Biologist s Answer: What are your goals? Deer Management. Define goals, objectives. Manager s Question: Should I cull or shoot spikes?

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1 Manager s Question: Should I cull or shoot spikes? Manager s Question: Should I cull or shoot spikes? Biologist s Answer: What are your goals? How futile it is to passively follow a recipe without understanding the mechanism behind it. Aldo Leopold There are times when we need education in the obvious more than investigations of the obscure. Oliver Wendell Holmes Deer Management Based on science Knowledge gained through research Management is an art Apply knowledge to achieve goals Management goals come from human values 4 Steps for a Deer Management Plan 1. Assess status of population, habitat 2. Define goals, objectives 3. Design management plan 4. Determine if plan achieved objectives Assess status of population, habitat Where do you stand NOW? Population surveys Habitat condition Past harvest data Number harvested Body weights Age Define goals, objectives Where do you want to be? Goals are: Designed to change status of habitat/resource Designed to change user satisfaction Goals should be: Defined clearly Arranged in priorities Series of steps integrated into larger, long-term 1

2 Define goals, objectives Goal Produce trophy bucks!! What is a trophy? Age, points, B&C score? Harvest trophies only? Mature, non-trophies available for family, friends, clients? Define goals, objectives Are goals contradictory? I want more trophy deer I want to sell as many calves as possible Are goals realistic? I have a ranch in Veracruz and I want to produce bucks scoring over 200 B&C I own 250 ha, 100 cows, and I want to manage for trophy bucks Important Considerations Habitat quality Broad scale: Some geographic areas have low quality habitat Forage quality limitations Never attain high diet quality regardless of density Often can see similar trends at regional scales t generally appreciated Habitat quality Habitat quality. 2

3 Habitat quality = deer condition Fawn production as a function of rainfall Arid lands = strong influence of rain Regional Soil Quality in Mississippi: May be highly variable Regional Variation in Antler Size Delta Loess Upper Coastal Plain Lower Coastal Plain Coast High Low Delta UCP Loess LCP Coast Antler size index Influence of soil quality on buck antler size Age class Soil regions in MS Delta UCP Loess LCP Coast Strickland & Demarais (2000) Journal of Wildlife Management 64: Define goals, objectives Are goals realistic? Consider time for management to take effect Age structure: 2 5 years Body weight, condition: 2 5 years Sex ratio: 2 5 years Design management plan How to achieve your goals? Determine what is limiting: food, age, etc. Address limiting factors Determine what can be done Population size: up or down? Age/sex ratios: adequate? Habitat and food supply: habitat management? 3

4 Define goals, objectives Methods and goals are not the same Can you accept the goals but not methods? Are you willing to do what it takes to achieve the management goals? Increase/decrease harvest Increase/decrease burns/herbicide/grazing Incentives/penalties Stick with the plan, be consistent Determine if plan achieved goals Is the plan working? Data, data, data Body weights, condition Age Antler size Reproduction, recruitment Surveys, numbers Assess progress, adjust if necessary Supplemental Feeding Supplemental Feeding What to feed? Depends on your goals Widely accepted in Texas t common or illegal in most other US states Common goals: Increase visibility Increase individual productivity Fawns/doe Body or antler size Supplemental Feeding For visibility, can t go wrong with corn Inexpensive Easy to handle Deer love it! Supplemental Feeding Feed to increase productivity: Pelleted feed, feeders Need 1 feeder to 80 ha! Will have little effect on productivity 4

5 Potential Problems with Supplemental Feed Increase non-target species Raccoons, pigs, rats Any animal that eats feed Spread of disease and parasites Potential Problems with Supplemental Feed Cost Money Time, labor Long-term commitment High fences High fences Why build a high fence? Keep deer from moving onto property Keep deer from moving to other properties Enable manager to control deer population Deer use landscape at a scale different than people use the landscape High fences Dispersal Bucks disperse to new range 3-30 km away Does remain near natal area Behavior to minimize inbreeding 5

6 Dispersal Dispersal: Possible Effects of Management White-tailed deer males disperse females philopatric Mother White-tailed deer males disperse females philopatric Mother Mother Mother Research on Dispersal Bucks establish a new home range many km away Should I cull or shoot spikes???? It depends. Your goals What you d like to harvest Your management intensity Your population status Nutrition, age structure Recruitment 1 size fits all recommendation Both culling and not culling have been successful Should I cull or shoot spikes???? Can young bucks express genetic potential? Deer density, habitat quality (nutrition) good Yes Yes Yes Yes Yes Yes Is fawn production and survival high? Are <40% of yearling bucks culls? Is the ranch large or high-fenced? Do hunters only harvest bucks >3.5 years? Are hunters frustrated with the antler size of most mature bucks? Culling is a viable Antler size of yearling and mature bucks Gross B&C spike fork Yearling Gross B&C Score 6

7 Gross 5+ years old Antler size at maturity Will culling affect genetics? Culling has 2 results: 1. You remove bucks with below-average antlers: genetic effect 2. Eliminate the breeding ability of those bucks: Potential genetic effect over multiple generations 80 Spikes >3 pts The difference is critical Culling: assumes desirable bucks will breed Example: King Ranch Trophy bucks do not do all of the breeding! Example: King Ranch Percent Many bucks breed, even young bucks! Age class. Bucks Avg in population Breeding Bucks 27 with antler scores In Population Parentage Assigned Gross B&C Score How Do You Know Antler Genetics Have Improved? Improved antler size after culling does NOT mean genetic change! How can that be? How long did you practice culling? What other management was done? Protein feed? Water development? Habitat improvement? Reduced grazing pressure? Time required for culling to affect genetics What if we began culling this year: 2009: Cull all undesirable bucks before the rut 2010: Fawns from 1 st year of culling are born 2015: Fawns from 1 st year of culling are 5 ½ years old Culling can not make rapid genetic changes: We can not cull does based on antler potential It is very difficult to cull all undesirable bucks Some bucks with poor antlers have good genetic potential 7

8 Time required for culling to affect genetics Culling for 5 Years: Can you cull intensively? The Corral: Permits perfect buck antler selection AND indications of a buck s genes from offspring AND some indication of doe antler genetics First noticeable results in year 2015 Effect of the 5 th year of culling appears in year 2020 Lose doe control outside of corral Genetic manipulation impossible: yearling dispersal Culling for genetic change requires a LONG time before you can even expect to see results. You have to think generationally about culling. A Corral Full of Deer 100 ha High Fenced Ranch 400 ha High Fenced Ranch 4,000 ha High Fenced Ranch 20,000 ha Low Fenced Ranch County Beyond Culling : Other Genetic Management Techniques 1. DMP Pens greater control over breeding Stock wild does, 1 buck, release fawns 2. TTP Permit Culling via a helicopter Greater culling intensity 3. Buying captive deer with good genetics Breeding Pens. Release captive bucks Survival? Breeding? Bred does How many? Will 5 or 6 does affect a population of 250 deer? Putting intensive management in perspective 1. Culling: big downside as long as recruitment is high Culling not efficient 2. DMP Pens: Downside: cost and risk of deer mortality, time Offspring might indeed be better; how many are needed? 3. TTP: The primary downside is cost, time Risk of losing bucks too young that might become giants 4. Buying deer with good genetics from deer breeders: Cost is high Inefficient, not proven Putting intensive management in perspective I am NOT saying these techniques won t work. Intensive selection works-- in a pen. I am saying that we don t know: What might work outside a pen? How intense does that effort need to be? How much time is required? What is the magnitude of change? What does that effort cost? 8

9 The truth about intensive management: Improvements in population antler size attributed to culling or captive deer are probably due to changes in the environment So What to Do? Primary downsides: cost and effectiveness If you have limited resources, what to do? Bring your feeder density up to 1 feeder per 80 ha? Habitat improvements, feeding Reduced grazing pressure, etc Control of harvest nutrition age Buy captive deer from deer breeders each year? My recommendation add feeders way to measure the impact (or lack of impact) of management on your herd s genetics over time Design management plan How to get there? Population density Sex ratio Other mgmt., But balance expectations and reality Determine if plan achieved goals Is the plan working? Determine what is limiting Address limiting factors first BEFORE YOU DO ANYTHING ELSE! Largest gains to be made Age, nutrition, habitat, etc. Determine what can be done Nutrition or Population size: up or down? habitat Age/sex ratios: adequate? Habitat and food supply: habitat management? Age structure Data, data, data Body weights, condition Age Antler, horn size Reproduction, recruitment Assess progress, adjust if necessary Things to remember. Do not implement a management practice unless you understand the fundamentals behind it! Or just because some other ranches are doing it Ask how management will help achieve goals Proportion of population affected Gain expected If you can not answer this question, do not implement the management- you will be disappointed! Define goals, objectives Are goals realistic? Consider what others nearby have done Consider positive, negative attributes of area Past grazing or land-use history Habitat, soil quality Time for management to take effect Your resources (time and money) Reasonable goals for some areas may be unreasonable on other areas 9