As the campus's environmental planner, Sid England can tell you where to find just about anything on campus, from the latest proposed building site to the birds that might be nesting in the trees above. But for England, knowing where birds nest is not merely another part of his job description. It's become a key to a passion to help the threatened Swainson's hawk find a place of refuge. England is one of a handful of ecologists who have been studying how these wild hawks have adapted to living around people. Although the hawk's habitat stretches from southern Canada to northern Mexico and east to Illinois, the Central Valley is the only area with regular urban nesting. "These birds are really neat compared to other hawks because, even though they are large, they primarily eat insects," he says. "They are also highly gregarious -- in the fall after breeding, you can find 100-150 in a harvested tomato field foraging for insects." While Swainson's hawks typically migrate to Argentina for the winter, research with satellite transmitters has found that Davis-area birds are different -- they migrate to southern Mexico and Central America. Since 1990, to minimize nesting disruption, England has been monitoring Swainson's hawks on campus. Although nests in the urban areas on central campus are screened fairly well by other trees and nearby buildings, their sites are taken into consideration when planning for large events. The birds are also on the environmental checklist when new construction sites are chosen. England's own interest in ecology developed during college in Southern California. Inspired by a professor of field biology, he majored in biology as an undergraduate at UC Riverside and later received a master's degree before setting out to work as a wildlife biologist in the deserts of Southern California. Curator stimulated interest Although he always had an interest in returning to graduate school to work on a Ph.D., it was only after he took a UC extension course in field ornithology from the curator of natural history at the San Bernadino County Museum that England decided to return to school and study birds. He was drawn to UC Davis by the reputation of its graduate program in ecology and began his position as environmental planner while continuing his graduate studies. He earned his Ph.D. in 1995. "The Davis campus is so different from other campuses because of its size and many natural resources such as Putah Creek and the wildlife it supports, including Swainson's hawks," says England. His interest has led him to serve as chair and now treasurer for a Swainson's Hawk Technical Advisory Committee and as conservation chair for the local chapter of the Audubon Society. Classified as a threatened species by the California Department of Fish and Game, Swainson's hawks were at one time widespread throughout most of the state. Now they are found only in a small portion of the Central Valley, centered in Sacramento, San Joaquin, and Yolo counties and in the extreme northeastern part of the state. The fact that they are found in the Davis area is only part of the story, England points out. Nest in back yards "Most people are unaware of the fact that these birds don't normally nest in urban settings, but here in Davis a small part of the population literally nests in people's back yards and in front of classrooms. In general, these particular birds have learned to tolerate nearby human activities," England says. Between 1990 and 1994, England and others interested in Swainson's hawks studied the urban nesting habits of the hawks in a few Central Valley locations including Davis. They learned that the birds chose to nest in older trees both on campus and in residential areas just off campus, as well as in Stockton and Woodland. "In the downtown area, people hear them in the tall trees, but they probably don't exactly know what they're hearing," England says. Adult hawks have several characteristic calls, one being a shrill "kreeeee," another more of a whistled "kree-e-e" or a high pitched "keeeoooooeee " or "keeeoooo." Besides downtown Davis, Swainson's hawks also are found on and near the campus in areas such as the trees along the Arboretum Waterway, the redwoods outside Wellman Hall, along College Park and on Old Davis Road, just south of Interstate 80. The researchers discovered a downside to the hawks' urban nesting habits. The number of urban fledglings observed was among the lowest reported for the species. Reproduction in 1998 was especially poor for Central Valley and UC Davis Swainson's hawks, according to Jim Estep, a UC Davis graduate working with Jones and Strokes in Sacramento, an environmental consulting company. "We don't know exactly why it's been such a poor year reproductively, but it is likely due to weather conditions, and their effect on prey. Also, some windstorms earlier in the year knocked out nest sites," Estep says. England says he suspects the trend of fewer young in urban areas may be due to the fact that the birds must fly farther to collect food -- mostly rodents and snakes -- for their young. This same reason might explain why the hawks are successful in Davis but not in other urban areas, such as Sacramento and Lodi, where large urban trees are located far from foraging areas. England attributes the hawks' continued existence in the Central Valley to the variety of agriculture allowing them the food sources necessary to survive and reproduce. "Foraging vegetation must be relatively low and open for them to use an area," England says. A prime foraging habitat is alfalfa fields, a number of which are in the area, including some on campus. Alfalfa height matters According to England, once alfalfa is 10 inches high, the hawks stop foraging there. They will return once the crop has been mowed, which happens about every 28 days. The fate of the threatened Swainson's hawk in urban settings will depend largely on what England describes as a ripple effect. As cities continue to grow out from their centers, adequate foraging habitats will decline and the mature trees that support nests in older neighborhoods will be farther away from the fields. The ripple effect occurs as trees in the newer neighborhoods closer to the agricultural fields begin to grow large enough to support nests. Time will tell whether the trees will grow fast enough to support a nesting urban Swainson's hawk population. Ultimately, however, England believes that the hawks' preservation will depend on protecting foraging habitat and the large trees for nests. England says hawk preservation is not a one-person job. "Campus awareness is one way the UC Davis community can help the hawks continue their existence on campus. As people become aware of nests, especially near their work areas, they become more interested and protective of the hawks," he says. As for campus nests, England remains optimistic about their future. "Over the long term the university is going to keep most of the west campus and Russell Ranch in agricultural crops," he says. In addition, the pattern of urban nesting that has been established should contribute to continued campus nesting sites. "Once a bird has learned the pattern and the young are produced in that setting, they will be back," England says. Estep says England's theory is holding true this year, with most all of the pairs returning to the area to nest in the Central Valley. Lisa Lucio Gough, a graduate student in cell and developmental biology, was Dateline's summer intern.