April 30 to May 4: First Big Wave Coming

Black-throated Green Warbler, one of the migrant species that should show up in good numbers during the next few days. Photo by Kenn Kaufman.

Saturday, April 28, 2018: As of today migration still seems delayed. The warblers and other stars of The Biggest Week In American Birding - which begins in six days - haven't arrived in big numbers yet. Fortunately, at this season, migration is not a gradual thing: big pulses of movement happen when conditions are right. Conditions should be right in a couple of days. With many migrants undoubtedly dammed up to the south of us, we should have a major arrival of variety and numbers starting around Tuesday, May 1, and continuing through the week.

This last week in woods near Lake Erie, the selection of species seemed more typical of early April, featuring Golden-crowned Kinglets, Winter Wrens, and other early birds. On Thursday, April 26, a modest influx brought in many White-throated Sparrows and Yellow-rumped Warblers, plus a few other early warblers such as Palm, Pine, and Orange-crowned. But northerly winds and some overnight rains stopped the flow again by Friday night. 

For birding in northwest Ohio this weekend, April 28-29, diversity of migrants from the tropics is likely to remain low, but there are fair numbers of early species. Leaves on the trees are just budding out, so birds are easier to see (and photograph) than they will be later in the season after full leaf-out. Area marshes are still holding a fair variety of ducks and other water birds. Some low-water spots along the Magee Marsh causeway are attracting shorebirds; two Willets were there on Friday, the 27th. 

A high-pressure area will slide gradually eastward over us this weekend, with light or northerly winds, and nighttime temperatures down near freezing. But by sometime Monday, as the high moves on east and a low approaches from the west, winds should switch around strongly to the southwest, with daytime temperatures up to the high 60s on Monday and the 70s on following days. The sustained southwesterly air flow should bring large numbers and greatly increased variety of migrants. The number of warbler species along the Magee Marsh boardwalk, for example, should jump from the current 3 or 4 up to something like 10 to 20, along with an arrival of orioles, Scarlet Tanagers, Rose-breasted Grosbeaks, and others. We're overdue for a big daytime flight of Broad-winged Hawks, and that could happen as early as Monday, if the wind shifts early enough.

When will be the best birding this week? It's hard to pick a favorite because Tuesday May 1 through Friday May 4 all appear to have great potential. Based on current weather forecasts I expect each of those days to produce new birds that have arrived overnight. Thunderstorm activity beginning Wednesday afternoon may have the effect of putting more migrants down, depending on exactly when and where those storms move through. Anyway, regardless of questions about exact timing, migration is just about to kick into high gear.