An active weather week will be in store for the West and the East, the former experiencing a pulse of favorable conditions early with light to moderate flights followed by largely unfavorable conditions and the latter exhibiting nearly the opposite pattern. Flights in the east, when favorable conditions are present, will be moderate to locally heavy. Note also that two strong low pressure systems are forecast to move through the central and eastern portions of the US, creating concentration and fallout potential when and where they pass.  Read more...

Although early week rain kept most migrants in the West grounded, more favorable midweek conditions spawned light and moderate flights in California and the Desert Southwest; meanwhile, most of the period saw the East experience a dynamic weather scene in which light and moderate flights alternated with precipitation and strong storms.  Read more...

The West sees a mixed bag of conditions including favorable southerly flow that will carry light to moderate movements this weekend and late in the work week as well as unfavorable (for birds at least!) precipitation that shuts down migration, while an active week in the East will see moderate flights, most widespread early in the work week and punctuated by periods of precipitation that shut down migration.  Read more...

Conditions in the West were more unfavorable than favorable this week, with only light movements early in the weekend and late in the work week, while localized light to moderate movements in the Great Plains and Texas and parts of the southeast were there highlights of migration in the East.   Read more...

Early migrants will be on the move in the West and the East. Favorable conditions this weekend and at the end of the coming week will see light to moderate movements scattered across the West, while a pulse of unseasonably warm air will inspire widespread light to moderate flights over the weekend in the Great Plains and for the first half of the work week in much of the East. Read on to find out what species will be on the move in your region!  Read more...

We posted previously on the exceptional movements of Franklin’s Gulls and Cave Swallows that occurred around 13 November 2015. The first post set the stage for how these species appeared so far out of range, and we follow with this post about some rumination about why this event took place. Here, we consider the combined effects […]  Read more...

November 13 saw an epic Franklin’s Gull and Cave Swallow flight to the East Coast of the United States, the likes of which have not been previously recorded. Here, we describe in the first of a three part series how and why this unprecedented event occurred.  Read more...

Some seriously anomalous displays of displacement, entrainment, diversion, and irruption, highlighted the birding landscape of 2012. Of particular note was the unprecedented invasion of Razorbills in the southeastern US and the Gulf of Mexico. BirdCast spent some time chronicling these events and begins a discussion of whether 2015 might see a similar occurrence.  Read more...

A late period arrival of favorable conditions will see light to moderate movements, primarily waterfowl, in the West, while the first half of the period in the East will see moderate flights scattered across the region.  Read more...

A quiet late season week in the West saw primarily scattered light movements, while a wild post-frontal passage ride of Franklin's Gulls and Cave Swallows in the Northeast highlighted the period's primarily localized light to moderate flights.  Read more...

Welcome to our latest 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 […]  Read more...

Mid to late period conditions will be favorable for scattered light to moderate pulses of movements featuring American Wigeon, Cooper's Hawk, Golden Eagle, American Coot, Snowy Owl, and Red-winged Blackbird in the West, while a strong frontal passage early in the weekend brings moderate to heavy flights of Mallard, Snow Goose, Hooded Merganser, Common Merganser, Purple Sandpiper, Bonaparte's Gull, and American Robin to the East.  Read more...

A generally quiet week in the West featured isolated light and moderate flights of Greater White-fronted Goose, Northern Pintail, Bufflehead, Common Goldeneye, Western Bluebird, and Yellow-rumped Warbler, while moderate flights of Red-breasted Merganser, White-winged Scoter, Franklin's Gull, American Robin, Savannah Sparrow, and American Tree Sparrow graced the East early and late in the period.  Read more...

A relatively quiet week of scattered light migration featuring Brant, Common Goldeneye, Barrow's Goldeneye, California Gull, Chestnut-collared Longspur, and Golden-crowned Sparrow is in store for this late migration period in the West, while the passage of two strong cold fronts spawn the season's last major moderate to heavy flights featuring Lesser Scaup, Long-tailed Duck, Bufflehead, Hooded Merganser, Great Cormorant, Purple Sandpiper, and Rusty Blackbird in the East.  Read more...

A quiet late season week in the West saw primarily light movements west of the Rockies featuring Brant, Red-breasted Merganser, Pacific Loon, Mew Gull, Bohemian Waxwing, Chestnut-collared Longspur, Grasshopper Sparrow, and Clay-colored Sparrow, while early and late period movements of moderate to heavy intensity in the East featured numerous waterfowl, Rough-legged Hawk, Northern Shrike, Cedar Waxwing, American Tree Sparrow, and Fox Sparrow.  Read more...

Migration events over the last week varied substantially in size. Last Friday night (23 October) saw a particularly large movement (see below to watch), followed by no (or extremely small) movements on the following night. Successive nights saw decreasing migration traffic rates; remember, a major low pressure system moved through the region with lots of precipitation.  Read more...

Favorable conditions from the weekend through early week in the West will see light to locally moderate flights of Canada Goose, Red-breasted Merganser, Common Merganser, Ring-billed Gull, Short-eared Owl, Marsh Wren, and Golden-crowned Sparrow, while a moderate to heavy pulse Friday along the Atlantic coast and along the Canadian border on Wednesday and Thursday nights will feature Snow Goose, Tundra Swan, Redhead, Hooded Merganser, Red-throated Loon, Common Redpoll and assorted western goodies.  Read more...

Light to moderate flights earlier in the period from the southern reaches of the West featured Tundra Swan, Canvasback, Bufflehead, Bonaparte's Gull, American Tree Sparrow, and Pine Siskin, while moderate to heavy flights last weekend and late in the current week featured Bufflehead, Hooded Merganser, Common Loon, Great Cormorant, Golden-crowned Kinglet, Snow Bunting, Fox Sparrow, and White-throated Sparrow in the East.  Read more...

A favorable beginning and end of the period for the West sees light to moderate flights of Gadwall, Bufflehead, Long-tailed Duck, Northern Harrier, Bonaparte's Gull, Hermit Thrush, Chestnut-collared Longspur, and American Tree Sparrow, while a late weekend and late week pulse of moderate to heavy flights in the East feature Hooded Merganser, Common Loon, American Coot, Ring-billed Gull, Snow Bunting, American Tree Sparrow, and Chipping Sparrow.  Read more...

Light to moderate mid and end of week flights in the West featured numerous waterfowl, Varied Thrush, Hermit Thrush, and Pine Siskin, while extensive moderate to heavy flights last weekend saw the passage of Brant, Bufflehead, Red-throated Loon, Bald Eagle, Wilson's Snipe, Merlin, Brown Creeper, Saltmarsh Sparrow, and Dark-eyed Junco.  Read more...