Best management practices for mitigating impacts to streaked horned larks on occupied airfields

The streaked horned lark (Eremophila alpestris strigata; “larks”) best management practices (BMPs) have been developed to guide airport and federal lands site management that enables the ongoing use and maintenance of site functionality for the site’s intended purpose while minimizing impacts to streaked horned larks. The streaked horned lark is listed as threatened under the Federal Endangered Species Act (ESA; 16 USC 1531 et seq., 78 FR 61451, listing effective November 4, 2013) and was listed as endangered by the State of Washington Fish and Wildlife Commission under the authority of the Washington Administrative Code (WAC) 220-610-110. The intent of the BMPs is to contribute to the recovery and conservation of the streaked horned lark while conducting regular airport operations and required safety and maintenance activities at airport sites occupied by larks. Incorporating the BMPs into site planning and management meets objectives of the ESA, particularly Section 7, where federal agencies must aid in listed species conservation and ensure their activities are not likely to jeopardize the species’ existence. It is agreed upon by the Washington Streaked Horned Lark, Airports and Federal Lands Working Group (hereafter “working group”) that not all options in the BMPs will be feasible to implement by all users, and the BMPs are not a finite or inflexible list. There are likely other project management options not considered within these BMPs that may be appropriate. This document is intended to be dynamic and to incorporate new, innovative practices that achieve the dual goal of site management and lark conservation while encouraging site managers to implement these actions voluntarily or through formal consultation. Federal lands and military installations can use these guidelines in establishing conservation measures with the USFWS. Site managers who employ new, yet successful site management strategies are encouraged to document in detail (e.g., description, phasing, photos) those strategies to be incorporated into future updates to this document so others are aware of their potential use.

Avoiding, Minimizing, and Mitigating Adverse Impacts

Activities that occur within habitat used by breeding larks may result in incidental take (i.e., take that is incidental to, and not the purpose of, the carrying out of an otherwise lawful activity) either through physical harm to individuals or reduced capacity of the habitat to serve essential life functions, such as reproduction, foraging, and survival. The application of these BMPs reduces the risk of incidental take of larks due to site management and use. Both the ESA and WAC requires that such impacts be avoided or, if unavoidable, minimized to the maximum extent practicable to protect listed species. Where impacts cannot be avoided or minimized, mitigation to compensate for unavoidable take may be appropriate.

The USFWS Section 7 consultation process outlines the requirements for projects conducted at federally obligated airports for which the FAA is the lead federal agency (i.e., providing funding for improvements or approving an action or airport management plan). Biological Opinions (BO) issued by the USFWS include Terms and Conditions for minimizing impacts to larks. USFWS consults with airport managers and FAA to incorporate conservation measures directly into project descriptions and contracts, thereby removing the need to require those conservation measures within the Terms and Conditions. Airports are required to comply with their FAA federal grant assurances. Nothing within this document replaces or supersedes this federal process; rather, these BMPs are intended to support and streamline that process for the applicant. The consulting agency (e.g., FAA) and the applicant (e.g., airport being represented by the agency) can include BMPs as Conservation Measures in their project description to minimize take, thus reducing or eliminating the necessity for additional Terms and Conditions within the required BO. Application of these BMPs is intended to make the consultation process smoother and more efficient. Airports must ensure that implementation of any BMP will not result in non-compliance with any FAA regulation, policy, or grant assurance, and must not impact the safety or efficiency of airport operations. From the state (i.e., WDFW) perspective regarding non-federal jurisdictional permit review (e.g., city or county), adherence to BMPs will also make that process smoother and help satisfy the state’s requirements for avoiding, minimizing, and mitigating impacts to larks. Most BMPs within this document can be used in conjunction with other applicable BMPs.

Non-federal entities must obtain an incidental take permit for taking of a listed species incidentally to, but not the purpose of, carrying out an otherwise lawful activity (16 U.S.C. 1539(a)(2)(A)(i)-(iv)). These incidental take permits are possible through section 10(a)(1)(B) of the ESA. This section 10 process involves three phases: development of a Habitat Conservation Plan (HCP), formal permit processing, and post-issuance. Nothing within this document replaces or supersedes the requirements of an adopted HCP where one exists. Rather, these BMPs are intended to support and streamline the inclusion of streaked horned lark conservation principles into the HCP process.

For the purposes of this document, the lark breeding and nesting season (which includes pair bonding and nest building) is mid-March through late August but can vary depending on climatic conditions and region (Pearson and Hopey 2004; Moore 2011; Wolf 2011). It is generally agreed upon by the working group that site activities planned outside of the nesting season that result in no adverse impacts to individuals and no permanent impact to or loss of suitable lark habitat will receive a “not likely to adversely affect” (informal consultation) or a “no effect” determination by federal and state agencies.

Caveats to the Implementation of Best Management Practices

Per the Memorandum of Understanding (MOU) between the USFWS and FAA (2019), airports cannot engage in “any process, procedure, or agreement that would lead to an increase in lark populations or the enhancement or creation of lark habitat within the boundaries of the airport property or adjacent to the airport property where the species could interfere with current and future departure and arrival airspace.” The MOU further states, “The recovery approach for lark populations on airports will be to maintain the current populations until alternate off-airport sites can be established. Only after new sites have been established and colonized by larks will it be appropriate to implement practices to make airports less attractive to larks, which will ultimately benefit both the larks (by discouraging them from using the inherently unsafe habitats on airports) and aviation (by reducing the risk of bird-aircraft strikes).” These BMPs are intended to help meet both objectives of the MOU. The working group recognizes the need to continue collaborating on establishing larks off-airports and will continue to spend time on this pursuit.

Compliance Monitoring, Adaptive Management, and Scientific Research 

In addition to being state and federally listed, streaked horned larks are a Species of Greatest Conservation Need under WDFW’s State Wildlife Action Plan (SWAP). The SWAP is part of a nationwide effort by all 50 states and five U.S. territories to develop conservation action plans for fish, wildlife, and their natural habitats and identify opportunities for species' recovery before they are imperiled and more limited. Streaked horned larks are also a Priority Species under WDFW's Priority Habitat and Species Program. Priority species require protective measures for their survival due to their population status, sensitivity to habitat alteration, and/or recreational, commercial, or tribal importance. The various BMPs contained within this document directly relate to lark survival and productivity on the airports and federal lands they inhabit as well as range wide lark recovery. The information gained through tracking compliance along with input from site managers should be used to adapt these BMPs. While these BMPs are recommendations and are not enforceable by law, monitoring the use of these BMPs is a critical component to improving the use of activities in occupied lark habitat.

Variables and values referenced herein are based on cited applicable research. Where research was lacking, guidance was developed based on the expertise of the working group. In all cases, best available science provided by WDFW and USFWS should be used and incorporated into the implementation of BMP activities.

All BMPs listed in this document are potentially applicable for use in occupied lark habitat and may have a benefit to the maintenance of lark populations. Specific BMPs are known to positively maintain lark populations most, particularly Avoidance, Sequencing, Mowing plan development, Least-impact mowing Equipment, and Disturbance buffers.