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Raising and monitoring tame ruffed grouse (Bonasa umbellus) for field studies.

INTRODUCTION

Behavioral and ecological studies of wild birds are often constrained by difficulties in observing undisturbed individuals at close range. An alternative technique for acquiring data which require close observations is the use of tame or imprinted birds. Previous investigations have used tame or imprinted ducks (Arias rubripes, A. platyrhynchos, and Aix sponsa; Hunter et al., 1985), wild turkey (Meleagris gallopavo; Healy et al., 1975; Healy, 1985), gray partridge (Perdix perdix; Erpelding et al., 1986) and ruffed grouse (Bonasa umbellus; Kimmel, 1982; Kimmel and Samuel, 1984; Rogers and Samuel, 1984) to assess habitat quality for brood rearing. These studies were generally limited to the use of young birds ([less than]8 wk old) before dissolution of parent-offspring bonds. However, close observation of older, human-imprinted wild turkeys in the field has been reported (Healy et al., 1975; Kimmel and Healy, 1987). We were interested in raising and observing ruffed grouse during the winter and spring to evaluate potential factors limiting over-winter survival in southern Illinois. We did not know, however, whether older, captive-reared grouse would remain tame enough for observations once they were released.

Kimmel (1982) reported that it became difficult to work with ruffed grouse chicks [greater than]7 wk of age and that it was nearly impossible to work with juvenile ruffed grouse in an unrestrained situation after 12 to 14 wk because of their natural instinct to disperse. He suggested that human-imprinted grouse would make excellent subjects to observe from a distance through winter and spring, if they were equipped with radios and allowed to disperse. Following up on these suggestions, we report here an evaluation of two techniques we used to raise and monitor tame ruffed grouse, up to 1.5 years of age, released into the wild.

STUDY AREA

The study was conducted in a 32-[km.sup.2] area of Union County, Illinois (37 [degrees] 22[minutes]N, 89 [degrees] 19[minutes]W), primarily in the Shawnee National Forest. Topography was generally steep (30-70% slopes) with elevations ranging from 110 to 250 m. The average annual temperature was 13.8 C (average January and July temperatures of 0.7 C and 25.6 C, respectively) and annual precipitation averaged 116.2 cm, with 34.5 cm as snowfall (Miles et at., 1976).

Thirty-five regenerating clear-cuts (1.1-42.3 ha) covered ca. 10% of the study area and were composed primarily of white sassafras (Sassafras albidum), flowering dogwood (Cornus florida) , hophornbeam (Ostrya virginiana) , tuliptree (Liriodendron tulipifera) , northern red and white oaks (Quercus rubra and Q. alba, respectively) and mixed hickory (Carya spp.). Stem densities ranged from approximately 18,500/ha in 6-10 year-old cuts to 6500/ha in 16-20 year-old cuts (Sharpe, 1991). The mature woodlands were dominated by white oak, black oak (Quercus velutina), pignut hickory (Carya glabra), red hickory (C. ovalis), hophornbeam, and white sassafras on the uplands; northern red oak, tuliptree, eastern cottonwood (Populus deltoides), beech (Fagus grandifolia) and sycamore (Platanus occidentalis) dominated lowland sites (Norris, 1986).

METHODS

Rearing. - We collected 63 ruffed grouse eggs from nests on and near the Whitewater Wildlife Management Area in southeastern Minnesota (44 [degrees] 7[minutes]N, 92 [degrees] 00[minutes]W) during spring 1989. We kept the eggs at 37.5 C in circulating air Hova-Bator[R] incubators with automatic egg turners (G.Q.F. Mfg. Co., Savannah, Georgia) before and following transport to Southern Illinois University at Carbondale (SIUC).

We placed the eggs in hatching units consisting of still air Hova-Bator[R] incubators without automatic egg turners 2 to 3 days before estimated hatch dates. We played a recorded whistle on a loop cassette tape placed near the hatching units, which would be used to call the chicks after hatching, to help synchronize hatching of clutches (Kimmel and Healy, 1987). We marked each hatched chick by clipping the skin between one or more toes with surgical scissors to identify its clutch. This method appeared painless, permanent, and did not disable the birds as toe clipping might.

Hatched birds were raised and maintained under a protocol approved by the SIUC Animal Care and Use Committee (IACUC Protocol No. 89-018). Intensive imprinting of chicks began immediately after hatching by placing the chicks in a sweatshirt pocket to dry. This provided maternal stimuli such as touch, sound and warmth (Kimmel and Healy, 1987). We provided the chicks with water containing Durvet[R] vitamin and electrolyte concentrate (Durvet Inc., Blue Springs, Missouri) and Terramycin[R], a broad-spectrum antibiotic powder (Pfizer, Agricultural Division, New York, N.Y.). These were initially supplied to each bird through an eye dropper and later added to their water dishes, which were mason jar-type water fountains filled with marbles to avoid the drowning of chicks (Bump et al., 1947). Chicks were fed mealworms until they fed consistently on Purina Gamebird Startena (Purina Mills, Inc., St. Louis, Missouri), usually by 1 wk of age. We started feeding the birds gamebird food by sprinkling moistened food on a paper towel or piece of paper (Bump et al., 1947). We ceased supplements of vitamins and antibiotics to their water at this time, but continued to supplement their diet with mealworms.

The birds initially ranged free in a small (3 x 3 m) room in the SIUC vivarium during the day and were placed in brooders at night (12:12 h photoperiod). A heat lamp with a 250-w red reflector bulb provided additional heat during the daytime. As the birds outgrew the brooder they were placed in metal rabbit cages (approximately 0.6 x 0.6 x 0.6 m) with 1-3 birds in each. They eventually became too large and active for the daytime room and remained in the rabbit cages continuously during the last few weeks indoors. Until this point, the birds had 10-24 h of daily human interaction, which included brooding of the younger birds and occasional hand-feeding.

We moved chicks to outdoor pens when they were approximately 12 wk old. Each pen was approximately 4.9 x 1.2 x 1.2 m with the floor raised 0.75 m above the ground. The cage sides and top were covered with 1.27-cm galvanized wire mesh; the floor with 2.54 x 1.27-cm wire mesh. Pens had a fiber-board roof and fiberglass roofing on three sides. Conifer branches within the pens provided perch sites and security cover.

Penned birds were hand-fed mealworms and raisins several times a week to reinforce tameness. We also provided commercial gamebird chow (Purina Gamebird Flight Conditioner, 24% protein) and water ad lib. Food trays were top-dressed with insoluble granite grit. Natural foods such as autumn olive berries (Elaeagnus umbellata), grape (Vitis sp.), sumac berries (Rhus sp.), honeysuckle (Lonicera sp.) and blackberries (Rubus sp.) occasionally supplemented the diet.

We collected 157 eggs from our tame birds during spring 1990. We removed eggs daily and placed them in an incubator. We used the same hatching technique as in 1989, but the resulting chicks were not provided with the long hours of daily human contact that the intensively imprinted birds received. These nonintensively imprinted birds were instead kept in brooders throughout the day ([less than]2 h of human contact per day) and moved to outdoor pens around 5 wk of age, the earliest age suggested for moving birds to outdoor pens without artificial heat (Bump et al., 1947). We used this nonintensive imprinting approach to examine whether we could obtain observable birds without intensive imprinting.

Release and monitoring of tame grouse in the field. - We fitted each bird with a poncho-mounted transmitter (Amstrup, 1980) weighing 3-5% of the bird's body mass ca. 1 wk before release. Six tame juvenile grouse were released from autumn 1989 through spring 1990 and four birds (two juveniles, two adults) from late autumn 1990 through late winter 1991 in forest clear-cuts ranging from 10-20 yr old. Birds were released one at a time and monitored until their death. We initially intended to recapture the birds after each day of observations to avoid overnight mortality, but this proved difficult, as the birds became increasingly timid with each recapture, making observations nearly impossible. Therefore, we allowed released birds to remain in the wild continuously and located them daily using radio telemetry.

After their initial release, birds avoided us (e.g., walked in the opposite direction or hid under heavy cover) when we approached, but would generally not flush. We allowed the birds 1-2 days to acclimate to the wild without close observations before starting data collection. By sitting ca. 10 m from the birds and making occasional noises (e.g., whistling, talking), the birds allowed close observations in 2-4 days. Within several days it was usually possible to approach within [less than]2 m of the bird while recording observations. While monitoring the birds we walked parallel to the birds instead of behind them to avoid driving the birds ahead of us. Tameness was reinforced in the field by allowing the birds to approach us for a small handout of raisins 2-3 times per week.

We generally made direct observations of birds for 1-5 h per day, recording continuous [TABULAR DATA FOR TABLE 1 OMITTED] observations of activity and forage selection. We divided activities into six major categories: flying, feeding, walking, standing, roosting and preening. We further classified feeding and roosting as occurring on or above the ground. During feeding bouts, the food species and number of bites taken were recorded. Observations of habitat use were recorded at 15-min intervals. These data were later used to calculate time-activity budgets, forage selection and habitat use. For simplicity of presentation, we combined all data for each bird.

RESULTS

Rearing. - Of 63 eggs collected from wild nests, 59 (93.7%) were fertile. Of these, 36 (61%) hatched, and 31 hatchlings (86%) survived until [greater than or equal to]12 wk of age. Only 29 (18.3%) of 157 eggs collected from 11 captive-reared birds were fertile and only 11 (38.2%) of these hatched. Three of these hatchlings (23%) survived past 12 wk of age. All of the fertile eggs came from only three hens. Considering only these three birds, 67% of the 50 eggs produced were fertile and 34% of these hatched.

Release and monitoring of tame grouse in the field. - The first four individuals released were all intensively imprinted juveniles (two male, two female). These birds were all killed within ! wk of their release, before we could collect sufficient data. The first bird (male) was killed the 1st night, probably by a bobcat (Felis rufus), as evidenced by puncture wounds in the back, sides and trachea, and because the carcass was cached in a shallow hole under dead leaves (McCord and Cardoza, 1987). The second two birds (one female, one male) were killed within 5 days and 2 days, respectively, probably by a great horned owl (Bufo virginianus), as evidenced by signs left at the carcasses and because the heads were removed from the carcasses. The fourth bird died within 5 days from unknown causes. Therefore, during the initial releases the average survival was only 3.25 days per bird. During these releases we were still developing our release and observation techniques, which may have influenced the birds' behavior and movement, possibly making them more vulnerable to predation. Once we reduced threatening behavior (e.g., approaching the birds), we collected data on five of six released birds and all survived at least 1 wk [Mathematical Expression Omitted]. We collected data on habitat and forage use and time-activity budgets for these birds for 15-39 days; 9-46 h of observational data were collected on each (Table 1).

All birds were generally active throughout the daylight hours and activity ranged from about 27% to 82% of the day, with a general increase in activity from November to March (Table 2; see Table 1 for release periods). Walking generally made up the largest portion of diurnal time-activity budgets, ranging from 21.2% to 71.2% of daily activities (Table 2).

We observed the birds consuming 16 identifiable foods and a variety of unidentified foods. Green herbaceous material generally comprised the largest portion of birds' diets by percentage of bites taken (Table 3). Foraging occurred primarily on the ground (85.0 [+ or -] 15.4% of foraging [Mathematical Expression Omitted], n = 5, range = 59-98%).
TABLE 2. - Percent of time spent in major activities by five tame
ruffed grouse released in southern Illinois, February 1990-March
1991

                                    Activity
Bird ID    Flying    Feeding   Walking   Roosting   Still   Preening

1           0.00       11.0      71.2       4.9      10.1     2.8
2           0.00       10.7      42.7      14.9      22.4     9.2
3           0.20       10.4      21.2      41.9      25.9     0.4
4           0.00        9.8      33.0      28.6      26.1     2.1
5           0.00       14.6      40.0      10.2      29.1     6.7

Mean        0.04       11.3      41.6      20.1      22.7     4.2
SD          0.10        1.9      18.5      15.0       7.4     3.6


Habitat use varied among individuals, but the birds tended to spend more time in regenerating clear-cuts (usually [less than]15 yr old) than any other habitat types [ILLUSTRATION FOR FIGURE 1 OMITTED]. Bird 3 (the only observed adult) was an exception, spending slightly more time in mature forest than in clear-cuts. No bird was observed in open areas (e.g., fields, clearings).

DISCUSSION

Rearing. - Our tame ruffed grouse did not respond to humans with stereotypical agonistic or sexual behavior after dissolution of brood bonds (Kimmel and Healy, 1987). This may be a result of continued hand-feeding of the birds throughout their life, unlike most studies with tame birds (e.g., Healy et al., 1975; Erpelding et al., 1986; Kimmel and Healy, 1987) that kept birds in brooders or outdoor pens with no apparent attempts to maintain their [TABULAR DATA FOR TABLE 3 OMITTED] tameness. Kimmel and Healy (1987) reported that human-imprinted ruffed grouse began to struggle when handled after they were several weeks old. We observed this behavior with our imprinted grouse also, which was especially problematic before moving the birds to outdoor pens, because we had to move them between the brooder and activity rooms daily. This handling could easily be eliminated by keeping the birds in a single room. Some social interaction, however, is important during the early life of a bird. Healy et al. (1975) found that turkey poults isolated from human contact during the 1st 72-h of life avoided humans and behaved differently than human- or hen-reared poults.

Our puny success with breeding the captive-raised birds was not unusual because obtaining fertile eggs from captive grouse has generally been difficult (Johnson and Boyce, 1991; Holman and Holman, 1994). McEwen et at. (1969) raised sharp-tailed grouse (Pedioecetes phasianellus), collected eggs daily from nestboxes, as we did, and found that only 49% of nearly 3900 eggs were fertile. Only 62% of the fertile eggs hatched and only 28% of the chicks reached maturity. As with our ruffed grouse, most of the mortality of hatchlings occurred within the 1st week. Johnson and Boyce (1991) also found low fertility of eggs laid by captive sage grouse (Centrocercus urophasianus). They suggested that specific nutritive factors may have been lacking because the diet of wild birds was not completely mimicked. They also suggested that the lack of specific nutrients, and/or bacterial infections passed from the hen, may have been responsible for the low viability of chicks. Providing antibiotics and more natural foods before and during nesting may increase both the fertility of eggs and viability of the chicks (Johnson and Boyce, 1991). Holman and Holman (1994) also described a technique for breeding ruffed grouse in captivity, which, for at least the three hens they allowed to breed, resulted in 78% egg fertility and 84% hatching. Therefore, with some modifications to our technique, it would probably be possible to greatly increase the success in rearing grouse in captivity.

Release and monitoring of tame grouse in the field. - There may be some question about the validity of using tame ruffed grouse to describe the behavior and ecology of wild grouse. Most results from the observations of our human-reared grouse were similar to those from studies of wild ruffed grouse in the southern portion of their range or agree with general observations of ruffed grouse throughout their range.

The activity levels of our birds were similar to those calculated from telemetric monitoring by Maxson (1989) of breeding ruffed grouse hens before incubation. The increase in our tame birds' activity from November to March and a subsequent decrease in April was probably a result of a decline in forage availability as winter progressed, followed by an increase in forage availability as new growth occurred in the spring.

The high use of green herbaceous forage by our tame grouse was similar to that reported in other southern portions of grouse range (Smith, 1977; Stafford and Dimmick, 1979; Seehorn et al., 1981; Norman and Kirkpatrick, 1984; Servello and Kirkpatrick, 1987). Furthermore, foraging almost exclusively on the ground has also been reported in SW Virginia (Servello and Kirkpatrick, 1988) and Alberta prior to the onset of permanent snow cover (Doerr et al., 1974). Huempfiner and Tester (1988) reported a sharp increase in arboreal feeding with the onset of permanent snow cover. They also reported that 87% of budding observations were in quaking aspen (Populus tremuloides) and that budding on other species decreased with decreases in grouse densities. The low levels of arboreal feeding observed in our birds may have been a result of little snow accumulation, the absence of aspen, and/or low grouse densities. Foraging above ground in our study area may have also increased heat loss through convection during cold periods because of an increase in wind speeds and a general lack of deciduous or coniferous leaf cover.

The importance of high stem densities as cover for grouse has often been emphasized and is consistent with the preference for young clear-cuts by our tame grouse. Grouse in central and northern regions, where aspen is found, have the highest productivity and longevity in hardwood forest stands that are 10-25 yr old (Gullion, 1972), containing 14,000-20,000 stems/ha (Thompson and Fritzell, 1988). High stem densities also seem to be preferred in southern regions, such as Tennessee (Gudlin and Dimmick, 1984), Missouri (Dacey, 1983; Thompson and Fritzell, 1989), and southern Illinois (Norris, 1986).

Continued hand-feeding of birds in the field may have had a slight influence on forage selection, but we believe that these supplements did not greatly affect the birds' behavior because these feedings were erratic, infrequent and only supplied a small amount of the energy needed for daily metabolic costs. Also, it is unlikely that the birds minimized their movements and habitat use in anticipation of our arrival with "treats" because observation periods were sporadic.

The tame grouse encountered high rates of predation, but these rates were similar to those of wild ruffed grouse translocated to southern Illinois. For instance, of eight wild ruffed grouse that we captured in the Whitewater Wildlife Management Area, radio-collared, and released in southern Illinois in September 1989, five birds were killed and two others were presumed dead within 70 days. Poncho-mounted transmitters may have increased predation risk, as we were often able to hear the tame birds before we could see them because their claws sometimes scraped on the poncho when they walked. This may have allowed predators to more easily detect the grouse, especially great horned owls, which were thought to be responsible for most of the mortalities because of signs left at the carcasses (e.g., white-wash, pellets) and because many of the carcasses had the head removed. Future releases may be able to reduce mortality by (1) reducing transmitter poncho size (less pendulous) or changing the type of transmitter package used; (2) spending more time with the birds in the field, especially at dusk when most of the mortality apparently occurred, and/or (3) releasing birds in areas that already support large grouse populations or have lower predator populations so that predation risk may be reduced.

Our results suggest that it is unnecessary to spend extended periods with young grouse during rearing to obtain tame birds that are observable in the wild. The grouse that received non-intensive imprinting did not display obvious behavioral differences compared to birds that received intensive imprinting. Although there was confounding between the imprinting techniques and generational effects (i.e., only second generation birds received nonintensive imprinting), we believe that the similar activity patterns, forage use and habitat use between the two groups of grouse (intensively vs. nonintensively imprinted) were a result of the effectiveness of both imprinting techniques and not the result of a generational effect because the second generation birds never had contact with first generation birds. Future studies could use both techniques on subgroups within each generation to eliminate this possible confounding. However, we believe that all that is required to obtain observable ruffed grouse are short periods of daily contact with some hand-feeding of mealworms, raisins or other foods to habituate chicks to humans and reinforce tameness. Admittedly, our sample sizes were small because only one of us (P. B. Sharpe) monitored the birds, so only one could be released at a time. A more intensive effort may need to be attempted to verify this technique, but our results are promising. Additionally, future efforts may need to focus more strongly on males because we successfully recorded observations on females only, although three of the 10 releases were of males. We can not determine at this point whether males are more difficult to watch, more susceptible to predation, or whether our failure to observe males occurred by chance.

The use of tame ruffed grouse in future research could provide useful information on many aspects of ruffed grouse behavior and ecology that may not be feasible with wild birds. We believe that with moderate effort, this or similar grouse species could be released and observed in the wild for extended periods, independent of the season or age of the birds. Because it is often difficult to determine whether forage and habitat availability and quality are adequate to support populations in areas with no grouse or low population densities, this technique may allow researchers to evaluate such factors in areas where grouse introductions are proposed or to be evaluated.

Acknowledgments. - We thank the Minnesota Department of Natural Resources and the staff of the Whitewater Wildlife Management Area for their cooperation in collecting eggs from wild nests. We also thank M. Roberts for directing the efforts to collect the eggs, and R. Gates, W. Jakubas, J. Connelly and T. E. Morrell for providing helpful comments on the manuscript. Funding was provided by the Ruffed Grouse Society and the Cooperative Wildlife Research Laboratory at Southern Illinois University at Carbondale.

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Author:Sharpe, Peter B.; Woolf, Alan; Roby, Daniel D.
Publication:The American Midland Naturalist
Date:Jan 1, 1998
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