A Nighthawk Migration on an Arizona Desert
A Nighthawk Migration on an Arizona Desert
When returning by automobile to Grand Canyon, Arizona, on July 29, 1941, Mrs. Bryant and I were astonished at the large number of migrating Nighthawks (Chordeiles mirror) to be seen in food-getting flight over the desert. After noting twenty or more we decided to take a census. The following results were obtained between 7:30 p.m. and 755 p.m., sunset included, on a stretch of the Grand Canyon approach road about 35 miles south of Grand Canyon. The country is covered with sagebrush, with occasional patches of juniper and pfion pine. Mrs. Bryant watched on one side and I on the other, while driving. All birds counted were within 200 yards of the highway so that the strip used in the census was not more than 400 yards wide. We doubt whether the birds were any more abundant near the road than on the open desert and believe this count is a reliable sampling of abundance. The car traveled at 50 miles per hour. Probably many birds were missed in the course of the last few miles because of poor visibility with darkness fast approaching.
Mile Nighthawks Mile Nighthawks
1st 5 10th 2
2nd 5 11th 2
3rd 8 12th 1
4th 6 13th 3
5th 3 14th 1
6th 4 15th 2
7th 3 16th 4
8th 2 17th 0
9th 0 18th 0
This made a total of fifty-one nighthawks, seen in a narrow belt over eighteen miles of desert, or an average of nearly three per mile, from a speeding car. And, of course, there were more birds than the eye could catch. The lack of bids in the last two miles may be attributed to the darkness.
H. C. Bryant
Grand Canyon, Arizona, September 6, 1941
