Stein heaton ay Soe ek ha rT 2, errata y = : ; ‘ aah - ewer , mamas ane ™ Sey a4 . rea 5 Staten) mes Aa S28 nee > =. ; Rey errr TS CLONER LRN f. : heicecsaet > s - 4% Siete ices ey ; eee Fo Pe ree > : Y PAK, hs in le ee ot IGHTLIGHTING: se in Capturing Pheasants, rie Chickens, Bobwhites, Cottontails NALD F. LABISKY ical Notes No. 62 OIS NATURAL HISTORY SURVEY A, ILLINOIS OCTOBER, 1968 STATE OF ILLINOIS RTMENT OF REGISTRATION AND EDUCATION NATURAL HISTORY SURVEY DIVISION Fig. 1.—Nightlighting is currently the most commonly used technique for capturing pheasants throughout the United States. This cock pheasant eluded capture on this trapping attempt, but was subsequently pursued and captured. NIGHTLIGHTING: Its Use in Capturing Pheasants, Prairie Chickens, Bobwhites, and Cottontails THE IDEA OF USING BRIGHT LIGHTS at night to blind ani- mals temporarily so that they may be captured is cer- tainly not new. Prehistoric man probably used the light from burning torches in capturing wild animals. Nightlighting in modern game management was first demonstrated by workers in South Dakota in the 1920's. Oscar Johnson (Leopold 1931:118) reported that about 22,000 pheasants, Phasianus colchicus, were captured in South Dakota during the winters of 1926— 1927 and 1929-1930 by “shining”’ roosting birds with automobile headlights. However, nightlighting did not become a commonly used technique in wildlife biology until research studies, which proliferated rapidly after the mid-1940’s, necessitated the capture of large num- bers of wild birds and mammals. Nightlighting has been used most commonly to capture pheasants, as is indicated by numerous pub- lished accounts, including reports from Idaho (Anony- mous 1952), South Dakota (Smith 1954), Nebraska (Anonymous 1955) , California (Hart et al. 1956:137) , Illinois (Labisky 1959), North Dakota (Oldenburg 1961), Indiana (Ginn 1964), and Towa (Lyon 1965:51) . The pheasant lends itself well to capture by nightlighting because it principally inhabits agricul- tural regions and thus roosts in cropland terrain that is traversable by vehicles equipped for nightlighting (Fig. 1). Nightlighting has been a particularly valuable tech- nique for capturing large numbers of pheasants in states such as Illinois, where bait trapping of pheasants in winter is precluded by an abundant, and usually available supply of waste grains. Vehicle-borne night- lighting rigs have also been used to capture cottontails, Sylvilagus floridanus, and nongame birds (Labisky 1959), skunks, Mephitis mephitis (Andrews 1963), and bobwhites, Colinus wvirginianus (Bartholomew 1967) . Nightlighting equipment installed various watercraft has been effectively used to capture water- fowl and marsh birds (Leitch 1958; Lindmeier & Jes- sen 1961; and Cummings & Hewitt 1964). Battery- powered headlamps or hand-held lights have been used to capture large numbers of woodcocks, Philohela minor (Rieffenberger & Kletzly 1967), and a variety of gulls and shorebirds (Taapken & Mooyman 1961). Also, generator-equipped, backpack nightlighting on This paper, published by authority of the State of Illinois, IRS. Ch. 127, Par. 58.12, is a contribution from Illinois Federal Aid Projects 30-R, 61-R. and 66-R, the Illinois Department of Conservation, the U.S. Bureau of Sport Fisheries and Wildlife, and the Illinois Natural History Survey, cooperating. Dr. Ronald F. Labisky is an Associate Wildlife Specialist in the Section of Wildlife Research at the Survey Ronald F. Labisky units have been proven effective for capturing birds and mammals in environments, either aquatic or up- land, where other methods of trapping were either inconvenient or unsuccessful (Drewien et al. 1967) . My previous article on nightlighting (Labisky 1959) was concerned primarily with the application of the technique to capturing pheasants. The purpose of this paper is to list improvements in equipment (and operational design) used in outfitting vehicles for nightlighting and to describe techniques for capturing bobwhites; prairie chickens, Tympanuchus cupido; cottontails; and pheasants. ACKNOWLEDGMENTS Acknowledgment is made to the following person- nel of the Illinois Natural History Survey. William L. Anderson offered advice on all aspects of nightlighting. Jack A. Ellis, Ronald L. Westemeier, and Keith P. Thomas contributed many of the capture statistics for prairie chickens and bobwhites, and read the manu- script. Robert O. Ellis and David B. Cooley assisted in designing and constructing the nightlighting equip- ment. All photographs were by Wilmer D. Zehr. The cover was designed by Richard M. Sheets. O. F. Glis- sendorf edited the manuscript. EQUIPMENT The basic equipment (Fig. 2) for outfitting a vehicle for nightlighting consisted of a floodlight clus- ter, a power source to operate the floodlights, and a spotlight. A vehicle equipped with 4-wheel drive is recommended, although not essential, for night- lighting. The floodlights have been operated from 110-volt a-c or 12-volt d-c power sources. The power supply for d-c systems was rigged by replacing the vehicle’s fac- tory-installed alternator with a high-amperage alter- nator, However, d-c systems provided less illumination than a-c systems because the available d-c lamps had lower candlepower ratings than a-c lamps. Consequent- ly, under ordinary situations, a-c systems were favored for nightlighting work, and thus are given primary consideration in this report. The a-c floodlight cluster consisted of five 150-watt PAR/FL projector floodlamps. These were held most satisfactorily by Killark Model SLH_~ lampholders mounted in a Killark Model SY wiring trough. The trough was mounted at the top of a modified tripod Fig. 2.—The basic equipment for nightlighting, excluding the hand-held spotlight, consists of a gasoline generator (with clamp) , floodlight cluster, and wiring system. The toggle switch for the floodlights appears in the left foreground; the netter’s platform (with clamp) is at left center; and the in-line fuse is visible in the center area of the major coil of cable. This identical set ot equipment is used on the different vehicles shown in Fig. 1 and Fig. 4. (Fig. 2) made from 3- or 4-foot sections of l-inch metal conduit. The tripod, depending on its design, was fastened to a sturdy, metal cartop carrier either with bolts or with clevis-type hinges. The clevis hinges per- mitted the floodlight cluster to be easily folded down for highway traveling or for avoiding low-hanging obstacles. The lampholders were individually adjustable so that the area illuminated by the lamps could be con- trolled. The lamps were tilted downward when cruising in cover that absorbed light (e.g., heavy green vegetation) and lifted slightly in cover that reflected light (e.g., snow). The floodlights ordinarily were adjusted to yield a semicircle of adequate light extend- ing about 10 yards on either side of the vehicle and 30 yards forward; beyond these distances the light was diffuse. Electrical power for the a-c floodlamps was supplied by a 110-120-volt, 1,250-watt, gasoline-powered gener- ator (Montgomery Ward model) , which could be pur- chased with or without an electric starting motor. The 1,250-watt capacity of the generator was sufficient to supply the starting electrical surge for the five, 150-watt floodlamps, which subsequently drew only 750 watts. This generator was small enough to be mounted, by bolting it to the frame, under the hood of some vehicles. Usually, however, it was mounted on a plat- form, or angle iron frame, which could be readily clamped to the rear bumper of a vehicle (Fig. 3). The power cable for the electrical system consisted of about 15 feet of neoprene-covered motor cord with 14-gauge, 600-volt wires. A polarized male plug to fit into the receptacle on the generator was attached to one end of the cable. About 10 feet from the generator an outlet receptacle, inserted in a handy box, was in- stalled in the line (Fig. 2). A 20-ampere cartridge-type fuse (automotive) was installed in this line between the generator and outlet receptacle. One wire of the power cable was extended through the handy box for about 5 or 6 feet to a single pole, single throw, 25- Fig. 3—The generator, mounted on a frame, is clamped to the rear bumper of the vehicle with two steel-strap hanger brackets that hook over the top edge of the bumper. The curled end of the center clamp is hooked over the bottom edge of the bumper, and the threaded end of this clamp, which is inserted through a drilled hole in the rear piece of the mounting frame, is secured with a wing nut. 5 ampere, 110-volt toggle switch, which was installed in a second handy box equipped with a switch-type cover plate. The return wire from the switch to the recep- tacle was attached to the second, or free, terminal of the receptacle to complete the circuit. A second length of cable, about 8 feet, leading from the wiring trough for the floodlamps and terminating in a male plug to be inserted into the outlet rec eptacle, was used to com- plete the circuit to the lamps. The toggle switch con- trolled the floodlights. The handy box with toggle switch was outfitted with clamps so that it could be attached either to the center of the dash or on the roof of the vehicle above the driver’s right shoulder. The switch was fitted with a 6-inch extension of semi- flexible rubber tubing so that it could be located easily and turned on or off with a flick of the hand. The hand-held spotlight used in this work was a Unity Model S6, 100,000 candle power, 12-volt auto- mobile searchlight. It was sometimes operated from the vehicle’s cigarette lighter socket. Usually, however, a short electrical cable, terminating in a female recep- tacle, was run from the posts of the vehicle’s 12-volt battery, through the firewall, to the interior of the vehicle. The spotlight cable was then fitted with a suit- able male plug. The latter system offered the most trouble-free performance. The a-c lighting system with a bumper-mounted gen- erator has the advantage of being interchangeable among different vehicles, particularly those of similar make (Fig. 1 and 4). All equipment can be rigged and readied for operation by two men within 10 minutes. Fig. 4.—The crew of this nightlighting rig is cruising a grain-stubble field to locate roosting pheasants 6 The net used to capture gallinaceous birds and cot- tontails had a 10-foot handle of 1-inch, thin-walled conduit, and a 30-inch hoop (diameter) of rolled 34-inch, thin-walled conduit. The bag of the met was constructed of I-inch heavy cord mesh and had a depth of about 15 inches. Nets with handles of lightweight materials or with bags of less than l-inch mesh were ineffective because they could not be quickly forced down to the ground in heavy vegetation. Bags of fine cord, particularly those with mesh sizes larger than 1 inch, were unsatisfactory because netted birds often became entagled in the mesh and suffered wing abra- sions. To give the driver good visibility, the netter rode on the right fender of the vehicle. He was provided a de- tachable bumper platform on which to place his feet (Fig. 2). A safety rope, which the netter could grasp in his left hand, was attached across the hood of the vehicle. The platform and safety rope were essential to the safety and performance of the netter. A two-man crew was adequate for the effective op- eration of this nightlighting rig. One man drove the vehicle, controlled the floodlights, and operated the spotlight, which he held out of the window of the vehicle. The other man netted the animals. TECHNIQUES AND EFFICIENCY OF CAPTURE Pheasants Pheasants were located at night by cruising, with the floodlights in operation, through fields of relatively flat terrain that offered roosting cover, such as hay- fields, small-grain stubble fields, and pastures (Fig. 4) . Such cruising was done at about 5 mph. When a roost- ing pheasant was observed in the arc of the floodlights, the driver simultaneously switched on the hand-held spotlight, pinpointed the bird with the spotlight beam, and switched off the overhead floodlights. He then drove toward the bird, keeping it centered in the spot- light beam until the netter could leap from the vehicle and make his netting attempt (Fig. 5). Inasmuch as the spotlight was held in the driver's left hand, the vehicle had to be maintained to the right, or right rear, of the bird, which normally moved away from the source of light and noise. Consequently, the most ef- fective vehicle maneuver in nightlighting was a coun- terclockwise circling action. To net a pheasant, or other bird, the netter ap- proached only from the rear or from the spotlighted, or “blinded,” side of the quarry. In the capture at- tempt for pheasants, the netter usually made a head- long dive from a running approach. He placed the’ net swiftly over the bird by a forceful, forward thrust in such a manner that the hoop passed only a few inches over the bird; the hoop was kept essentially parallel to the ground at all times. This method of net placement allowed the netter to adjust for sudden, last-instant reactions of the bird, thereby increasing trapping efficiency and lessening the chances of injur- ing the bird. The action of the driver and the netter had to be closely coordinated to achieve a high degree of efficiency in capturing pheasants. Most pheasants were captured at distances of 25-50 feet from the vehicle. Long chases, away from the ve- hicle, of elusive birds by a netter on foot were usually unsuccessful; they not only tired the netter but also wasted time and flushed birds that otherwise might have been captured. Although some birds were taken at or within a few feet of their roosting sites (Fig. 5), most birds either ran or flushed from their sites when they were disturbed (Fig. 1). The latter pheasants were spotlighted and pursued until they were captured or reached an inaccessible area. When a pheasant flushed, it could be “knocked down” at distances up to 150 yards by the spotlight beam if the bird was oriented in flight so that the light reached one of its eyes, temporarily blinding the bird. When a group of pheasants was flushed at one time, several birds could often be “knocked down’ with the spotlight before they flew very far. In such cases the driver mentally noted the positions of the downed birds and subse- quently pursued them one by one. When pursuing running or flying pheasants, speeds of from 15 to 20 mph were often necessary to put the vehicle (and netter) in position to attempt capture; such chases often covered distances of several hundred yards. Under these circumstances, the driver had to be well acquainted with the terrain because his only light source was the spotlight beam which was directed at the fleeing bird. Adult, or essentially full grown, pheasants were cap- tured more easily when they were found roosting singly or in groups of two or three than when they were found in larger groups. If a single member of a large group flushed, several of the other pheasants in the group usually flushed also, some of which often flew into nearby fields that were inaccessible to the nightlighting rig. Many of the pheasants that flushed flew only short distances before alighting and were available for subsequent capture attempts. Young pheasants, still in broods, were very easily captured. Pheasants were usually easier to capture after they had been roosting for a few hours than they were shortly after sunset or immediately before sunrise. Repeated nightlighting within the same field caused pheasants to become skittish, which made them in- creasingly difficult to trap, but did not markedly alter their nighttime use of the field. Although there were never nights during which a worthwhile number of pheasants could not be cap- tured by nightlighting, nighttime conditions influenced the susceptibility of birds to capture. Strong wind ~I Fig. 5.—In this capture effort the relative positions of vehicle, typical. (15 mph or more) caused roosting pheasants, particu- larly those in large flocks, flush wildly. Wind also caused vegetation to wave, which made it difficult for the observers locate and follow pheasants that ran from their roosting sites. Although fog or rain often caused pheasants to “hold tight” conditions usually hindered the more than they aided it because of low visibility, re to their roosting sites, these same weather trapping operation duced effectiveness of lights, and, in the case of rain, soft fields. Pheasants were most susceptible to capture when the vegetation was wet with dew or covered with frost. Cold temperatures (—10° to 10°F.) when the ground was covered by snow, caused roosting , particularly pheasants to be flighty. Under the latter conditions in Illinois, pheasants often roosted in corn stubble (rather than in small-grain stubble or hay) , which made thei capture by nightlighting very arduous because it is dificult to maneuver the vehicle in row-crop fields Pheasants were more susceptible to capture by night- lighting on moderately cold, cloudy nights following rain in autumn, and on relatively warm nights fol lowing a marked cold spell in winter. In late winter and spring, soft fields, which prevented vehicle access, hampered the capture of pheasants more than any other factor. Pheasants were skittish and difhcult to capture on netter, and pheasant about to be captured at his roosting site are bright moonlit nights, particularly when the vegeta- tion was dry or covered by snow. When the vegetation was dew-laden or frosty, moonlight seemed to have little effect on the flightiness of pheasants. Nearly half of all pheasants initially observed during nightlighting operations in autumn (prehunting sea- son) were captured, whereas only about a third of those located in winter tured (Table 1). were less alter (posthunting season) were cap- Although total pheasant numbers each hunting season than before, the number of roosting pheasants per unit of trappable cover was greater after the hunting season than before. and hay fields se- verely reduced the amount of cover that had been used Fall plowing of small-grain stubble by roosting pheasants in autumn, and by the beginning of winter the birds were concentrated in the fields that offered vegetation suitable for roosting. Even when large blocks of roosting cover were available, pheas ants often roosted in large flocks, sometimes as many as 200 birds, on winter nights. In general, the per- centage of pheasants captured varied inversely with the number of pheasants that were flushed per unit of covel searched. The time required to capture a pheasant averaged 5.5 minutes in autumn and 6.8 minutes in winter dur- ing the 6 years, 1956-1962 (Table 1). In autumn the capture time per bird decreased population abun- TABLE 1.—Statistics on the efficiency of capturing pheasants by nightlighting during prehunting season (October and early No- vember) and posthunting season (principally January) periods on the intensively farmed, 23,200-acre Sibley Area in Ford and McLean counties of east-central Illinois, 1956-1962. Capture Period Pheasant Density Number of Capture: Flush Ratio* Average Capture and (Birds per Pheasants (Percentage Time (Minutes Year Square Mile) Captured Captured) per Bird) Autumn or Prehunt 1956 150 267 37 7.0 1957 145 220 47 74 1958 295 354 50 4.8 1959 210 183 53 5.4 1960 285 181 40 5.3 1961 370 369 54 4.1 Total or Mean 1,574 46 bee Winter or Posthunt 1957 60 189 36 8.5 1958 110 127 42 10.0 1959 95 177 16 5.0 1960 110 182 40 54 1961 150 187 38 6.0 1962 (160) + 260 37 No data Total or Mean ME 22 31 6.8¢ “Efforts were made to include only the initial flush of pheasants; repeat flushes were ignored because they were a product of capture attempts. +Estimate. tExcludes 1962. dance increased. In winter there was little relationship between capture time and population abundance be- cause the birds were usually concentrated in fields of- fering roosting cover. Mortality attributable to the nightlighting operation totalled 1.7 percent of 2,696 pheasants captured and processed (weighed, measured, and marked) . The ma- jority of this mortality occurred during the time that the pheasants were held in burlap bags prior to proc- essing. Such losses were mitigated if only one or two pheasants were placed in each burlap bag, if cocks and hens were held separately, if the pheasants were held no longer than 1 hour prior to processing, and if the bags containing the captured birds were kept outdoors. Prairie Chickens Efforts to capture prairie chickens by nightlighting were restricted to a single colony of birds located on a 10,000-acre tract of agricultural land in south-central Illinois. This colony numbered about 300, 200, and 150 prairie chickens in the autumns of 1962, 1963, and 1964, respectively. In autumn these birds were found roosting, usually in small groups, in as many as 20 different fields of small-grain stubble or tame hay. Prairie chickens were much less susceptible to cap- ture by nightlighting than were pheasants. Only 57, or about 17 percent, of 527 prairie chickens that were initially observed (repeat flushes not included) while nightlighting during the late summer and early fall’ periods of 1962-1964 were captured (Fig. 6) . The cap- ture efficiency was about 19 percent in August (17 of 88 birds) , nearly 28 percent in September (28 of 101 birds) , and only about 9 percent in October (12 of 138 birds). Young birds were more easily captured than adults in August and early September, but had gained the wariness of adults by October. The techniques for nightlighting prairie chickens were essentially the same as those used in capturing pheasants. However, the entire tempo of the operation, after observation oF the bird, had to be accelerated to effect capture. Even with experienced nightlighting personnel, the capture of prairie chickens was not as- sured. Prairie chickens were almost impossible to capture by nightlighting on clear and/or moonlit nights. Under these conditions the spotlight was completely ineffec- tive in “knocking down” prairie chickens that flushed. The flushed birds usually flew out of sight before alighting, which prevented subsequent capture at- tempts. Cloudy, cool, and damp nights in early autumn were the best for capturing prairie chickens. To illustrate, on one night in mid-September, 1963, 21 (55 percent) of 38 prairie chickens that were flushed were captured —9 were adults and 12 were juveniles. This particular night was characterized by the arrival of a low-pressure weather front. It was very dark, due to a heavy cloud layer; mildly wet, due to a persistent mist; and cool (about 45° F.). The success in capturing prairie chick- ens on this night was convincing evidence that they could be effectively captured by nightlighting under proper nighttime conditions. 9 Fig. 6.—This prairie chicken, captured by nightlighting, was marked for subsequent identification with a plastic backtag prior to its release. (Most of the pheasants and bobwhites captured by nightlighting were also marked with backtags to facilitate behavioral and ecological studies.) Bobwhites Bobwhites were susceptible to capture by nightlight ing, but the problems involved in capturing them were much different from those encountered in capturing pheasants Ol prairie chickens. Locating coveys ol roost ing bobwhites was perhaps the most time-consuming part of the operation. This problem was most acute in areas where bobwhite densities were low or where uneven topography, often characteristic of good bob white range in Illinois, made it impossible to use a vehicle. Beforehand knowledge of covey ranges les sened the cruising time expended in locating roosting coveys at night. Bartholomew (1967:3) tried to ex pedite the problem of locating coveys at night by working pointing dogs ahead of the lights, but con cluded that the systematic search of fields with the nightlighting rig was still the best method for locating roosting bobwhites. Usually the first indication of the presence of a roosting covey was when the birds flushed in the light ahead of, and usually close to, the vehicle. If a covey was sighted in a roosting rosette and could be pin pointed in the spotlight beam, all or most of the covey members could be captured in a single netting attempt. When a covey flushed, individuals scattered in all di rections, but usually alighted within 5—75 yards of the flush point. Consequently, the floodlights were often left on when a covey flushed so that both driver and netter could observe the flightlines and flush distances of as many of the birds as possible In these instances the spotlight was still used to “knock down” individual birds, particularly those that flew beyond the area illuminated by the floodlights The techniques used for trapping bobwhites de pended on the type of habitat. When vegetative cover was relatively light, as in fields of small-grain stubble, birds from a flushed covey usually walked or ran afte alighting. It was not unusual for a covey to “pop” into the air, alight immediately, and then run, often stay 10 ing together in a loose unit. Capture efficiency was high under these circumstances because the fleeing birds could be easily observed on the ground. Inas- much as scattered bobwhites were not particularly prone to flush, the birds were relatively easy to net (Fig. 7). A skilled netter could sometimes maneuver so as to make multiple catches, usually two or three birds. Bobwhites were more difficult to capture when roost- ing in heavy vegetative cover. After the covey was flushed, individuals usually settled into the cover and remained sedentary. Most of these birds had to be relocated by slow, methodical cruising, and the best method was to cruise in a spiral pattern, moving out- ward from the flush site. To capture a bobwhite in this heavy cover, it was necessary to see the bird on the ground, detect it by its movement (by sight or sound) in the vegetation, or reflush it. When a bird was either seen or detected by its movement, netting was usually done in the illumination of the floodlights. Reflushed bobwhites were spotlighted and pursued in the normal way, and the netter usually trapped the bird by thrust- ing the net over the spotlighted site where it alighted. When nightlighting in heavy vegetation, many of the captured bobwhites were netted “blind’’—the netter trapped the bird by placing his net over a spot of vegetation where the spotlight operator had detected movement and directed the light beam. Wind was the weather condition that most ham- pered the capture of bobwhites by nightlighting; it set the vegetation in motion, making it difficult or im- possible to detect the birds’ movements. Quiet, dark, cloudy nights with heavy dew, light rain, or frost were favored for nightlighting bobwhites. About half of all bobwhites flushed in farmland habitats, but only a third of those flushed in nonfarm- land habitats, were captured by nightlighting in au- tumn (Table 2). The capture efficiency in the two broad habitat types was influenced by two factors. First, nightlighting for bobwhites on farmland was done principally in fields of small-grain stubble, where often the vegetation was either short (sometimes mowed) or light to moderate in terms of stem density. In such cover bobwhites were observable and, thus, eas- ily trapped. On nonfarmland, nightlighting usually had to be conducted in fields of undisturbed grasses and weeds that were interspersed with deciduous woods. Scattered bobwhites were difficult to relocate Fig. 7.—Here an undetected bobwhite from a_ previously flushed covey was reflushed as the netter approached another spot- lighted covey member (on ground) from the outer fringe of the area illuminated by the floodlights. The driver instantaneously centered the flushing bobwhite in the spotlight beam so as to quickly “knock” him down Tas_e 2.—Statistics on the efficiency of capturing bobwhites by nightlighting during autumn and on nonfarmland habitats in south-central Illinois, 1963—1967. Number OE aa Coveys Flushed Type of Habitat and Year Number of Bob- whites in Coveys 1] (prehunt) on farmland habitats Number of Bob- whites Captured Percentage of Bobwhites Captured Farmland* 1963 15 147 1964 8 102 Total or Mean 23 249 Nonfarmland+ 1963 17 227 19644 17 196 1965+ 9 110 1966 8 109 1967 11 195 Total or Mean 62 837 91 62 36 35 127 51 101 14 74 38 41 37 21 19 45 23 282 34 *Bobwhite densities averaged about 1 covey per square mile. *Bobwhite densities averaged about 12 coveys per square mile. tTwo nightlighting rigs, in this dense vegetation. Second, on nonfarmland many flushed bobwhites flew into nearby woods or rough terrain where they could not be pursued. This problem was not often encountered on the compara- tively flat, farmland terrain. The use of two nightlighting rigs usually improved the capture efficiency for bobwhites (Table 2), par- ticularly in heavy vegetation or rough terrain, because it was possible to note where more of the birds from a covey alighted after the initial flush. Also, one rig and crew could often intercept and quickly capture indi- viduals that were flushed by the other rig. The time required to capture a bobwhite is unpre- dictable. Usually attempts to capture birds from an average-sized covey reached the point of diminishing returns within 30-45 minutes in light cover and 60—90 minutes in heavy cover. On one occasion, where the birds were roosting in clipped grain stubble, we cap- tured 16 birds from a covey of 18 in less than 30 min- utes. On the other hand, we captured only 4 of 22 bobwhites during a 2-hour period following a covey flush from a field of tall grasses and weeds. Although we did not engage specifically in night- lighting for bobwhites during the winter, those bob- whites flushed while trapping pheasants were suscepti- ble to capture. They were exceptionally vulnerable when snow covered the ground because they were readily visible against the white background. Mortality of bobwhites attributable to the night- lighting operations averaged less than 1 percent. Roost- ing behavior was not seriously affected by nightlight- ing activities, as nightlighted coveys could be relocated at, or near, the same sites on subsequent nights. Cottontails Capturing cottontails (Fig. 8) by nightlighting was a difficult task. We have, however, captured more than 300 rabbits by nightlighting during the past decade. Nightlighting, by itself, was not a feasible technique for capturing large numbers of cottontails for popula working as a dual unit, were used in trapping in 1963 and at least part of the time in 1964 and 1965 tion studies. However, it did prove to be an adequate and convenient technique for capturing live cotton- tails for laboratory studies or for stocking enclosures with animals for subsequent biological investigations. Nightlighting cottontails was a hard and fast opera- tion. At night the cottontail was strikingly “an an- imal of the edge.’ Generally, it foraged only short dis- tances, usually less than 50 yards, into fields, or, more accurately, away from its escape cover. And as soon as the cottontail was disturbed, it streaked toward its escape cover. Consequently, the first and most im- portant step in attempting to capture a rabbit was to Fig. 8 Although success in capturing cottontails by night- lighting on any given night is unpredictable, an experienced crew can usually capture a few rabbits on almost any night 12 maneuver the vehicle between the rabbit and its escape cover. To accomplish this, spurts of speed up to 35 mph were often necessary, and thus only fields with smooth terrain could be safely and effectively night- lighted. Because the “target” rabbit had to be kept in the spotlight beam at all times, it was imperative that nightlighting be done in fields in which the vegetation permitted the rabbit to be seen at all times; when the animal was lost from view, it usually escaped. If a rabbit could be cut off from escape cover, it often paused momentarily; at this moment the rabbit was potentially most vulnerable to capture. To effect cap- ture at this precise time, the driver had to have the vehicle in such a position that the netter could literally pounce, directly from the vehicle, upon the rabbit with the net. An experienced nightlighting crew can, on the aver- age, expect to capture about one of every five rabbits flushed. On different nights in autumn, we have cap- tured as many as 13 of 36 cottontails (36 percent) in 3 hours of nightlighting and as few as 3 of 51 (6 per- cent) in 7 hours. Subadult cottontails were more susceptible to cap- ture by nightlighting than were full grown rabbits. However, the nighttime behavior of cottontails, and thus their trappability, was quite unpredictable at any time. Cottontails were most skittish on very cold, moonlight nights when snow covered the ground and were most susceptible to capture on dark, cloudy nights when the vegetation (or ground) was wet. As a rule, cottontails held best on cold, rainy nights in autumn, on cool nights following a thaw or snow in winter, on warm, humid nights in spring, and on cool, dewy nights in summer. LITERATURE CITED ANpreEws, RicHarp D. 1963. Collecting skunks by nightlighting. Illinois Wildlife 19 (1) :6. ANnonyMous. 1952. Pheasants in the spotlight. Idaho Wildlife Review 4 (5) :3. AnonyMous. 1955. 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