Bulletin Vol. 53, No. 1-2 (2020)
Total Page:16
File Type:pdf, Size:1020Kb
Victoria County Birds—an Avian Crossroads Special Feature … BULLETIN OF THE TEXAS ORNITHOLOGICAL SOCIETY Vol. 53 No. 1–2 December 2020 www.texasbirds.org THE TEXAS ORNITHOLOGICAL SOCIETY 2020 OFFICERS CHRISTINE TURNBULL DANIEL HODGES PRESIDENT VICE-PRESIDENT KENDRA KOCAB JOHN BERNER SECRETARY TREASURER JACK EITNIEAR PUBLICATIONS EDITOR MEMBERSHIP Any person interested in the birds of Texas is encouraged to become a member of the Texas Ornithological Society. Individual membership rates are $35.00 per year, $5.00 or more each month at the Sustaining level, $15.00 Student, Family $50.00, $400.00 Life, Organizational $25.00, and Life: $400.00 or Life w/ Spouse/Partner: $500.00. These memberships include print versions of Texas Birds Annual, and digital access to the Bulletin of the Texas Ornithological Society and TOS News. To become a member mail check or money order in U.S. funds with complete name and address to: Texas Ornithological Society Memberships, 11101-9 Leopard Sq., PMB 1039, Corpus Christi, Texas 78410. Memberships can also be obtained by consulting www.texasbirds.org PUBLICATIONS The Bulletin of the Texas Ornithological Society is an annual1 journal devoted to the biology and conservation of the birds that occur in Texas and adjacent areas. Membership includes digital access to the Bulletin. Guidelines for authors can be found at http://texasbirds.org/publications/bulletins/ guidelinesForAuthors.pdf Texas Birds Annual (TBA) is published each year and includes new birding areas, recent media, vagrants and noteworthy birds from the previous year, articles on bird conservation issues and species profiles. Membership includes a print copy of the TBA. TOS News is a tri-annual full color electronic newsletter produced by TOS. The newsletter is no longer a membership benefit but “open access” on our webpage at www.texasbirds.org. Occasional Publication Series is published on an irregular basis on scientific works too long for publication in the Bulletin. When published it is provided free to all members as an extra benefit of membership during the year of publication. The series can be downloaded at www.Texasbirds.org Submissions to all publications should be e-mailed to the editor (email: [email protected]). Changes of address and queries about memberships or missing copies: E-mail TOSmember@ yahoo.com or submit in writing to the address above. Additional copies of publications can be obtained by contacting the editor. PERMISSION TO COPY The Texas Ornithological Society hereby grants permission to copy articles (in whole or in part) appearing in The Bulletin of the Texas Ornithological Society (Bulletin) and Texas Birds Annual (TBA) for personal use, or educational and/or personal use, without payment, provided the material reproduced includes the statement “©2020 The Texas Ornithological Society” and contains the full citation, including names of all authors. TOS does not maintain copyright for Figuregraphic material therefore does not allow any reproduction of such material without written consent of the Figuregrapher. Any use not specifically granted here, and any use of Bulletin or TBA articles or portions thereof for advertising, republication, or commercial uses, requires prior approval from the Editor. 1Starting with Vol. 42 both issues were combined.. Cover Figure: Duck skull sketch from the notebook of Edward Harrison Compton completed between 1906 and 1960 in Germany. Original owned by editor. Frontispiece. Northern Bobwhite (Colinus virginianus). Art compliments of Lynn Delvin.. BULLETIN OF THE TEXAS ORNITHOLOGICAL SOCIETY ESTIMATES OF IMMIGRATION AND EMIGRATION FOR TWO NORTHERN BOBWHITE POPULATIONS IN TEXAS Trent W. Teinert1,3,4, Leonard A. Brennan1, Stephen J. DeMaso1,5, Fidel Hernández1, and Dale Rollins2,6 1Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX 78363, USA. 2Texas AgriLife Extension Service, San Angelo, TX 76901 ABSTRACT.—Estimating emigration and immigration has not been well documented and is generally assumed to be equal in Northern Bobwhite (Colinus virginianus) populations because of the complexity of documenting movement and defining population size. In the winters (20 Oct to 29 Feb) of 2007-08 and 2008-09 we used mark-recapture techniques to sample bobwhites in the Rolling Plains and South Texas Plains and develop capture histories for each individual. We used the “Pradel ” model in Program MARK to estimate finite population growth rate () and then inferred emigration and immigration rates from these estimates. We found that in the Rolling Plains, in 2007-08 was 0.999 (95% CI 0.996–1.002, n 112) and in 2008-09 was 0.998 (95% CI 0.995–1.002, n 106). This was the same as the South Texas Plains in 2007-08 with 1.003 (95% CI 0.998–1.008, n 174) and 0.993 (95% CI 0.983–1.004, n 49) in 2008- 09. With being essentially 1, it implies that bobwhites were either sedentary or emigration and immigration occurred at the same rate. This concludes that previous assumptions of emigration and immigration being equal during the winter are true. INTRODUCTION (Brander 1968) problems with recording movements Immigration is the movement of new individuals still exist due to the relatively weak frequencies into a population. Emigration is the movement emitted by small transmitters. In this chapter, we of individuals out of a population. Immigration present an approach to quantifying immigration and emigration are seldom estimated for northern and emigration based on mark-recapture of banded bobwhite populations because of the difficulty bobwhites. This approach was developed by Pradel quantifying movements with current research tools (1996) where he stated that by reversing the capture such as band returns or radiotelemtery. However history of an individual it is possible to determine immigration and emigration are potentially seniority and calculate finite population growth rate important population parameters for examining () based on the probability of an individual being how wildlife populations fluctuate through both present in the past and being present in the future. space and time. This advice was then incorporated into Program Even though radiotelemetry has been used to MARK (White and Burnham 1999) where direct monitor upland game birds for nearly 40 years estimates of can be obtained for a population over 3 E-mail: [email protected] 4 Current Address: Texas Parks and Wildlife, Gonzales TX, 78629 5 U.S. Fish and Wildlife Service, Gulf Coast Joint Venture, Lafayette, LA, 70506 6 Rolling Plains Quail Research Foundation, Roby, TX, 79543 USA Bull. Texas Ornith. Soc. 53(1-2): 2020 2 a given time period. Lambda 1 indicates a stable was approximately 400 ha in size. The vegetation population (no ingress or egress); 1 indicates community was dominated by honey mesquite, a decreasing population (emigration); and 1 oaks, huisache (Acacia minuata), granjeno (Celtis indicates an increasing population (immigration). pallida), brazil (Condalia hookeri), prickly pear (Opuntia lindheimeri) doveweed (Croton spp.), STUDY AREA sunflower (Helianthus spp.), gulf cordgrass (Spartina This research was conducted in 2 ecoregions of spartinae), sandbur (Cenchrus incertus), and purple Texas: Rolling Plains and South Texas Plains (Gould threeawn (Aristida purpurea)(Teinert 2009). 1975). These ecoregions experience high annual and seasonal variability in rainfall amount (Correl METHODS and Johnston 1979); thus, bobwhite populations therein exhibit irruptive behavior (Jackson 1969, Trapping Lehmann 1984:8). Trapping took place from 20 October 2007 to 29 February 2008 and 20 October 2008 to 1 March Rolling Plains 2008. This time period coincided with the bobwhite The Rolling Plains study area was located in hunting season and the winter period although some Fisher County near Roby, Texas. Land uses were variation occurred due to logistic restraints. To primarily cattle production and lease hunting. properly sample a defined population, we sampled Soils in the area are Paducah loam (55.0%) evenly across the population of interest. We placed and Woodward loam (32.0%) (NRCS Web Soil funnel-type traps (Stoddard 1931:442) baited Survey 2008). Average annual precipitation for with milo 250 m apart on a trapping grid (grid this region is 55.9 cm with an average snowfall created using ARC GIS 9.2, ESRI, Inc., Redlands, of 25.4 cm (National Climate Data Center 2007). CA). Individuals were classified by sex and age Average winter temperature (Nov–Mar) is 7.7°C (Rosene 1969:44–54) and all bobwhites captured and summer temperature (Apr-Aug) is 23.3°C were banded. Bobwhites captured the first season (National Climate Data Center 2007). The study were banded on the left leg, and second season on pasture was approximately 400 ha in size. The the right. Each time a bobwhite was captured or vegetation community was predominantly honey recaptured we recorded time and date of capture. mesquite (Prosopis glandulosa), lotebush (Ziziphus obtusifolia), netleaf hackberry (Celtis reticulata), Data Analysis prickly pear (Opuntia spp.), silver bluestem With this information we built an encounter history (Bothriochloa saccharoides), threeawns (Aristida to use in the “Pradel Survival and Lambda” (Pradel spp.), sideoats grama (Bouteloua curtipendula), and 1996) platform in Program MARK. This platform buffalo grass (Buchloe dactyloides) (Rollins 2007). uses binary data to represent encounter histories in LLLL format (White and Burnham 1999). South Texas Plains Finite population