Fall's Journey South Update: October 2, 1998
Today's Report Includes:
Hurricane Georges on Sept 27
Despite the hurricane, hawks put on a record-breaking show in Corpus Christi, Texas at Hazel Bazemore County Park (27.30N, 97.60W). Broad-winged Hawks all move together on few days each fall, migrating in huge numbers along the Gulf coast. In the late 1980s birders noticed that they could see a lot of them over this tiny county park. During the years since then, they've had a few days when counters found about 100,000 hawks in a single day, but this year they had four days in a row with counts of over 100,000. On September 26 alone, they had 306,766 Broad-wings-over a quarter of a million! The thrilled and amazed birders have already broken their all-time record for the season total with 904,121 hawks by September 30. The hawks don't seem to have been affected by the hurricane at all,
Photo by Harlen and Altus Aschen
Don't Pressure Me!
Some strong-flying birds avoid the impact of hurricanes by flying in advance of the storm, carried by the winds at the outer reaches of the storm system. How do they know these winds come from storms rather than normal weather conditions? They can feel drops in barometric pressure.
We humans feel changes in pressure, too. Did you ever ride an elevator in a tall building? Our ears pop when air pressure changes. Birds have more sensitive inner ears, feeling much smaller changes in pressure. The drop in pressure from the ground to the top of the Sears Tower in Chicago is the same drop you'd feel in a hurricane (but without all that wind!)-1.7 inches of mercury. The normal air pressure at the top of the Sears Tower is about the same as the pressure in the eye of Hurricane Georges at its fiercest!
Letter from Florida
When birds detect an approaching storm, especially in fall when they don't have a nest or babies to protect, they sometimes hightail it out of there fast.
Some birds don't go too far. Phil Berry, a birder in Gulf Breeze, Florida, wrote to Journey North on September 30: "We are ending our 5th day of Georges here. I live on the intercoastal waterway, within sight of the Gulf. We have experienced fallouts of several species of migrating warblers. Shorebirds have left the beach and have been in my back yard (a golf course) since Sunday morning. Access to the beach has been curtailed for them, so they find it necessary to move to the golf course to find food. Other than the above, things appear normal. my hummer feeders were left up during the storm and were well-used."
Other birds are picked up by the storm system and carried long distances-there are records of White-billed Tropicbirds from Bermuda being blown up to Vermont after one hurricane. Birders search for rare birds after hurricanes, and Journey South will report on interesting birds they find.
South Pelto platform
Click to see larger image
Based on the weather map for September 25,1998, it might be a good idea to issue a traveler's alert in the large
area of fog in all of western Michigan (including Lansing) southern Wisconsin (including Milwaukee and Madison),
northern Illinois (including Chicago), just about all of Iowa, most of Nebraska, and the northeastern tip of Colorado.
Rain and clouds would be expected in all the areas with green on the map, where high and low pressure areas are
colliding, especially in the Florida Keys and Caribbean Islands--that system is Hurricane Georges!
How to Respond to Today's Challenge Question # 5: