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Call number: LD2668 .T4 1984 S58 / Master of Science

Texas A&M University (TAMU) supports a substantial breeding population of mourning doves (Zenaida macroura) with one of the highest nest densities in Texas. There has been a long history of mourning dove research on the TAMU Campus, with initial population studies conducted in the 1950’s, and the most recent studies occurring in the 1980’s. The TAMU Campus and surrounding areas have experienced substantial changes associated with urbanization and expansion over the last 50 years, altering mourning dove habitat on and around campus. The objective of this study was to examine mourning dove nesting and production in an urban setting and determine how microhabitat and landscape features affect nest-site selection and nest success. Specifically, I (1) examined trends in mourning dove nesting density and nest success on the TAMU Campus, and (2) identified important microhabitat and landscape features associated with nest-site selection and nesting success. Mourning dove nests were located by systematically searching potential nest sites on a weekly basis from the late-March through mid-September. Nests were monitored until they either failed or successfully fledged at least 1 young. A total of 778 nests was located and monitored on campus. All nest locations were entered into ArcView GIS. An equal number of nests were randomly generated in ArcView and assigned to non-nest trees to evaluate habitat variables associated with nest-site selection for mourning doves. Binary logistic regression was used to evaluate the significance of microhabitat and landscape variables to nest-site selection and nest success. Comparisons with data collected in 1950, 1978, and 1979 showed relatively similar nesting densities, but a significant decrease in nest success over time. A comparison of microhabitat features between actual nest trees and random locations (non-nest trees) indicated increasing values of tree diameter at breast height and tree species were important predictors of mourning dove nest-site selection. Landscape features found important in dove nest-site selection were proximity to open fields, roads, and buildings. Proximity to roads and buildings also were significant predictors of nest success. Combining significant microhabitat and landscape variables for nest-site selection increased the predictability of the model indicating a possible hierarchical nest-site selection strategy.

Previous field studies of hunter-harvested mourning doves (Zenaida macroura) have reported lead (Pb) shot ingestion rates of 1 &ndash 6.5%. However, considerable uncertainty exists concerning mechanisms affecting pellet ingestion across different habitats. To reduce some of this uncertainty, an experiment was conducted to test the Pb shot ingestion rate of mourning doves on bare soil (typical of a managed dove field). Wild doves were trapped and held in captivity 5 &ndash 13 weeks prior to treatment. One week prior to treatment, a blood sample was taken from each bird before placement in open-bottomed treatment pens on a disked field. Each of 3 treatment groups of 80 birds was divided into 35 low density (1.5 million pellets/ha), 35 high density (29.5 million pellets/ha), and 10 control (0 pellets/ha) animals. Five positive control birds were gavage &ndash dosed with 2 Pb shot in trials 2 and 3. Pb shot and mixed seed were scattered uniformly on the loosely packed soil of their pens and birds were exposed for 4 days. Birds were x &ndash rayed post &ndash treatment on days 2 and 4 for the presence of Pb shot in the digestive system, and euthanized following the drawing of a blood sample on day 4. Overall, 2.9% of doves voluntarily ingested &ge 1 pellet. The shot ingestion rate for birds in the high density Pb treatment (4.9%) was not statistically different (P = 0.0977) from birds in the low density Pb treatment (1.0%). Pb concentrations in liver, kidneys, and blood reached maxima of 94.402, 346.033, and 13.883 ppm wet weight, respectively, and were statistically greater in birds that had ingested shot than in controls (P < 0.0083). Delta-aminolevulinic acid dehydratase (ALAD) activity decreased by an average of 92.2% post-treatment as compared to pre-treatment in birds that had ingested shot, while increasing by 1.1% in control birds. Heterophil:lymphocyte ratio increased by 28.2% in birds that ingested shot as compared to 1.5% in controls, while packed cell volume decreased by 7.6% in birds that ingested shot and 0.6% in controls. No significant difference in weight among groups was observed post-treatment (P = 0.3131). If managers deem the number of mourning doves at risk of Pb shot ingestion unacceptable, some options are to ban Pb shot either on entire management areas or only on high shot deposition areas like dove fields, or to disk fields after dove hunting to reduce Pb shot availability.

Ball State University LibrariesLibrary services and resources for knowledge buildingMasters ThesesThere is no abstract available for this thesis.

This thesis presents the results of an examination conducted to determine the status of mourning doves in Throckmorton County, Texas.