23 September 2024
This month warblers and thrushes are making lengthy journeys from North America to Central and South America. Each week there’s a brand new cohort of species and a few species go by means of on the identical time.
Recently I’ve observed that after I discover a number of American redstarts there are additionally many magnolia warblers. Once I discover Tennessee warblers there are sometimes Nashville and black-throated inexperienced warblers as effectively.
Chicken banders questioned about this phenomenon, too, so 5 banding stations together with Powdermill Avian Analysis Heart gathered 20+ years of banding information for a long run research of spring and fall migration. They grouped the banding information by season, by mist internet and the date-time every fowl was captured, and by species. Once they examined which species had been discovered collectively patterns emerged, revealed of their research Persistent species relationships characterize migrating fowl communities throughout stopover websites and seasons.
Two species captured in the identical internet on the identical time, time and again for a interval of 20 years, signifies they’re feeding collectively at stopover websites and are doubtless touring collectively, too.
The research’s chart of fall migrants exhibits that American redstarts (AMRE) and magnolia warblers (MAWA) are sometimes discovered collectively throughout fall migration (the thick crimson line). So are Tennessee warblers (TEWA), Nashville warblers (NAWA) and black-throated inexperienced warblers (BTNW). [See chart of 4-letter bird banding codes used in the diagram.]
There’s even a correlation amongst thrushes. Discover the faint line between Swainson’s thrushes (SWTH) and gray-cheeked thrushes (GCTH), above.
This fall I observed that whereas many Swainson’s thrushes are touring by means of southwestern Pennsylvania I’ve additionally seen a sprinkling of gray-checked thrushes. The road on the chart might be faint as a result of gray-cheeked thrushes are far much less quite a few than Swainson’s.
So who does this blackpoll warbler journey with? His touring buddy just isn’t on the chart however I can guess.
Are you able to say “baypoll” warbler?
Learn concerning the research in Audubon Journal: A New Examine Reveals Migration Isn’t a Solo Affair—It’s the Social Occasion of the Season.
See the complete research in PNAS: Persistent species relationships characterize migrating fowl communities throughout stopover websites and seasons.
