Forecast and Analysis

24-30 April Migration Analysis

Andrew Farnsworth The Cornell Lab Apr 30, 2015

Black-throated Green Warbler © Ian Davies

Black-throated Green Warbler © Ian Davies

Continental Summary

Moderate movements, particularly in the latter half of the period from California and the Desert Southwest, included Spotted Sandpiper, Wilson’s Phalarope, Olive-sided Flycatcher, Western Wood-Pewee, Swainson’s Thrush, Yellow-breasted Chat, Western Tanager, and Black-headed Grosbeak in the West, while the migration machine kicked into a higher gear with moderate to heavy flights in the East that included Least Flycatcher, Philadelphia Vireo, Veery, Mourning Warbler, Bay-breasted Warbler, Black-throated Green Warbler, Yellow-breasted Chat, Rose-breasted Grosbeak, Dickcissel, Orchard Oriole, and Baltimore Oriole.

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

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 wave of cooler temperatures in the region kept a lid on migration for much of the period. Light to moderate movements were scattered locally across Great Lakes and Mississippi and Ohio River valleys early, with even more widely scattered light movements in New England during this window of time. By Tuesday and Wednesday, more moderate flights were apparent in the mid Atlantic states and into New England, but these events never expanded far beyond these areas. Although New York, New Jersey, and portions of New England saw some of these moderate flights to end the period, another weak disturbance passing through the Appalachians had already shut down or inhibited most movements elsewhere. A bit farther afield, some interesting European migrants appeared close to or just into the North American realm, including a Eurasian Hobby, European Golden-Plovers, and Black-tailed Godwit.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Yellow Warbler 114% 11.4
Gray Catbird 111% 8.7
Baltimore Oriole 328% 3.3
Wood Thrush 143% 5.2
Black-throated Green Warbler 209% 3.8
Great Crested Flycatcher 122% 4.3
Rose-breasted Grosbeak 308% 2.4
Orchard Oriole 154% 3.1
Chimney Swift 65% 10.8
Warbling Vireo 78% 4.6
Ovenbird 84% 5.4
Red-eyed Vireo 72% 4.9
Black-and-white Warbler 63% 7.1
House Wren 52% 12.7
Ruby-throated Hummingbird 78% 4.1
Northern Waterthrush 94% 2.6
American Redstart 122% 1.8
Eastern Kingbird 68% 4.6
Indigo Bunting 79% 2.5
Blue-headed Vireo 55% 5.4
Spotted Sandpiper 50% 5.2
Scarlet Tanager 90% 2.1
Common Yellowthroat 40% 8.3
Nashville Warbler 120% 1.2
Yellow-breasted Chat 258% 0.7

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Ring-necked Duck -28% 3.9
Fox Sparrow -39% 0.6
Dark-eyed Junco -18% 11.8
American Tree Sparrow -32% 1.2
Common Merganser -27% 3.3
American Black Duck -24% 2.8
American Wigeon -28% 1.4
Hooded Merganser -25% 3.2
Tundra Swan -84% 0
Bufflehead -14% 7.4
Horned Grebe -27% 3.1
Greater Scaup -37% 0.7
Green-winged Teal -14% 4.6
Common Goldeneye -37% 0.6
Gadwall -16% 3.4
Pied-billed Grebe -13% 6.4
Common Loon -21% 5.1
Northern Gannet -29% 0.3
Canvasback -37% 0.4
Northern Shoveler -12% 5.3
Snowy Owl -74% 0
Little Gull -69% 0
American Coot -10% 7.1
Long-tailed Duck -26% 0.6

Bay-breasted Warbler © Ian Davies

Bay-breasted Warbler © Ian Davies

Gulf Coast and Southeast

Widespread moderate to heavy migration took place, particularly on Saturday night along the entire Gulf Coast, as many concentrated and grounded birds and arriving trans-Gulf migrants took flight. This intensity and extent of migration did not continue unabated far into the work week, with a strong low pressure center ushering a wave of unfavorable conditions on Tuesday and Wednesday for all areas away from Florida and the southeastern coastal plain. With its departure and high pressure prevailing and moving east, moderate movements returned to much of the region on Wednesday night and increased in intensity for most of the region on Thursday night.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Magnolia Warbler 117% 7.5
Bay-breasted Warbler 126% 4
Chestnut-sided Warbler 46% 7.2
Veery 74% 4.2
Least Flycatcher 105% 2.6
Yellow Warbler 34% 10.8
American Redstart 33% 13.6
Dickcissel 36% 6.2
Blackpoll Warbler 29% 7.5
Philadelphia Vireo 60% 2.7
Bobolink 70% 2.2
Wilson's Warbler 114% 1.8
Western Tanager 199% 0.8
Black-throated Blue Warbler 27% 6.8
Western Kingbird 36% 5.4
Spotted Sandpiper 23% 9.3
Mississippi Kite 31% 3.5
Mourning Warbler 827% 0.4
White-rumped Sandpiper 67% 1
Rose-breasted Grosbeak 14% 14.8
Gray-cheeked Thrush 35% 3.2
Canada Warbler 51% 1.5
Eastern Wood-Pewee 17% 8.7
Ovenbird 19% 10.2

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Cerulean Warbler -54% 1.1
Sora -37% 1.8
Worm-eating Warbler -34% 3.8
Black Skimmer -39% 2
Forster's Tern -28% 4.1
Willet -24% 6.8
Red-breasted Merganser -42% 0.8
Pied-billed Grebe -31% 3.6
Brown Pelican -21% 7.9
Orange-crowned Warbler -31% 2
Short-billed Dowitcher -31% 2.1
Northern Harrier -47% 0.7
Yellow-bellied Sapsucker -78% 0.2
American White Pelican -35% 1.6
American Avocet -33% 1.7
Marbled Godwit -38% 0.9
Laughing Gull -18% 14.9
Sanderling -24% 3.2
Ruddy Turnstone -28% 3.6
Snowy Egret -17% 11.1
American Coot -19% 7.6
Dunlin -24% 2.6
Royal Tern -20% 5.7

Swainson's Thrush © Ryan Schain

Swainson’s Thrush © Ryan Schain

Great Plains

A patchwork of light to moderate movements peppered the region for the first half of the forecast period, with weak disturbances and associated precipitation grounding birds in some areas. However, with the departure of these conditions to the east, Tuesday night saw the beginnings of more regional light to moderate flights. By Wednesday night migration had increased to more moderate levels in more areas, particularly in the southern Plains. And despite an approaching frontal boundary moving across the northern Plains, moderate to locally heavy movements bloomed in the central and southern Plains.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Baltimore Oriole 131% 9.9
Dickcissel 537% 2.8
Great Crested Flycatcher 95% 9.1
Swainson's Thrush 129% 5.2
Western Kingbird 87% 9.5
Eastern Kingbird 54% 11.5
Summer Tanager 71% 5.2
Warbling Vireo 51% 9.6
House Wren 43% 13.3
Indigo Bunting 67% 4.7
Yellow Warbler 126% 2.5
Clay-colored Sparrow 84% 3.3
Bell's Vireo 346% 1.3
Gray Catbird 144% 1.9
Forster's Tern 43% 6.4
Least Flycatcher 252% 0.9
Sora 69% 2.9
Willet 21% 7.7
Long-billed Dowitcher 49% 4.2
Spotted Sandpiper 18% 11.4
Rose-breasted Grosbeak 149% 1
Chuck-will's-widow 181% 1.2
Orange-crowned Warbler 24% 11.4

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Dark-eyed Junco -41% 2.6
Hudsonian Godwit -48% 2.3
Ruby-crowned Kinglet -20% 8.2
Louisiana Waterthrush -26% 3.2
Northern Harrier -22% 4.2
Herring Gull -78% 0.2
Franklin's Gull -34% 12.6
Fox Sparrow -66% 0.2

Yellow Warbler © Ryan Schain

Yellow Warbler © Ryan Schain

West

Scattered precipitation kept migrants on the ground in a number of the recently hotter zones of migration for the weekend and early work week. But Monday night brought more favorable conditions, particularly from California into the Desert Southwest, where moderate movements occurred. These movements were more widespread on Tuesday night, not only in evidence in these areas but also along the eastern front of the Rockies. The end of the period mostly saw the extent and intensity of these flights continue from California east through the Rockies. Note that the Pacific Northwest did not experience much of a flight week, experiencing instead generality less favorable conditions for birds to move.

Top Movers

Increasing

Species Increase from Last Week % of Checklists Reporting
Wilson's Phalarope 129% 2.9
Western Tanager 63% 6.6
Swainson's Thrush 183% 1.5
Spotted Sandpiper 61% 5.9
Black-headed Grosbeak 51% 13.1
Wilson's Warbler 30% 14.5
Yellow-breasted Chat 43% 3
Lazuli Bunting 38% 5.5
House Wren 32% 13.8
Yellow Warbler 30% 9.3
Brown-headed Cowbird 26% 15.1
Warbling Vireo 32% 7.2
Western Wood-Pewee 58% 1.9
Broad-tailed Hummingbird 41% 4.4
Western Kingbird 26% 12.7
American Goldfinch 22% 15.8
Plumbeous Vireo 43% 2.2
Townsend's Warbler 27% 3.8
Brown-crested Flycatcher 43% 1.7
Bullock's Oriole 26% 8.5
Eared Grebe 19% 6.1
Olive-sided Flycatcher 44% 1.5
Barn Swallow 16% 20.4

Decreasing

Species Decrease from Last Week % of Checklists Reporting
Golden-crowned Sparrow -24% 6.8
Green-winged Teal -23% 7.5
Cackling Goose -29% 1.4
American Pipit -23% 1.9
Black-bellied Plover -30% 1.3
Greater Yellowlegs -20% 5.2
Bufflehead -18% 7.4
Fox Sparrow -27% 1
White-crowned Sparrow -13% 19.4
Franklin's Gull -23% 1.9
Common Merganser -14% 3.6
Pacific Wren -16% 2.3
Merlin -29% 0.5
Rough-legged Hawk -56% 0.1
Ring-necked Duck -11% 5.5
Long-tailed Duck -90% 0
Horned Grebe -16% 2

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Farnsworth and Van Doren

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