Spring Movements, Roosting Activities, and Home-Range Characteristics of Male Merriam's Wild Turkey Author(s): Richard W. Hoffman Source: The Southwestern Naturalist , Sep., 1991 , Vol. 36, No. 3 (Sep., 1991), pp. 332-337 Published by: Southwestern Association of Naturalists Stable URL: https://www.jstor.org/stable/3671684 REFERENCES Linked references are available on JSTOR for this article: https://www.jstor.org/stable/3671684?seq=1&cid=pdf- reference#references_tab_contents You may need to log in to JSTOR to access the linked references. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at https://about.jstor.org/terms is collaborating with JSTOR to digitize, preserve and extend access to The Southwestern Naturalist This content downloaded from 128.227.183.183 on Fri, 31 Jan 2025 21:07:48 UTC All use subject to https://about.jstor.org/terms THE SOUTHWESTERN NATURALIST 36(3):332-337 SEPTEMBER 1991 SPRING MOVEMENTS, ROOSTING ACTIVITIES, AND HOME-RANGE CHARACTERISTICS OF MALE MERRIAM'S WILD TURKEY RICHARD W. HOFFMAN Colorado Division of Wildlife, Wildlife Research Center, 317 West Prospect Road, Fort Collins, CO 80526 ABSTRACT-Movements, roosting activities, and home-range characteristics of adult and subadult male Merriam's wild turkeys (Meleagris gallopavo merriami) were studied in south-central Colorado during spring 1986, 1988, and 1989. Adult males moved 5.3 ? 3.8 (SD) km from winter ranges to spring breeding areas and had an average harmonic mean spring home range size of 5.2 ? 3.3 km2. Subadult males moved farther (8.7 + 3.1 km, P = 0.03) and occupied larger (12.3 ? 4.9 km2, P < 0.01) harmonic mean home ranges than adults. Minimum convex polygon home ranges for both age classes were >100% larger (P < 0.01) than harmonic mean home ranges. The median distance between morning and evening roosts used on the same day was 996 m for subadults and 1,074 m for adults. Median distances between consecutive roost sites increased during the hunting season compared to preseason and postseason periods. Subadults returned to the same roosts more often (29%) than adults (19%). Departure and roosting times during the hunting season indicated shooting hours should start at sunrise and end 0.5 h before sunset to discourage roost shooting and promote ethical hunting practices. Seasonal movements, roosting activities, and home-range characteristics of Merriam's wild turkey (Meleagris gallopavo merriami) have been extensively studied throughout its native and ex- panded range (Jonas, 1966; Hoffman, 1968; Boeker and Scott, 1969; Scott and Boeker, 1972, 1975; Mackey, 1982, 1984; Schemnitz et al., 1985; Lutz and Crawford, 1987, 1989). The emphasis has been on studying females and describing physical features of trees and cover types used for roosting, with little attention given to males or behaviors associated with roosting. Thus, the ob- jectives of this study were to compare winter to spring movements, spring home-range size, and spring roosting patterns of adult and subadult males. Specific roosting patterns measured in- cluded spatial relationships among spring roost- ing sites, fidelity to spring roosting sites, and tim- ing of roosting activities. MATERIALS AND METHODS-Trapping was con- fined to Longs Canyon and two tributary canyons, Sowbelly and Martinez, approximately 17 km south- west of Trinidad, Las Animas Co., Colorado. From trap sites, radio-marked birds ranged over 448 km2 of surrounding areas during the breeding season, includ- ing portions of north-central New Mexico (Hoffman, 1990). Turkeys were captured during February and March in 1986, 1988, and 1989 using drop or cannon nets. Adult males were trapped in 1986 and 1989 and sub- adults in 1988; no birds were captured in 1987 due to unfavorable trapping conditions (i.e., mild weather plus an abundance of acorns and pinyon nuts). Captured birds were banded with serially numbered aluminum leg bands. Numbered Allflex livestock tags were at- tached to the patagium. Fifteen adult (> 18 months of age) males and 10 subadult (8 to 10 months of age) males were fitted with lithium battery-powered trans- mitters attached with a poncho collar (Amstrup, 1980) or tail-clip (Bray and Corner, 1972). The poncho pack- age weighed <40 g, the tail package weighed <35 g. The principal method of radio-tracking was from the ground using a hand-held, three-element Yagi antenna. Locations were based on visual observations and re- corded to nearest 50 m as Universal Transverse Mer- cator Coordinates. Spring was defined as 1 April to 15 June and cat- egorized as preseason (approximately 1 to 15 April), hunting season (approximately 16 April to 15 May), and postseason (approximately 16 May to 15 June). Actual opening and closing dates of the spring hunting season varied by 3 days over the study period. Attempts were made to locate each male twice per week at 3-day intervals to conduct a gobbling index (Hoffman, 1990). Consecutive locations were alternated between morn- ing and evening. The initial order in which males were located was randomly selected. If a male could not be This content downloaded from 128.227.183.183 on Fri, 31 Jan 2025 21:07:48 UTC All use subject to https://about.jstor.org/terms September 1991 Hoffman-Movements and roosting of Merriam's wild turkey 333 found on the scheduled day, the next male on the list was located. Priority was then given to finding the missing male. Although order of location was adhered to whenever possible, some males were located less often than others because of their greater mobility. Harmonic mean transformation (HMT; Dixon and Chapman, 1980) was used to estimate spring home- range size for males that survived from 1 April to 15 June and were located >20 times during this period. Home-range size was calculated based on the 90%- contour of area using the computer program MCPAAL (Stuwe and Blowhowiak, 1986). For comparative pur- poses, the more common minimum convex polygon (MCP) procedure (Mohr, 1947) also was used to cal- culate home-range size using the same computer pro- gram. Movements from wintering to breeding areas were measured as the minimum straight line distance between the winter trap site and the arithmetic mean center of the spring home range. Mean movements and home-range sizes of adult and subadult males were compared using t-tests. Roosting sites were located while conducting gob- bling indices (Hoffman, 1990). A gobbling index lasted 1 h from 0.5 h before to 0.5 h after sunrise or sunset and included time when birds were on and off the roost. Roosting times were determined by observing or hear- ing birds fly to and from the roost. Distances between roost sites were calculated from consecutive locations (same day) and for locations -53 days apart. A roost site was considered reused if the same bird was located within 150 m of a previous roost location. This was determined to be the minimum distance that a roost site could be safely approached without disturbing the birds. The Kruskal-Wallis test was used to test the null hypotheses of no difference in roosting times and no difference in distances between roosting sites among males within an age class. Comparisons between age classes were made using the Mann-Whitney-Wilcoxon test. The Wilcoxon signed-rank test was used to com- pare median distances between roost sites for the same male during preseason, hunting season, and postseason periods. Frequency of use of previously occupied roost sites by adults and subadults was compared with a chi- square 2 x 2 contingency table. RESULTS--Estimates of home range size were calculated from 278 locations (20 to 28 locations/ male) of 11 adult males and 289 locations (20 to 31 locations/male) of eight subadult males that were monitored from 1 April through 15 June; 72% of these locations were roost sites. Departure and roosting times were recorded for 183 (133 adults, 50 subadults) morning observations and 105 (70 adults, 35 subadults) evening observa- tions. Adult males moved 5.3 ? 3.8 (SD) km from winter to breeding areas. Their HMT spring range size averaged 5.2 ? 3.3 km2. Movements (P = 0.15) and spring home-range size (P = 0.22) of adults did not differ between years. Subadults moved farther (8.7 + 3.1 km, P = 0.03) and occupied larger (12.3 + 4.9 km2, P < 0.01) HMT spring home ranges than adults. Minimum con- vex polygon home ranges for both age classes were substantially larger (P < 0.01) than HMT es- timates, averaging 13.9 ? 8.2 km2 for adult males and 28.7 ? 13.8 km2 for subadult males. All six adult males monitored in 1986 shared a portion of their spring home range with at least one and up to four other radio-marked males. In 1989, three of five adult males shared spring home ranges, and in 1988, seven of eight subadults had overlapping home ranges with one to three other radio-marked subadults. Spring and winter home ranges overlapped for five of 11 adult males and three of eight subadult males. Three adult males with distinct winter and spring home ranges left the winter range during the first week of April; the other three adults and five subadults did not leave until the third week of April in conjunction with peak departure of hens. For those males with overlapping winter and spring home ranges, it was not clear when they moved onto their spring range in April. The median distance between morning and evening roosts on the same day was 996 m (n = 44, range of 0 to 6,900 m) for subadults and 1,074 m (n = 25, range of 50 to 2,507 m) for adults. The median distance between roost sites located <3 days apart, but not on the same day, was 1,272 m (n = 62, range of 798 to 1,979 m) for adults and 1,041 m (n = 82, range of 859 to 3,389 m) for subadults. Neither comparison was sig- nificant (P > 0.44). However, differences (P = 0.04) were apparent among males within an age class as evidenced by the wide range of movements by individuals between roosting sites. Median distances between roost sites increased during the hunting season compared to preseason (P = 0.03 for both adults and subadults) and postseason (P = 0.03 for adults, P = 0.08 for subadults) periods, but were similar (P = 0.35 for adults, P = 0.71 for subadults) during the preseason and postsea- son (Table 1). The frequency with which adult males were found at previously-used roost sites was 19%. Subadults returned to the same roosts more often (29%) than adults, although the difference was marginal (P = 0.14). All subadult males reused This content downloaded from 128.227.183.183 on Fri, 31 Jan 2025 21:07:48 UTC All use subject to https://about.jstor.org/terms 334 The Southwestern Naturalist vol. 36, no. 3 TABLE 1-Median distance (meters) between roosting hunting season. Distances are based on roost sites loc Adult Subadult Period n Median Range n Median Range Preseason (1-15 April) 39 1,137 50-1,371 51 869 761-2,055 Season (16 April-15 May) 59 1,765 917-2,961 50 1,823 925-5,162 Postseason (16 May-15 June) 53 1,165 800-1,597 21 1,068 600-2,055 at least one roost site, but two adult males did not. No roost site was used more than four times and seldom (adults = 4%, subadults = 9%) was a roost site used on the same day (i.e., morning and evening). However, subadults (median = 7 days, range of 0 to 24) returned to previously- occupied roosts sooner (P < 0.01) than adults (median = 12 days, range of 1 to 78). Departure and roosting times did not differ (P = 0.35 and 0.45 for adults, P = 0.24 and 0.30 for subadults, respectively) among males within an age class. There was approximately a 20-min period when birds went to roost or left the roost (Table 2). Extreme variations in roosting times were usually associated with overcast conditions accompanied by snow or rain. Males did not take full advantage of increasing daylength by departing roosts earlier or entering roosts later. Instead, they tended to leave roosts later in relation to sunrise and enter roosts earlier in relation to sunset as the spring monitoring period progressed (Table 2). Adult and subadult males left the roost about 11 to 13 min before sunrise during the preseason and 5 to 7 min after sunrise during the postseason. During the hunt- ing season, adults continued to leave the roost before sunrise, about 9 min earlier (P = 0.04) than subadults, which were departing at or just after sunrise. Preseason roosting times of adults and subadults occurred 6 to 7 min after sunset. During the hunting season, subadults roosted just before sunset, and adults slightly after sunset. By the postseason period, adults and subadults were flying to roost before sunset. DIscussIoN-Both HMT and MCP estimates indicated male Merriam's wild turkeys occupied large spring home ranges. The MCP home rang- es of Merriam's wild turkeys in Oregon (Lutz and Crawford, 1989) also were larger than HMT and MCP home ranges reported here, averaging 1,655 ha for adult males and 2,345 ha for sub- adult males. Conversely, MCP home ranges (X = 150 ha) of subadult males in Washington (Mackey, 1982) were much smaller. Both of thes investigators studied introduced populations and relied on triangulation techniques. Brown (1980 found similar but less extreme disparities in pub- lished home-range sizes for eastern wild turkey (M. g. silvestris), which he partly explained by differences in sampling and analyses from on study to another. The MCP home ranges included all location points between 1 April and 15 June. The HMT method, using the 90%-contour interval, elimi nated outlier locations and, thus, excluded som areas that were part of the MCP ranges. Ther was behavioral evidence that supported using th HMT approach and suggested the MCP ap- proach included areas that were seldom used an portions of the winter and transitional ranges tha were not part of the spring range. For example all males used portions of their range more in- tensively than others. In addition, few males moved directly from winter to spring ranges but, instead left the winter range over a period of about 3 weeks and used transitional ranges in the interim before moving onto spring ranges. Finally, som males used portions of their winter range throughout the spring period, whereas others ha distinct winter and spring ranges. Subadults occupied larger spring home range and used more areas within their ranges than adults. This was consistent with findings of Lut and Crawford (1989) but contradicts the reported observations of Fleming and Webb (1974) fo eastern wild turkeys. Subadults frequently local ized in certain areas within their range, some times for as long as 2 weeks, but seldom returne to these areas once they left. In comparison, adult repeatedly used several different areas within the spring ranges. Occasionally, they ventured away from normal areas of activity, but usually re turned in <1 week. These intense use areas var- This content downloaded from 128.227.183.183 on Fri, 31 Jan 2025 21:07:48 UTC All use subject to https://about.jstor.org/terms September 1991 Hoffman-Movements and roosting of Merriam's wild turkey 335 TABLE 2-Spring departure (minutes before or after sunrise) and roosting (minutes before or af times of male Merriam's wild turkeys in relation to the hunting season. Positive departure va minutes off the roost before sunrise and negative values minutes off the roost after sunrise. Posit values indicate minutes on the roost after sunset and negative values minutes on the roost before s Adult Subadult Departure Roosting Departure Roosting Period n Xf SD n X SD n f SD n X SD Preseason (1-15 April) 26 +10.6 10.8 20 +7.2 8.4 18 +12.7 7.1 11 +5.9 8.0 Season (16 April-15 May) 46 +8.2 8.4 26 +0.5 8.2 20 -0.7 7.4 13 -3.2 9.2 Postseason (16 May-15 June) 37 -5.3 8.9 19 -7.5 10.9 12 -6.5 7.0 11 -13.5 5.6 ied from <0.5 to almost 6 km apart. Wigley et al. (1986) also found widely separated areas of intense activity within home ranges of eastern wild turkeys in Arkansas. Poor quality habitat has been cited as an ex- planation for large annual home ranges occupied by eastern wild turkeys in Arkansas (Wigley et al., 1986) and Merriam's wild turkeys in Oregon (Lutz and Crawford, 1989). Spring ranges of males may be influenced by other factors in ad- dition to habitat quality. Porter (1977) noted that during the breeding season, males moved more, and with less predictability, than females. He contended that the male's reproductive drive was the primary factor controlling spring movements. The period of increased movements of males, as indicated by distances between roosting sites, occurred from mid-April to early May and co- incided with the period when hens were moving to nesting areas. This increase in mobility of males also occurred in conjunction with the spring hunt- ing season. However, due to limited access to private lands, hunting pressure was minimal and not considered a factor influencing movements. Based on chronology of nesting events (Hoffman, 1990), mid-April to early May also was the pe- riod when hens were most receptive to males. Since males did not associate with the same hens throughout the breeding season, they periodically searched for other receptive hens. Males were more sedentary both before and after the hunting season, when hens were still in flocks on winter range or localized on nesting areas. These obser- vations partially agree with Porter's (1977) con- tention and suggest that size of a male's spring range was at least partially dependent upon avail- ability of hens. Male Merriam's wild turkeys demonstrated low fidelity to spring roosting sites. This was not surprising considering the size of their spring home ranges. Even adults, which repeatedly used the same areas within their spring ranges, did not select the same roosting sites within these areas. In Oregon, Lutz and Crawford (1987) identified few traditionally used roost sites during any sea- son. They did not quantify fidelity but reported all spring roosting sites were only lightly used. I interpreted this to mean that at least some sites were used more than once. In New Mexico, hen turkeys used only one of 29 summer roosts more than once, whereas 29 winter roosts were used repeatedly (Schemnitz et al., 1985). Rio Grande wild turkeys (M. g. intermedia) in Oklahoma consistently left the roost about 15 to 20 min before sunrise throughout spring (Logan, 1973). Roosting times ranged from sunset to 30 min after sunset, becoming later as spring pro- gressed into summer. Early spring (analogous to the preseason period) departure times of Mer- riam's wild turkeys monitored in a previous study in Colorado (Hoffman, 1968) ranged from 10 to 15 min before sunrise; roosting times were more variable, ranging from 3 min to 19 min after sunset. I observed a wider range of departure times than reported by Logan (1973) or Hoffman (1968) but a comparably broad range of roosting times. Hens were often present or nearby when I was monitoring roosting behavior. When this occurred, males departed and roosted concur- rently with hens. In the absence of hens, adult males remained on the roost longer in the morn- ing but did not alter evening roosting patterns. CONcLUSIONs-Home-range characteristics for wild turkeys differ greatly across their geographic range. Even within the range of individual sub- species, home-range sizes vary markedly. Expan- sion into non-historic habitats has added to this This content downloaded from 128.227.183.183 on Fri, 31 Jan 2025 21:07:48 UTC All use subject to https://about.jstor.org/terms 336 The Southwestern Naturalist vol. 36, no. 3 variation and created problems in develo management plans for general application t broad range of environments occupied by turkeys. This especially applies to the conce home range because it is not always defin calculated the same way and is affected by a ber of interacting factors. Brown (1980) re mended that instead of developing manage plans based on home-range data obtained f several studies conducted over a wide area, it be more appropriate to develop separate p each specific to the region where the data collected. Brown's (1980) recommendation may be ex- cessive. An alternative approach might be to stan- dardize sampling methods and data analysis. Care also must be taken to define the time frame as- sociated with the estimate of home range and what activity areas are included within the home range. For example, spring as defined here in- cluded the period when some males were in tran- sition between winter and spring ranges, while other males were still on winter range. This had a pronounced influence on the estimate of home- range size, and, had it not been identified, the estimates would have been misleading. Home-range estimates revealed little about spring movements of males but, in combination with data on spatial relationships of roosting sites, it was apparent that males moved extensively during spring. Scott and Boeker (1972) did not consider the extent of spring movements and in- consistent gobbling patterns (Hoffman, 1990) of Merriam's wild turkeys when they proposed that gobbling surveys could be used as a population index for this subspecies. Even with the tight control of extrinsic variations that was accom- plished by Porter and Ludwig (1980), use of gob- bling surveys to monitor relative abundance and trends in population growth of Merriam's wild turkeys it questionable without further research. Management recommendations regarding spring hunting seasons should consider roosting behavior. Current regulations in most western states allow shooting from 0.5 h before sunrise to sunset. Spring departure times during the hunt- ing season occurred at or slightly before sunrise. To discourage roost shooting and promote ethical hunting practices, legal shooting hours should start at sunrise. Legal shooting hours that end 0.5 h before sunset also would give birds adequate time to roost without being exposed to roost shooting in the evening. I thank J. L. Aragon, R. L. Holder, and T. J. Spezze for help with baiting and trapping and T. D. Abell, B. D. Linkhart, and R. K. Mueckler for assistance with data collection and analyses. The Colorado De- partment of Parks and Outdoor Recreation provided trailer space and use of shop and office facilities at Trinidad State Recreation Area. I am especially grate- ful to the many landowners who allowed access. This paper is a contribution of Colorado Division of Wildlife Federal Aid in Wildlife Restoration Project W-152-R. LITERATURE CITED AMSTRUP, S. C. 1980. A radio-collar for game birds. J. Wildl. Mgmt., 44:214-217. BOEKER, E. L., AND V. E. SCOTT. 1969. Roost tree characteristics of Merriam's turkey. J. Wildl. Mgmt., 33:121-124. BRAY, O. E., AND G. W. CORNER. 1972. A tail clip for attaching transmitters to birds. J. Wildl. Mgmt., 36:640-642. BROWN, E. C. 1980. Home range and movements of wild turkeys-a review. Proc. Natl. Wild Turkey Symp., 4:251-261. DIXON, K. R., AND J. A. CHAPMAN. 1980. Harmonic mean measure of animal activity areas. Ecology, 61:1040-1044. FLEMING, W. H., AND L. G. WEBB. 1974. 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