Henslow’s Sparrow © Benjamin Van Doren

Continental Summary

With peaks of spring movements in the rear view for most species, this week will see scattered light flights across much of the West, with moderate flights along the eastern front of the Rockies, that will feature Black Tern, Cordilleran Flycatcher, Willow Flycatcher, MacGillivray’s Warbler, and Blue Grosbeak, and moderate to heavy midweek flights where and when precipitation does not fall in the East, featuring Black-bellied Plover, Black Tern, Olive-sided Flycatcher, Alder Flycatcher, Yellow-bellied Flycatcher, and Mourning Warbler.

Wondering what birds were on the move last week? Check out our analysis!

Arrows show wind speed and direction (arrow points in the direction to which wind is blowing) 100 m above ground level. Areas with southerly winds are colored red; northerly winds colored blue. Accumulated precipitation (in 6 hour intervals) is green, outlined by white. Broadly speaking, areas of the map in red will experience conditions that are favorable for migration, and areas where red and green (and red and blue) intersect and overlap may experience migrant concentrations and fallouts as migrants interact with precipitation.

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Need a review of our definitions for regions, species on the move, and migration amounts? Please visit this link.

Quick Links to Regions

Upper Midwest and Northeast	Gulf Coast and Southeast
Great Plains	West

Upper Midwest and Northeast

A cold blast to start the holiday weekend will make many migrants think twice, although moderate flights may occur if northerly and westerly winds are lighter than forecast. But by Sunday warmer air flows across the region, bringing with it widespread moderate to heavy flights. Aside from scattered precipitation in the days that follow, these conditions persist through Wednesday with similar intensity and extents of movements following suite. Although a late week frontal passage will inhibit movements in portions of the Appalachians and Northeast, the late date and need for birds to arrive on territory will keep moderate movements of migrants on the move.

Olive-sided Flycatcher © Benjamin Van Doren

Species on the Move

Beginning to Arrive What is this?

Arriving

Peaking

Departing

Gulf Coast and Southeast

Although bookended by some unfavorable and unseasonable conditions, this week sees generally warm and southerly flow in many areas, giving the last movements of this season the conditions to fly. Moderate flights will be the norm, with some locally heavy flights in the western Gulf Coast region during the middle of the week. Note also that, despite the late date, precipitation is forecast in many areas and may bring local concentrations of late migrant passerines and waterbirds.

Yellow-bellied Flycatcher © Ian Davies

Beginning to Arrive What is this?

Arriving

Peaking

Departing

Great Plains

Moderate to heavy flights are likely this week during the periods of favorable winds when and where rain is absent. Several loosely organized disturbances pass through the region, with particularly unfavorable effects late in the week in the central and northern Plains; however, birds will want to move, and even marginal conditions at this time of year will likely see larger flights. Birders should watch the distribution of rain and southerly winds, as local shorebird concentrations may occur where stronger storms interact with late season and high flying migrants.

Nelson’s Sparrow © Luke Seitz

Species on the Move

Beginning to Arrive What is this?

Arriving

Peaking

Departing

West

Similar to last week, scattered precipitation is forecast for many areas over the course of this forecast period. Given the date, and that migration timing is generally earlier in many areas of the West than in the East, scattered light migration is the expectation where and when favorable conditions occur. However, east of the Rockies often sees a different pattern more aligned with the Plains and East – favorable conditions during this week along the eastern front, including the prairies and grasslands of Montana, will bring moderate and perhaps locally heavy flights early to mid period before late period precipitation and cooler temperatures shut down these movements.

Common Nighthawk © Benjamin Van Doren

Species on the Move

Beginning to Arrive What is this?

Arriving

Peaking

Departing

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