Thursday, May 12 was a great migration day in the dunes. The overnight period brought warm southerly winds, but a massive storm cell marched across northern Illinois and into Lake Michigan creating a blockage for migrants, in addition to an excellent pre-dawn lightning show over the lake. During all of this the dunes remained dry, and those out before the sun rose could hear the chips of warblers and other migrants flying over.
The list was the most diverse yet, with 109 species being recorded. 3,689 individual birds were counted. The goodies were numerous. The Grube Magnitude Index, which is used to score the intensity and diversity of our longshore flights was exceptional. Thursday’s flight was 78.61, which is the fifth highest count recorded from the tower. 49 species really added to the count. Major contributors were Rose-breasted Grosbeak- 65 (9th largest Ind count) contributed 9.3 points, Eastern Kingbird- the 257 counted (8th largest Ind count) generated 4.28 toward the total, and Yellow Warbler- 16 were tallied, which came to 4.68 Grube Mag points. Others posting great counts were 1,207 Blue Jays, 311 Balimore Orioles, 448 Pine Siskins, and 476 American Goldfinch. Wow!
Just this week 13 new species have been added to the annual tower list. On Thursday, three were added. Those being Blackpoll Warbler, Yellow-breasted Chat, and White-winged Dove. Chats are very hard to find in the dunes. The dove has become nearly an annual from the tower site. Total species now for the year stands at 192. Will we hit 200 before it’s done?
To read the complete list for Thursday, May 12, check the ebird list here.