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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.

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…

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.