Airports servicing metropolitan areas are frequently
constructed away from urban centers and the decisions of where to
build them are usually based on socio-economic and political arguments
rather than on biological factors. Con-sequently, airports are often
placed in undeveloped areas that have high potential as wildlife
habitat and may also serve as sites for municipal waste treatment
and disposal. Wetlands, in particular, can be found in the vicinity
of numerous airports because these habitats generally are left undeveloped
and therefore may provide for airport approaches involving less
risk to the public than approaches over developed areas.
wetlands near Augusta's Bush Field Regional Airport.
In the case of Augusta, Georgia, for example, the 1997 construction
of artificial wetlands, for testing the feasibility of wastewater
treatment, placed 60 acres of wetland marsh and open water habitat
within a mile of the Augusta Regional Airport at Bush Field. If
successful, the artificial wetlands project could be expanded to
include as much as 360 acres. Although the airport lies adjacent
to the Savannah River and there are already more than 5,000 acres
of both man-made and natural wetland habitats within five miles
of the airfield, the U.S. Federal Aviation Administration concluded
that the creation of these artificial wetlands increased the potential
for bird-aircraft collisions near Bush Field.
|American Coots (top)
and Ring-necked Ducks are just two species of waterfowl commonly
found in wetlands of the SE United States.
Over a one-year period, The University of Georgias Savannah
River Ecology Laboratory conducted weekly aerial surveys of birds
using the entire wetland complex to the north and northeast of Bush
Field, including the newly constructed wetlands. These surveys were
designed to provide precise information on the temporal and spatial
distributions of birds within the area of interest.
Approximately 42,000 birds representing 52 species, including the
federally endangered Wood Stork and threatened Bald Eagle, were
seen during the aerial surveys. More than twice as many birds were
observed during the winter and spring/fall migratory periods (OctoberApril)
as during the breeding and post-breeding seasons (MaySeptember).
During the winter and migratory periods, waterfowl (including ducks,
geese, and swans) and the closely allied American Coot dominated
the avian assemblage, averaging 65% of all birds counted. Aerial
surveys indicated that other portions of the overall wetland complex
within five miles of the airport supported as many or more birds
than the artificial wetlands. Flood conditions associated with periods
of high rainfall increased habitat available to aquatic birds in
some portions of the wetland complex and thus affected bird numbers.
Herons and egrets
are wading birds that are
often found in wetlands of the SE United States.
In contrast, during the breeding and post breeding seasons, medium-to-large
wading birds (herons, egrets, storks, and ibises) were the most
abundant, accounting for 56% of the birds typically seen. During
the summer months, habitat changes within the artificial wetlands,
including drawdowns, produced fish kills and exposed mudflats, thereby
increasing use of the site by wading birds and shorebirds. Low water
conditions throughout the wetland complex during late summer favored
increased use by these same species.
Bird strike and incident reports from the airport indicated that
birds were most often hit while on or over the airfield itself.
Although the species involved was not always certain in the bird
strike reports, no aquatic birds were implicated, and most could
be placed within the small-to-medium songbird category. Incident
reports of birds further implicated small-to-medium songbirds. Starlings
on the airfield accounting for the majority of sightings.
|Numbers of birds observed
from January 1998-January 1999 in wetlands near the Bush Field
Airport, Augusta, GA.
Results from this study indicate:
Efforts to reduce bird strikes will require effective habitat
management on the airport property, with a goal of reducing numbers
of small land birds
Seasonal differences in species types
and abundance are an important consideration in developing plans
for reducing bird hazards to aircraft throughout the area.
The artificial wetlands currently
are not any more attractive to most birds than are other portions
of the wetland complex within the five-mile zone.
Thoughtful and effective management
can minimize bird use of the artificial wetlands by making them
less appealing to birds, thus displacing birds to more attractive
habitats further from the airport.
Weather patterns affect flooding
and water levels, favoring different bird groups under different
Human impacts on habitats outside
of the immediate survey area, but within the local region, could
represent yet another factor affecting bird populations around
Additional studies will be needed
to address questions of annual variation in patterns identified
during the first year.
Birds, and Airports
to Research Snapshots)