Bone-dry: The Drought and its Effects on Wildlife
James Swan 12.17.12
The National Climatic Data Center reports that the US is struggling with its worst drought since 1956. About 75% of the US is in some state of drought, 55% of the country is in moderate drought, and 20% is facing extreme or exceptional drought. The national average of precipitation 1.19” for November is almost half normal and we’ve just had the eighth-driest November on record in the US. Add to this that in the past half year, 28 states east of the Rocky Mountains set temperature records and 170 all-time temperature records were set in June alone.
Where I live in the New Mexico high desert, it’s hard to perceive drought because it’s normally an arid climate where our bird bath is the only open water for at least a mile. Just what the drought was doing to the countryside and its wildlife was not apparent until I recently went on a Canada goose management hunt at the Las Vegas National Wildlife Refuge, which lies on east side of the Sangre de Cristo Mountains of northeast New Mexico. This is a popular draw hunt and we were really excited at getting drawn for the second day. Last year we were drawn and did not get a goose, but we saw several thousand and sandhill cranes were even more common.
We knew the layout the refuge from last year, and where our assigned blind was located. We skipped scouting, got up early, and drove over in darkness for an hour and half, arriving at the 5:30AM check-in at headquarters, where the refuge staff loaned us two dozen decoys to add to our flock.
In the darkness, my son and I put out a total of 150 goose decoys and two sandhill crane confidence decoys and settled into the pit blind located in an agricultural field. As the sun came up, we could see that the field was devoid of any crop and it was dusty dry. A raven was the first visitor to the spread: the first and only bird in sight for the first hour.
Finally a string of half a dozen Canada geese appeared and I began to work the flag and my trusty Canada goose call, which is at least 80 years old. The lead bird acting as a scout came in close and we got him. That nine-pound goose turned out to not only be the only bird we shot, but the only goose taken for seven blinds that morning. In five hours of hunting, we saw a total of 20 geese and 12 sandhill cranes.
After shooting time ended, we drove the long way back to the refuge headquarters, discovering that all the ponds, marshes and lakes –“playa wetlands,” shallow wetlands of the Great Plains that fill periodically from heavy rainfall–were bone-dry. Over 60,000 such wetlands are found throughout northern Texas, western Oklahoma, Kansas, Nebraska, eastern New Mexico, and Colorado and they are critical for waterfowl nesting in the US as well as supporting migratory birds.
Perhaps the most dramatic was McAllister Lake (pdf pamphlet), which lies within the refuge but is managed by New Mexico Game and Fish. In pre-drought times, McAllister is 100 acres, 25’ deep, and holds 20” rainbow trout, as well as ducks and geese. Last year, year one of the drought, it was half full. This year there was no water at all.
You may have read in the newspaper that the last two years in New Mexico have been dry, and this year’s November is the warmest on record and the second driest, but until you see the barren ground where a marsh or lake used to be, and taste the dust that swirls up with the wind, it does not sink in just how bad things are.
At the refuge office we learned that they had planted food crops for geese and cranes last spring, but no rain fell and the crops didn’t come up. Same was true for nearby farmer–no crops came up this year. The first real rain came in August, making the total for the year 7.1 inches. It had not rained or snowed since August, and nearby Storrie Lake, which provides water for the town of Las Vegas, New Mexico, is also seriously down, so there was not much help there. Hence, the clouds of Canada geese, snow geese, and sandhill cranes that normally are there were nowhere to be seen.
When I got back home, I drove over to the Galisteo Dam, which is a Corps of Engineers flood control dam 164’ high and half a mile across, to do a local reality check. While the reservoir only fills up during heavy rains, there is usually an acre or so of water at the bottom where waterfowl congregate. The water depth stakes that indicate a maximum depth of 560’ now are a row of stark white poles that go down to bone-dry bottom land. Only bird seen was one raven passing over quickly. There was a trickle of water in the Galisteo River upstream, but only a trickle, in a stream that once held trout.
The drought’s effects on wildlife and habitat
The early predictions for waterfowl for this year were rosy. The US Fish and Wildlife Service estimated the 2012 waterfowl production in North America at a record high of 48.6 million (pdf report). That’s 7% higher than the 45.6 million ducks estimated in 2011 and 43% above the long-term average. So where are the birds?
Ducks and geese migrate according to food and water. The birds have been holding up north with warm weather, and then either moving toward the coasts, or just skipping normal stopovers that have gone dry, flocking on larger lakes that still hold water, and heading directly south where there is more water.
In drought situations, avian cholera is also more likely. The warm water with decaying protein matter allows Clostridium botulinum bacteria to blossom. Large bacterial populations produce toxins that can be fatal to birds. When I lived in California this was a problem at the Klamath National Wildlife Refuge along the California-Oregon border. In some dry years, thousands of birds congregated in limited ponds die of avian cholera.
For upland game birds, this year is tough. California Fish and Game Warden Jerry Karnow reports that in the northeast high desert along the Nevada border, chukar partridge, which are drought-tolerant, are very scarce. Similar smaller populations of pheasants and quail are reported in Texas and all across the Midwest.
Deer, bear, and elk may find themselves drawn into urban areas for water, and/or concentrate around bodies of water that still are there. Kenneth Baca, a conservation officer for New Mexico Game and Fish, says that the drought has caused mule deer and elk to concentrate around remaining water, making poaching easier. Poachers stake out water holes to shoot trophy animals and then just take the antlers to sell. Of, course predators follow food, and in my area that means coyotes in the backyard and bears raiding apple trees.
Habitat also is influenced by drought. Drought-stressed trees are less able to repel bark beetle and wood boring insects. Unless winter snows are strong, chances are good next summer that we will have many fires like the last couple of years.
One more drought-related condition to be aware of is blastomycosis, which is a fungal disease associated with lower water levels, warm weather, and decaying wood, especially around beaver ponds. Dogs are particularly vulnerable but humans can also contract the disease, which affects the lungs, becoming Gilchrist’s disease.
Some perspective
Mention the drought and some people will immediately attribute it to global warming. Not so fast. Driven partly by El Niño, La Niña, and other major oceanic influences, atmospheric circulation patterns can differ dramatically from one year to the next, with accompanying swings in annual precipitation of 50% or more. This has been going on for a very long time. There were significant droughts in the 1930s and 1950s (droughts tend to occur every two to three decades), but the bigger picture suggests that the West has endured far drier periods. Tree-ring studies going back 1,000 years show 200-and 700-year drought cycles that go back to the Little Ice Age.
The drought’s benefits
There is a brighter side to droughts, according to Ducks Unlimited. In aquatic environments, organic material accumulates at the bottom over time, and this mat of “organic soup” locks up nutrients. This ultimately reduces productivity, reducing annual plant growth and resulting in more growth by perennials. This translates into less and less open water. When a drought occurs, and the bottom materials are exposed to air, oxygen helps decomposition taker place, resulting in fertilization.
In hot, dry weather, water and food mitigation projects will save flocks of upland birds. Use this time as a reminder to plan projects so next year will be better. A drought is an opportunity to get into places with heavy machinery and do some land shaping, removing unwanted vegetation, and channel deepening, all in anticipation for a future time when normal rainfall will fill those now dry wetlands to the brim with cool clear water. And with water will come more birds than you have seen in years.