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.

This study was conducted to determine basic data on the incidence of lead shot in ducks us ing the Great Salt Le.lee Basin. The study has been divided into two parts; (1) incidence of ducks carrying lead shot in their tissues and (2) incidenoe of ducks carrying ingested lead shot.

Three collimators were designed and built with mouse irradiation in mind. They were made to have a shapeable aperture that could deliver strange or complex dose shapes to spots on the animals. Current collimators are either custom-built, expensive, or only provide limited dose shapes. These provide self-customizable collimation at a minimum of cost. A mouse holder was also devised to reproducibly hold a mouse under the collimator. Construction of the holder and of each collimator is also covered. Each collimator was analyzed for flaws, holes, and penumbral width across various shapes of interest. A Norelco MG300 X-ray generator at the Texas A&M Nuclear Science Center was used in these tests. The lead collimator had a radial penumbra of 1.2 mm. The clay / lead shot collimator had a radial penumbra of 1.6 mm. The brass collimator had a radial penumbra of 1.75 mm. Vertical and horizontal penumbras are dependent on distance from the center of the beam. All readings are + 0.3 mm according to the resolution of the scanner used in this experiment. Each collimator is useful for different purposes.