How many does do you need to shoot this season and how do you determine the amount?  Is your herd population increasing or decreasing?  These questions can be answered by understanding your Fawn Recruitment rate.  FRR data is critical for implementation of Quality Deer Management.  Keep in mind that QDM is not “Trophy Deer Management”.  Rather, QDM improves overall health and maximizes genetic expression for the entire herd.  Without knowing how many fawns are recruited into your herd annually, you’ll lack statistics to set effective yearly management goals.  Objectives that will boost your gross antler potential and maintain balanced sex ratios.  

What is Fawn Recruitment Rate?

The statistic indicates how many fawns, both male and female, have been “recruited” into the herd by early fall. By late September fawns have survived the 4-month gauntlet from birth.  Learning to stand within minutes and walk within hours, fawns develop rapidly.  Traits that have proven successful for likely the most adaptive prey species on North America. 

To calculate the FRR, divide total fawn observations by total doe observations.  Rates can vary tremendously within counties and are mostly based on habitat conditions.  Generally speaking, open ground lacking cover will yield lower Fawn Recruitment Rates.  Fawns will be exposed and easy targets for predators.  The best offense for predators, especially coyotes, isn’t a rifle it’s better habitat.  I detailed this within an article I wrote for MeatEater:  How to Create Ideal Fawning Cover for Whitetails. 

Let’s look at a herd model example to see how FRR plays out annually after hunting season.  I’m going to use a deer population of 100 to keep it simple and run herd models for Doe:Buck ratios or 1:1, 2:1, 3:1, 4:1, and 5:1.  The sex ratio indicates how many does are present in relationship to bucks.  “Present” on your land is somewhat vague as deer move across the landscape and don’t acknowledge boundaries unless you’re high fenced with pen / domesticated deer.  You may run herd statistics, but your neighbor may not.  Just keep in mind that there are subjective takes that should be considered.  All “case by case”. 

I used a 50% Fawn Recruitment Rate for the model.  On average, each doe, 1 year+ has successfully recruited .50 fawns into the herd.  Replacements that will continue the species to counter hunter kills, natural mortality, predation, and automobile collisions.   

I kept the hunter harvest figure constant throughout the entire model to illustrate the importance of Quality Deer Management record keeping and the necessity of periodic adjustments.  As shown below, being unsure of the sex ratio means you’re unsure of how your population increases or decreases.  The first model shows a harvest of 10 with a .50 FRR and the second shows a harvest of 20 with a .25 FRR.  Running identical annual harvests identifies the importance of tweaking this figure seasonally for balance and better buck hunting.  

I included fawns into harvest kills because we all know this happens.  Every year a friend of mine shoots a “doe” at dark that magically morphs into a 6-month-old buck fawn once recovered from the poor shot.         

Mortality was kept at 10% (10 deer annually based on a herd of 100).  This figure includes disease, old age, car accidents, weather conditions, and predation.  You may question why I did not include the fawn recruitment figure into the subtraction.  I have seen this displayed both ways within deer management literature.  It’s of my opinion that it should not be incorporated as the FRR already deducts mortality.

Methods:

The easiest methods to implement are observational hunter logs and trail camera surveys.  With observation logs, make sure you instruct hunters to accurately identify fawns from 1+ year old female deer.  An effective approach is to compare body sizes when multiple deer are within view and to pay attention to behaviors.  This becomes tricky late season as fawns have shed spots and show proportional muscle definition.  Trail camera surveys should be run beginning mid to late September as fawns readily travel with their mothers. 

 As hunters and wildlife stewards it’s far more advantageous to be proactive than reactive.  Running herd models annually will pinpoint where your population is trending.  Whether you’re shooting too many deer or not enough.  Do you need to lay off antlerless deer kills or ramp it up.  It will also indicate if you have a fawn recruitment problem.  If that’s the case, as mentioned above, targeting ‘yotes is not the sole solution.  Coyotes are a wildly thriving and colonizing species.  Habitat is the best defense but that’s for a future article. 

I’m sure you have noticed signs of population ebbs and flows on your land.  Whether it’s food plots that are browsed down and killed before the plant develops or trail camera survey sites that yield concerningly low deer.  Either scenario can be adjusted by learning your Fawn Recruitment Rate.