Sunday, May 5, 2013

4/25 IL Migration Report

And to think, a week ago, it was snowing and in the 30's. Early (and I mean early) tomorrow, conditions for migration will drastically improve from what they are now. Right now, we are under the influence of high pressure with extremely weak southeast winds, and as such only light migration is occurring throughout IL right now (for a neat visualization of the winds, see here:, though reports especially of raptor movement among other things were frequent today (clearer skies = thermals, westerly to southerly winds help it along). If you look at Illinois on this map, most of the migration is concentrated around the southern tip of IL and southwest IL. Say we drew a line from St. Louis to Evansville, most of the migration in Illinois is for now occurring below this line. So for many of us, *most of* tonight won't be all that spectacular...the big news comes tomorrow for a fantastic start to the weekend.

Predicted Surface Analysis at 3 AM Central
By 3 AM tomorrow, a fantastic combination of meteorological elements will come together to form perfect conditions for migration. The high-pressure system we are under the influence of now will, by then, have passed east of us, and seeing as winds rotate clockwise around high pressure systems, this brings us into the southerly winds of its backside. That's not all; a low-pressure system developing in the west will be moving towards us, and seeing as winds rotate counterclockwise around low-pressure systems, this will mean that we will be under the influence of the southerly winds of its frontside, and this at the same time as we have the southerly winds of the high-pressure system's backside. Also remember that winds rotate more quickly around low-pressure and more slowly around high pressure, so adding low pressure to the equation will give birds that much more southerly force to work with. This will set the stage for southerly winds throughout the day tomorrow until it all culminates tomorrow night, when southerly 
Predicted winds at 3AM Central

winds should continue and carry moderate to heavy concentrations of migration northward. The southerly winds should continue into Saturday morning, when winds will become E/SE. Saturday night, it is forecast that winds will shift from easterly to northerly, in which case northerly winds would last through Sunday into sunday night, when they will shift from southerly to westerly, and westerly to southerly again. So as far as migration goes, expect tonight and tomorrow night to have the most favorable conditions for migration, and therefore expect that tomorrow and Saturday will be the best days to get out there and find some cool stuff! I'm about you?!

So what should you be expecting? This totally depends on where you are, as some parts of the state have remained a little warmer and now hold some decent insect life to feed northbound migrants, whereas others don't. Where exactly the migrants will be the morning after migration is next to impossible to predict, so this is where you come in! With more sightings reported, a more complete picture of migration in IL can be painted, so if you have a chance, don't hesitate to go birding. In general around the state keep an eye out for arrivals and influxes of any of the following: BLACK-CROWNED NIGHT-HERONS, GREEN HERONS, BROAD-WINGED HAWKS, SORAS, VIRGINIA RAILS, COMMON GALLINULES, maybe SEMIPALMATED PLOVERS, PECTORAL, SPOTTED, LEAST, and SOLITARY SANDPIPER, DUNLIN, UPLAND SANDPIPERS, WILLET, FORSTER'S TERNS, COMMON TERNS, COMMON NIGHTHAWKS, CHIMNEY SWIFT, RUBY-THROATED HUMMINGBIRDS, EASTERN WOOD-PEWEE, GREAT CRESTED FLYCATCHERS, LEAST FLYCATCHER, BLUE-HEADED, WHITE-EYED, WARBLING and RED-EYED VIREOS, HOUSE WRENS, MARSH WRENS, all the expected swallows, all the expected sparrows (especially take note of LE CONTE'S SPARROWS, HENSLOW'S SPARROWS, GRASSHOPPER SPARROWS, and LARK SPARROWS), SWAINSONS'S, GRAY-CHEEKED, and WOOD THRUSHES, warblers including but not limited to BLUE-WINGED WARBLERS, ORANGE-CROWNED WARBLERS, PRAIRIE WARBLERS, BLACK-THROATED GREEN WARBLERS, PINE WARBLERS, YELLOW WARBLERS, HOODED WARBLERS, BLACK-AND-WHITE WARBLERS, NORTHERN PARULAS, LOUISIANA + NORTHERN WATERTHRUSHES, WORM-EATING WARBLERS, COMMON YELLOWTHROATS, SCARLET and SUMMER TANAGERS, ORCHARD and BALTIMORE ORIOLES, BREWER'S, RUSTY, and YELLOW-HEADED BLACKBIRDS, INDIGO BUNTINGS, and possibly early DICKCISSELS or BOBOLINKS.

That's today's report, folks. Get excited! Early tomorrow morning, favorable conditions will take over the state and last into Saturday, so there will very likely be some considerable arrivals and influxes.

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