Light to moderate movements featuring Green Heron, Osprey, Rufous Hummingbird, White-throated Swift, and Common Yellowthroat will be the norm from Friday through the middle of the coming work week in the West, as moderate to heavy flights come to many parts of the East and feature Ruddy Duck, Whimbrel, Northern Flicker, Tree Swallow, Golden-crowned Kinglet, Louisiana Waterthrush, and Indigo Bunting.
Wondering what species are migrating through right now? Check out our analysis for the past 7 days.
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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A period of changeable conditions arrives in the region, and with the mix of alternating southerly winds, warming temperatures, forecast precipitation, and passing low pressure centers will come some nights of moderate to locally heavy movements as well as the potential for local concentrations of migrants. As these disturbances pass, conditions will fluctuate among favorable before they pass, marginal as they are passing and unfavorable after passage in many areas. In favorable conditions, in particular on Sunday night, widespread moderate movements, some of which will be locally heavy, will occur; however, in less favorable conditions, for example to end the week in the Great Lakes region, movements will be minimal. Birders should watch carefully for the passage of precipitation after birds are already migrating at night, as local concentrations and fallouts are likely in many areas of the East forecast to experience such conditions.
The arrival of a cold front to kick off the weekend brings the potential for fallouts to the western Gulf (particularly circum-Gulf migrants) and moderate to heavy flights farther east of the frontal boundary. The effects of the front are short-lived, as favorable conditions for moderate to heavy flights return by Sunday night (with the exception of Florida). These conditions largely continue, especially in the western Gulf toward which Caribbean easterly flow may push birds, for the duration of the period. Scattered precipitation is also forecast in some areas, shutting down migration when precipitation persist through sunset into the night and concentrating migrants when precipitation begins fall well after sunset. Note, an end of the week frontal boundary arrives just as trans-Gulf flights arrive; birders along the western Gulf Coast should watch for fallouts as migrants meet this frontal boundary.
Saturday night begins an active period of moderate to locally heavy movements in the central and southern Plains that spans nearly the entire period. Precipitation is forecast for many nights, and its timing will have drastic implications for migrant exodus, groundings, or concentrations. Saturday through Monday will see the most extensive of these movements across the region, with more extensive and organizing precipitation arriving thereafter to shutdown many movements by late in the week.
Widespread favorable conditions on Saturday, Monday, and Tuesday nights will spawn the greatest extents of light to moderate movements (with some locally heavy in the Desert Southwest and California) across the region. However, Wednesday’s forecast sees much more localized conditions favorable for migration, primarily limited to the southern Rockies where moderate and locally heavy flights are expected; and by Thursday most of the West experiences primarily unfavorable and marginal conditions with locally light to moderate flights.
