Shot ducks shift to closed water, and in Mississippi rest days added none

STEP 1 · Same clock

Glass the hunted hole and the closed water three mornings running

On a marsh you already hunt, our rule is a paired count. Write down the hole you shot and the nearest water where guns are closed. Use one clock time on hunt morning and on the next two mornings.

If the hole is thin the next morning while birds sit on closed water and the hole fills again after days without guns, that is what the Danish evening shoots produced. Duck numbers on three Mississippi wildlife areas at four days of hunting each week did not separate in a detectable way from two days of hunting each week. Our read is that a nearby quiet refuge counts for more than added rest days on the hunted side. If those quiet mornings stay empty, check daytime walkers or vehicles on the refuge before blaming the guns.

STEP 2 · Refuge line

Quarry ducks followed where hunting stopped

Madsen reported in the Journal of Applied Ecology on two coastal wetlands in Denmark. Hunting-free ground was shifted each year across 4 years. Those refuges were then left standing and watched through another 4 years. Quarry geese and quarry dabbling ducks moved as the hunting-free boundary moved. Protected species did not follow that boundary. From the years before the experiments to the years after them, quarry geese rose 6 to 8 fold. Quarry dabbling ducks rose 4 to 50 fold. They also kept staging into winter.

In that paper goldeneye and coot count as quarry and neither shifted with the boundary. Protected waterfowl did not either and their counts swung or rose between 2 fold and more than 50 fold. Food, off-refuge recreation, weather and population size could not explain the quarry goose and dabbling duck gains. The richest gain in species came where a refuge held shallow water along with salt marsh. Madsen judged that quarry species had been displaced by hunting and that building refuges improved conservation value. Those folds are counts on the two wetlands in this refuge test.

STEP 3 · Sunset shoot

Mallard numbers fell on the day after one evening hunt

Bregnballe and Madsen tested one marsh day of shooting at a time on a large coastal wetland in Denmark and published in Wildlife Biology. In 1998 shoots were spaced three weeks apart. In 1999 they were spaced two weeks apart. In 2000 and in 2001 they were spaced one week apart.

Shooting fell near sunset on salt marsh that normally lay inside a large shooting-free refuge. Counts covered the hunt day plus the next two days. Once the guns had fired the first 1 to 7 shots, dabbling ducks moved out to the open-water refuge. Geese and waders departed toward places more than 5 miles (8 km) off.

Mallard numbers were significantly lower the day following those hunts on the salt marsh and on the shallow ground beside it. Wigeon and teal changed with the conditions. Floodwater covered the salt marsh early in autumn 2001. Wigeon, teal and lapwing then shifted only inside unshot parts of that marsh.

On days without shooting the birds kept feeding on the ground that had been hunted. The authors tied that mild response to the broad refuge lying next to the shot marsh. A weekly gap still meant one sunset shoot beside a refuge large enough to receive the flight. A morning hunt of that same hole on every day was outside the trial.

STEP 4 · Weekly rate

Two and four days a week matched on three areas

St. James and colleagues compared hunted portions of three wildlife management areas in Mississippi. The paper is in the Journal of Fish and Wildlife Management. One schedule was 2 days a week. The other was 4 days a week. Abundance of all ducks showed no detectable difference between those schedules. The same was true for mallards, for northern shovelers and for green-winged teal.

Sanctuary use rose about 30% through the opening 1.25 hours past sunrise. The rise showed with hunters present and with hunters absent. Duck abundance did not climb when the number of rest days climbed. The authors said these areas may be hunted on 4 days a week and may still see no significant drop in abundance. Daily use of the sanctuaries may be vital for keeping ducks on the areas.

No detectable difference here is only for 2 days a week versus 4 days a week on those three areas.

STEP 5 · Opening weekend

Flight rose and daytime sanctuary use stayed elevated

McDuie and colleagues fitted GPS units to 15 dabbling ducks tracked in California. The paper is in the Journal of Environmental Management. Flight and sanctuary use both changed at the 2018 season opener. The tracks spanned about 4 weeks across October and November 2018. Fixes were saved every 2 minutes across three days. Those days were 2 weeks prior to the season, opening weekend and a hunting weekend 2 weeks after the opener.

Daytime gunfire was high disturbance. Dawn and dusk activity that did not kill birds was moderate. Night counted as low.

Against the pre-season weekend, flight time and distance on opening weekend more than doubled at moderate disturbance and at low disturbance. During high disturbance those flight measures rose about 50%. Sanctuary use tripled at moderate disturbance and at low disturbance. During high disturbance sanctuary use rose about 50%.

Two weeks after the opener, flight dropped at every disturbance level. Only the high-disturbance hours put flight under the pre-season level. Sanctuary use dropped only at night and still sat above the level from before the season. Daytime sanctuary use doubled. The share moved off about 45% and reached more than 80%.

Scope here is 15 dabbling ducks tracked in California during 2018.

STEP 6 · Sanctuary traffic

People on foot moved mallards harder than a covered vehicle

Blake-Bradshaw and colleagues followed GPS mallards through planned disturbance on sanctuaries and published in Wildlife Biology. Dates ran from November 1 through February 28 across seasons from 2019 to 2022.

Covered vehicles supplied 140 disturbances. Pedestrians supplied 40. Uncovered vehicles supplied 43 across 10 sanctuaries. The trials included 195 mallards disturbed at least once. Per bird the disturbance median was 2 and the range ran from 1 to 12.

The authors reported that daytime sanctuary use "exceeded 83% of proportional use" in every period. Mallards lowered sanctuary use only after an uncovered vehicle disturbed them before the hunting period. Hourly movement jumped right away on a morning with pedestrians or with an uncovered vehicle. Pedestrians produced the strongest response across the whole day. Disturbed birds doubled space use in the pre-hunt period and again in the early-hunt period. Vehicles cut movement solely when the birds were outside the hunting period. During hunting each added disturbance lined up with 12% less space used. Sanctuary fidelity stayed the same. The authors tied that tight pattern to few other safe places and had expected habituation if disturbance repeated.

STEP 7 · Closed water

Females on Lake St. Clair selected marsh closed to hunting

Palumbo and colleagues wrote in Ecology and Evolution about adult female mallards on southern Ontario's Lake St. Clair. GPS backpacks went onto 59 birds caught on a private Canadian shore. Catch work fell in late August and also in early September. The 2014 sample was 20 birds. The 2015 sample was 39 birds.

Selection was best explained by the model classing resources together with presumed hunting risk. That model ranked first before hunting and during hunting and after hunting.

In every season and at every hour they selected marshes under federal management and private refuges used for feeding with hunting prohibited on both.

Guns were barred inside a radius of 0.25 mile (400 m) around the feeding sites. Public access areas opened at civil sunrise and closed at twilight. Michigan state land, Walpole Island and private property received an intermediate risk score. Timing, place and hunter numbers are regulated on those lands. The score presumes the risk from ownership.

About 98% of wetlands were already gone across Essex, Kent and Lambton. Ducks chose complexes under federal, state and private ownership when refuge and food exceeded what public hunting ground offered.

The shared pattern is close refuge water with no people on it in daylight and food still where you hunt.

State totals will not pick your hole. The ducks per hunter page uses U.S. Fish and Wildlife Service harvest surveys. That page says statewide results cannot rank separate marshes. A one-duck gap cannot rank states with confidence. Rest days and refuge lines differ by state. Check your wildlife agency page before a rest day locks the plan.