When Do Pronghorn Come to Water?

Camera data from New Mexico show pronghorn drink at midday, mostly in hot dry spells. Rifle pressure on pronghorn is short. Here is the evidence.

Pronghorn come to water in the middle of the day, not at first and last light. They come more when it is hot and has been dry for weeks. And when rifle season opens, the pressure on them is heavy but brief.

The evidence for this is narrow. The time-of-day finding comes from one camera study on one refuge. The pressure finding comes from an agency guide that summarizes older field studies. Both are worth knowing, with those limits in mind.

The camera study

Researchers ran trail cameras on between 23 and 36 water sources at Sevilleta National Wildlife Refuge in central New Mexico, from late June 2009 to mid September 2014. That is more than five years of continuous monitoring across a refuge of about 930 square kilometers. ^[1]

Pronghorn showed up in 581,163 images, which the researchers grouped into 14,654 separate visits. ^[1]

Time of day

Pronghorn visits peaked at midday, and very few happened at night. The authors point out that this was the opposite of the other animals they tracked. Elk, mule deer and oryx came mostly at night and around dawn and dusk, and so did the mountain lions that hunt them. ^[1]

How long they stay

Short. The median pronghorn visit lasted 4 minutes, and 99% of pronghorn visits were over within 45 minutes. ^[1]

Pronghorn also came back sooner than any other hoofed animal in the study. The average time before pronghorn returned to a given water was about 21 hours. ^[1]

Weather

Two things raised pronghorn visits: higher daily maximum temperature, and less rain over the previous six weeks. Of the two, the six-week rain total mattered more, by about a third. ^[1]

So a single hot afternoon matters less than a long dry stretch. After a wet month, expect far fewer animals at water even on a hot day.

Time of year

Peak pronghorn use of water ran for three months, May through July. ^[1] That is before most hunting seasons open. Use during an August or September hunt will be lower than the peak this study measured, and the study does not say by how much.

Midday water, morning and evening glass

The midday water pattern fits with what agency biologists say about spotting pronghorn.

Wyoming's survey handbook tells its own biologists to fly pronghorn counts in the first two to three hours after daylight and the last two or three hours before dark. The stated reason is that bedded animals, bucks especially, are harder to see at midday. The same handbook notes that in August, farm fields and the areas around water are where pronghorn densities are high. ^[4]

Put together: glass early and late when animals are up and visible. If you are going to sit water, the middle of the day is when the camera data say they drink.

Does sitting water work

A range-wide pronghorn management guide reports that archery success in Arizona rose from 7% in 1981 to 1983 to 18% in 1994 to 1996, a period when archers took up blinds near water, decoys, calls and better equipment. In northwest Colorado, where archers often use pit blinds near water, the guide says success typically exceeds 60%. ^[2]

The same guide gives a warning. In arid country, hunters waiting at water can cause pronghorn to avoid drinking. ^[2]

It also gets crowded. Idaho's pronghorn plan says archery participation and harvest nearly tripled between 2002 and 2020, and lists hunter crowding and competition for water holes among the concerns. ^[3]

Rifle pressure is short

The management guide makes two points about rifle seasons that matter for anyone with a tag. ^[2]

• During the first weekend of rifle season, most permit holders are in the field and about 90% of the harvest is taken. After that there is little disturbance for the rest of the season.
• In a Wyoming study the guide cites, hunting during the rut made dominant bucks leave their harems and territories. But rifle hunters usually stayed only a day or two, and bucks were defending their territories again by the third day of the season.

Idaho's plan puts pronghorn breeding at mid September to early October, and notes that most pronghorn hunting there falls in the breeding season. ^[3]

For a rifle hunter who can stay past the opening weekend, that is useful. The crowd is gone after two days, and the one study cited found bucks back on their ground by day three.

What this means for your hunt

• If you sit water, sit it through the middle of the day. Dawn and dusk are for glassing.
• Be set up and within range before animals arrive. A four-minute visit leaves no time to move.
• Weigh the last six weeks of weather. Hot and dry favors water. Recent rain works against it.
• Give other hunters and the animals room at water. Crowded water can stop pronghorn drinking at all.
• With a rifle tag, consider hunting day three and later instead of fighting the opening weekend.
• Check your state's rules on blinds, cameras and hunting near water before you plan a water sit. Rules differ by state and change from year to year. Confirm with the agency.

What this does not tell you

• The time-of-day result is from one refuge in New Mexico. No second study in another state was found to confirm it.
• The cameras recorded both sexes together, mostly in May through July. The study did not measure a hunted herd during a season.
• The rifle pressure figures come from an agency guide that summarizes field work from the 1980s. We read the guide, not the original studies, and it gives no sample sizes.
• The 60% archery figure for northwest Colorado is the guide's general statement, with no years or hunter counts attached.
• Nothing here measures how pronghorn change their use of water once hunters are sitting on it, beyond the guide's one-line warning.
• These sources do not measure how green forage changes a pronghorn's need for open water in a given week.

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Sources

1. Harris, G., Sanderson, J.G., Erz, J., Lehnen, S.E. and Butler, M.J. (2015). Weather and prey predict mammals' visitation to water. PLOS ONE 10(11):e0141355. https://pmc.ncbi.nlm.nih.gov/articles/PMC4641626/
2. Western States and Provinces Pronghorn Workshop (undated copy). Pronghorn Management Guide, Part II: Management Recommendations. North Dakota State Library copy. https://www.library.nd.gov/statedocs/gamefish/prong-mgmt-pt3.pdf
3. Idaho Department of Fish and Game (2023). Idaho Pronghorn Management Plan 2023-2028. https://idfg.idaho.gov/sites/default/files/pronghorn_plan_2023_2028.pdf
4. Wyoming Game and Fish Department (undated). Handbook of Biological Techniques, Chapter 1: Pronghorn Antelope. https://wgfd.wyo.gov/media/3416/download