REPRODUCTIVE SUCCESS AND BROOD HABITAT USE OF GREATER PRAIRIE CHICKENS AND SHARP-TAILED GROUSE ON THE FORT PIERRE NATIONAL GRASSLAND OF CENTRAL SOUTH DAKOTA

BY MARK A. NORTON

A thesis submitted in partial fulfillment of the requirements for the Master of Science Wildlife and Fisheries Sciences South Dakota State University 2005
This thesis is approved as a creditable and independent investigation by a candidate for the Master of Science degree and is acceptable for meeting the thesis requirements for this degree. Acceptance of this thesis does not imply that the conclusions reached by the candidate are necessarily the conclusions of the major department.
Dr. Kent C. Jensen Major Advisor

/1- ;'f- 2DOt)

Dr. Charles O. Scalet Head, Department of Wildlife and Fisheries Sciences
iii ACKNOWLEDGEMENTS Funding for this project was provided by the Federal Aid in Wildlife Restoration Act (Project W-75-R, Study No. 75108) administered through the South Dakota Department of Game, Fish, and Parks and through matching funds from South Dakota State University. I would like to start by thanking Dr. Les Flake for providing me the opportunity to work on this project and earn a Master of Science degree. It has been a valuable and unforgettable learning experience. Thank you, as well, to my committee members of Dr. Ken Higgins, Dr. Gary Larson and Dr. Kurt Bassett for all of your insight and suggestions to make this thesis better. I would also like to thank Tony Leif, Greg Wolbrink, and Tom Kirschenmann from the South Dakota Department of Game, Fish & Parks. Tony played a vital role in getting this project rolling. He also placed his faith in me that I would get the job done and do it well. Greg was my right hand man, or the other way around, in much of my field work. I learned just about everything I know about telemetry and capturing prairie grouse from him. Tom was only involved with this project for one year, but his selfless volunteer efforts to help in the middle of the night to capture chicks during nearly all of the chick captures in 2005 will always be remembered. All three of these guys stuck their neck out to help me and this project. Thank you for making this research project the best experience any graduate student could ask for. My advisor K. C. Jensen also deserves a vote of thanks for all of his advice and time spent proofing presentations and this thesis. He also was of great support through
iv organizing and arranging the equipment critical to the completion of this project. K. C. is an excellent advisor and always believed in the work we were doing. I would like to acknowledge the technicians that worked for me during the course of this project. Marcus Rock, Matt Hart, Andy Korth, and Ryan Williamson, all provided invaluable time and effort in tracking radioed birds and assistance capturing chicks. Ryan also assisted me in collecting vegetation samples, which greatly enhanced the power of my results. Thank you all for your new friendships and assistance. I also need to acknowledge the U.S. Forest Service and particularly the staff at the Fort Pierre office for allowing me to conduct my research on the Fort Pierre National Grassland. It was an ideal study site and I am grateful for all of their assistance and insight throughout the course of this study. Doug Backlund deserves appreciation for showing the project where some leks were at during our first field season. Without his experience and assistance, it would have been very time consuming and difficult to get this project on the ground. Last, but not least, I would like to thank my wife, Laura Norton, for moving with me to Pierre over the last three summers. She always supported and believed in the work I was doing. My wife is my base and is always there to love and support me. I am forever in debt to her understanding of those 3 a.m. chick captures.

v ABSTRACT

REPRODUCTIVE SUCCESS AND BROOD HABITAT USE OF GREATER PRAIRIE CHICKENS AND SHARP-TAILED GROUSE ON THE FORT PIERRE NATIONAL GRASSLAND OF CENTRAL SOUTH DAKOTA Mark A. Norton December 2005
Greater prairie chicken (Tympanuchus cupido) (PC) and sharp-tailed grouse (Tympanuchus phasianellus) (ST) ranges overlap in central South Dakota. Although the ranges of both species have been reduced during recent history, South Dakota is one of only a few states where their populations have remained stable. Survival, reproduction and habitat use data from these populations provide insight to important variables contributing to the dynamics and management of the populations on the Fort Pierre National Grassland (FPNG). Additionally, these data may shed light on efforts to reestablish populations in restricted portions of the greater prairie-chicken range. The objectives of this study were to estimate PC and ST brood habitat use, nest success, and hen and brood survival. To fulfill these objectives I radio-collared and monitored 62 PC and 38 ST hens and 26 PC and 21 ST broods on the FPNG during the breeding seasons of late March August of 2003 2005. Habitat use was determined from 18 PC and 17 ST broods during 2004 and 2005. Overall nest success for PC was 0.80 (n = 50) and 0.72 (n = 36) for ST from 2003 2005. Breeding season hen survival during the three years of
vi this study was 0.84 (n = 62) for PC and 0.80 (n = 38) for ST. Brood survival for PC was 0.83 (n = 26) and 0.89 (n=21) for ST. Chick survival for PC was 0.34 (n = 85) and 0.40 (n = 65) for ST. Chick survival was higher in 2005 than the previous two years, probably attributable to increased precipitation and warmer temperature patterns. PC broods utilized habitats with a mean vegetation height of 32 cm (n=8), and with ground cover of 18% grass and 10% forbs in 2004. During 2005, PC broods used habitats with a mean vegetation height of 38 cm (n = 10) and 18% grass and 5% forb ground cover. ST broods used habitats with a mean vegetation height of 43 cm during both 2004 (n = 8) and 2005 (n = 9). During 2004, ST broods utilized habitats with 14% grass and 20% forb ground cover, while in 2005 they used habitats with 17% grass and 4% forb ground cover. PC broods preferentially selected habitats composed of western wheatgrass (Pascopyrum smithii), green needlegrass (Nassella viridula) and Japanese brome (Bromus japonicus). They avoided habitats composed of smooth brome (Bromus inermis) and porcupine grass (Hesperostipa spartea). ST broods preferentially selected habitats composed of sweet clover (Melilotus spp.), other forb-dominated vegetation, and green needlegrass. They avoided habitats dominated by Japanese brome and smooth brome. High nesting success and survival rates found during this study are likely attributed to the vast grassland ecosystem and the implemented rotational grazing regime, both of which had multiple positive influences. Predators had to spend more time searching to find a nest or bird to prey on in larger unfragmented grasslands. The large expanse of grassland is maintained by a grazing regime that provided an ample food source of invertebrates and a mosaic of habitats needed for brood rearing hens.

vii TABLE OF CONTENTS

Page ACKNOWLEDGEMENTS.... iii ABSTRACT.... v LIST OF TABLES.... ix LIST OF FIGURES.... xi LIST OF APPENDICES... xiii CHAPTER 1 - INTRODUCTION... 1 CHAPTER 2 - STUDY AREA... 4 CHAPTER 3 - BROOD HABITAT USE... 7 INTRODUCTION.... 7 METHODS.... 9 RESULTS.... 11 DISCUSSION.... 21 CHAPTER 4 - REPRODUCTIVE ECOLOGY... 26 INTRODUCTION.... 26 METHODS.... 28 RESULTS.... 32 Hen Lek Visitation.... 32 Nesting Chronology... 33 Nest Success.... 34 Hen Survival.... 35
viii Chick and Brood Survival.... 38 DISCUSSION.... 43 MANAGEMENT IMPLICATIONS... 52 LITERATURE CITED.... 55
ix LIST OF TABLES Table 1. Mean vegetation heights (cm) at locations used by greater prairie chicken (PC) and sharp-tailed grouse (ST) broods in relation to mean vegetation heights at random locations.... 12 Table 2. Mean estimated ground cover (%) by grasses at locations used by greater prairie chicken (PC) and sharp-tailed grouse (ST) broods in relation to mean estimated ground cover (%) at random locations.. 12 Table 3. Mean estimated ground cover (%) by forbs at locations used by greater prairie chicken (PC) and sharp-tailed grouse (ST) broods in relation to mean estimated ground cover (%) at random locations.. 12 Table 4. Total monthly precipitation and mean monthly temperature during April, May, and June of 2004 and 2005 on the Fort Pierre National Grassland, South Dakota, USA (Western Regional Climate Center automated weather station located at 44 06' 55" N and 100 18' 05" W.)... 22 Table 5. Mean clutch size and mean initiation dates for initial nests and renests of greater prairie chickens (PC) and sharp-tailed grouse (ST) on the Fort Pierre National Grassland in central South Dakota, USA, during 2003-2005.. 33 Table 6. Nest success rates (Mayfield 1961) for prairie grouse nests found on the Fort Pierre National Grassland, South Dakota, USA, during 2003-2005. 34 Table 7. Total number and hatchability of prairie grouse eggs on the Fort Pierre National Grassland, South Dakota, USA, during 2003-2005.. 35 Table 8. Greater prairie chicken (PC) and sharp-tailed grouse (ST) hen survival during the breeding season from 2003-2005 on the Fort Pierre National Grassland, South Dakota, USA.... 36 Table 9. P-values generated in program CONTRAST (Sauer and Williams 1989) for comparisons of greater prairie chicken (PC) and sharp-tailed grouse (ST) chick survival rates by year and by species... 38 Table 10. Age-specific and overall greater prairie-chicken (PC) and sharp-tailed grouse (ST) chick survival rates from 2003-2005 on the Fort Pierre National Grassland, South Dakota, USA.... 39 Table 11. Brood survival rates and 95% confidence intervals for greater prairie chicken (PC) and sharp-tailed grouse (ST) broods on the Fort Pierre National Grassland, South Dakota, USA.... 42

x Table 12. Greater prairie chicken (PC) and sharp-tailed grouse (ST) mean clutch size, hatchability, and apparent nest success by study and state (Peterson and Silvy 1996).... 45 Table 13. Departure from average precipitation and mean temperature on the Fort Pierre National Grassland, South Dakota, USA 2003-2005 (National Weather Service weather station located at 44 22' N and 100 17' W).. 48
xi LIST OF FIGURES Figure 1. Study area outlined on the Fort Pierre National Grassland, South Dakota, USA.... 6 Figure 2. Vegetation type (habitat) availability for prairie grouse broods on the Fort Pierre National Grassland, South Dakota, USA, 2004 and 2005. 14 Figure 3. Mean scores (Aebischer et al. 1993) and standard errors for vegetation types selected by sharp-tailed grouse broods in relation to habitats available during the breeding seasons of 2004 and 2005 on the Fort Pierre National Grassland, South Dakota, USA. Other is short for other forb-dominated vegetation. 15 Figure 4. Mean scores (Aebischer et al. 1993) and standard errors for vegetation types selected by greater prairie chicken broods during 2004 and 2005 in relation to habitats available during the breeding season on the Fort Pierre National Grassland, South Dakota, USA. Other is short for other forbdominated vegetation... 17 Figure 5. Mean scores (Aebischer et al. 1993) and standard errors for habitat types selected differently (P < 0.05) by greater prairie chicken and sharp-tailed grouse broods in relation to habitats available on the Fort Pierre National Grassland, South Dakota, USA.... 18 Figure 6. Mean scores (Aebischer et al. 1993) and standard errors for sweet clover use by sharp-tailed grouse (ST) and greater prairie chicken (PC) broods. Sweet clover was selected significantly (P < 0.05) more by ST and PC broods during 2004 than in 2005 and significantly (P < 0.05) more by ST broods than PC broods in 2005 in relation to sweet clover availability on the Fort Pierre National Grassland, South Dakota, USA.. 19 Figure 7. Mean scores (Aebischer et al. 1993) and standard errors for significant differences (P < 0.05)between 2004 and 2005 Kentucky bluegrass and bare ground use by greater prairie chicken (PC) broods in relation to availability on the Fort Pierre National Grassland, South Dakota, USA.. 20 Figure 8. (A) Example of a star pattern walk-in trap set up around a lek. (B) Example of a two parallel W Lines pattern walk-in trap set up on a lek. 29 Figure 9. Number of greater prairie chicken and sharp-tailed grouse hens captured using walk-in traps on leks in relation to date... 32
xii Figure 10. Survival rate and 95% confidence intervals (dashed lines) for all radiocollared hen prairie grouse on the Fort Pierre National Grassland, South Dakota, USA, 23 March 28 August (159 days) during 2003-2005.. 37 Figure 11. Survival rate and 95% confidence intervals (dashed lines) of radio-marked prairie grouse chicks on the Fort Pierre National Grassland, South Dakota, USA, 19 May28 August (101 days) in 2003-2005. Chick survival was estimated starting at the 18-day apparent survival rate of 0.55 (261 of 473). 41

25 grouse broods is therefore reduced (Fredrickson 1996). However, these effects may be ameliorated during years when sweet clover is abundant. The USFS management of the FPNG adjusts the grazing regime during dry years by increasing the area that is rested. In 2003, little rain was received after May and in turn the USFS rested 20% of the FPNG from grazing. The drought continued during 2004 and 24% of the FPNG was rested from grazing. Precipitation amounts were closer to average through June of 2005, but the FPNG received very little rain in July and August and the USFS rested more than the minimum 10% again. The reduction in grazing pressure in response to reduced precipitation likely provided prairie grouse broods habitat with needed vegetation composition and structural components.
26 CHAPTER 4 REPRODUCTIVE ECOLOGY INTRODUCTION Understanding the reproductive rates of prairie grouse populations is an important component to effective management. Since PC and ST are polygamous, most reproductive measures are dependent upon hens. Hen survival during the breeding season can directly influence the number of young recruited into the population. However, little information exits on prairie grouse hen survival during the breeding season (Newell et al. 1987, Manzer 2003). Hen survival relates to the number of nests that can potentially hatch, and consequently the number of hatched nests relates to the number of broods that donate recruits to the population. Across North American, PC nesting success has ranged from 40% to 72% and ST nesting success has ranged from 50% to 70% (Amman 1957, Sedivec et al. 1990, Kantrud and Higgins 1992, Kirby and Grosz 1995, Peterson and Silvy 1996). Limited information on brood survival of prairie grouse (the proportion of broods that fledge at least one chick) exists for prairie grouse populations, while even less is known about sympatric populations (Hillman and Jackson 1973). Only one study (Rice and Carter 1982) has been conducted on sympatric prairie grouse populations, and it focused on grazing practices and their influences on PC and ST nesting on the FPNG. The quality and quantity of brood-rearing habitat are considered to be the one of the most important factors related to prairie grouse population levels (Hamerstrom et al. 1957, Kirsch 1974) and brood survival can be limited by brood habitat quality (Svedarsky et al. 1999). Quantitative data on nesting success and hen and brood survival can be
27 valuable for determining how grazing management affects prairie grouse populations. Good range conditions are necessary for satisfactory PC and ST nesting success, and brood survival and can be restricted by intense grazing (Fredrickson 1996). Measures of nesting success and survival of prairie grouse hens and broods could be used as an indicator of the quality of the cover provided by grazing management. Central South Dakota is one of the few remaining places in the world where sympatric PC and ST exist in stable populations (Svedarsky et al. 2000). Survival and reproductive success data from these populations will provide baseline information for management decisions concerning South Dakota prairie grouse populations. Additionally, information from the stable PC populations in South Dakota can provide a benchmark for success of reestablishment efforts in other more restricted portions of the species range (Snyder et al. 1999). The objectives of this study were to determine PC and ST nesting success, hen and brood survival, and cause specific mortality of both hens and chicks during the breeding season in central South Dakota.

28 METHODS PC and ST hens were captured on display grounds (leks) using walk-in traps (Schroeder and Braun 1991). Traps were arranged in either a circular-shaped pattern or in two parallel W-shaped lines (Figure 8). The traps were connected with 8-m long by 0.6-m tall chicken wire fence or plastic snow fence from one opening on each trap. One hole on each trap had two fences connected to it, which formed a funnel to the trap. When the W trap line pattern was used, break-up fences constructed of the same 0.6-m tall fence, were placed perpendicular to the parallel trap lines to direct the grouse towards the traps. Rebound fences of approximately 0.6-m length were attached to the 8-m chicken wire fence about 1.5-m away from the trap entrance to redirect any grouse that tried to back away from the trap entrance. Traps were placed on leks starting in late-March and remained on leks through the end of April. The number of traps placed on each lek varied depending upon its size. Traps remained on one lek until all the birds using it had been captured. Traps were checked twice daily, once in the morning no later than 9 a.m., and once immediately after sunset. Nest dragging and bow nets were also used to augment the sample by capturing hens on nests. Nest dragging was done with a 30.5-m log chain pulled between to two ATVs to flush hens off the nest (Higgins et al. 1969). Upon locating an incubating hen, a bow net with a 15-m trigger rope was placed around the nest, with the capture occurring the following day.

Trap LEK Rebound fences

Break-up fences

Rebound fences

Figure 8. (A) Example of a star pattern walk-in trap set up around a lek. (B) Example of a two parallel W Lines pattern walk-in trap set up on a lek.
30 All captured males were leg banded, aged (immature or adult), weighed, and released on the lek on which they were captured. Females underwent the same procedures, but were also radio marked with an 11-g necklace-mounted transmitter (Holohil Systems Ltd., Carp, Ontario, Canada). Females were located a minimum of 3 times per week by triangulation of direction signals using a null-peak radio telemetry system, mounted in a pickup. Radios that transmitted mortality signals were approached and recovered after an investigation of the immediate area for evidence of bird fate and predator identification. Hens that had not moved for 3 days were assumed to have started nesting. Once a hen was determined to be on a nest, the nest was located and marked with a GPS and 3 wire flag markers approximately 10-m away from the nest. After the hen had left the nest, nest fate was determined (hatched, depredated, or abandoned). Egg hatchability was estimated as the proportion of the total eggs laid that hatched. Nesting success was estimated using the Mayfield method (Mayfield 1961). If the nest was successful, the number of eggs hatched was counted as a baseline measure to determine chick survival. Two to three weeks after nest hatch, each radio marked hen was flushed to determine the presence or absence of chicks. If chicks were present, or absent and the hen had not moved far (< 0.8-km) from the nest, the brood was captured under the stealth of darkness using a technique developed by G. Wolbrink and T. Leif (South Dakota Dept. of Game, Fish, & Parks; personal communication). The hen was approached using a receiver and a yagi antenna. Once the signal was strong enough, the receiver was used

Mean nest initiation date 29 April 25 April 24 April 26 April 22 April 30 April 26 April 1st nest clutch size 13.7 14.4 14.3 13.8 13.3 13.7 13.5 1st nest clutch size range 12 - - - - - - - 17 Mean renest initiation date 20 May 22 May 18 May 20 May 24 May 28 May 8 May 18 May Mean Renest clutch size 11.7 10.8 12.0 11.3 11.12 11.4 Renest clutch size range 8 - -- - - 10 - -14

Species PC

Year 2005 Total 2005 Total

n 9 19

34 Nest Success Prairie grouse nest success was estimated from 88 nests (50 PC, 36 ST, 1 hybrid, 1 unknown to species) (Table 6). Overall nest success was 75.5%. Predation was the main cause of nest failure (80%), followed by abandonment (15%), and unknown causes (3%). There were a total of 26 known failed nests; 5 were re-nesting attempts (4 hatched and 1 was depredated). The overall probability that a PC egg would survive during incubation (Mayfield Egg Hatchability) was 0.62 (n = 959) versus 0.54 (n = 371) for a ST egg (Table 7). The proportion of eggs laid that hatched in successful nests (Apparent Egg Hatchability) was 0.90 (n = 473) for PC and 0.91 (n = 273) for ST (Table 7). Table 6. Nest success rates (Mayfield 1961) for prairie grouse nests found on the Fort Pierre National Grassland, South Dakota, USA, during 2003-2005.
Year 2005 Total Sharp-tailed Grouse 60.5% 76.5% 70.2% 71.6% N Greater Prairie-Chicken 100.0% 83.8% 71.6% 80.2% N All Prairie Grouse 85.7% 78.5% 69.9% 75.5% N 42 88
35 Table 7. Total number and hatchability of prairie grouse eggs on the Fort Pierre National Grassland, South Dakota, USA, during 2003-2005.
Species Greater prairie-chicken Year 2005 Total 2005 Total Total Mayfield Egg Survival 0.89 0.78 0.72 0.77 0.64 0.75 0.80 0.76 0.76 Mayfield Egg Hatchability 0.89 0.66 0.51 0.62 0.39 0.57 0.56 0.54 0.58 N 959 Apparent Egg Hatchability 0.87 0.86 0.96 0.90 0.92 0.89 0.94 0.91 0.91 N 746

Sharp-tailed grouse

All Prairie Grouse
Hen Survival Survival was not different for ST and PC hens between years (Chi-square < 1.15, df = 1, p > 0.28) and species (Chi-square < 0.75 df = 1, p > 0.39), so survival estimates for both species and all years were pooled (Table 8). Due to the small sample size of ST hens (4) in 2003, survival comparisons were not made using that data. Hen survival during the nesting seasons of 2003-2005 was 0.92 (95% CI: 0.87 to 0.97) (Figure 10). Cause-specific mortality of incubating hens was due to canid predation (2). Three cases were due to unknown. Seven (13%, n=53) radio-marked brood rearing hens died during 2003-2005. Three were depredated by raptors, two by canids, one became caught in a barbed wire fence, and one died due to a bacterial infection and tested positive for West Nile virus RNA presence. Prairie grouse hen survival during the brood rearing season was 0.89 (95% CI: 0.84 to 0.96), while overall reproductive season hen survival was 0.82 (95% CI: 0.74 to 0.89).

Table 8. Greater prairie chicken (PC) and sharp-tailed grouse (ST) hen survival during the breeding season from 2003-2005 on the Fort Pierre National Grassland, South Dakota, USA.
Year 2003 Species PC ST Both PC ST Both PC ST Both PC ST All Survival 0.76 1.00 0.82 0.90 0.78 0.82 0.83 0.79 0.81 0.84 0.80 0.82 S.E. 0.11 0.00 0.09 0.07 0.12 0.07 0.08 0.09 0.06 0.05 0.07 0.% Confidence Interval Lower Upper 0.54 0.98 1.00 1.00 0.65 0.99 0.77 1.00 0.55 1.00 0.65 0.95 0.68 0.98 0.62 0.97 0.69 0.93 0.75 0.94 0.67 0.93 0.74 0.89 N 14 35* 38 101
* During 2004 there was one hybrid hen.
Median Nest Intitiation 2 May
1 0.98 0.96 0.94 0.92 0.9 0.88 0.86 0.84 0.82 0.8 0.78 0.76 0.74 0.72 0.61

Median Hatch 6 June

Breeding Period

Nesting Period

Brood Rearing Period

141 151

Time (days)
Figure 10. Survival rate and 95% confidence intervals (dashed lines) for all radiocollared hen prairie grouse on the Fort Pierre National Grassland, South Dakota, USA, 23 March-28 August (159 days) during 2003-2005.
38 Chick and Brood Survival The study monitored 47 radio-marked prairie grouse broods during 2003-2005 to estimate chick and brood survival. Over the three breeding seasons, 26 PC females with 85 chicks and 21 ST females with 65 chicks were monitored from hatching until the end of August. Survival was not significantly different between ST and PC chicks (Chisquare < 3.23, df = 1, p > 0.07), therefore all data were pooled for prairie grouse chick survival (Table 9). During the 2004 season, radio-marked ST chick survival (0.77, 95% CI: 0.62 to 0.91), although not statistically different (P = 0.53), was approximately 10% higher than radio-marked PC chick survival (0.67, 95% CI: 0.49 to 0.86) (Table 10). Table 9. P-values generated in program CONTRAST (Sauer and Williams 1989) for comparisons of greater prairie chicken (PC) and sharp-tailed grouse (ST) chick survival rates by year and by species.
Comparison 03 PC vs. 04 PC 03 PC vs. 05 PC 04 PC vs. 05 PC 03 ST vs. 04 ST 03 ST vs. 05 ST 04 ST vs. 05 ST 03 PC vs. 03 ST 04 PC vs. 04 ST 05 PC vs. 05 ST 03 Both vs. 04 Both 03 Both vs. 05 Both 04 Both vs. 05 Both All PC vs. All ST Chi-square value 0.19 2.34 1.15 0.23 1.01 0.63 0.05 0.40 0.12 0.38 3.23 1.90 1.28 Degrees of Freedom 1 Probability 0.66 0.13 0.28 0.63 0.31 0.43 0.82 0.53 0.73 0.54 0.07 0.17 0.26

47 this study did not find drastic differences in nesting success (0.70 to 0.86) and brood survival (0.48 to 1.00) as did Fredrickson (1996). The USFS has since changed their grazing management on the FPNG and now requires a minimum of 10% of the FPNG to be rested from grazing annually. The proportion of the total area rested from grazing was also dependent on the amount of precipitation received during that year. During the course of this study the USFS rested up to 24% during 2004, the driest year. This likely offsets the effects of drier conditions with enough area to provide good nesting and brood habitat cover. PC chick survival in 2003 (0.30) was similar to that in North Dakota for PC (0.28) (Newell 1987), but was higher the following two years (0.34 and 0.44 respectively). ST chick survival followed a similar pattern to PC chick survival ranging from 0.31 in 2003, 0.40 in 2004, to 0.48 during 2005. In 2003, I radioed every chick in seven broods for a mean of 5.1 chicks per brood, whereas in 2004 I radioed 4 chicks per brood (16) and 3 chicks per brood (19) in 2005. The lower sample size in 2003 may have skewed the survival estimates downward. During 2003, there was above average precipitation in April and May, but June received approximately 50% the precipitation that normally falls during the month (Table 13). Reduced precipitation coupled with a cooler than average mean temperature in June likely reduced the growth of the cool season grasses and forbs on the FPNG. Stunted vegetative growth in 2003 failed to provide broods with an adequate amount of protective cover, food, and roosting sites.
48 Table 13. Departure from average precipitation and mean temperature on the Fort Pierre National Grassland, South Dakota, USA 2003-2005 (National Weather Service weather station located at 44 22' N and 100 17' W).
Precipitation (mm) Year Average 2005 April 51.31 18.54 -43.43 4.32 May 79.76 16.51 -8.64 3.56 June 88.65 -48.51 -28.96 3.05 Total 219.71 -13.46 -81.03 10.92 Mean Temperature (C ) April 8.44 1.06 1.17 1.17 May 14.94 -1.33 -0.50 -1.94 June 20.39 -1.56 -2.56 0.44
During 2004 there was a bloom of forb production, particularly sweet clover, which may have enhanced brood and chick survival. Sweet clover grows quickly to heights > 1-m and provides an open understory for easy chick mobility, a dense canopy providing protection from avian predators, and likely an ample food source of invertebrates for chicks. Sweet clover is also a biennial, and during the years when it grows on the FPNG it is widespread and can cover large areas of the landscape. It also has a thick stem and branches that persist throughout the brood rearing season providing shade on hot days and overhead cover for protection from predators. The high chick survival during 2005 can be attributed to a wet spring and above average June temperatures. Cool-season grasses and forbs on the FPNG grew more quickly and taller than in previous years, providing good escape, feeding, and roosting habitat for broods. Warmer temperatures in June may have also decreased the loss of chicks to the cold, since they can be dependent on the hen for warmth during the first 5 weeks of life (Toepfer 2003). Chicks are most vulnerable to mortality during the first few weeks post-hatch since they have limited flight capabilities, are easier prey for predators, and are in need of regular brooding from the hen (Svedarsky and Van Amburg 1996). This study found

53 The USFS could also use fire more often to create this same mosaic on the landscape and perhaps even enhance some of the native species of vegetation which may be suppressed by a grazing regime. A higher level of vegetative diversity on the grassland would only enhance the productivity of prairie grouse on the FPNG. Fire would also increase the productivity of the forage for a variety of herbivores that use the FPNG like pronghorn (Antilocapra Americana), white-tailed deer (Odocoileus virginianus), mule deer (Odocoileus hemionus), and cattle. PC and ST broods do use habitats differently on the FPNG. PC broods need a minimum visual obstruction height of 26 cm and ST broods need at least 33 cm. PC broods used Japanese brome significantly more than ST broods and sweet clover was used inversely, however I am not advocating exclusively planting sweet clover to improve ST habitat or Japanese brome to improve PC habitat. The locations of ST and PC broods tracked in this study should be compared to determine if there was a trend of segregation by topographical features of the landscape. If there is a definite segregation perhaps habitat managers could manage hilltops for taller vegetation species, like sweet clover, porcupine grass, and green needlegrass for ST broods and valleys and flats for shorter vegetation species like western wheatgrass and Japanese brome specifically for PC broods. Habitats that provide a diverse community of forbs were important to both species of prairie grouse in this study. Managers should make it a point to incorporate a diverse herbaceous component into grasslands managed for prairie grouse broods. These habitats are an important source of invertebrates and they provide an open understory for ease of movement by chicks and overhead cover from avian predators and the sun.
54 There is a need for monitoring PC and ST grouse populations during the winter on the FPNG to determine winter survival and habitat use. This may provide insight about the importance of the interspersed agricultural cropland throughout the FPNG to prairie grouse annual survival and population status.
55 LITERATURE CITED Aebischer, N., P. Robertson, and R. Kenward. 1993. Compositional analysis of habitat use from animal radio-tracking data. Ecology 74:1313-1325. Blums, P., J. Nichols, J. Hines, M. Lindberg, and A. Mednis. 2005. Individual quality, survival variation and patterns in phenotypic selection on body condition and timing of nesting in birds. Oecologia 143:365-376. Bouzat, J., H. Cheng, H. Lewin, R. Westemeier, J. Brawn, and K. Paige. 1998. Genetic evaluation of a demographic bottleneck in the greater prairie chicken. Conservation Biology 12:836-843. Buhnerkempe, J., W. Edwards, D. Vance, and R. Westemeier. 1984. Effects of residual vegetation on prairie-chicken nest placement and success. Wildlife Society Bulletin 12:382-386. Burkepile, N., J. Connelly, D. Stanley, and K. Reese. 2002. Attachment of radio transmitters to one-day-old sage grouse chicks. Wildlife Society Bulletin 30:9396. Caffrey, C. 2000. Correlates of reproductive success in cooperatively breeding western American crows: if helpers help, its not by much. The Condor 102:333-341. Duabenmire, R. 1959. A canopy-coverage method of vegetational analysis. Northwest Science 33:43-64. Dzus, E., and R. Clark. 1998. Brood survival and recruitment of mallards in relation to wetland density and hatching date. The Auk 115:311-318.

56 Faulkner, A., 1999. Soil survey of Jones County, South Dakota. USDA NRCS in cooperation with USFS and South Dakota Agricultural Experiment Station. Fredrickson, L. 1996. The greater prairie chicken. South Dakota Conservation Digest 63:10-12. Hamerstrom, F., Jr., O. Mattson, and F. Hamerstrom. 1957. A guide to prairie chicken management. Technical Bulletin No. 15. Wisconsin Conservation Department. Madison. 128 pp. Hamerstrom, F., Jr. 1963. Sharp-tail brood habitat in Wisconsins northern Pine Barrens. Journal of Wildlife Management 27:793-802. Hamerstrom, F., Jr. and F. Hamerstrom. 1973. The prairie chicken in Wisconsin. Wisconsin Department of Natural Resources Technical Bulletin 6:52. Higgins, K. F., L. M. Kirsch, I. J. Ball Jr., and I. J. Ball Jr. 1969. A cable-chain device for locating duck nests. Journal of Wildlife Management 33:1009-1011. Hillman, C. N. and W. W. Jackson. 1973. The sharp-tailed grouse in South Dakota. South Dakota Dept. of Game, Fish, & Parks. Technical Bulletin Number 3, 62 pp. Horak, G. 1985. Kansas prairie chickens. Kansas Fish and Game Commission, Wildlife Bulletin, No. 3 Emporia, Kansas. 65pp. Houston, C. S. 2002. Spread and disappearance of the greater prairie-chicken, Tympanuchus cupido, on the Canadian prairies and adjacent areas. The Canadian Field-Naturalist 116:1-21.
57 Johnson, J. R. and G. E. Larson. 1999. Grassland Plants of South Dakota and the Northern Great Plains. South Dakota State University College of Ag & Bio Sci., South Dakota Ag Experiment Station, Brookings, SD 57007., 288pp. Johnson, M. D. 1964. Feathers from the prairie. Fed. Aid in Wildl. Restor. Proj. W-67R-5, N. Dak. Game & Fish Dept., Bismarck, 240 pp. Jones, R. 1963. Identification and analysis of lesser and greater prairie chicken habitat. Journal of Wildlife Management 27:757-778. Kantrud, H. and K. Higgins. 1992. Nest and nest site characteristics of some groundnesting, non-passerine birds of northern grasslands. The Prairie Naturalist 24:6784. Kaplan, E., and P. Meier. 1958. Non parametric estimation from incomplete observation. Journal of the American Statistical Association 53:457-481. Kirby, D. and K. Grosz. 1995. Cattle grazing and sharp-tailed grouse nesting success. Rangelands 17:124-126. Kirsch, L., A. Klett, and H. Miller. 1973. Land use and prairie grouse relationships in North Dakota. Journal of Wildlife Management 37:449-453. Kirsch, L. 1974. Habitat management considerations for prairie chickens. Wildlife Society Bulletin 2:124-129. Koricheva, J., C. Mulder, B. Schmidt, J. Joshi, and K. Huss-Danell. 2000. Numerical responses of different trophic groups of invertebrates to manipulations of plant diversity in grasslands. Oecologia 125:271-282. Manske, L., and W. Barker. 1988. Habitat usage by prairie grouse on the Sheyenne National Grasslands. U.S. Forest Service General Technical Report., RM-159. p.

58 8-20. WR 211 Paper presented at a Symposium on Prairie Chickens on the Sheyenne National Grasslands, September 18, 1987, Crookston, Minnesota. Manske, L., W. Barker, and M Biondini. 1988. Effects of grazing management on grassland plant communities and prairie grouse habitat. U.S. Forest Service General Technical Report., RM-159. p. 58-72. WR 211 Paper presented at a Symposium on Prairie Chickens on the Sheyenne National Grasslands, September 18, 1987, Crookston, Minnesota. Manzer, D. 2003. Survival of sharp-tailed grouse chicks and hens during the breeding season. Presented at the 25th Prairie Grouse Technical Council, September 29October 3, 2003, Siren, Wisconsin. Mayfield, H. 1961. Nesting success calculated from exposure. The Wilson Bulletin 73:255-261. Moyles, D. 1981. Seasonal and daily use of plant communities by sharp-tailed grouse (Pediocetes phasianellus) in the parklands of Alberta. The Canadian FieldNaturalist 95:287-291. National Weather Service. 2003. Climatology Information, Pierre SD. http://www.crh.noaa.gov/abr/climate/summary.htm Newell, J. 1987. Nesting and brood rearing ecology of the greater prairie chicken in the Sheyenne National Grassland, North Dakota. M. S. Thesis. Montana State University, Bozeman. 111pp. Newell, J., J. Toepfer, and M. Rumble. 1988. Summer brood-rearing ecology of the greater prairie chicken on the Sheyenne National Grasslands. U.S. Forest Service General Technical Report., RM-159. p. 24-31. WR 211 Paper presented at a
59 Symposium on Prairie Chickens on the Sheyenne National Grasslands, September 18, 1987, Crookston, Minnesota. Paton, P. 1994. The effect of edge on avian nest success: How strong is the evidence? Conservation Biology 8:17-26. Peterson, M., and N. Silvy. 1994. Spring precipitation and fluctuations in Attwaters prairie-chicken numbers: hypothesis revisited. Journal of Wildlife Management 58:222-229. Peterson, M., and N. Silvy. 1996. Reproductive stages limiting productivity of the endangered Attwaters prairie chicken. Conservation Biology 10:1264-1276. Pollock, K., S. Winterstein, C. Bunck, and P. Curtis. 1989. Survival analysis in telemetry studies: the staggered entry design. Journal of Wildlife Management 53:7-15. Rice, L., and A. Carter. 1982. Evaluation of South Dakota grassland management practices as they affect prairie chicken populations, 1974-1978. Completion Report No. 84-11, South Dakota Department of Game, Fish, and Parks, Pierre, South Dakota. 25 pages. Robel, R., J. Briggs, A. Dayton, and L. Hulbert. 1970. Relationships between visual obstruction measurements and weight of grassland vegetation. Journal of Range Management 23:295-297. Sauer, J. R., and B. K. Williams. 1989. Generalized procedures for testing hypothesis about survival and recovery rates. Journal of Wildlife Management 53:137-142. Schroeder, M. and C. Braun. 1991. Walk-in traps for capturing greater prairie-chickens on leks. Journal of Field Ornithology 62:378-385.

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