Research Article Evaluation of Auditory Counts for Estimating Breeding Populations of White-Winged Doves MARIO SEPU ´ LVEDA, Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX 78363, USA FIDEL HERNA ´ NDEZ, 1 Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX 78363, USA DAVID G. HEWITT, Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX 78363, USA WILLIAM P. KUVLESKY, Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX 78363, USA GARY WAGGERMAN, Texas Parks and Wildlife Department, San Marcos, TX 78666, USA RALPH L. BINGHAM, Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX 78363, USA Abstract We evaluated an unverified index (auditory counts) used to estimate breeding populations of white-winged doves (Zenaida asiatica) in Texas, USA. Our objectives were to determine optimal survey time of day, year, and count duration, determine if a relationship existed between number of calling doves and population size (nest and dove density), and evaluate an electronic counter to estimate breeding density. We collected data on 15 sites in the Lower Rio Grande Valley of Texas during May–August of 2002– 2003. Peak calling occurred between mid-May and late June during 0600–0800 hours. We detected about 60% of calling doves during 2-minute auditory counts. Estimates of breeding doves (pairs ha 1 ) as determined by auditory counts were positively correlated with both population density (r . 0.90, P , 0.01) and nest density (r . 0.94, P , 0.01). The electronic coo-counter tally also exhibited a positive relationship with population density (r . 0.77, P , 0.01) and nest density (r . 0.92, P , 0.04). However, the high correlations observed for auditory counts and electronic counter were influenced by 2 high dove-density sites. Our data did not provide convincing support for the premise underlying auditory counts of white-winged doves (i.e., number of doves calling reflects dove abundance). The electronic coo counter was limited in application because it tabulated dove calls based solely on acoustic frequency and therefore could not discriminate against other avian calls with acoustic frequencies similar to those of white-winged doves. Auditory counts may be appropriate as coarse-resolution reconnaissance surveys to locate new white- winged dove areas in need of monitoring but not to obtain reliable abundance estimates. The use of an electronic counter to estimate breeding populations of white-winged doves holds promise, given technical modifications, and warrants further research. Given the current limitations of both auditory counts and electronic counters, alternative survey methods that incorporate detection probabilities (e.g., distance sampling) need to be evaluated for white-winged doves. (JOURNAL OF WILDLIFE MANAGEMENT 70(5):1393–1402; 2006) Key words auditory counts, coo counts, Lower Rio Grande Valley, surveys, Texas, white-winged dove, Zenaida asiatica. Auditory counts are a common technique used to assess avian populations during the breeding season (McClure 1939, Duke 1966, Scott and Boeker 1972, Dolton 1993). Although auditory techniques vary methodologically, most are based on a common procedure where the number of individuals heard calling along prescribed routes is recorded (Wakeley et al. 1990). An important assumption of indices is that number of birds heard calling provides an accurate index to abundance (Sisson 1968, Keppie et al. 1970). However, because factors such as observer variability and weather can affect detectability of calling birds (LaPerriere and Haugen 1972, Shields 1977, Baskett et al. 1978), this assumption may be violated, thereby invalidating indices (Anderson 2001, Thompson 2002). An auditory-count index has been used by Texas Parks and Wildlife Department to monitor white-winged dove populations in the Lower Rio Grande Valley of Texas, USA, since 1949 (Uzzell 1949, Cottam and Trefethen 1968). The procedure involves counting the number of calling white-winged doves during 2 minutes at predeter- mined stops and converting that number to an estimated breeding-pair density using a conversion table (Appendix 1; Uzzell and Kiel 1950). There are 2 primary concerns regarding the validity of this index. First, the methodology is based on the premise that number of calling doves is related to population density, a relationship that has been both questioned (Olson et al. 1983, Armbruster and Basket 1985, Rappole and Waggerman 1986) and supported for doves (Sisson 1968, Keppie et al. 1970). A second and more critical issue is the unknown origin and development of the Uzzell and Kiel (1950) conversion table. An account of the methodology or data used to develop the table does not exist. In fact, according to the only living coauthor, the conversion table was not developed by Uzzell and Kiel (1950) but was already in existence at the time of his hire in 1949 (W. H. Kiel, retired wildlife biologist, personal communication). Despite the historic and widespread use of an unverified index to monitor white-winged doves in Texas, the validity of the auditory-count index is largely untested (Rappole and Waggerman 1986). In addition, basic survey protocol remains unsubstantiated. For example, timing of surveys is based on subjective estimates of peak diurnal and seasonal calling. The 2-minute duration of auditory counts also represents an arbitrary time period. Our objectives were to 1 E-mail: fidel.hernandez@tamuk.edu Sepu ´ lveda et al.  Evaluation of Auditory Counts for White-Winged Dove 1393