Asheville, North Carolina

Thoughts of Autumn by Scott Dean – Part 2

 

Another fascinating change that takes place at this time of year is the migration of various species to their winter territories. 

            Ruby-throated Hummingbirds will be leaving the region starting in mid-September, and most will be gone by mid-October.  Banding studies have indicated that individual birds are very loyal to their migratory route, to the extent that many are observed at the same site on the same date each year. These beautiful little birds will travel south, stopping on the gulf coasts of Texas and Louisiana to rest and feed.  Studies have shown that these birds can increase their fat reserves and double their body weight in roughly ten days.  This weight/fuel gain will soon be vital to them as at some unknown signal they will take off and fly as much as 600 miles, non-stop, across the Gulf of Mexico to their wintering sites.  Those that successfully complete the trip will return to the same nest sites and feeders, year after year.  In the Asheville area, the first males are usually seen during the first week in April.  The males precede the females by a week or two and spend that time establishing, and fiercely defending, their territories against any and all threats. 

            A more obvious migration is that of the Broad-winged Hawk.  These are common summer residents here in the mountains of North Carolina, but are much rarer as you near the coastal plain. After spending spring and summer here these large birds migrate to tropical South America for the winter.  During late September and early October the Broad-wings migrate southwards in large groups known as "kettles". At this time of year I look forward to cold fronts moving south, as these are usually followed by the hawks.  To see the “Broadies” I like to go to the Standing Indian area near Franklin, NC.  Pickens Nose Ridge is a good spot to see them, and, on a good day, it is not unusual to see several kettles with 40 or 50 birds in each.  Closer to Asheville is the Craggy Pinnacle which is just north of the Craggy Visitors Center on the Blue Ridge Parkway.

            Their mode of travel is one I think I would like.  These birds locate uprisings of air created in one of two ways.  On overcast days or early in the mornings they find uprisings where the winds are deflected upwards against the sides of mountains.  On sunnier days, usually in the afternoon when the ground has been heated by the sun, they find rising columns of hot air known as thermals.  In either case the birds circle upwards, rarely flapping their wings, until they run out of lift. At this point they leave the thermal, gliding southwards and looking for another thermal or deflective uprising to repeat the process. They can cover hundreds of miles in a single day, and by "surfing" the air can do it with hardly any effort.        

Scott Dean

 

 

 

Scott has worked at the Asheville WBU for the past 5 years