University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln USDA National Wildlife Research Center - Staff U.S. Department of Agriculture: Animal and Plant Publications Health Inspection Service 2013 Wildlife in Airport Environments: Chapter 2 Behavior and Physiologyin the Development and Application of Visual Deterrents at Airports Bradley F. Blackwell USDA/APHIS/WS National Wildlife Research Center, [email protected] Esteban Fernandez-Juricic Purdue University, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/icwdm_usdanwrc Part of the Life Sciences Commons Blackwell, Bradley F. and Fernandez-Juricic, Esteban, "Wildlife in Airport Environments: Chapter 2 Behavior and Physiologyin the Development and Application of Visual Deterrents at Airports" (2013). USDA National Wildlife Research Center - Staff Publications. 1660. https://digitalcommons.unl.edu/icwdm_usdanwrc/1660 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Animal and Plant Health Inspection Service at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USDA National Wildlife Research Center - Staff ubP lications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. From Wildlife in Airport Environments: Preventing Animal-Aircraft Collisions through Science-Based Management, ed. T.L. DeVault, B.F. Blackwell, & J.L. Belant (Baltimore: Johns Hopkins University Press, 2013). 2 Behavior and Physiology BRADLEY F. BLACKWELL ESTEBAN in the Development and FERNAN DEZ-J URIC IC Appl ication of Visual Deterrents at Ai rports n the first major treatise on the science of wildlife dogs to protect livestock against mammalian preda­ I damage management, Conover (2002) dedicated tors (Rondinini and Boitani 2007) and contact with a short review of visual stimuli used to deter wildlife wild ungulates (Gehring et al. 2010). Visual stimuli from specific areas or resources. The brevity of the that cue alert responses, as opposed to provoking fear, review reflects the fact that these techniques have have been investigated relative to deer-vehicle colli­ traditionally been developed over short periods and sions (D'Angelo et al. 2006, Blackwell and Seamans used to confront an immediate problem, generally 2009) and in eliciting desired behavioral responses through trial and error. Because humans perceive vi­ in birds (e.g., avoiding collision with static objects sual stimuli differently than other animals (Schwab [Martin 2011]; enhancing detection and response to 2012), deterrents based on human perception likely approaching aircraft [Blackwell and Bernhardt 2004; fall short in saliency of the stimuli (Le., how well the Blackwell et al. 2009, 2012a; Fernandez-Juricic et al. stimuli stand out against a background). However, as­ 2011 D. In this chapter we distinguish between visual sessment of visual stimuli (both deterrents and cues) methods that serve as the primary deterrent or cue in the context of animal sensory physiology and be­ and color cues used as conditioned stimuli in the havior holds promise for the development of novel context of chemical repellents (Chapter 3). We refer and more effective methods to mitigate negative to visual stimuli intended to provoke fear and cues human-wildlife interactions. designed to enhance detection of objects as visual de­ As Conover (2002) noted, visual deterrents are terrents. generally intended to provoke a fear response. Ex­ The immediate and long-term effectiveness of visual amples include scarecrows or other human forms, ob­ deterrents varies by species (e.g., Koehler et al. 1990, ject movement (e.g., Mylar tape; Dolbeer et al. 1986), Mason 1998), season, group size (Dolbeer et al. 1986), predator models (Conover 1982, 1985; Conover and habitat, and even legal constraints (Conover 2002). Perito 1981), animal effigies (Avery et al. 2002, Sea­ Moreover, the effectiveness of visual deterrents (or mans 2004), methods that provoke neophobia (e.g., lack thereof) targeting birds or mammals is inherently coyote [Canis latrans] response to novel objects; linked to detectability, discriminability, and memora­ Windberg 1997), and methods that combine move­ bility, the three factors that govern design of animal ment and neophobia (e.g., use of lasers in bird disper­ signals (Guilford and Dawkins 1991; see also Endler sal [Blackwell et al. 2002, Gorenzel et al. 2002] and 1992). In this initial section of the chapter, unless oth­ fladry against wolves [c. lupus; Musiani et al. 2003]). erwise cited, we relate the discussion of these factors We can also include the use of border collies (c. famil­ to Guilford and Dawkins (1991). iaris) against birds at airports (Sodhi 2002) and other The environment through which the signal is trans- 12 WILDLIFE MANAGEMENT TECHNIQUES mitted, the sensory capabilities of the receiving ani­ remainder of this chapter is to discuss the importance mal, and the cognitive processing of the receiver affect of visual physiology, behavior, and ecological context as detectability of natural signals. Signal discriminabil­ components in the design and effective use of visual de­ ity connotes that the receiver recognizes in the signal terrents against mammals and birds. We review briefly stimuli some category by which a particular behavior (1) vision in mammals and birds relative to other sen­ (e.g., flight, avoidance of a prey item) is warranted. sory paths and deterrent efficacy, (2) threat recognition Memorability of the signal is linked to learning, where in animals, and (3) how visual deterrents are currently the signal is eventually associated with a particular used in the airport environment, as well as the efficacy outcome. From the perspective of natural signals, Guil­ of these methods. ford and Dawkins (1991) assigned these three factors as components of strategic signal design and tactical Vision as a Sensory Pathway design, or of signal efficacy. Whereas strategic design in animal signaling is Vertebrates have two types of photoreceptors: rods concerned with whether or why (in terms of fitness) and cones (McIlwain 2006, Schwab 2012). Rods deal the receiver responds appropriately, the second com­ with dim conditions and are not activated by bright ponent-efficacy-affects the probability that the light. The ability to perceive color is dependent on signal will reach its target destination and elicit a re­ the number of different visual pigments present in sponse. For instance, a signal might be salient because the cone photoreceptors (Cuthill 2006). Animals it is both easily detectable and occurs within the con­ with a single visual pigment cannot perceive color but text of familiar habitat (e.g., coyote response to an in­ can determine differences in brightness of a signal truder's sign or a novel object within the animal's ter­ (Land and Nilsson 2002). Animals with two or more ritory; see Windberg 1997). Taken another way, if this visual pigments can perceive color. This capability is same coyote encountered a novel object outside its explained by the way the visual system works. Light territory, though the object is readily visible, it would entering the retina stimulates the visual pigments of likely show little interest simply because there is not the photoreceptors to different degrees (depending an apparent intent (i.e., fitness consequence) to the on the wavelength distribution of light and the peak signal. sensitivity of the visual pigments). The visual system Efficacy in animal signaling also entails aspects of at the retinal level (amacrine cells, bipolar cells, hori­ what Guilford and Dawkins (1991) termed the receiv­ zontal cells, ganglion cells) uses stimulation ratios er's "psychological landscape;' or the cognitive process­ (instead of absolute stimulation values of a given vi­ ing of the signal that takes place behind the immediate sual pigment type) to estimate how much each pho­ sensory organs (in this case the eyes). Specifically, an toreceptor is stimulated compared to the others, and animal's signal might be composed of cues important then sends this information to the visual centers in within one context but intended for another. For ex­ the brain (Land and Nilsson 2002). Color perception ample, Guilford and Dawkins (1991) note that peacock is based on these stimulation ratios, which will vary (Pavo cristatus) tail coloration (i.e., the eye spots) will depending on the number of visual pigments in the draw the immediate attention of the peahen from a retina and the wavelength peak sensitivity of each vi­ vigilance perspective, but divert her attention to indi­ sual pigment (Gouras 2007). Animals with two visual cators of male fitness. pigments are known as dichromats, three visual pig­ Unquestionably, signaling and signal reception by ments as trichromats, four visual pigments tetrachro­ animals are multifaceted and complex (Endler 1990, mats, and so on. 1992; Endler and Thery 1996). For a visual deterrent to effectiv~ly communicate some a priori risk to a tar­ Mammals get animal or cue that attracts the animal's attention, we must ask what traits or conditions are required for The relevance of the visual systems of mammals varies detectability, both to reinforce signal strength and to widely across taxa (e.g., Langley 1983, and references extend the period of effectiveness. Our purpose in the therein) because some species, such as ungulates, rely VISUAL DETERRENTS 13 more on olfaction and hearing than on vision. However,