Flight response of geese to helicopter traffic. Offshore oil drilling near an Alaskan estuary has led to increased air traffic—mostly large helicopters—in the area. The U.S.

Fish and Wildlife Service commissioned a study to investigate the impact these helicopters have on the flocks of Pacific brant geese that inhabit the estuary in the fall before migrating (Statistical Case Studies: A Collaboration between Academe and Industry, 1998). Two large helicopters were flown repeatedly over the estuary at different altitudes and lateral distances from the flock. The flight responses of the geese (recorded as “low” or “high”), the altitude (in hundreds of meters), and the lateral distance (also in hundreds of meters) for each of 464 helicopter overflights were recorded and are saved in the GEESE file. The data for the first 10 overflights are shown in the following table.

Overflight Altitude Lateral Distance Flight Response 1 0.91 4.99 HIGH 2 0.91 8.21 HIGH 3 0.91 3.38 HIGH 4 9.14 21.08 LOW 5 1.52 6.60 HIGH 6 0.91 3.38 HIGH 7 3.05 0.16 HIGH 8 6.10 3.38 HIGH 9 3.05 6.60 HIGH 10 12.19 6.60 HIGH Source: From Erickson, W., Nick, T., and Ward, D. “Investigating Flight Response of Pacific Brant to Helicopters at lzembek Lagoon, Alaska by Using Logistic Regression.” Statistical Case Studies: A Collaboration between Academe and Industry, ASA-SIAM Series on Statistics and Applied Probability, 1998.

Copyright © 1998 Society for Industrial and Applied Mathematics. Reprinted with permission. All rights reserved.

a. The researchers categorized altitude as follows: less than 300 meters, 300–600 meters, and 600 or more meters. Summarize the data by creating a contingency table for altitude category and flight response.

b. Conduct a test to determine whether flight response of the geese depends on altitude of the helicopter. Test, using a = .01.

c. The researchers categorized lateral distance as follows:

less than 1,000 meters, 1,000–2,000 meters, 2,000–3,000 meters, and 3,000 or more meters. Summarize the data in the GEESE file by creating a contingency table for lateral distance category and flight response.

d. Conduct a test to determine whether flight response of the geese depends on lateral distance of helicopter from the flock. Test, using a = .01.

e. The current Federal Aviation Authority (FAA) minimum altitude standard for flying over the estuary is 2,000 feet (approximately 610 meters). On the basis of the results obtained in parts a–d, what changes to the FAA regulations do you recommend in order to minimize the effects to Pacific brant geese?