ACCESS NUMBER: 30951-16808 

STUDY TITLE: Interactions Between Migrating Birds and Offshore Oil and Gas Structures Off 

the Louisiana Coast 

REPORT TITLE: Interactions Between Migrating Birds and Offshore Oil and Gas Platforms in 

the Northern Gulf of Mexico: Final Report 

CONTRACT NUMBER: 1435-01-99-CA-30951-16808 

SPONSORING OCS REGION: Gulf of Mexico 

APPLICABLE PLANNING AREAS: Eastern Gulf of Mexico, Central Gulf of Mexico, Western 

Gulf of Mexico 

FISCAL YEARS OF PROJECT FUNDING: 1998; 1999; 2000; 2001; 2002; 2003 

COMPLETION DATE OF REPORT: March 2005 

COSTS: FY: 1998: $535,375; 1999: $362,981; 2000: $0; 2001: $0; 2002: $0; 2003: $0 

PROJECT MANAGER: Robert W. Russell 

AFFILIATION: Louisiana State University 

ADDRESS: 2179 Energy, Coast and Environment Building, Baton Rouge, LA 70803 

PRINCIPAL INVESTIGATOR: Robert W. Russell 

KEY WORDS: migratory birds; trans-Gulf migration; Gulf of Mexico; oil and gas platforms 

BACKGROUND: Year after year millions of birds migrate during the spring and fall seasons. 

During these migration seasons, birds will travel over the Gulf of Mexico using oil and gas 

platforms as stopover sites. This study provides data and analyses of trans-Gulf bird migration 

from three years of intensive study on 13 platforms located in offshore waters in the northern 

Gulf of Mexico, and provides environmental information concerning the possible influence of 

platforms on migrating birds. 

OBJECTIVES: This study was conducted over a three-year period on 13 platforms located in 

offshore waters of the Gulf of Mexico and sought to address the following: 1) which species are 

migrants; 2) are there specific migration routes; 3) when do migrants use platforms for 

stopovers and how does the timing of platform use relate to seasonal and diel timing and 

weather; 4) how many migrants use platforms as stopovers and how does that number relate to 

the total trans-Gulf migration traffic aloft; 5) what is the condition of birds that use platforms and 

what determines how long they stay; 6) do migrants use platforms in predictable ways; 7) and 

how many migrants that stop on platforms depart successfully versus die, and why do some 

birds die?. 

DESCRIPTION: The platforms selected are representative of both structure and geography. 

Field work was conducted on five platforms from mid-March to mid-May in spring 1998 and 

1999 and from mid-August to mid-November in fall 1998. The study expanded with ten 
ACCESS NUMBER: 30951-16808 

platforms staffed from early August through mid-November in fall 1999, and nine platforms 

staffed from early March to late May in spring 2000. One platform was staffed year round in 

1999-2000. 

Field observers conducted a “platform census” while walking around the platform on a 

prescribed route, with the goal of locating, counting, and identifying all living birds on the 

platform at different times of the day. The following information about a migrant was recorded 

whenever possible: species, age, sex, details of behavior, and apparent physiological condition. 

Additionally, visual surveys of the airspace around platforms was assessed to determine the 

volume of flyby migration traffic and to quantify the flight behavior of trans-Gulf migrants. 

To estimate the density of migration traffic, the use of radar was employed. Radar reflectivity 

can be converted into migration traffic rates using the theoretical and empirical models of radar 

cross section, provided that one has information concerning the approximate size distribution of 

the radar scatterers, such as that available from the platform observations. 

SIGNIFICANT CONCLUSIONS: In both spring and fall, variation in the direction of travel may 

have been influenced by wind. Many species may select days of travel when tail winds may 

prevail and correlate with synoptic weather patterns over the continental United States. 

Favorable weather patterns may persist for more than one day. Small differences in wind 

direction between favorable synoptic weather patterns may correlate with subtle differences in 

migration routes of many species if they are somewhat steered by prevailing wind directions. 

STUDY RESULTS: The study found that platforms appear to be a suitable stopover habitat for 

most species, and most of the migrants that stopped over on the platforms benefited from their 

stay, particularly in spring. The migrants used the platforms in nonrandom ways and the 

structures facilitated the trans-Gulf migration by providing “steppingstones” across the Gulf of 

Mexico.

STUDY PRODUCTS: Russell, R.W. 2005. Interactions between migrating birds and offshore 

oil and gas platforms in the northern Gulf of Mexico: Final Report. U.S. Dept. of the Interior, 

Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study 

MMS 2005-009. 327 pp.