When, where, and how far will birds migrate? Our migration forecasts will answer these questions for the first time.
Pulses of favorable migration conditions this week in the West will bring moderate flights featuring Turkey Vulture, Pectoral Sandpiper, Parasitic Jaeger, Common Tern, Mountain Bluebird, Summer Tanager, and Orange-crowned Warbler, while the East experiences scattered moderate to heavy flights featuring Eastern Wood-Pewee, Yellow-bellied Flycatcher, Red-eyed Vireo, Blue-headed Vireo, Swainson's Thrush, Magnolia Warbler, and Common Yellowthroat when conditions allow. Another tropical system off the Atlantic coast brings potential for interesting observations, as does a tropical system moving across the Gulf of California and into the southern Rockies and western Texas.
Moderate movements were the norm in many areas of the West this period and featured Say's Phoebe, American Pipit, Ruby-crowned Kinglet, Townsend's Warbler, Fox Sparrow, and Lincoln's Sparrow, while moderate to heavy flights featuring Sharp-shinned Hawk, Merlin, Ruby-crowned Kinglet, Swainson's Thrush, Gray-cheeked Thrush, Magnolia Warbler, Palm Warbler, and Yellow-rumped Warbler dominated the early and late days of the period in the East. Hurricane Irma brought a nasty dose of devastation to portions of the Southeast, while carrying a large array of storm-borne vagrants.
Hurricane Irma will transport numerous species of birds far from their normal haunts. This is a dangerous storm that has already devastated many areas of the Caribbean, and it is forecast to make landfall in the US this weekend. Our hearts go out to those affected by this storm and the recent Harvey, and we hope that all those still in the path of this storm heed all warnings from the National Hurricane Center. Significant storms like this often trap (or 'entrain') birds in their circulation, depositing them far from where they originated. We still do not fully understand many of the mechanisms involved in birds getting 'entrained' and then deposited by storms, which is one reason why Team BirdCast (and many others) are interested in sightings associated with these storms.
Light to moderate movements featuring Sora, Pacific-slope Flycatcher, Warbling Vireo, House Wren, Swainson's Thrush, Common Yellowthroat, and early Golden-crownd Sparrows will be widespread from Saturday to Wednesday in the West, while two pulses of favorable migration conditions sandwiched around Irma will bring heavy flights featuring American Golden-Plover, Least Flycatcher, Swainson's Thrush, Yellow-throated Vireo, Blue-gray Gnatcatcher, Ovenbird, and Chestnut-sided Warbler in the East. Irma comes ashore after devastating the Caribbean, bringing with it a large haul of pelagic and nearshore species.
Light to locally heavy flights, particularly in the first half of the period, occurred in the West and featured Common Loon, Black-bellied Plover, Say's Phoebe, Swainson's Thrush, White-crowned Sparrow, and Lincoln's Sparrow, while numerous moderate to heavy flights featuring Gray-cheeked Thrush, Swainson's Thrush, Blackpoll Warbler, Tennessee Warbler, Orange-crowned Warbler, Wilson's Warbler, and Lincoln's Sparrow were the norm across the East following the passages of a significant frontal boundary.
Pulses of early and mid period favorable migration conditions will bring similarly time pulses of moderate flights to many areas of the West featuring American White Pelican, Killdeer, Elegant Tern, Cassin's Vireo, Yellow Warbler, and MacGillivray's Warbler, while a significant mid period cold front will spawn moderate to very heavy flights in the East featuring Buff-breasted Sandpiper, Common Nighthawk, Least Flycatcher, Olive-sided Flycatcher, Warbling Vireo, numerous warblers, and Bobolink. As the remnants of Harvey plod through the eastern US early in the period, a new and currently strong tropical system (Irma) will be approaching the southeastern US by the end of the period; BirdCast will be watching closely.