Master Naturalists: Hawk watch 2012 is worth watching
By Paul and Mary Meredith
Oct. 11, 2012 at 5:11 a.m.
Winter comes to the Great Plains and the Eastern U.S. Small birds run out of food - insects hibernate, seeds are scarce.
As it has for eons, migration begins to warmer climes and food in Central and South America.
With and behind the small birds come their predators: raptors. Raptors include hawks, eagles, falcons, kites, owls and vultures.
Our Coastal Bend geography (our "funnel" of land east of the U.S. and Mexico mountains), and the reluctance of raptors to fly over open water, draw almost all raptors living east of the Rockies to migrate through our area in September and October.
Little birds fly at night; raptors rest at night. Flying during the day, raptors use rising, sun-heated air (thermals) to lift them to altitudes from 1,000 to nearly 6,000 feet. Gradually descending from the height they reach, they can coast 15 miles - sometimes as much as 50 miles. When they encounter other thermals, nature's elevator lifts them to glide again and again - until the sun goes down, earth cools and thermals disappear. Flying using thermals saves raptors energy.
Fall weather fronts give raptors another boost. The north winds of the fronts help propel them south at extraordinary speeds. In numbers and densities so high, they are detected as streams of birds on weather radar in Corpus Christi.
Their migration is why we can enjoy Hawk Watch, one of the biggest in the U.S., at Hazel Bazemore County Park near Calallen (at Farm-to-Market Road 124 and County Road 69, west of Corpus Christi), basically starting in August and continuing through mid-November. Some raptors likely have already been through the area earlier; many others are still coming.
The vast majority of U.S. and Canadian hawks are headed to their winter homes. Unlike some hummers who migrate over water, raptors avoid that migration path. The way raptors fly causes them to lose a larger percentage of their weight than hummers do. So "over water" is not as safe for them, considering the distances they have to fly. And where could they land to rest if they tired over water?
No other U.S. site lists more species than Bazemore. And different times during the period are best for viewing different species. The best days for seeing Cooper's hawk and American Kestrel are Sept. 20-Oct. 15. Broad-winged hawks are the most common and are seen almost the whole time.
Peak migration generally occurs Sept. 23-30. Typically, an average of more than 500,000 raptors are counted then, and several days' counts are more than 100,000. An average of 730,000 raptors are seen during the watch.
At Bazemore, there's a platform for watching. For fall watching, you're advised to take a lawn chair, plus some other equipment, including skin protection.
Sources: Birding Corpus Christi and the Coastal Bend, Jamie Ritter; Hawk Watch Opens at Hazel Bazemore Park, Phyllis Yochem, Corpus Christi Caller-Times; "Hummingbirds of North America," Sheri L. Williamson
Paul and Mary Meredith are master naturalists. Contact them at firstname.lastname@example.org.