Breeding Forest Birds

Monitoring Objectives

• Determine trends in breeding forest-bird species distribution, diversity, and detection/non-detection in SECN Parks

Background
Birds are an important component of park ecosystems, and 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. It has also been suggested that management activities aimed at preserving habitat for bird populations, such as Neotropical migrants, can have the added benefit of preserving entire ecosystems and the associated ecosystem processes (Maurer 1993).

Long-term trends in the community composition and relative abundance of breeding-bird populations provide a measure for assessing the ecological integrity and sustainability in southeastern systems. Long-term patterns in community composition and relative abundance in relation to changes in the structural diversity of vegetation resulting from fire and other management practices will improve our understanding of the effects of various management actions.

Monitoring Approach
Bird surveys are limited to the breeding season (April through mid-June) in an attempt to sample species that have the highest likelihood of reproducing within a park. Point counts of birds will be conducted with the variable circular plot (VCP) methodology (Reynolds et al. 1980, Buckland et al. 1993, Nelson and Fancy 1999) and will occur from 0530 – 1100. Station locations are determined by the spatially-balanced random sampling design utilized by this protocol and several other terrestrial vital signs (e.g., plant communities, amphibians). At each station, counts are separated into three time segments, 0-3 minutes (to allow comparisons with breeding bird survey data), 3-5 minutes, and 5-10 minutes. Each station is sampled three times over the course of a two-week period to capture different environmental conditions and facilitate generation of the percent area occupied (PAO) metric (MacKenzie and Nichols 2004, MacKenzie and Royle 2005, MacKenzie et al. 2006) for all detected species. All birds, regardless of distance detected from the observer are counted and recorded. An important benefit of using the variable circular plot method is the ability to accommodate a wide range of bird species, each of which possesses a different singing style and each of which may occur in a variety of acoustically-different habitats. VCP counts operate by essentially allowing the habitat to determine the size of the area being surveyed. Habitat data are collected under the co-located SECN Plant Community Monitoring Protocol within one month of VCP-data collection. Measures collected by this protocol include: 1) species detection/non-detection, 2) detection location, and 3) detection counts. Breeding forest-bird monitoring will be conducted on a three- to five-year rotating schedule for all parks.

Parks Where Protocol Will be Implemented
All SECN Parks

Principal Investigator
Michael W. Byrne, Terrestrial Ecologist