Progress 05/01/98 to 06/09/04
Outputs The Olive-sided Flycatcher (OSFL) is a Neotropical migrant songbird whose numbers have been in steady decline over the past 30 years. Managing OSFL populations requires an understanding of how they are affected by landscape-level processes such as wildfire. We looked at the short-term effects of wildfire (1st and 2nd breeding seasons post-disturbance) on OSFL habitat quality by comparing nesting success, aerial insect abundance, and foraging rates between burned and unburned locations in Six Rivers National Forest of northern California. Nesting success, foraging rates, and aerial insect abundance were significantly all higher on unburned than burned sites. This suggests that OSFLs are food limited in burned territories shortly after wildfires and that this food limitation reduces reproductive success either directly, through chick starvation, or indirectly, through (1) decreased incubation time and concomitant lower hatching success or (2) decreased nest vigilance and
increased nest predation. We speculate that reduced aerial insect abundance in burned territories is a result of the short-term reduction in live vegetation (herbivore and pollinator habitat) and course woody debris (decomposer habitat). This study was made possible by funding from the McIntire Stennis Foundation (in 2000, contributed $10,000; in 2001, contributed $15,000) and in-kind support from the Hoopa Valley Indian Reservation - Tribal Forestry Department (in 2000, contributed maps and GIS data worth $150), the USDI Forest Service - Six Rivers National Forest (in 2000, contributed maps and GIS data worth $150), and the Humboldt State University Wildlife, Forestry, and Biology Departments (in 2000 and 2001, contributed lab facilities, equipment, and supplies worth approximately $6000 and field gear worth approximately $3000).
Impacts Severe forest fires modify forest habitats in several different ways. This study is examining the effect of such a fire on the habitat of the Olive-side Flycatcher, a Neotropical migrant songbird. A better understanding of such wildlife-forest relationships will assist managers in the development of appropriate mangement stategies for such declining wildlife species.
Publications
- No publications reported this period
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Progress 01/01/00 to 12/31/00
Outputs The Olive-sided Flycatcher (OSFL) is a Neotropical migrant songbird whose numbers have been in steady decline over the past 30 years. This project is designed to assess the hypothesis, suggested in the literature, that unburned post-timber-harvest habitat provides less insect prey for OSFLs than burned post-forest-fire habitat. During the summer of 2000, it was found that the foraging rates of OSFLs were twice as high in unburned territories as they were in burned territories. A preliminary examination of samples collected in aerial insect nets indicates that the aerial insect community was more diverse and abundant in unburned territories than in burned territories. Habitat variables positively related to foraging rates were the amount of live ground cover, dead wood ground cover, live shrubs/seedlings, and live trees. Taken together, the results suggest that, one year after a forest fire, burned OSFL habitat does not provide individuals with more insect prey than
unburned OSFL habitat. However, the results indicate that insect prey in burned OSFL habitat will increase as trees begin to fall and the plant community begins to regenerate. Graduate students = 2
Impacts Severe forest fires modify forest habitats in several different ways. This study is examining the effect of such a fire on the habitat of the Olive-side Flycatcher, a Neotropical migrant songbird. A better understanding of such wildlife-forest relationships will assist managers in the development of appropriate mangement stategies for such declining wildlife species.
Publications
- Hazard, G. C., and T. L. George. 1999. Landbird abundance and diversity in different-aged stands of coast redwood forests in northwestern California. Northwestern Naturalist 80:99-109
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Progress 01/01/99 to 12/31/99
Outputs Breeding bird survey data suggest that olive-sided flycathchers(Contopus borealis) have been declining throughout their range. To investigate possbile causes this decline, their density and habitat use in three contrasting landscapes was examined. Several interesting associations between olive-sided flycathchers and the managed forest in which they were studied were found. Perch sites were distinguished from random sites by three variables: perch height, perch diameter and the height of the perch tree. Flycatchers use small limbs at the extreme top of a tall tree. At the next larger scale it was found that they generally choose areas within their territory with a higher snag density than random locations. The largest scale we examined was the placement of territories within the study plot. This level of analysis indicated that olive-sided flycatcher's territories are located in areas that are structurally herterogeneous. Typically these areas include stream buffers
and mature stands adjacent to recent clearcuts. The results suggest several management activities that many improve habitat for olive-sided flycatchres. Territories were often associated with stream buffers and perch sites were frequently located in trees within these buffers. In addition, maintaining small groups of standing timber within clearcuts may increase this bird's presence. Finally, retention of standing dead trees may positively affect the bird's density as the landscape shifts from mature timber to young stands. Graduate students = 1
Impacts Surveys suggest that olive-sided flycatchers have been declining throughout their range. This study examines bird density and habitat use in contrasting forested landscapes in an attempt to understand possible causes for this decline.
Publications
- No publications reported this period
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Progress 05/01/98 to 12/31/98
Outputs Field work for the first year of the olive-sided flycatcher (Contopus cooperii) research project was conducted from May to August 1998. The habitat use of olive-sided flycatchers was examined in three distinctly different managed forest landscapes: a recently harvested landscape (>50% harvested within last 15 years), a mature forest landscape (>50% harvested 40-50 years ago), and a 10 year-old, high intensity burn. The young and mature plots have recent clearcuts. Salvage logging was conducted in the burned plot and it was not replanted. Each plot encompasses a minimum of 6 km2. These sites span the ranges of landscape types found in managed forest of the redwood region and therefore will provide insight into factors influencing the abundance of olive-sided flycatchers in the region. A total of 27 male territories were found on the three study sites. Vegetation measurements were collected at known bird locations and at randomly chosen points. Preliminary analysis
shows many variables differsignificantly between occupied and random locations. Graduate students = 1
Impacts (N/A)
Publications
- No publications reported this period
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