When, where, and how far will birds migrate? Our migration forecasts will answer these questions for the first time.
Favorable migration conditions dominate the period in the West, where light to moderate movements featuring Common Merganser, Cooper's Hawk, Red-shouldered Hawk, Black-bellied Plover, Townsend's Warbler, Brewer's Blackbird, and Savannah Sparrow will be widespread, while favorable migration conditions become widespread in the latter half of the period in the East, with moderate to very heavy movements featuring Osprey, Broad-winged Hawk, Sora, Northern Flicker, Gray-cheeked Thrush, Black-throated Blue Warbler, Ovenbird, American Redstart, and Clay-colored Sparrow.
Moderate to locally heavy flights occurred in many areas of the West this period and featured Cackling Goose, Greater White-fronted Goose, Ring-necked Duck, Merlin, American Pipit, Fox Sparrow, Golden-crowned Sparrow, and Lincoln's Sparrow, while moderate to locally very heavy flights occurred in the East, featuring Sharp-shinned Hawk, Gray-cheeked Thrush, Ruby-crowned Kinglet, Yellow-rumped Warbler, Palm Warbler, Savannah Sparrow, Harris' Sparrow, White-crowned Sparrow and White-throated Sparrow.
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.