EPA/600/A-93/159 ECOTOXICOLOGICAL PRINCIPLES FOR AVIAN FIELD STUDIES USING RADIOTELEMETRY OR REMOTE SENSING Anne Fairbrother U.S. Environmental Protection Agency Environmental Research Laboratory 200 SW 35th Street Corvallis, OR 97333 In this section, I will provide a wildlife toxicologist's perspective of avian field studies. I will focus my remarks on the type of information needed when conducting studies in field situations to determine how a specific use of a single pesticide affects indigenous birds. I view radiotelemetry as only one subset of wildlife ecotoxicological studies that could be done, although it is a powerful tool for determining how free-ranging animals come in contact with a variety of contaminated environments and what the short and long-term effects might be. I will make no attempt in my remarks to limit myself to discussions of applications of extant technologies. Rather, I will discuss the information that we wish to gain and the context in which it will be used. By stating the needs of the end-user, I hope to provide a challenge to telemetry experts to advance the engineering aspects of radiotelemetry and other remote sensing technologies. Hopefully, this will provide us with better tools for collecting ecologically relevant data in a cost-effective, real-time fashion. APPROACH Put succinctly, the objective of a pesticide field study usually is to test the null hypothesis that application of a pesticide will have no effect on indigenous birds. Of course, this simple statement leads to many further questions: what is the ecological significance of "effect"? what do we mean by "no" effect? what do we know about dose-response relationships? is the "application" a single application or multiple applications? what is the time period of concern? I will not attempt to ------- address broad ecological concerns at this time, but will limit my comments to direct, biological and toxicological responses of birds to a pesticide applied under a selected field regime. Within this context, the wildlife toxicologist is interested in gathering information in three general areas: (1) what can we observe about birds' movements and behavior patterns that are likely to result in their exposure to the chemical; (2) what is the actual exposure of each individual, and the population, to the chemical; and (3) what are the physiological and behavioral consequences to the individual and population of chemical exposure (including mortality and reproductive endpoints)? Once we have this information, we can develop simple cause-and-effect relationships between pesticide application and bird responses. Given an appropriate study design, we can make further inferences about how the observed responses vary depending upon the application rate (dose-response relationships) or the relative hazards of various compounds (comparative risk), and differences in the magnitude of the effects on the various species present (comparative toxicology). What are examples of the type of data we collect in order to develop these cause-and-effect relationships? Location and Movement: One vital piece of information is knowledge of the location of the population of birds of interest within the study area, in three-dimensional space. Latitude and longitude coordinates are needed in order to know when the birds are in the field to which the pesticide is being applied. Multiple readings over time are needed to know when the birds are present and, therefore, have the potential to be exposed to the chemical. Spatial movement patterns can also provide information about what the bird is doing (flying, resting, feeding, nesting) which, in turn, provides keys to exposure potential as well as information about the effect of the pesticide application (did behaviors change after the spray event in a manner that differs from control plots?). Data about movement in the third dimension ------- (elevation) can be used to augment information about certain behaviors (flying versus moving on the ground) and to infer others (are canopy-dwelling birds spending too much time on the ground?). Knowing the location of birds in real time is also useful for retrieving carcasses (from pesticide-induced mortality or other causes) for quantifying mortality and for diagnostic procedures or for capturing live birds for sampling purposes. Special modifications (e.g., mortality switches, activity recorders, physiological-measurement devices) are useful but technologically difficult additions. Behavior; Once we know where the birds are located, we then need to know what they are doing there and if their behaviors are altered due to the pesticide application. In particular, we are interested in determining the effects of pesticide applications on those behaviors that will impact population demographics, i.e., mortality, natality, and dispersal. It is important to gather information about mortality in a time-dependent fashion. In other words, we wish to know when birds die as well as how many die. This will contribute to our ability to link mortality to the pesticide application, both by a time association and through various biochemical procedures (e.g., cholinesterase activity) that degrade with time after death. Ultimately, we calculate the survival rate, rather than mortality rate, but these data are obviously related. Reproduction; Reproduction is another behavior that we typically measure. Reproduction is, actually, the sum of a series of integrated behaviors. We use the word "reproduction" to encompass the entire process from mating behaviors, through actual fertilization, egg incubation, and raising of young until they leave the nest. In strict ecological terms, we should include the period from fledging (leaving the nest) until the individual matures and engages in mating behaviors itself. However, I will leave the discussion of the postfledging time to ------- the ecologists and focus on the period from initiation of mating behaviors until the young fledge. Mating behaviors in birds can be very complex and frequently rely on visual cues. Conspicuousness or condition of plumage is a factor in mate selection which could be altered by pesticide exposure (1). Birds must initiate appropriate behaviors in the correct sequence and phenology and then must be able to respond appropriately to behaviors of conspecifics. This type of behavior has both learned and innate components so it is not surprising that neurotropic pesticides have been shown to alter these patterns (2-4). Once mating has occurred, egg production can be reduced due to pesticide exposure (5,6) as can proper formation of the egg and eggshell (7,8). Information about fertility and eggshell quality generally is gathered in controlled laboratory studies, but it would be extremely useful to be able to gather similar data in the field to expand our knowledge about interspecific differences and the interactions of other environmental stressors (parasites, disease, extreme weather) with pesticide exposure. Nesting behaviors (amount of time spent sitting on eggs, how frequently the eggs are turned, whether the nest is incubated until term or abandoned early) have only occasionally been studied in relation to pesticide effects (9-11) but provide additional clues about cause-and-effect relationships relative to the final reproductive output. Physiological Effects (Biomarkers): In addition to gathering data on pesticide effects on survival and reproduction, ecotoxicological studies would benefit from data concerning sublethal physiological effects. This area of study has largely been ignored to date due to the difficulty of obtaining the required information. Examples of questions that could be addressed within an ecological context include, but certainly are not limited to: (1) does exposure to pesticide applications change the metabolic rates of the birds, thereby altering the ------- amount of food and subsequent foraging time needed for survival or reproductive efforts (12) ; (2) does exposure to pesticides make birds more susceptible to concomitant environmental stressors such as disease and parasitism (13); and (3) do pesticides change hormone production patterns and interfere with growth and reproduction patterns or other more subtle behaviors (9)? Answers to these types of questions would help to make definitive cause-and-effect relationships between pesticide application and subsequent changes in the local populations. More importantly, they would provide clues to the mechanisms by which the pesticides exert their effects on the birds. This would provide us with stronger predictive models about the ecotoxicological effects of pesticides and allow modifications of application regimes or new pesticide formulations to be made with a strong scientific basis. Remote sensing applications for monitoring physiological measurements will be discussed in more detail in another chapter. DISCUSSION It is very important in field studies to know how much exposure to the pesticide each individual has received. Without this information, cause-and-effect relationships must, therefore, be based on strong correlative relationships. There also are available surrogate measures (biomarkers) of exposure such as cholinesterase activity in brain and plasma (14) and chemical residue on crop and stomach contents. For some chemicals, we have direct exposure measurements through analysis of residues of parent compounds or breakdown products (e.g., oxones) in various tissues and excreta. Tissue residue studies are not ideal, however, as the current generation of pesticides frequently do not leave such residues. Those that do generally require destructive sampling of the animal and provide information only about the amount of chemical present at the time of sampling. Excreta measures of chemical content would be non- destructive and could be sampled repeatedly through time. Excreta collected ------- from nests can be related to a specific individual (or two), but this restricts our ability to measure what is occurring in non- nesting birds or during the portion of the day when the bird is not in the nest. Merely locating the individual coincident with pesticide application in time and space does not provide a measure of exposure. For example, foliage can provide shelter from exposure while preening activities can increase total exposure. Therefore, I challenge you to begin thinking about how remote sensing technologies could be applied to this problem of exposure assessment. From an ecotoxicological point of view, this is the weakest part of pesticide risk assessment studies. SUMMARY In summary, ecotoxicological studies for pesticide risk assessments strive to develop cause-and-effect relationships between pesticide application and adverse effects on birds (both as individuals and as populations) and to determine the mechanisms by which the observed effects occur. In order to accomplish this, data are collected to determine if the location of the birds put them into potential contact with the pesticide, how the pesticide changes behaviors and the physiology of the animals, and how these changes result in increased mortality and reduced reproduction. Radiotelemetry and other remote sensing technologies can be powerful tools to aid in gathering this data. Hopefully, the summary presented here will leave you with thoughts about how to extend the current capabilities of these tools yet continue to provide information in real-time and in a user-friendly fashion. DISCLAIMER The information in this document has been funded by the U.S. Environmental Protection Agency. It has been subjected to Agency review and approved for publication. ------- REFERENCES 1. Hamilton, W.D. and M. Zuk. 1982. Heritable true fitness and bright birds: A role for parasites? Science 218:384- 387. 2. Forsyth, D.J. 1980. Effects of dietary fenitrothion on the behavior and survival of captive white-throated sparrows. In: I.W. Varty, ed. Environmental surveillance in Mew Brunswick, 1978-79. Effects of spray operations for forest protection against spruce budworm. Committee for Environmental Monitoring of Forest Insect Control Operations, Dept. For. Res., Univ. New Brunswick, Fredericton, pp. 27-28. 3. Grue, C.E. and B.K. Shipley. 1981. Interpreting population estimates of birds following pesticide applications — behavior of male starlings exposed to an organophosphate pesticide. Stud. Avian Biol. 6:292-296. 4. Busby, D.G., L.M. White and P.A. Pearce. 1990. Effects of aerial spraying of fenitrothion on breeding white-throated sparrows. J. Appl. Icol. 27:743-755. 5. Stromborg, K.L. 1981. Reproductive tests of diazinon on bobwhite quail. In: D.W. Lamb and E.E. Kenaga, ed., Avian and Mammalian Wildlife Toxicology: Second Conference. ASTM STP757. American Society for Testing and Materials, Philadelphia, PA pp. 19-30. 6. Rattner, B.A., L. Sileo and C.G. Scanes. 1982. Oviposition and the plasma concentration of LH, progesterone and corticosterone in bobwhite quail (Colinus virginianus) fed parathion. J, Reprod. Fert. 66:147-155. ------- 7. Bennett, J.K. and R.S. Bennett. 1990. Effects of dietary methyl parathion on northern bobwhite egg production and eggshell quality. Environ. Toxicol. Chem. 9:1481-1485. 8. Scott, M.L. J.R. Zimmermann, S. Marinsky, P.A. Mullenhoff, G.L. Rumsey and R.W. Rice. 1975. Effects of PCBs, DDT, and mercury compounds upon egg production, hatchability, and shell quality in chickens and Japanese quail. Poultry Sci. 54:350-368. 9. Bennett, R.S., B.A. Williams, D.W. Schmedding and J.K. Bennett. 1991. Effects of dietary exposure to methyl parathion on egg laying and incubation in mallards. Environ. Toxicol. Chem. 10:501-507. 10. White, D.H., C.H. Mitchell and E.G. Hill. 1983. Parathion alters incubation behavior of laughing gulls. Bull. Environ. Contam. Toxicol. 31:93-97. 11. Busby, D.G., L.M. White and P.A. Pearce. 1990. Effects of areal spraying of fenitrothion nonbreeding white-throated sparrow. J. Appl. Ecol. 27:743-755. 12. Dominguez, S.E., J.L. Menkel, A. Fairbrother, B.A. Williams, and R.W. Tanner. Effect of 2,4-dinitrophenol on metabolic rate of bobwhite quail. J. Appl. Toxicol. Phamacol. (in press). 13. Porter, W.P., R. Hinsdill, A. Fairbrother., L.J. Olson, J. Jaeger, T.M. Yuill, S. Bisgaard, W.G. Hunter, and K. Nolan. 1984. Toxicant-disease-environment interactions associated with suppression of immune system, growth, and reproduction. Science. 224:1014-1017. ------- 14. Mineau, P. 1991. Choiinesterase-inhibiting Insecticides: Their Impact on Wildlife and the Environment. Elsevier. Amsterdam, The Netherlands. 348pp. ------- M TECHNICAL REPORT DATA (rtcnt ma Instmeiioiu on the re vent he fort eom/rf 1. REPORT NO, EPA/600/A-93/159 2. PB93-212793 a.TITLt AND SUBTITLE Ecotoxicological Principles for Avian Field Studies Using Radiotelemetry or Remote Sensing I. REPORT DATE ». PERFORMING ORGANIZATION CODE 7. AUTMOR(S) Anne Fairbrother I. PERFORMING ORGANIZATION REPORT NO, •.PERFORMING ORGANIZATION NAME AND ADDRESS US EPA, ERL-Corvallis, OR 1C. PROGRAM ELEMENT MO. lireONTRACT/QRANT NO. 12. tPONSORlNC AGENCY NAME AND ADDRESS US Environmental Protection Agency Environmental Research Laboratory 200 SW 35th Street Corvallis, OR 97333 13. TYPE OP REPORT AND PERIOD COVERED Symposium paper 14. SPONSORING AGENCY CODE EPA/600/02 IB, SUPPLEMENTARY NOTES 1993. Pellston Workshop; Asilomar, CA. Radiotelemetry for Avian Field Studies, IS. ABSTRACT In this section, I will provide a wildlife toxicologist's perspective of avian field studies. I will focus my remarks on the type of information needed when conducting studies in field situations to determine how a specific use of a single pesticide affects indigenous birds. I view radiotelemetry as only one subset of wildlife ecotoxicologieal studies that could be done, although it is' a powerful tool for determining how free-ranging animals come in contact with a variety of contaminated environments and what the short and long-term effects might be. I will make no attempt in my remarks to limit myself to discussions of applications of extant technologies. Rather, I will discuss the information that we wish to gain and the context in which it will be used. By stating the needs of the end-user, I hope to provide a challenge to telemetry experts to advance the engineering aspects of radiotelemetry and other remote sensing technologies. Hopefully, this will provide us with better tools for collecting ecologically relevant data in a cost-effective, real-time fashion. 7. KEY WORDS AND DOCUMENT ANALYSIS DESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group radiotelemetry, birds, remote sensing, pesticides S. DISTRIBUTION STATEMENT Release to Public »» SECURITY. Ct,ASS (T*H Htpertj UncTas smear 21. NO. Of PACES 9 »0 SECURITY CLASS Unclassified 22. PRICE KPA P»rm §220-1 (»-7J) ------- |