This year's extremely dry weather, even with this weekend's rain, could mean a sharp decline in the number of baby deer that survive in Arizona's deserts and mountains.
And that comes after a two-decade reduction in statewide deer populations because of long-term drought.
This summer, fawn survival rates could drop 25 percent to 80 percent from the average, the Arizona Game and Fish Department says. That will be followed by more declines next year in the adult deer population.
The food sources for deer — leaves from trees, shrubs and weeds — are scarce because of the dry spell, one of the worst on record in the Tucson area.
A drop in deer herds also brings a financial hit to the state Game and Fish agency because it means fewer deer available for hunting, at $24.50 a tag.
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But the decline doesn't just hurt the state treasury.
Mountain lions depend on deer for food. Their populations could drop, or lions may come into the Tucson metro area this year — a potential danger for people — to look for javelina, rabbits, coyotes and even bobcats to eat.
The mountain lions may also go after some of the 60 to 70 desert bighorn sheep living in the Silverbell Mountains northwest of the city, the last remaining sheep herd in the Tucson area, said Paul Krausman, a University of Arizona expert on sheep and deer.
Alice Olson, a longtime hiking guide who has lived since 1980 in the Catalina Mountains southeast of Oracle, said she and her husband, Jack, used to regularly see deer come into their yard and even onto their porch in search of water — until the last few years. Now, they see deer maybe once a month.
She also notices a drop in the number of deer she sees when she leads hikes in wilderness areas for the Southern Arizona Hiking Club.
The weather was good for deer last year, when after several years of dry weather, the animals were lucky enough to get good rains, said Jim DeVos, Game and Fish's research chief.
"We saw a lot of fawns, and the deer from last year will probably do well," DeVos said. "Our concern when we see a prolonged dry period is the ability of moms to raise fawns. Both white tail and mule deer commonly have twins. The energy demand of twins is very, very high. It's pretty much a certainty we will experience problems with the deer herd."
If the current dry weather persists into the summer as most forecasters predict, many fawns will die within days or weeks of being born, Game and Fish officials say. Fawns are typically born in the summer.
Right now, the mothers' energy demands are peaking, DeVos said, because the fawns are growing very rapidly as fetuses.
The next crucial period will be right after birth, when mothers are lactating. Fawns live solely off their milk.
"The next five months are a pretty important time from a nutritional standpoint for the deer," DeVos said. "The fawns aren't born yet, but mom needs a whole lot of groceries to make those fawns be fat and happy."
If the drought is really bad, fawns won't be as big and healthy as they need to be and will survive only days or weeks. With less vegetation to shield them, fawns are much more vulnerable to predators.
Mule deer numbers have dropped about 33 percent, and white-tailed deer have dropped 15 percent statewide since the wetter years of the early 1980s, said Brian Wakeling, a big-game management supervisor for Game and Fish.
The extended drought began about a decade ago.
The species aren't in danger of vanishing from Arizona, DeVos said.
"Mule deer evolved in the Southwest. They are a desert-adapted species here," he said. "What we're looking at is a species that will persist at lower numbers till we get additional rainfall."
The drought has made deer more vulnerable to other stresses, however: overgrazing, predation, disease, development and other human intrusions into their habitat, UA's Krausman said.
For small populations such as those in the Baboquivari Mountains and Organ Pipe National Monument southwest of Tucson, the drought could be devastating, he said.
Because of the lower deer population, Game and Fish has since 1994 reduced the number of deer hunting tags it sells by 46 percent, to 36,665 annually.
That has sliced deer tag revenues to the state by about $788,000. The reduction costs the state nearly $2.4 million more annually in federal matching contributions, according to department officials.
Longtime deer hunter Brian Dolan recalls that two decades ago, he didn't have to look very hard to find deer — they would sometimes bump into him. Now, he needs binoculars to find them, said Dolan, a member of the Southern Arizona Sportsmen's Alliance.
The issuing of fewer deer tags is a big concern, he said, because the fewer people who can hunt, the fewer people who are involved in wildlife conservation projects such as encouraging control burns.
The decline in deer hunting also hurts the local economies of some small towns that typically draw a lot of hunters, DeVos said, although there isn't data to prove it.
"This is a fairly complex economic issue, not just to the department, but to hotels, gas stations and local sporting goods stores," DeVos said.
● Top five dry spells, Oct. 1-March 14:
2005-06: 0.54 inches rain
1966-67: 0.84 inches
1903-04: 1.03 inches
1999-00: 1.16 inches
1998-99: 1.37 inches
1920-21: 1.52 inches
● Top six dry spells, from Jan. 1 to March 14:
1. No rain in 1972.
2. 0.01 in. in 1999.
3. 0.016 in 1947.
4. 0.019 in 1924.
5. 0.019 in 1925.
6. 0.022 in 2006.
● State deer hunting permits:
l 68,849 permits sold in 1994.
l 36,665 permits sold in 2004.
l At $24.50 per deer tag, that's a $788,508 decline in revenue from 1994 to 2004.
l That decline also has cost the state three times that much in federal matching aid, or another $2.365 million.
Sources: National Weather Service and Arizona Game and Fish Department
