Balancing aviation with wildlife at Denver International Airport
Ricardo Martinez-Marrero, Denver International Airport’s Wildlife Co-ordinator, writes exclusively for International Airport Review about how the airport balances aviation safety and wildlife conservation through innovative strategies, ensuring safe operations for over 82 million passengers annually.
Managing wildlife hazards for safety
An expanse of land big enough to comfortably fit entire cities such as San Francisco, or Boston within its bounds; Denver International Airport (DEN) is situated on grassland prairie next to the foothills of the Rocky Mountains. This location is not just home to an abundance of resident birds and native mammals, but also provides a travel corridor which facilitates the seasonal migrations of waterfowl and raptors. Wildlife Hazard Assessments and monitoring of wildlife populations have identified several species considered to pose a threat to aviation such as columbidae (doves and pigeons), icterids (blackbirds and meadowlarks), passerines (lark buntings and horned larks), waterfowl (ducks and geese), and raptors (hawks and eagles); several mammal species are also listed to include coyotes, deer and antelope.
Wildlife Hazard Assessments and monitoring of wildlife populations have identified several species considered to pose a threat to aviation
As the sixth busiest airport in the world, third busiest in the United States, DEN accommodates roughly 2,000 flights per day, ending 2024 with a passenger count of just over 82 million. DEN is a critical component of the National Airspace System. For this aerotropolis to keep the world moving, it requires the collaboration of approximately 40,000 employees to support its 24/7 operation. At its core lies the Operating Certificate issued by the Federal Aviation Administration (FAA), with one of its more demanding requirements being the upkeep of the Wildlife Hazard Management Plan (WHMP). It emphasises identification and abatement of wildlife hazards within the airfield, as well as addressing wildlife attractants within five miles of the field. Sections of this plan are explained ahead.
Collaborative efforts to mitigate wildlife hazards
First, the plan begins with the ‘Authority’ section which lays out the roles and responsibilities of the groups who work together on the implementation of the plan. It starts with the Senior Vice President of Operations who designates a Wildlife Co-ordinator and establishes the Wildlife Hazard Committee (WHC) which is made up of the following groups: airport operations, wildlife services/Biologists, maintenance staff, engineers, air traffic control (ATC), media relations, contract management and commercial business. Each of these groups plays an important role in the success of the wildlife programme.
Airport operations carries out a vast majority of the responsibilities outlined; these include inspection of runways and taxiways, co-ordination efforts for wildlife control activities, monitoring facilities for wildlife-related problems, collection of bird strike samples to be submitted to the Biologists, documentation of all wildlife activity and strikes, obtain appropriate permits to conduct wildlife mitigation activities, issuance of Notice to Airmen (NOTAMs), pre-approve landscape changes to refrain from creating additional wildlife attractants and removal of trash and debris on the airfield.
Another group just as heavily involved is the United States Agricultural Department (USDA) – Wildlife Services which includes the Qualified Airport Wildlife Biologists. Their objectives revolve primarily around the WHMP by assisting airport personnel in monitoring the airport environment for wildlife hazards, taking corrective action and submitting findings to the Wildlife Co-ordinator. In addition, they assist with wildlife identification reporting, provide all required training to airport personnel, co-ordinate with other government agencies involved with wildlife management, assist DEN in reviewing proposed land changes, construction plans and mitigation projects for wildlife hazards, and consider DEN’s subject-matter experts for writing and making amendments to the WHMP.
Credit: Benjamin Allen-USA, Denver International Airport
Maintenance and engineering play important roles in passive management and habitat modification. These efforts encompass maintaining the perimeter fence, mowing vegetation, shaping ditches and fields for proper water flow, minimising pooling and drainage issues on the tarmac, installing and maintaining exclusionary devices, and reviewing all plans involving landscaping and addition of new structures/facilities.
Other members of the WHC include the ATC who assists with project reviews, warns Pilots of wildlife hazards and notifies airport operations of any wildlife activity impacting traffic. Meanwhile, media relations will spread awareness of wildlife activities and provide necessary public relations support. Finally, the commercial business manages the airport’s contracts with tenant property owners who farm the agricultural fields around the outskirts of DEN. These tenant farmers are a vital piece in properly maintaining what would otherwise be vast tracts of remote wilderness throughout the perimeter of the airfield while, at the same time, generating non-aeronautical revenue.
Reducing wildlife attractants
It’s been proven over the years that habitat management yields the most successful results when mitigating wildlife hazards in airports. Habitat management is the manipulation of the airfield environment to make it less attractive to wildlife. This can be accomplished through physical removal, implementation of exclusion devices and/or complete renovation of an area. At DEN, habitat management is broken down as follows: project prioritisation, water management, vegetation management and structure management.
Credit: Benjamin Allen-USA, Denver International Airport
Project prioritisation showcases wildlife projects in a table format divided into two categories. The first table lists items that are either ongoing, scheduled, or recommended and puts them in order according to their priority levels starting with the most urgent. A column for progress made is also included. For instance, improvements to drainage can be found near the top of the list as standing water is a wildlife attractant for all species. The ‘progress’ column shows the completion dates of drainage projects around the airfield followed by the next drainage project on the list which involves continued planning for additional trickle channels along RWY 17L/35R. The second table displays a list of completed wildlife projects along with corresponding dates and comments. Items on this list include ‘evaluate the use of wildlife exclusion materials on navigational aids and ‘establish/enforce a strict no-feeding policy’.
Structure management examines new and existing structures, how they may provide shelter and perches and exclusion efforts to lessen their attractiveness for wildlife
Importantly, the management of water, vegetation and sections of structures identify attractants and proper mitigation practices. The water management section focuses on the several wetlands, water detention basins and glycol ponds that exist on the airfield and a large lake to the northwest; these are attractive to waterfowl and must be monitored continuously. Vegetation management identifies the diverse vegetation types found at DEN and focuses on those attractive to wildlife. Grass management involves maintaining proper grass height, removing shrubs and trees where applicable and controlling grass types used in construction projects and crops grown by tenant farmers. Structure management examines new and existing structures, how they may provide shelter and perches and exclusion efforts to lessen their attractiveness for wildlife. The structures reviewed range from the terminal to parking structures and the perimeter fence.
Balancing wildlife conservation and aviation safety
The environment is a primary focus of the FAA and DEN alike. The Triple Bottom Line proposes that maintaining harmony between people, the planet and profit is imperative for the health of businesses. It is taught throughout various disciplines in higher education and is emphasised in the aviation industry. One of the more effective methods in promoting ‘planet’ is through legislation. DEN dedicates a section of the WHMP to discuss applicable laws and regulations that govern wildlife management efforts. The section begins with an overview of Colorado Wildlife Regulations and Federal Regulations naming the multiple agencies that oversee wildlife programmes and the governmental acts that give them their jurisdiction for enforcement. Furthermore, birds and mammals found at DEN are categorically listed to describe the rules and regulations that apply, as well as the required permits, for the sake of each species. There is another segment for protected wildlife that discusses the endangered species list, habitat conservation efforts, pesticide application requirements and pertinent FAA Regulations.
Credit: Benjamin Allen-USA, Denver International Airport
Utilising technology and tools for wildlife control
The ‘Resources’ section refers to the wildlife control supplies that are kept on hand at DEN and utilised by trained personnel. Examples of these resources include pyrotechnic launchers, field guides, binoculars, bird strike kits, et cetera. This section standardises the minimum required supplies that should always be available in airport operations vehicles. It also specifies the resources that are only to be handled by USDA personnel.
Using drones for wildlife dispersal has been a hot topic at DEN since it was recently approved on DEN’s Migratory Bird Depredation permit by the U.S. Fish and Wildlife Service. Airport operations personnel have been experimenting with DJI drones. So far, it has proven to be effective on flocks of geese migrating through the area
‘Wildlife Control Procedures’ relates to how the resources are used for wildlife control. Topics such as bird strike response, reporting procedures and communications with the ATC are explained here. Wildlife control methods are also listed including raptor trapping/relocation, auditory frightening techniques (pyrotechnics and propane cannons) and visual frightening techniques (vehicle patrols and the recently approved usage of Unmanned Aerial Vehicles (UAVs/Drones for wildlife dispersal). Using drones for wildlife dispersal has been a hot topic at DEN since it was recently approved on DEN’s Migratory Bird Depredation permit by the U.S. Fish and Wildlife Service. Airport operations personnel have been experimenting with DJI drones like the Mavic 3 and Matrice along with spotlight and speaker attachments. So far, it has proven to be effective on flocks of geese migrating through the area. Other variables such as weather and traffic patterns also factor in the success of the drones.
Compliance through reviews and continuous training
The last two sections of the WHMP examine the procedures for conducting WHMP Reviews. These are conducted after triggering events (strikes involving multiple birds, damage, or engine ingestions) and/or once every 12 consecutive calendar months by the WHC. The ‘Evaluation’ section also sets the requirement for the WHC to meet quarterly to discuss projects, concerns and share data.
Lastly, the ‘Training’ section details the annual training requirements for Airport Operations personnel to include wildlife identification, review of hazard trends, understanding the WHMP, use of pyrotechnics and strategies for dispersing birds.
As the Wildlife Co-ordinator at Denver International Airport, Ricardo Martinez-Marrero, or Ricky as he’s known to those around him, has the responsibility of providing direction for the airport’s wildlife programme which is primarily dictated by the Wildlife Hazard Management Plan. As an avid enthusiast of the natural world and having allowed his love of aviation to guide his life’s work, this position could not be a better fit.
With nine years of experience in airport operations, Ricky has worked in several airports around the U.S., four of those years being at DEN with airside operations. Throughout this time, his primary role has been in Part 139 compliance with a background in special projects ranging from fuelling to gate management, and now wildlife.
A lifelong learner, Ricky earned his degree from Jacksonville University in Aviation Management, has acquired several certifications from AAAE, and is currently pursuing his AAE.
