Fire, Drought, Beetles, and Birds
FeederWatchers notice the impact of natural disasters on jays and nutcrackers
As wildfires raged through California in the fall of 2003, the flames threatened the livelihoods of people as well as the birds and other wildlife that resided on the dry, forested hillsides. The difficult challenge for the birds dispersing from burning forests was to find adequate habitat elsewhere in which to live. Where did the birds go? How have their populations been affected? As in past natural disasters, citizen scientists helped answer these questions.
After widespread fires across much of the West during the summer of 2002, for example, participants in Project FeederWatch reported changes in the abundance of birds including Pinyon Jays, Steller’s Jays, and Clark’s Nutcrackers at their backyard feeding stations. Extensive drought combined with a bark beetle infestation may have further influenced the movements of these birds.
The three species inhabit coniferous woodlands, where their life cycles are interwoven with those of the pines. A single Clark’s Nutcracker caches as many as 98,000 seeds to store for one winter. A flock of 250 Pinyon Jays stores some 4.5 million pine seeds in autumn, when seeds are plentiful. Steller’s Jays have a more varied diet but they also cache and consume pine seeds. In return, the birds help disperse seeds and regenerate forests in burned areas. Forgotten caches grow into new trees, often in clusters where the seeds had been hidden together. When the forests mature, the jays and nutcrackers harvest the seeds they need to survive winter and feed their young. When crops fail, jays and nutcrackers irrupt in large numbers in search of food.
Searching for food after fires
In September 2002, fires brought Pinyon Jays to the yard of FeederWatcher Helen Mixa for the first time in 30 years of observations. The Mixas live in Vernal, Utah, just south of Flaming Gorge Reservoir, where fire burned 20,000 acres of pines. According to Helen, “The fire reduced the pinyon pines to ash. There weren’t even skeletons of trees left. Nothing.” After the fires, the jays began coming to the feeders every day—as many as 160 at a time.
Fires also took their toll on Pinyon Jay habitat in Wyoming. Jim and Gloria Lawrence of Casper, Wyoming, occasionally see jays in their yard, but they report that in 2002 “the unusual thing was that the Pinyon Jays came and stayed for about three weeks, visiting the yard daily to feed for up to five hours a day.” The Lawrences live south of Mount Bessemer, which burned in 1998, and Mount Coal, which burned in 2001.
In other regions as well, fires may have caused Steller’s Jays to move into new areas. Colorado, Arizona, and Oregon recorded their largest fires in the last 100 years, according to the National Interagency Fire Center. Bill Howe, a biologist with the U.S. Fish and Wildlife Service, reported, “last winter marked one of the largest flights of Steller’s Jays into the lowlands. The jays were everywhere from the plains of Colorado to the lowlands of the Rio Grande. People were reporting them on birding lists and seeing them fly over cities.” Because there were still Steller’s Jays in the mountains of New Mexico and because the species is typically scarce in the lowlands in winter, Howe suspects that the fires in Colorado, combined with drought conditions throughout the Southwest, drove jays into new habitats.
Ironically, fire suppression practices in many areas may be contributing to widespread problems for coniferous birds. Natural fires, although they destroy trees, also help regenerate healthy new forests by burning mature stands and releasing seeds from cones to germinate. In the northern Rocky Mountains, where fires have been suppressed, nutcrackers have suffered major losses of high-elevation habitat. Without fire, whitebark pine communities have aged and become susceptible to outbreaks of introduced white pine blister rust and pine beetles, or yielded to other tree species less favorable for nutcrackers. Meanwhile, fire suppression policies in southwestern ponderosa-pine forests have provided fuel for huge, uncontrolled wildfires that consumed thousands of hectares of Pinyon Jay habitat in the late 1990s.
Food shortage: drought, bark beetles, and dying trees
Droughts also might explain why some FeederWatchers were seeing more jays and nutcrackers at their feeders. Dr. Russ Balda, a leading expert on Pinyon Jays, studied populations near Northern Arizona University in Flagstaff. Balda and his students banded hundreds of jays at feeders, taking numerous measurements and assessing the health of the birds. [We learned a few years after this article was published that Balda and his team banded Pinyon Jays at the count site of FeederWatcher, Pam Koch, in Flagstaff, Arizona. See a related article in the 2008-09 issue of Winter Bird Highlights (PDF), page 3.]
According to Balda, the drought-stricken pinyon pines near Flagstaff hadn’t produced a seed crop since 1999. The researchers found that each year since 1999 juvenile Pinyon Jays were weighing less, indicating that food resources are limited. The research showed that birds were moving across vast regions in search of food, showing up in places where they had not been recorded before, such as Santa Rosa, California, and even Mexico. Pinyon Jays were seen at more FeederWatch locations in 2002–2003 than during the previous season (see Figure 1), indicating that birds left their native habitat and sought supplemental food at feeding stations.
Drought sent Pinyon Jays into the yard of Claire Bassett in Pueblo West, Colorado. In the five years she lived in Pueblo West, she had never seen Pinyon Jays in her yard. During the winter of 2002–2003, up to five jays visited almost every day. She said that the trees died in the foothills to her west where Pinyon Jays were commonly found and the nearby reservoir was at its lowest level in 15 years.
According to the Sunday Journal in Albuquerque, New Mexico, a bark beetle infestation damaged thousands of pinyon pines in New Mexico, pushing Pinyon Jays into new habitats. The infestation of these native beetles is associated with widespread drought.
When a beetle bores into bark, a healthy tree responds by producing pitch that drowns or evicts the beetle. During infestations in times of drought, however, trees may not produce enough sap pressure to control the hundreds of beetles that may attack. The insects carve pathways under the bark, eventually killing the afflicted trees. The outbreak in New Mexico was the worst since at least 1950, according to Debra Allen-Reid of the USDA Forest Service, and it was so widespread that control methods were not feasible.
The effects of drought and insects were not lost on Barbara Smith of Silver City, New Mexico. In her yard the evergreen oak trees lost their leaves in autumn, something that normally only happened in the spring as new leaves replace the old. According to Smith, Steller’s Jays usually stayed in the pine forests on top of the hills several miles from her home, but the drought the previous summer caused the jays to move down into the foothills. “In Santa Fe I saw whole hillsides of dead junipers and pinyon pines killed by the bark beetle,” said Smith.
In a normal FeederWatch season she would see only one or two Steller’s Jays during the entire winter, but during the winter of 2002–2003, she always had six or seven jays, and one day she had twelve.
The combined data from FeederWatchers counting birds across the region also revealed interesting shifts in sightings of nutcrackers. In 2001–2002, FeederWatchers reported Clark’s Nutcrackers on the eastern front range of the Colorado Rockies, but in 2003 reports of this species also came from the valleys on the western side of the mountains, presumably because of failures in seed crops. According to The Birds of North America, “Poor condition of many irrupting birds indicates that some may not survive; some settle in new areas with cone crops and may not return home.”
Unfortunately, Clark’s Nutcrackers and Pinyon Jays may have fewer choices about where to go than in the past. According to The Birds of North America, approximately 1.2 million hectares of pinyon/juniper woodland were converted to grazing land between 1950 and 1964. Along with the effects of fire, fire suppression, drought, and bark beetle infestation, prime habitats for these species are becoming more difficult to find.
Reference: Tomback, D. F.; Balda, R. P. The Birds of North America, Nos. 331 and 605. The Birds of North America, Inc., Philadelphia, PA.
Originally published in BirdScope, Winter 2004, Volume 18, No. 1