Button Bucks for Each 100 Does: A Rough Harvest Clue to Fawn Production

For each 100 does reported in Iowa, the button-buck harvest is roughly a fifth below its level before 2017. The ratio averaged 16.4 during 2022 to 2024, compared with 20.7 during 2007 to 2016. This hunter-reported measure roughly resembles the fawn proportion agencies calculate after determining the ages of antlerless deer. Use it to follow changes within a state; it does not count fawns. Ohio's records begin with 2019. During the seasons available for both states, each ratio stays within a range of two points.

Iowa hunters report each tagged deer under a category: doe, button buck, antlered buck or shed-antler buck. A button buck is a male fawn. Reporting categories leave doe ages undivided: female fawns go into the doe column alongside adult females. To calculate the ratio, divide the button-buck count by the doe count, then multiply the result by 100. The result describes reported harvest rather than the number of fawns living in the herd. More male fawns being born and reaching fall can raise it. Changes in the fawn crop's sex balance, hunters' shooting decisions or their reporting classifications can move it as well. For Iowa's 2024 county records, the combined counts are 8,130 button bucks and 48,905 does, yielding 16.6. The statewide totals are 8,141 and 48,943, respectively, and likewise yield 16.6.

Agencies calculate a similar measure using more informative records. The Pennsylvania Game Commission examined the juvenile share of harvested antlerless deer. Researchers determined ages through tooth wear and concluded that the share may indicate productivity and effects from predators. Among management units with stable populations, the proportion ranged between 0.34 and 0.46. No individual ratio value therefore establishes herd health; the pattern over time within a management unit is the key. The researchers cautioned that hunter decisions, such as increasingly sparing young deer, can alter the harvest signal. Our ratio is a rougher indicator because the county tables contain no age information and leave deer classification to hunters.

Reported harvest records for Iowa begin with 2006. According to the state, estimates from the preceding mail surveys cannot be compared with those reports. We explain that break in our paper on the two series. During 2007 to 2016, values ranged between 19.8 and 22.4. The ratio dropped to 18.1 for 2017, then to 17.3 for 2018. It reached 16.8 for 2020 and 15.8 for 2022. The statewide figures published by Iowa DNR for 2025 yield 15.7. For the initial reporting season of 2006, the value was 17.9. Whether the new reporting system affected that result remains unknown.

Harvest counts also show the shift. Across the summed county records, the reported button-buck harvest shrank 52 percent between 2007 and 2024, going from 16,846 down to 8,130. Doe harvest decreased 35 percent, while the antlered-buck decline was 17 percent. The report Iowa DNR issued for 2025 to 2026 describes a statewide herd that shrank during 2006 to 2013, remained stable during 2013 to 2017, grew slightly through 2023, and has since held steady or declined. A declining ratio alongside a stable or growing herd is consistent with a reduced fawn crop relative to the number of does. Hunters choosing to spare button bucks would also fit those figures. The records cannot distinguish these explanations.

The county records available for Ohio span 2019 to 2025. Its values ranged between 18.7 and 20.7. Pooling 2019 to 2021 yields 20.0; pooling 2023 to 2025 yields 18.9. Among Ohio's counties, 73 out of 88 have lower values in the later period, with a median decline of 1.3 points. During those years, Iowa moved from a ratio of 17.2 for 2019 to 16.6 for 2024, then 15.7 for 2025.

Describing Iowa as declining while Ohio stays steady is tempting, but the shared years do not support that comparison. Iowa's shift predates the Ohio records, leaving Ohio's pattern during 2007 to 2016 unknown. Column definitions also differ between states. Their 2.1-point difference for 2024 combines the effects of those definitions with any actual differences in deer; these records cannot tell those effects apart. Compare a state's line with its own history. Neither state's reported ratio collapsed during their shared reporting seasons. That observation provides no direct answer about herd abundance or fawn survival.

Doe harvest warrants checking first. Each reported doe increases the denominator, and states have distinctive balances of harvested does and bucks, as shown in our buck-to-doe paper. Iowa's reported harvest amounted to 144 does for each 100 antlered bucks in 2007, followed by 102 in 2016 and 114 in 2024. Within counties, an additional ten does for each 100 antlered bucks is associated with 0.33 fewer button bucks for each 100 does. The relationship runs in the expected direction, but its size is small. The period saw fewer does relative to antlered bucks, which should have increased the ratio. Accounting for that shift expands the decline from 4.4 to 4.8 points. This calculation adjusts only for harvest composition. Hunting pressure, hunter effort and decisions to pass deer remain unmeasured. It eliminates that explanation while leaving the others unresolved.

Harvest tables cannot test the choices hunters make. Iowa leaves deer classification to hunters and includes bucks without forked antlers in the antlerless category. A shift in shooting or reporting decisions would therefore alter the ratio even with fawn numbers unchanged. We examined an indirect connection. Surviving male fawns become yearling bucks the following fall. With unchanged survival, a larger ratio should be followed by a larger antlered-buck harvest in the next season. We fitted four regressions relating the following season's antlered harvest to the current ratio, using logarithms for both and accounting for county and season effects. The tests looked one or two seasons forward, with each horizon tested both with controls for antlered bucks and does and without them. Three produced no clear relationship. One test, looking a season forward with controls, found a small positive relationship. Its coefficient of 0.05 associates a ratio higher by 10 percent with approximately 0.5 percent more antlered harvest the following season. Support from one of four tests does not establish the connection, which remains unproven.

Random variation also falls short of explaining the differences among counties. County-to-county variation is 4.2 times the amount expected from chance alone. Some actual difference exists, whether in permits, hunter behavior or fawn survival. Even the extreme county values shown below have random uncertainty ranging from 0.5 to 1.4 points apiece.

Combine your county's button-buck counts across three seasons, and do the same for does. Divide the first total by the second and multiply the result by 100. Next, estimate random uncertainty at one standard error. Multiply the ratio by the square root of the following sum: 1 divided by the button-buck total, plus 1 divided by the doe total. Smaller pooled counts produce greater uncertainty. Comparing a change involves two pools, both with their own random variation. The final table column shows the difference needed to stand out when two pools have equal sizes.

Our approach would use pooled seasons to calculate your ratio and compare two periods within your state's records. We would treat a change as real only if it exceeds the final column's threshold, roughly 2.8 times the uncertainty of one period. A change below that threshold is not newsworthy. When a difference clears it, consult the agency's recruitment measure before debating doe permits. Ohio's summary identifies fawns per doe as a recruitment measure calculated from deer whose ages were determined. Where states publish an age-based measure, that figure is preferable.

Our counts come from county-level tables published by Iowa DNR for 2006 to 2024 and Ohio DNR for 2019 to 2025. For Ohio, adding bucks, does and button bucks reproduces the total for every one of the seven seasons. Its 2025 category counts also agree exactly with the annual summary published by Ohio DNR: 99,008 bucks, 111,958 does and 21,261 button bucks. For Iowa, county sums reproduce the statewide total for 16 out of 19 seasons. The remaining seasons have shortfalls of 9, 372 and 66 deer across those three totals. For 2023 and 2024, our ratios differ from Iowa DNR's statewide calculations by no more than 0.03.

These limits matter. Random uncertainty assumes the counts behave as random tallies; it cannot account for changes in shooting decisions or reporting. We did not find an independent count of fawns in either state for comparison. Only two states are represented, and harvest figures tally reported kills rather than living deer. The Iowa value for 2025 uses the statewide figures rather than county-level records.