Management and Conservation Note Monitoring Golden-Cheeked Warblers on Private Lands in Texas BRET A. COLLIER, 1 Institute of Renewable Natural Resources, Texas A&M University, College Station, TX 77843, USA MICHAEL L. MORRISON, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA SHANNON L. FARRELL, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA ANDREW J. CAMPOMIZZI, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA JERROD A. BUTCHER, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA K. BRIAN HAYS, Institute of Renewable Natural Resources, Texas A&M University, College Station, TX 77843, USA DARRYL I. MACKENZIE, Proteus Wildlife Research Consultants, P.O. Box 5193, Dunedin, New Zealand R. NEAL WILKINS, Institute of Renewable Natural Resources, Texas A&M University, College Station, TX 77843, USA ABSTRACT A majority of North American breeding habitat for neotropical migrants exists on private lands, requiring monitoring strategies focused on habitat in these private holdings. We outline study designs and protocols using repeated presence–absence surveys across a gradient of patch sizes to develop a range-wide monitoring program for the endangered golden-cheeked warbler (Dendroica chrysoparia) in Texas, USA. We surveyed 200–400 point-count locations across approximately 30 private properties annually from 2005 to 2008. We used data from our surveyed patches (n 5 147) and the Y (occupancy), p (detection), and c 5 1 2 e parameterization to estimate patch dynamics and associated detection probabilities for golden-cheeked warblers. Patch size had a strong association with patch occupancy, and all patches .160 ha were predicted to be occupied. We found no evidence that large golden-cheeked warbler populations located on public lands in the vicinity of our study area influenced occupancy dynamics. We conducted simulations across a range of detection probabilities to evaluate potential sample sizes for both standard- and removal-based occupancy modeling. Simulations using parameter estimates from our analysis indicated that removal-based sampling is superior to standard sampling. Based on our results, surveying golden-cheeked warbler presence in oak–juniper (Quercus–Juniperus) patches under a removal modeling framework should be considered as one alternative for range-wide monitoring programs because patch-level monitoring would be necessary to estimate proportion of range occupied. Large contiguous patches are rare across the species’ range; hence, conservation and management of the mosaic of smaller patches within a landscape context would be required for maintaining species viability. Thus, we recommend the identification of areas where smaller, contiguous patches represent a significant portion of the available habitat within the local landscape and targeting these areas for habitat maintenance and improvement. KEY WORDS breeding range, Dendroica chrysoparia, fragmentation, golden-cheeked warbler, habitat loss, patch area, patch occupancy, Recovery Credit System. The golden-cheeked warbler (Dendroica chrysoparia) is a federally endangered neotropical migratory passerine with a known breeding range across about 35 counties ( L 95% private ownership) in central Texas, USA (Fig. 1; Pulich 1976, Deboer and Diamond 2006, Magness et al. 2006). Within the warblers’ breeding range, mature oak (Quercus spp.)–Ashe juniper ( Juniperus ashei) woodlands provide foraging habitat, nesting cover, and shredded bark used as nesting substrate (Pulich 1976, Ladd and Gass 1999). However, declines in oak–juniper woodlands (United States Fish and Wildlife Service 1992) and the small percentage of breeding habitat found on public lands (,5% of total area within the breeding range) requires that conservation planning for the warbler must incorporate habitat on private lands. Understanding the combined impacts of habitat loss and fragmentation, as well as the impacts of private lands on species distribution and demography, is vital to recovery (United States Fish and Wildlife Service 1992). Several models of habitat distribution of the golden- cheeked warbler have been constructed to guide conserva- tion efforts (e.g., DeBoer and Diamond 2006, Magness et al. 2006). Habitat delineations are usually based on presence or absence data collected during point-count surveys on private and public lands (Wahl et al. 1990). However, current habitat models have been based on a limited number of survey points across the species’ range (n 5 49, DeBoer and Diamond 2006; n 5 202, Magness et al. 2006). Although attempts have been made to predict distribution of warbler habitat, recent studies have relied on short-term (single season) and limited-visit ( M 2) surveys to establish species presence for identifying general habitat metrics (Wahl et al. 1990, DeBoer and Diamond 2006, Magness et al. 2006). Limited data exist for modeling golden-cheeked warbler demographics across the species’ range, with most data derived from studies on Ft. Hood, Coryell County (Fig. 1; Anders 2000, Alldredge et al. 2004, Anders and Dearborn 2004, Baccus et al. 2007, Peak 2007). Recent efforts to quantify golden-cheeked warbler population size have been based on a combination of density estimates from approx- imately 30 years ago (Pulich 1976), from the intensively managed Ft. Hood populations (Jettj et al. 1998), or from a small number of transects (n 5 11, Wahl et al. 1990). Density estimates are then combined with aforementioned estimates of available breeding habitat (e.g., Wahl et al. 1990, DeBoer and Diamond 2006, Magness et al. 2006) to estimate population size (Rappole et al. 2005). These derived population estimates remain unreliable for use in the range-wide management and conservation of the species. 1 E-mail: bret@tamu.edu Journal of Wildlife Management 74(1):140–147; 2010; DOI: 10.2193/2008-551 140 The Journal of Wildlife Management N 74(1)