Introduction. Introduction 4/4/2011. Northern bobwhite (Colinus virginianus) population decline. Breeding Bird Survey

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1 Steven Brinkley, M.S. Candidate Department of Forestry, Wildlife, and Fisheries Wednesday, March 30, :20 1:10 pm 160 Plant Biotech Building Introduction Northern bobwhite (Colinus virginianus) population decline Breeding Bird Survey Survey wide: 3.0%/year Florida: 3.6%/year Sauer et al Introduction Causes of Population Decline Habitat loss/degradation (Brennan 1991) Urban sprawl Changing farming practices Conversion from native grasslands to exotic Overharvest? (Roseberry and Klimstra 1984, Williams et al. 2009) Weather/Rain? (Frye 1954, Cooper et al. 2009) Source: 1

2 Introduction Why the alarm? Economics 1991: $95 million spent on bobwhite hunting in Southeast (Burger et al. 1999) Small communities ii depend don income Management $ Quail constituency group dollars Tax dollars Hunting and recreation license fees Bobwhite habitat supports many other species! Stewardship Objectives To determine the effect of rain and/or rain events on bobwhite survival and nest survival in southwest Florida To determine the effect of hunting pressure and harvest regulation changes on bobwhite survival in southwest Florida Babcock Webb WMA (BWWMA) Located 8 km east of Punta Gorda, FL 26,612 ha Southern pine / palmetto flatwoods with virgin, native herbaceous understory Popular hunting, fishing, and recreational area in southwest Florida Study Area 2

3 Study Area Regular Quail Hunting Season Regulations 6 week hunting season Mid November December 4 hunt days/week WdTh Wed, Thurs, St Sat, and Sun 6 birds/hunter/day Zones A and B 10 hunters/day Zones C and D Unlimited hunters/day Zone F: closed Regulations 848 hunter day quota / year Max 6 week hunting season Mid November December 4 hunt days/week Wed, Thurs, Sat, and Sun 6 birds/hunter/day Zones A, B, C, and D Attempted even hunters/day Zone F: closed Regular Season Quail Hunting Pressure/Zone A 10 hunters/day C Unlimited hunters/day B F No Hunting 10 hunters/day Unlimited Hunter Days D Unlimited hunters/day Check Station 3

4 Regular Season Quail Hunting Pressure/Zone A 228 Hunter Days C 247 Hunter Days F No Hunting B 227 Hunter Days 2007 Quota 848 Hunter Days for Entire WMA D 174 Hunter Days Check Station Regular Season Quail Hunting Pressure/Zone A 212 Hunter Days C 213 Hunter Days B F No Hunting 212 Hunter Days 2008 Quota 848 Hunter Days (212/Zone) D 212 Hunter Days Check Station Zone F Quail Hunt Season Day Quota Hunt Saturday and Sunday at the end of January Max 25 hunters/day 6 birds/hunter/day 4

5 Capturing bobwhites Bait trap (Stoddard 1931) 711 bobwhites Call back trap 755 bobwhites Cast net Dog: 459 bobwhites Night: 54 bobwhites Day: 202 bobwhites Night mist net 44 bobwhites Methods Measurements Age (juvenile or adult) wing* Sex plumage* Mass (gram) Marking for ID Leg Band all bobwhites Neck loop radio transmitter with mercury switch All bobwhites > 130 g Methods * Rosene 1969 Radio Telemetry year round Homing (20 m) via ATV GPS location date, time, zone, and status (alive or dead) 4 to 10 days Survival Checks Checked status of bobwhites during inclement weather and hunting season Methods 5

6 Nest location Mid March Mid October Checked every bobwhite s location closely Same location for 2 consecutive encounters Nests flagged for further location and avoidance Nest monitoring 1 3 days until fate Success = hatched Failure = destroyed or abandoned Methods Data Survival Survival histories for 2000 bobwhites over 7 years Accurate check station data (hunter days/zone) for each day of each hunting season during the study Daily rainfall data from Charlotte County Airport (< 1 km west of BWWMA) Nest Survival Nest survival histories for 400 nests over 7 years Habitat (vector) data in GIS for nest habitat composition Burn status for each nest Daily rainfall data from Charlotte County Airport (< 1 km west of BWWMA) Analysis Survival Program MARK: known fate models (White and Burnham 1999) AIC and AIC to determine best model(s) Encounter histories (breeding and non breeding) with 2 periods/week Monday Thursday and Friday Sunday Covariates Sex, age, and zone for each bird Hunting pressure (hunter days) for each zone by time period Total season hunting pressure for each zone Monthly and seasonal rainfall totals Bobwhite density per zone by year and available birds/hunter day by zone by year Average daily temperature by encounter period 6

7 Analysis Nest Survival Program MARK: Nest Survival (White and Burnham 1999) AIC and AIC for best model(s) Covariates: Total rainfall 3, 12, and 23 days prior to fate Rain event 7.62 cm 3 days prior to fate (yes or no) # of rain events 7.62 cm 12 days prior to fate % composition of favorable habitat types 100m and 1000m radius of nest Favorable habitat(s) determined by compositional analysis (Aebischer et al. 1993) Burn status (burned < 1 year and burned > 1 year) Temperature: average daily 12 days prior to fate Analysis Nest Survival (cont.) Hierarchical approach Stage 1a: find best temporal and environmental models Stage 1b: find best habitat models and test burn status Stage 2: take best models from stages 1a and 1b for final model suite adding interactions if needed Management Implications Hunting Pressure Allow management to set logical future hunting pressure quotas so that the local bobwhite population is not over exploited Rainfall Assess potential nest mortality by rainfall amounts and/or events Adjust hunting regulations the following fall to reduce pressure on the population after a summer of potentially low productivity 7

8 Acknowledgments Committee: Dr. David Buehler, Dr. Ralph Dimmick, Dr. Arnold Saxton, and Dr. Joe Clark Billy Minser Field Crew: A. Brinkley, D. Caudill, J. Coker, Dr. S. Dimmick, M. Green, D. Holt, C. Jones, J. Scott, and J. Sloan Florida Fish and Wildlife Conservation Commission BWWMA staff University of Tennessee Department of Forestry, Wildlife, and Fisheries Volunteers: SW Florida Flatwoods Quail Forever and quail hunters Literature Cited Aebischer, N. J., P. A. Robertson, and R. E. Kenward Compositional Analysis of Habitat Use From Animal Radio Tracking Data. Ecology 74: Brennan, L. A How Can We Reverse the Northern Bobwhite Population Decline? Wildlife Society Bulletin 19: Burger, L. W., D. A. Miller, and R. I. Southwick Economic Impact of Northern Bobwhite Hunting in the Southeastern United States. Wildlife Society Bulletin 27: Cooper, S. M., J. C. Cathey, D. L. Alford, and S. S. Sieckenius Influence of Rainfall, Typte of Range, and Brush Management on Abundance of Northern Bobwhites (Colinus virginianus) insoutherntexas Texas. SouthwesternNaturalist 54: Frye, O. E. J Charlotte County Quail Investigation. Report Project Florida W Roseberry, J. L., and W. D. Klimstra Population Ecology of the Bobwhite. Southern Illinois University Press, Carbondale, USA. Sauer, J. R., J. E. Hines, and J. Fallon The North American Breeding Bird Survey, Results and Analysis Version , USGS Patuxent Wildlife Research Center, Laurel, MD. Stoddard, H. L The bobwhite quail: its habits, preservation and increase. Charles Scribner's Sons, New York, New York, USA. White, G. C., and K. P. Burnham Program MARK: survival estimation from populations of marked animals. Bird Study 46: Williams, C. K., R. S. Lutz, R. D. Applegate, and P. William Winter Survival and Additive Harvest in Northern Bobwhite Coveys in Kansas. Journal of Wildlife Management 68: Questions? Steven Brinkley sbrinkl1@utk.edu 8