Research Projects

Vegetation Height and Impacts on Deterring Small Birds on Airports

Vegetation and grass height is suggested to be between 7-14 inches on airports to deter small bird species; this concept has been tested in the past, with mixed results. I suggest a study should be conducted building on the previous publications keeping in mind new technologies and different grass management strategies to determine if current best management strategies are sufficient or may need to be updated.

Background (Describe the current situation or problem in the industry, and how your idea would address it.)

The U.S. Air Force recommends vegetation height for ground cover (specifically grass) to deter birds from loafing or feeding is 7 to 14 inches (18-36 cm). This information is based on European studies conducted in the 1960s and 1970s. The FAA Wildlife Hazard Management at Airports manual (Cleary and Dolbeer 2005) states that more information is needed to develop specific guidelines. Washburn and Seamans (2013) specifically discuss many of the previous studies, their flaws, knowledge-gaps, and provides future suggestions of research. In leu of specific guidance many airports will use the 7 to 14 inch management scheme. Other studies investigated if vegetation height impacts use by birds and have reported mixed results. The proposed research for the IdeaHub will look at previous research and provide a more controlled, systematic methodology to investigate vegetation height effects use by birds. "Grass" or ground covering on airports are rarely composed of only grass species and the added diversity of multiple species of plants may not be accounted for how the area is used by birds. Additionally, the types of birds effected is important to consider. This proposed research suggest that the management is intended to be effective on small bird species that are a higher threat to aircraft safety (Dolbeer et al. 2000, 2010, DeVault et al. 2011). Geese have been studied determining if they prefer short or tall grass resulting in no preference (Seamans et al. 1998), but the intent of the 7-14 inch grass height was in response to movement of European starlings and gulls (Washburn and Seamans 2004). Finally, bird behavior should be included to inform how birds react to different management schemes or composition.

Objective (What is the desired product or result that will help the airport industry?)

The desired objective is to provide further evidence to support a widely used management practice for wildlife. As new technologies or best management practices are developed then suggested management strategies should be updated. Wildlife Hazard Management Plans can incorporate the data from the proposed research to provide specific applications to reduce bird strikes at airports.

Approach (Describe in general terms the steps you think are needed to achieve the objective.)

The key to this study is the methodology to determine what factors of vegetation at different heights and possibly composition is most effective to deter small birds. Additionally, using bare ground and comparing synthetic grass may be of interest. This study requires an area or multiple areas with replicated plots of planted or existing vegetation accessible to observers. Trained biologists with the possible support of trail cameras are needed to observe birds and their behavior to determine use.

Cost Estimate and Backup (Provide a cost estimate and support for how you arrived at the estimate.)

The scope of this survey could cost approximately $100,000, for a 12–18-month study, more for a long-term study. A pilot study could be done for approximately $30,000-$40,000. The greatest factor is the time and cost to install the study plots. A few acres of land will need to be available and prepared that would cost from $10,000-$20,000 for labor and materials. Field work to conduct bird observations will need to be replicated over time using trained biologists or specialized equipment. Finally, professionals will be needed to complete the report and findings accurately and on time.

Related Research - List related ACRP and other industry research; describe gaps (see link to Research Roadmaps above), and describe how your idea would address these gaps. This is a critical element of a synthesis topic submission.

Cleary, E. C. and R. A. Dolbeer. 2005. Wildlife hazard management at airports, a manual for airport operators. Second edition. Federal Aviation Administration, Office of Airport Safety and Standards, Washington, DC, USA. 348 pages. (

Barras S.C., R.A. Dolbeer, R. B. Chipman, G. E. Bernhardt, and M.S. Carrara. 2000. Bird and small mammal use of mowed and unmowed vegetation at John F. Kennedy International Airport, 1998 to 1999. Proceedings of the Vertebrate Pest Conference, 19(19).

Seamans, T.W, R.A. Dolbeer, M.S. Carrara, and R.B. Chipman. 1998. Does tall grass reduce bird numbers on airports?: results of pen test with Canada gees and field trails at two airports, 1998. 1999 Bird Strike Committee-USA/Canada, First Joint Annual Meeting, Vancouver, BC. 29. Comparison of 2 vegetation-height management practices for wildlife control at airports (2007). Human-Wildlife Interactions. 131.

Seamans, T.W, S.C. Barras, G.E. Bernhardt, B.F. Blackwell, and J.D. Cepek. 2007.

Washburn B.E. and T.W. Seamans. 2004. Management of vegetation to reduce wildlife hazards at airports. USDA National Wildlife Research Center – Staff Publications. 396.

Washburn B.E. and T.W. Seamans. 2013. Managing turfgrass to reduce wildlife hazards at airports. USDA National Wildlife Research Center – Staff Publications. 1603.

The research idea proposed will fill in gaps in the above research by creating experimental plots of vegetation at different heights (and possibly composition) that can be repeated to control variables. Utilizing a more controlled experiment should provide more statistically rigorous understanding of how each variable will impact use by birds, that the previous research could not determine. The addition of new technologies or management techniques should also be included in the study such as synthetic grass and fescue with fungal endophytes to give airports further options. The study should focus on small hazardous bird species with a higher risk to aircraft operations to provide airports with small bird management-specific guidance. Additionally, behavior has not been studied may be a missing element in understanding how vegetation height or composition effects use by each bird species.



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Idea No. 598