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Charles W. Shaiffer

Publications and source records attributed to Charles W. Shaiffer.

8 recordsLinked to original sources
USGS1992

Band reporting rates of mallards in the Mississippi alluvial valley

We captured 2,182 mallards ( Anas platyrhynchos ) in eastcentral Arkansas and marked 730 with standard bands, 728 with 10 reward bands, and 724 with 'dummy' radio transmitters during November 1986-89 to estimate band reporting rates in the Mississippi Alluvial Valley (MAV). Assuming all transmitters were reported, reporting rates were 0.16 (SE=0.049) for standard bands and 0.34 (SE=0.081) for 10 reward bands. Interviews with hunters indicated that flock size distributions differed ( P =0.03) between mallards wearing transmitters and those wearing bands (standard or reward). Mallards wearing transmitters were more likely to be alone and less likely to be in large flocks when recovered than were mallards wearing bands. These results suggest that either band reporting rates of mallards in the MAV are substantially less than those of midcontinent mallards ( P =0.03), or marking mallards with external transmitters increases susceptibility to hunting mortality.

Arkansas↗
USGS1988

A field test for differences in condition among trapped and shot mallards

We tested predictions from the condition bias hypothesis (Weatherland and Greenwood 1981) regarding the effects of sampling methods of body weights of mallards ( Anas platyrhynchos ) at White River National Wildlife Refuge (WRNWR), Arkansas, during 24 November-8 December 1985. Body weights of 84 mallards caught with unbaited rocket nets in a natural wetland were used as experimental controls and compared to the body weights of 70 mallards captured with baited rocket nets, 86 mallards captured with baited swim-in traps, and 130 mallards killed by hunters. We found no differences (P > 0.27) in body weight among sampling methods, but body condition (wt/wing length) of the birds killed by hunters was less (P < 0.02) than that of the controls. Power of the test statistics to reject the null hypothesis of equal body weights among sampling methods was > 0.75 for differences > 50 g. The condition bias hypothesis probably applies to ducks killed by hunters but not to trapping operations when substantial (> 20 at 1 time) numbers of birds are captured.

Arkansas↗
USGS1985

Mallard recruitment in the agricultural environment of North Dakota

Recruitment of a mallard (Anas platyrhynchos) population was assessed on a 10,041-km2 study area in central North Dakota during 1977-80. We equipped 338 hens with radio transmitters and monitored them during the breeding season. Two hundred thirty-five of these hens furnished data reported here. Habitat use, nest site selection, fate of nests, and the rate of renesting were measured. Survival of hens during April-September and survival of young were determined. There was a high negative correlation between nest initiation date and mean April or May temperature. Hens selected nest sites most frequently in grassland and least frequently in cropland, but habitat use compared to availability indicated preference for road right-of-way and odd areas of cover and rejection of cropland. Use of other habitats was in proportion to their availability. Nest success was only 8% during the study. Hen success, a function of nest success and renesting rate, averaged 15% and varied among years because of increased renesting in wet years. In all years, 2-year-old and older hens were twice as successful as first-year nesters. Nesting effort was correlated with water conditions as derived from aerial photographs. April-September survival of hens averaged 80% because predation was heavy when hens were on nests. Only 74% of the hens that hatched a clutch were observed later with at least 1 surviving duckling. On average, hens in the spring population recruited only 0.27 young females to the fall population. Based on this recruitment estimate, published survival estimates and a model previously developed for a closed population, we predict a 20% annual population decline. Nest success of 15% and a resulting hen success of 31% would be required for a stable population. The results suggest that the population on the study area is not maintaining itself but is being supplemented by pioneering birds. A serious recruitment problem has resulted from nest predation. Additional research is needed to determine the geographic extent of the problem. If the problem is widespread, management techniques must be devised to overcome nest destruction, mortality of hens, and mortality of ducklings.

Wildlife Monographs↗
USGS1981

Procedures for the use of aircraft in wildlife biotelemetry studies

This is a report on the state of the art methodology and on questions that arise while one is preparing to use aircraft in a biotelemetry study. In general the first step in preparing to mount an antenna on an aircraft is to consult with a certified aircraft mechanic. Aircraft certification is discussed to provide background information concerning the role of the Federal Aviation Administration (FAA) in regulating the use of biotelemetry antennas on aircraft. However, approval of any specific design of antenna mount rests with local FAA authority. Airplane and helicopter antenna attachments are described. Performance of the receiving antenna system is discussed with emphasis on how variables as aircraft type and antenna configuration may influence reception. The side-looking vs. front-looking antenna configuration and the VHF vs. HF frequency band are generally recommended for most aerial tracking studies. Characteristics of receivers, transmitters, and antennas that might influence tracking are discussed. Specific topics such as calibration of receivers and transmitter quality control are considered. Suggestions in preparing for and conducting tracking flights that will improve overall efficiency and safety are presented. Search techniques, including procedures for conducting large and specific area surveys as well as methods to improve and evaluate search efficiency, are discussed. A concluding section considers special topics such as low-level operations and the use of helicopters. Diagrams of antenna mounts, equipment check-off lists, and antenna test procedures are included as appendices.

Resource Publication↗