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WILD GEORGIA: Peak time now for southbound migratory birds

By Charles Seabrook, For the AJC #atlanta-ga

Charles Seabrook’s “Wild Georgia” column appears weekly in The Atlanta Journal-Constitution.

From now through early October is peak fall migration time for Georgia’s 54 species of Neotropical songbirds — warblers, vireos, orioles, tanagers and the like. After nesting here during spring and summer, countless numbers of them now are heading south for the winter to Caribbean islands and the tropics of Central and South America.

Joining them are as many as three dozen other southbound Neotropical species that nested elsewhere in North America and are passing through the state — stopping maybe a few days to rest and refuel before resuming their arduous journeys to the tropics.

Do you ever wonder about these southbound travelers? How far do they go? What do they eat in the tropics? Where do they prefer to live there? What dangers do they face in tropical forests?

As far as migration distances are concerned, the number varies considerably among species and among individuals within a species. Ruby-throated hummingbirds may fly more than 2,000 miles from Georgia to Mexico and as far as Costa Rica. Common nighthawks, cliff swallows and purple martins, however, may travel as far as 6,000 miles to Argentina.

Why some Neotropical birds migrate longer distances than others probably has to do with their habitat preferences — similar to the choices they make when returning to North America to nest in spring. For instance, the orchard oriole prefers open forests and forest edges with flowering trees in its wintering grounds from Mexico to northern South America — similar to its spring nesting habitat in Georgia.

Nearly all Neotropical migrants are primarily insect eaters, switching partly to berries around migration time. In the tropics, they maintain similar diets. The threats they face there also are similar to those facing them in North America — deforestation, loss of habitats, predators, climate change and others.

Come April, though, most of the birds will have survived to return to North America for spring nesting, and once again we will celebrate the “miracle of migration.”

IN THE SKY: From David Dundee, Tellus Science Museum astronomer: The moon will be full on Thursday night. Mercury is low in the west just after sunset. Venus rises in the east about two hours before sunrise. Mars rises in the east just after dark and will appear near the moon on Friday night. Jupiter and Saturn are high in the southeast after dark.