IMPORTANT NOTE: Team Birdcast is focusing on preparing for tomorrow’s Global Big Day, and as a result we haven’t been able to write a thorough forecast and analysis by our usual Friday deadline. Here is an abbreviated forecast, with weather maps and species lists; the analysis for the past week and potentially a supplemental forecast […]  Read more...

Migration conditions will be generally more favorable across southern half of the West this week where moderate flights will feature Wilson's Phalarope, Red-necked Phalarope, Black Tern, Willow Flycatcher, Yellow Warbler, MacGillivray's Warbler, and Green-tailed Towhee, while midweek in the East will see the most extensive moderate to heavy flights of Black-crowned Night-Heron, Semipalmated Plover, Short-billed Dowitcher, Black Skimmer, Common Nighthawk, Black-billed Cuckoo, Acadian Flycatcher, Eastern Wood-Pewee, Canada Warbler, Blackpoll Warbler, and American Redstart in a pulse of significantly warmer air.  Read more...

Moderate movements, particularly from California east through the central and southern Rockies, featured Black Tern, Cordilleran Flycatcher, Plumbeous Vireo, Swainson's Thrush, Black-headed Grosbeak, and Western Tanager and highlighted the period in the West, while moderate to heavy flights, particularly in the central and southern US, featured Common Nighthawk, Yellow-bellied Flycatcher, Least Flycatcher, Philadelphia Vireo, Veery, Magnolia Warbler, and American Redstart and highlighted the period in the East.  Read more...

When birders in Cape May awoke on Monday morning, an interesting pattern was emerging (interesting is the norm in Cape May!). Numerous observers reported that numbers of migrants had arrived during and after the night and were still coming ashore from the Atlantic Ocean. The first real pulse of arrivals of this spring for a number of species had clearly occurred in Cape May. The combination of on the ground reports from eBird, nightly northeastern US radar data processing with BirdCast algorithms, and the excitement of spring arrivals inspired Team BirdCast to look a bit more closely at the events leading up to this movement.  Read more...

Welcome to this installment of BirdCast Traffic Reports, posts describing northeastern US nocturnal bird migration traffic rates, as calculated from a completely automated pipeline of algorithms. The images you see in Traffic Reports present the migration traffic rate (MTR), direction of bird movement, and speed of bird movement. See our first report or scientific paper (currently a preprint) for more information about the […]  Read more...

Favorable migration conditions in the latter half of the period for the West will bring extensive light to moderate movements of Spotted Sandpiper, Olive-sided Flycatcher, Dusky Flycatcher, Warbling Vireo, MacGillivray' Warbler, Lark Bunting, Clay-colored Sparrow, and Chipping Sparrow, while a highly variable period for weather in the East will bring similarly variable and patchily distributed moderate to heavy movements featuring Least Sandpiper, Forster's Tern, Olive-sided Flycatcher, Least Flycatcher, Acadian Flycatcher, Wood Thrush, Swainson's Thrush, Golden-winged Warbler, Nashville Warbler, Cape May Warbler, Blackburnian Warbler, and Baltimore Oriole.  Read more...

Light to moderate flights, primarily in the Desert Southwest and the eastern Rockies, were the highlights of the week in the West and featured Wilson's Phalarope, Vaux's Swift, Western Wood-Pewee, Hammond's Flycatcher, Brown-crested Flycatcher, Warbling Vireo, Yellow Warbler, Hermit Warbler, Summer Tanager, Western Tanager, and Lark Sparrow, while moderate to heavy flights featuring Mississippi Kite, Willet, Ruby-throated Hummingbird, Western Kingbird, Gray Catbird, Bay-breasted Warbler, Black-throated Blue Warbler, Rose-breasted Grosbeak, Blue Grosbeak, Dickcissel, and Baltimore Oriole were extensive in many areas of the East.  Read more...

Team BirdCast has been experimenting with ways to detect changes in bird distributions as they are occurring. With the help of two talented Cornell undergraduates, Alex Wiebe and Benjamin Van Doren, who are leading the charge, we introduce the BirdCast Anomaly Detector. To detect unusual events–such as the beginnings of a Snowy Owl invasion, or […]  Read more...

The most favorable migration conditions in the West bring light to moderate movements of Vaux's Swift, Broad-tailed Hummingbird, Western Kingbird, Bank Swallow, Virginia's Warbler, Hermit Warbler, Lazuli Bunting, and Lark Sparrow during the work work, while the East experiences moderate to heavy flights featuring Forster's Tern, Solitary Sandpiper, Least Sandpiper, Yellow-billed Cuckoo, Blue-headed Vireo, Kentucky Warbler, Chestnut-sided Warbler, Magnolia Warbler, American Redstart during a wave of favorable and unfavorable migration conditions associated with the movements of a strong frontal boundary.  Read more...

Welcome to this installment of BirdCast Traffic Reports, posts describing northeastern US nocturnal bird migration traffic rates, as calculated from a completely automated pipeline of algorithms. The images you see in Traffic Reports present the migration traffic rate (MTR), direction of bird movement, and speed of bird movement. See our first report or scientific paper (currently a preprint) for more information about the […]  Read more...

Light and moderate flights featuring White-faced Ibis, Semipalmated Plover, Olive-sided Flycatcher, Red-faced Warbler, and Western Tanager were frequent in many areas of the West, while the East saw moderate and locally heavy flights featuring Spotted Sandpiper, Chimney Swift, Warbling Vireo, Red-eyed Vireo, Blackpoll Warbler, Cape May Warbler, and Prairie Warbler in the southerly flow ahead of a frontal boundary.  Read more...

Increasingly favorable conditions for light to moderate movements will build across the West for the work week, featuring Green Heron, Marbled Godwit, Short-billed Dowitcher, Cassin’s Vireo, Barn Swallow, Gray Flycatcher, and Summer Tanager, while the East experiences moderate to heavy flights of Broad-winged Hawk, Sora, Semipalmated Plover, American Avocet, Barn Swallow, Wood Thrush, Black-and-white Warbler, Prothonotary Warbler, Scarlet Tanager, Rose-breasted Grosbeak, Baltimore Oriole, and Lark Sparrow in the Plains for the first half of the period and similarly intense movements farther east later in the period.  Read more...

Scattered moderate movements featuring Swainson's Hawk, Vaux's Swift, Bank Swallow, Yellow-breasted Chat, Summer Tanager, and Western Tanager were the migration highlights for the period in the West, while moderate to locally heavy movements associated with the passage of a strong frontal boundary through the East featured Green Heron, Broad-winged Hawk, Sora, Common Nighthawk, Warbling Vireo, House Wren, Palm Warbler, and Baltimore Oriole.  Read more...

Welcome to our first spring 2016 installment of the traffic report describing northeast US nocturnal bird migration traffic rates, as calculated from a completely automated pipeline of algorithms. The images you see in Traffic Reports present the migration traffic rate (MTR), direction of bird movement, and speed of bird movement. See our first report or scientific paper (currently a preprint) for […]  Read more...

Warming conditions, occasionally punctuated with scattered precipitation, will generally see light to moderate flights across the West, particularly during the second half of the period, while a cold and quiet start to the weekend in the East will change markedly to begin (and end) the work week with moderate to locally heavy flights.  Read more...

Moderate movements including White-faced Ibis, Swainson's Hawk, Nashville Warbler, MacGillivray's Warbler, Lazuli Bunting, and Black-headed Grosbeak highlighted the period in the West, particularly along the Pacific Coast and in the Desert Southwest, while moderate to locally heavy movements featuring Spotted Sandpiper, Yellow-billed Cuckoo, Chimney Swift, Red-eyed Vireo, Cliff Swallow, Northern Parula, and Blue Grosbeak graced the southern reaches of the East.  Read more...

Favorable conditions this weekend and later in the workweek will bring light to moderate movements including Green Heron, Caspian Tern, Ash-throated Flycatcher, Nashville Warbler, and Brewer's Blackbird through the West, while cooler weather following two strong frontal passages will contrast starkly with the period's favorable conditions and their moderate to heavy flights of Snowy Egret, American Bittern, Broad-winged Hawk, Virginia Rail, Upland Sandpiper, Whimbrel, Cliff Swallow, Ovenbird, Black-throated Green Warbler, Palm Warbler, Blue Grosbeak, and Indigo Bunting in the East.  Read more...

The light to moderate movements featuring Common Loon, Double-crested Cormorant, Pacific-slope Flycatcher, Wilson's Warbler, and Black-headed Grosbeak along the Pacific Coast and in the Desert Southwest highlighted the period's migration in the West, while the East featured American White Pelican, Osprey, Least Sandpiper, Solitary Sandpiper, Chimney Swift, Northern Flicker, Eastern Kingbird, Barn Swallow, Chipping Sparrow scattered light to moderate flights, most consistent in the Gulf states.  Read more...

Light to moderate migration reach its greatest extents in the West as favorable conditions arrive primarily from Sunday through Wednesday, while the East will experience two waves of moderate and locally heavy flights late in the weekend and in the middle of the work week.  Read more...

Light to moderate flights along the Pacific Coast and in portions of the Desert Southwest highlighted the period in the West, while light to moderate flights reached their greatest extents on Tuesday night in the East.  Read more...