The Catharus thrushes that are regularly occurring Nearctic-Neotropical migrants on the Gulf Coast (Swainson's, Gray-cheeked, and Veery) are of particular interest to our research. Delaware State University Master's student Mariamar Gutierrez-Ramirez is studying the stopover refueling performance of these species on the island after trans-Gulf migration. Analysis of residual plasma triglyceride levels will indicate whether the birds are refueling on the island. To do this, a small sample of blood is quickly taken from all thrushes that are captured in our mist-nets. Birds are then banded, measured, and released unharmed.
Catharus thrushes have been particularly photogenic along our transects this past week. If you stand still they will often come within just a few meters, intent upon their foraging efforts. See if you can pick out the subtle differences in their plumage.
It won't be long until they return to their northern breeding grounds, where their distinctive, flute-like songs are unparalleled in beauty.
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| Veery (Catharus fuscescens) |
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| Swainson's Thrush (Catharus ustulatus) |
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| Gray-cheeked Thrush (Catharus minimus) |
Nice photos showing the plumage differences. Do Wood Thrushes stop over there too? How closely related are the Catharus thrushes to the American Robin?
ReplyDeleteThanks for the comment! Yes, Wood Thrushes do stopover on St. George Island in decent numbers. we have banded ~10-15 Wood Thrushes this spring, and seen several more on our transects.
DeleteIronically, American Robin is the one thrush species we have yet to see on St. George Island. Here in the deep south, they are strictly winter visitor. American Robins, in the genus Turdus, are pretty closely related to Catharus. If you look at the juvenal plumage of the American Robin, you can see a similar pattern to that exhibited by all ages of Catharus thrushes.