Passerine Monitoring in the Central Alaska Network of National Parklands

Mizel, Jeremy

Passerine species are monitored in all three Network parks using repeat count surveys conducted along roads as well as in select mini-grids and other off-road areas during early summer. During each standard three-minute point count, all birds heard and all birds seen within 400m of the point are recorded. Survey routes are located along the Denali Road, the McCarthy and Nebesna Roads in Wrangell-St. Elias, and along the northern section of the Taylor Highway in Yukon-Charley Rivers. Detection of song birds is strongly correlated to habitat and the timing of surveys. Therefore, in addition to recording birds, other data are collected during surveys as well, including covariates for detection, environmental variables, and number of passing motorized vehicles. Between 1992 and 2008, several different techniques were employed to determine the most appropriate field techniques to meet the objectives of the monitoring program. Recent analysis by Network staff of repeat count data collected annually in Denali from 1994 and 2005 demonstrates the need for monitoring programs to address all components of the detection process, including probabilities of presence and availability. The current two-stage methods of repeat point counts address these components and meet the objectives of the monitoring program. The analysis and associated recommendations are published in the April 2013 issue of Biological Conservation. Land birds comprise more than 70% of the bird species in the CAKN. Passerines, or song birds, are an important component of park ecosystems. Their high body temperature, rapid metabolism, and high ecological position in most food webs make them a good indicator of the effects of local and regional changes in ecosystems; they often respond quickly to changes in their environment. Of all the vertebrates that occur in Central Alaska Network, passerines are easy and economical to detect and a single survey can cover many species. Passerines include a wide variety of species that occupy many habitats over many environmental gradients and may represent unique response variables relative to changes in vegetation. Objectives 1. Population Trends of Common Species. Monitor population trends of common passerine species during the breeding season in each network park with methods that also allow the data to contribute to detection of statewide trends. 2. Community Composition and Distribution. Detect longterm changes in the distribution and composition of breeding passerine bird communities in each network park in relation to changes in their habitats. 3. Integration. Using data from the vegetation and other components of the CAKN Vital Signs monitoring program, develop and update habitat models for common passerine species and for species of conservation concern. Link changes in passerine abundance and distribution to changes in vegetation and other environmental attributes. These linkages will provide insight into the relationships among ecosystem components. 4. Ecology of Species of Conservation Concern. For passerine bird species of conservation concern (due to declining population trends) within Alaska/western Canada, provide demographic information and detect changes in demographic parameters for selected populations within CAKN parks. Current species of conservation concern include olive-sided flycatcher, gray-cheeked thrush, arctic warbler, blackpoll warbler, and rusty blackbird. `

Passerine Monitoring in the Central Alaska Network of National Parklands

Program

Products