Utah Partners in Flight (UPIF), a cooperative organization of state, federal, private, and
non-governmental organizations dedicated to conserve Utah’s landbirds, established this study in
1992 to document bird population trends in Utah’s riparian areas. The work was initially
designed to compliment existing efforts, to respond to rising regional concerns, and to provide
land managers and the public with relevant local information. Specifically, we designed the
study to detect a 50% linear decline in abundance over 10 years with 80% power at an alpha
level of 0.10.
This report summarizes the first 14 years of this on-going effort, and concludes that
riparian bird populations have undergone statewide declines of approximately 5% per year
during the 1992-2005 period. Linear trends in the two most sensitive metrics used in the study,
abundance and annual survival, agree in the direction and magnitude of these declines. Declines
observed in abundance are considered statistically significant. There was no significant linear
trend in overall species richness. This first analysis is intentionally large-scale and
taxonomically inclusive, capturing statewide patterns in broad strokes. On-going and planned
analyses will work to detail the site, species, ecoregion, and agency-specific trends. These
results do not implicate specific causes or mechanisms, but on-going management activities,
concurrent regional drought, and regional anthropogenic impacts are briefly discussed.
This work represents the longest continuous study of this extent western North America.
Thirty-one riparian sites were initially chosen for monitoring using point transect (detectabilitycorrected
abundance estimation) beginning in 1992. Additional sites were added in later years;
37 sites with consistent data representing statewide patterns were chosen for this monitoring
analysis: 15 sites total on Bureau of Land Management (BLM) managed lands, 13 on United
State Forest Service (USFS) managed lands, 2 sites on National Park Service (NPS) managed
lands, 2 sites on United States Fish and Wildlife Service (USFWS) managed lands, and 5 on
either Utah Division of Wildlife Resources (UDWR), Bureau of Reclamation (BOR), or
privately managed lands. Four of these sites were selected for continuous effort mist net
sampling (survivorship estimation via mark-recapture banding) beginning in 1994, with four
more sites subsequently added. These 37 sites are most representative of low and mid-elevation
riparian areas on publically managed lands.
Data from the study has established bench-marks for riparian habitats in Utah and the
region. As such it represents a great success in UPIF’s cooperative, diversified, funding model
for long-term and large-scale applied ecological research. Current and future uses of these data
include: 1) providing managers with the region- and habitat-specific set of references, with
important estimates of natural variation, needed for assessments of habitat quality, managementaction
impacts, and restoration success; 2) providing managers and researchers with the first
baseline abundances and survival estimates for many of Utah’s riparian species; 3) estimating
trends in population and survivorship for individual species of management concern; 4)
correlational analyses designed to formulate testable hypotheses about the causes and scales of
population change, and 5) compilation into bird species- and community-habitat associations
designed to help guide conservation and restoration activities.