102 TURKEY NESTING SUCCESS OM A FLORIDA STUDY AREA LOVETT E. WILLIAMS, JR., Game and Fresh Water Fish Commission, Gaines- ville, FL 32601 DAVID H. AUSTIN, Game and Fresh Water Fish Commission, Lake Placid, FL 33852 TOMMIE E. PEOPLES, Game and Fresh Water Fish Commission, Gainesville, FL 32601 Abstract: Nesting success of wild turkeys (Meleagris gallopavo) was measured for 108 nests of radio-tracked hens on a Florida study area during an 8-year period. During 4 years of the study, poisoned eggs were distributed in a part of the study area to measure their effect in reducing nesting losses and to obtain carcasses of predators for identification. Most predation was by 4 mammal species; several poten- tial predators, including feral hogs (Sus scrofa), common crow (Corvus corvus), and armadillo (Dasypus novemcinctus) were not significantly involved. Nesting success was 59% in 4 of the years when no poisoned eggs were distributed and 72% during 4 years in the treated area. A high rate of compensatory nesting was detected, the effect of which would probably negate any advantages of such a control effort. In 1968 through 1976 wild turkey nesting success was measured and the major nest predators were identified on a study area. As far as we can determine, this is the first report of its kind on turkey nesting success. We thank Charles P. Lykes and Ben Swendsen of Lykes Brothers, Inc., owner of the study area; and William B. Frankenberger, Jerry Peoples, and Neal F. Eichholz for assistance in the field. This is a contribution of Florida Pittman-Robertson Project W-41. METHODS This work was done in connection with a larger study of turkey ecology and behavior on Lykes Fisheating Creek Wildlife Management Area in Glades County, Florida. The study area has been described in detail (Williams et al. 1973). One hundred forty hens were radio-tracked to find their nests so that they could be checked to determine their fates. Other objectives of the study required a certain amount of disturbance to the turkeys which led to occasional nest desertion (i.e., eggs were deliberately taken in order to observe the tendency to renest following nest loss). Only data from 108 undisturbed nests are used in this report. Turkey and chicken eggs injected with sodium monofluoracetate ("10-80") or strychnine alkaloid were placed in about one-half the study area 103 to test whether this would materially lower the level of nest predation, and to help identify the major predators involved. Regular searches for predator carcasses were made to identify which species of animal were eating eggs. Steel leghold traps were occasionally placed in predated nests to capture predators that visited the nests a second time or to capture secondary nest predators. RESULTS AND DISCUSSION Predators Involved Although there was no means of accurately counting the numbers of predators killed by the poisoned eggs, we found many dead skunks (Spilogale putorius and Mephitis mephitis), raccoons (Procyon lotor) and opossums (Didelphis virginianus). It is safe to say that they had eaten the poisoned eggs. It is likely that they would also eat un- poisoned turkey eggs and that they were the predators of turkey nests in this study. These 4 species were frequently captured when traps or poisoned eggs were placed in predated nests. In many cases, the sign that different predators left at predated nests could be recognized which further implicated these same mammals as the main species in- volved. Only 2 gray foxes (Urocyon cinereoargenteus), 1 bobcat (Lynx rufus), and 1 crow that we know of, and no hawks, owls, armadillos, or feral hogs were killed, although these were abundant on the study area. This indicates that these species were not important predators of turkey nests on our study area. Armadillos have been suspected of serious predation on ground nesting birds but this was not so in this study. An armadillo was suspected of eating eggs in only 1 case, because of sign at the destroyed nest, and we know that 2 nests were abandoned when armadillos rambled through and rolled out some of the eggs without breaking them. Feral hogs were almost as abundant as turkeys in parts of the study area but did not take poisoned eggs or destroy a turkey nest as far as could be determined. Cattle were also abundant but in no case did we think that one had stepped in a turkey nest. Although dogs are rare on the study area, at least 1 nest was destroyed by a dog and dogs were suspected in another case. In several cases the evidence suggested that the usual predatory species were not involved. These cases included dime-sized holes in eggs, which indica- ted a small animal, probably a rat or mouse; and gradual disappearance of part of the clutch without destruction of the nest, which may have been done by a snake. It has been said that gobblers will destroy nests. Although this has been generally discredited, there has been no definite evidence against it. In this study we found no evidence of a gobbler molesting a nest. Indeed, the behavior of laying and setting hens virtually precluded the gobblers from knowing the location of the nests. 104 Nesting Success In this study, the turkey had a 59% success rate in the natural (no poisoned eggs used) area and a 72% success where predator control was being carried out during the nesting season (Table 1). Galliform birds in general have nesting success of about 45% (Hickey 1955). It is in- teresting to note that the galliform species with the best nesting success seem to be those that occupy principally natural habitat--these are ruffed grouse (Bonasa umbellus) with 61% (Darrow, 1947), willow Ptarmigan (Lagopus lagopus) with 80% (Kristoffersen 1937), and sage grouse (Cen- trocercus urophasianus) as high as 60% (Rassmussen and Griner 1938); while the ring-necked pheasant (Phasianus colchicus), a species norm- ally associated with farms and highly altered habitats, averages about 36% (Hickey 1955) and is sometimes as low as 20% (Randall 1940). The bobwhite quail under manipulated conditions in southern Georgia and northern Florida, had only about 36% nesting success (Stoddard 1931) and about 20% (Simpson 1976). Turkey nesting success in our study compares with success rates usually given for species of grouse and is substantially higher than is usually observed in pheasant and bobwhite, or the average for the galliformes. Table 1. Numbers of successful and unsuccessful turkey nests on the study area. Treated Area Control Area Years of No Treatment Year Hatched Predated Hatched Predated Hatched Predated 1968 No treatment 12 9 1969 3 0 1 4 1970 1 1971 6 5a 1 5 4 6 0 1972 2 3 5 0 1973 5 3 3 0 1974 No treatment 3 7 1975 No treatment 8 3 1976 No treatment 7 2 Total 21 (72%) 8 (28%) 20 (71%) 8 (29%) 30 (59%) 21 (41%) a Includes nests from which eggs were removed by predators but which still resulted in at least some eggs hatching. Effect of Predator Control Nesting success was 72% on the treated portion of the study area while poisoned eggs were being distributed (during 1969 through 1973) and was 71% on the nearby control area (Fig. 1) during the same years (Table 1). It was only 59% in the 4 years during which no poisoned eggs were distributed, suggesting the possibility that the predator con- trol effort had an effect on the nearby study area (Fig. 1). The com- bined success rates for the untreated parts of the study area (during predator control years) and for the total nesting in years when there was no predator control was 63%. Thus, the true success rate was between 59% and 63% when predator control was not practiced. Fig. 1. Study area map showing the approximately 3 square mile treated area joined on east and west by the untreated parts (control). Turkey habitat is entirely along the creek-- there was no nesting habitat immediately to the north or south. 106 It is unclear whether the use of poisoned eggs was responsible for the 13% higher nesting success during the 4 years they were distributed (72% compared to 59%). When this study was being contemplated in 1967, it was thought that the wild turkey had a low reproductive potential. Supposedly the hens would not begin to nest until 2 years old, frequently deserted their nests, and would only rarely renest in the same year (and, if they did, hatchability and clutch size were said to be lower the second time). Under such circumstances, it would appear that nesting losses could be very limiting on turkey productivity and that it warranted study. Concurrently with the present study, however, we found that the productivity potential for the hen turkey is higher than formerly believed (Williams et al. 1976)--hens usually renest after the loss of a nest while laying or early in incubating behavior and may renest several times in the same year. And young hens nested freely. Consequently, nesting losses are probably much less limiting on the species than previously thought. The off-setting effect of renesting probably negates any benefits of preventing nesting losses through predator control. A more definitive study of this would be useful in assessing the value, if any, of nest predator control for wild turkeys. LITERATURE CITED DARROW, R. W. 1947. Predation. Pages 207-350 in G. Bump, R. W. Darrow, F. C. Edminster, and W. F. Crissey. The ruffed grouse: life history, propagation, management. New York State Conservation Dept., Albany. HICKEY, J. J. 1955. Some American population research on gallinaceous birds. Pages 326-396 in A. Wolfson, ed. Recent studies in avian biology. Univ. Illinois Press, Urbana. KRISTOFFERSEN, S. 1937. Undersokelser over lirypens forplantingsforhold. Tromso Museums rypeundersokelser. Nytt Mag. Naturv. 77:141-194. (original not seen) RANDALL, P. W. 1940. The life equation of the ring-neck pheasant in Pennsylvania. Trans. North Am. Wildl. Conf. 5:300-320. RASMUSSEN, D. I. and L. A. GRINER. 1938. Life history and management of the sage grouse in Utah, with special reference to nesting and feeding habits. Trans. North Am. Wildl. Conf. 3:852-864. SIMPSON, R. C. 1976. Certain aspects of the bobwhite quail's life history and population dynamics in southwest Georgia. Ga. Dept. Nat. Resour. Tech. Bull. WL1. 117pp. STODDARD, H. L. 1931. The bobwhite quail: its habits, preservation and increase. Charles Scribner's Sons, New York. 559pp. WILLIAMS, L. E., JR., D. H. AUSTIN, and T. E. PEOPLES. 1976. The breed- ing potential of the wild turkey hen. Proc. Southeast. Assoc. Game Fish Commr. 30:371-376. 107 WILLIAMS, L. E., JR., D. H. AUSTIN, T. E. PEOPLES, and R. W. PHILLIPS. 1973. Observations on movement, behavior, and development of turkey broods. Pages 79-99 in G. C. Sanderson and H. C. Schultz, eds. Wild turkey management: current problems and pro- grams. Univ. of Missouri Press, Columbia.