most intense and extensive movements on 6-7 May. More local moderate to heavy flights continued thereafter, mostly in the northern and central Plains, particularly on 12-13 May. Similarly intense and local flights continued through much of the remainder of the period. But 17-19 May saw a noticeable decline in intensities and extents as strong storms passed through the region, shutting down movements where they passed.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Blackpoll Warbler 1179% 11.7
American Redstart 915% 13.5
Orchard Oriole 444% 19.8
Eastern Wood-Pewee 686% 14.9
Yellow Warbler 299% 42.4
Least Flycatcher 343% 20
Black Tern 1063% 6.6
Red-eyed Vireo 277% 21.4
Tennessee Warbler 484% 12.6
Gray Catbird 235% 22.4
Baltimore Oriole 163% 37
Philadelphia Vireo 1786% 3.4
Swainson's Thrush 148% 29.8
Yellow-billed Cuckoo 739% 4.4
Magnolia Warbler 3278% 2.9
Eastern Kingbird 115% 31.5
Cedar Waxwing 192% 15.6
Acadian Flycatcher 1014% 3.5
Chestnut-sided Warbler 1409% 3.4
Alder Flycatcher 48923% 2.2
Western Kingbird 132% 23.1
Great Crested Flycatcher 123% 23.4
Ovenbird 509% 3.9
Black-headed Grosbeak 1010% 3.2
Wilson's Warbler 535% 5

Decreasing

Species Decrease from Last Week % of Checklists Reporting
White-crowned Sparrow -84% 3.1
White-throated Sparrow -84% 2.1
Lincoln's Sparrow -82% 2.9
Harris's Sparrow -79% 2.9
Ruby-crowned Kinglet -85% 1.4
Orange-crowned Warbler -76% 3.9
Franklin's Gull -78% 2.9
Yellow-rumped Warbler -63% 10.9
Savannah Sparrow -75% 2.9
Lesser Yellowlegs -73% 3.6
Pied-billed Grebe -67% 3.8
Osprey -88% 0.4
Long-billed Dowitcher -69% 2.3
Greater Yellowlegs -70% 1.8
Forster's Tern -62% 3.5
Solitary Sandpiper -75% 0.9
Double-crested Cormorant -50% 6.9
Ring-billed Gull -52% 4.4
American Coot -44% 8.5
Bufflehead -82% 0.5
Lesser Scaup -59% 1.9
Baird's Sandpiper -51% 2.7
Ruddy Duck -48% 3.2
Eared Grebe -53% 1.9
Great Blue Heron -22% 18.6

Swainson’s Thrush. Tony Varela/Macaulay Library. eBird S36893060.

West

Moderate to locally heavy flights occurred from 5-7 May, particularly from California and the Desert Southwest east and north along the Rockies. These flights shut down as widespread precipitation created much less favorable conditions, with largely light to locally moderate flights in the days that followed. California and Montana were exceptions, as more intense flights continued in those locations. By 11-12 May light to moderate flights were apparent, primarily in the Desert Southwest. But following these movements conditions were generally much less favorable for flights, with precipitation and unfavorable winds keeping migrants grounded in many areas. Light to locally moderate flights persisted in some locations through the period, especially in California and in portions of the Desert Southwest and northern and southern Rockies.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Western Wood-Pewee 359% 13.2
Yellow Warbler 127% 24.2
Swainson's Thrush 236% 6.1
Black-headed Grosbeak 58% 23.3
Yellow-breasted Chat 104% 5.8
MacGillivray's Warbler 132% 4.1
Cliff Swallow 44% 18
Willow Flycatcher 7463% 1.5
Western Kingbird 42% 16.4
Warbling Vireo 44% 11.8
Olive-sided Flycatcher 83% 3.3
Dusky Flycatcher 82% 3.2
Western Meadowlark 18% 16
Cedar Waxwing 37% 5.8
Bank Swallow 58% 3.2
Northern Rough-winged Swallow 17% 13.7
Horned Lark 19% 4.3
Chipping Sparrow 15% 9.5

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Western Sandpiper -89% 0.5
Bufflehead -84% 1
Golden-crowned Sparrow -89% 0.6
Semipalmated Plover -97% 0.1
Dunlin -96% 0.1
Yellow-rumped Warbler -41% 11.7
Green-winged Teal -64% 2.1
Orange-crowned Warbler -35% 9.6
Marbled Godwit -79% 0.5
Nashville Warbler -69% 1.1
Least Sandpiper -103% -0.1
Long-billed Dowitcher -64% 1.3
Ruby-crowned Kinglet -54% 2.6
American Wigeon -60% 2.1
Black-throated Gray Warbler -46% 3.3
Ruddy Duck -35% 4.9
American Coot -26% 10.6
Greater Yellowlegs -69% 0.7
Whimbrel -57% 1.2
White-faced Ibis -44% 2.3
Black-bellied Plover -70% 0.5
Western Grebe -32% 4.5
Eared Grebe -30% 4.1
Surf Scoter -49% 1.3
Canada Goose -11% 24.5

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Farnsworth and Van Doren

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