James W. Grier

Differential effects of coyotes and red foxes on duck nest success

Low recruitment rates prevail among ducks in the Prairie Pothole Region of North America, primarily because of high nest depredation rates. The red fox (Vulpes vulpes) is a major predator of duck eggs, but fox abundance is depressed by coyotes (Canis latrans). We tested the hypothesis that nest success of upland-nesting ducks is higher in areas with coyotes than in areas with red foxes. We conducted the study during 1990-92 in uplands of 36 areas managed for nesting ducks in North Dakota and South Dakota. Overall nest succes averaged 32% (95% CI = 25-40) on 17 study areas where coyotes were the principal canid and 17% (CI = 11-25) on 13 study areas where red foxes were the principal canid (P = 0.01). Both canids were common on 6 other areas, where nest success averaged 25% (CI = 13-47). Habitat composition, predator communities with the exception of canids, and species composition of duck nests in coyote and red fox areas were similar overall. Upon examining only nests with ≥6 eggs on the last visit prior to hatch or depredation, we determined nests with evidence characteristic of fox predation accounted for 4% of depredated nests in coyote areas and 27% in fox areas (P = 0.001). An expanding coyote population is contributing to higher overall nest success. Management of coyotes may be an effective method for increasing duck nest success

Animal population dynamics

Counting methods evolution and population dynamics the numerical analysis of population change the natural limitation of animal numbers the natural history of numbers decision-making time, space and chance.

Occurrence of the Upper Cretaceous ammonite Rhaeboceras in the Baculites eliasi Zone of the Pierre Shale

The discovery of a specimen of Rhaeboceras coloradoense Cobban, 1987, in the Baculites eliasi zone in east-central Montana is significant for three reasons: 1) it is the most geologically recent occurrence of Rhaeboceras ; 2) it connects more closely than previous specimens the lineage between the genus Rhaeboceras Meek and Ponteixites Warren, its apparent smaller descendant; and 3) it significantly extends the geographical range of the species.

New findings of the ammonite Rhaeboceras, including a new species, from the Pierre Shale of eastern Montana

A third known specimen of the ammonite Rhaeboceras burkholderi Cobban, 1987, has been discovered in the upper part of the Pierre Shale of early Maastrichtian age (Late Cretaceous) Baculites eliasi zone of Dawson County, Montana. This finding extends both the geographical and stratigraphic ranges of the species. In addition, R. cedarense new species is described from the Baculites baculus/grandis zone of the same region, which extends the stratigraphic range of the genus as currently recognized. The new species is a small form of Rhaeboceras that appears to be closely related to and probably descended from R. burkholderi.

Quadrat Sampling of a Nesting Population of Bald Eagles

An aerial stratified random sample survey of nesting bald eagles (Haliaeetus leucocephalus) was conducted during 1974 on 173,900 km2 of northwestern Ontario and southeastern Manitoba, Canada. I sampled less than the total (target) area to reduce cost and to avoid a search bias in areas previously visited. Fifty-three 100 km2 quadrats provided estimates of 428 ? 158 (37% ) eagles, excluding nestlings, and 291 ? 88 (30%) breeding areas for the sampled area and 579 ? 165 breeding areas for the entire area. Stratification reduced the variance of the means by roughly 22 percent for breeding areas in the entire area. A real visibility bias requires rigorously standardized techniques and, unless measured, limits the usefulness of estimates of actual numbers. The techniques should be feasible for a larger region and repeated sampling would provide a measure of trends in the status of this species of eagle. J. WILDL. MANAGE. 41(3):438-443 Claims that bald eagle populations have declined or not are based largely on reproductive information (Braun et al. 1975, Broley 1958, Gerrard 1973, Grier 1974, Laycock 1973, Sprunt 1966, 1969, Sprunt et al. 1973, U.S. Dept. of Interior 1974). The lack of simultaneous information on age-specific mortality and age of first breeding precludes the modeling of bald eagle population dynamics (Brown 1974, Brown and Cade 1972, Henny et al. 1970, Mertz 1971, Whitfield et al. 1974, Young 1968). Lack of adequate census data also hinders the determination of population status based upon changes in numbers of individuals. Counts of eagles on wintering areas (Fawks 1961 plus yearly updates, Hancock 1974, Higby 1975, Lint 1975, Southern 1963, 1964, Wrakestraw 1973) or during migrations (McClelland 1973, Spofford 1969, U.S. Dept. of Interior 1971) are of limited value because they reflect annual variations in weather and food availability. Furthermore, it is difficult to ascertain the source of eagles observed on migration or wintering areas. The National Audubon Society, U.S. Fish and Wildlife Service, and others have attempted to determine the total number of nesting bald eagles in the 48 contiguous states (Braun et al. 1975, Laycock 1973, Sprunt 1966, U.S. Dept. of Interior 1974). The majority of nesting birds, however, are found in Alaska and Canada, where only scattered attempts have been made to assess the eagle populations (Davis 1966, Gerrard 1973, Gerrard and Whitfield 1967, Grier 1967, 1969, King et al. 1972, Mansell 1965, Whitfield et al. 1974). All that is clear from the numbers of birds seen nesting in Alaska and Canada, and on wintering areas in the contiguous United States is that the present population of bald agles in North America must be relatively larg (Braun et al. 1975). Reliable censuses are needed to determine the status of the continental breeding population for management purposes. King et al. (1972) conducted a quadrat sample survey of bald eagles in southeastern Alaska. In searching for a technique to gain information on bald eagle numbers in Canadas boreal forest, in northwestern Ontario and southeastern Manitoba, I conducted a similar survey during 1974. The results of that survey as reported herein were encouraging and, with some modification, the techniques can provide useful trend information in future years. This research was supported by the Canadian Wildlife Service, Eastern Region, Project No. 6145/74-75. R. Buckler was my field assistant and pilot; without his valuable help the project would not have been con438 J. Wildl. Manage. 41(3):1977 This content downloaded from 207.46.13.112 on Mon, 03 Oct 2016 05:01:18 UTC All use subject to http://about.jstor.org/terms SAMPLING NESTING BALD EAGLES * Grier 439 Table 1. Classification and distribution of quadrats in the study area. Eleven quadrats with much human activity (towns, mines) and considered unsuitable for eagles were excluded

New System for Digital to Analog Transformation and Reconstruction of 12-Lead ECGs

Introduction We describe initial validation of a new system for digital to analog conversion (DAC) and reconstruction of 12-lead ECGs. The system utilizes an open and optimized software format with a commensurately optimized DAC hardware configuration to accurately reproduce, from digital files, the original analog electrocardiographic signals of previously instrumented patients. By doing so, the system also ultimately allows for transmission of data collected on one manufacturers 12-lead ECG hardware/software into that of any other. Materials and Methods To initially validate the system, we compared original and post-DAC re-digitized 12-lead ECG data files (∼5-minutes long) in two types of validation studies in 10 patients. The first type quantitatively compared the total waveform voltage differences between the original and re-digitized data while the second type qualitatively compared the automated electrocardiographic diagnostic statements generated by the original versus re-digitized data. Results The grand-averaged difference in root mean squared voltage between the original and re-digitized data was 20.8 µV per channel when re-digitization involved the same manufacturers analog to digital converter (ADC) as the original digitization, and 28.4 µV per channel when it involved a different manufacturers ADC. Automated diagnostic statements generated by the original versus reconstructed data did not differ when using the diagnostic algorithm from the same manufacturer on whose device the original data were collected, and differed only slightly for just 1 of 10 patients when using a third-party diagnostic algorithm throughout. Conclusion Original analog 12-lead ECG signals can be reconstructed from digital data files with accuracy sufficient for clinical use. Such reconstructions can readily enable automated second opinions for difficult-to-interpret 12-lead ECGs, either locally or remotely through the use of dedicated or cloud-based servers.

Genetic Variation and Nesting Bald Eagles

As habitats become fragmented, once-contiguous populations may be spatially isolated and reduced in size. In addition, new populations may arise through dispersal and colonization. When this occurs, the founding population is often small and there is a reduced chance that the founding individuals represent the full genetic compliment found in the parent population. Resulting populations may be characterized by reduced heterozygosity and allelic diversity. We assessed genetic variation in two nesting populations of Bald Eagles (Haliaeetus leucocephalus): a small isolated one in Colorado and a large contiguous one in Ontario, Canada. We predicted that the Colorado population would have reduced heterozygosity and allelic diversity when compared with the Ontario population.

An Inexpensive Apparatus for Time-Lapse Photography

The object of time-lapse photography is to take fewer pictures than 16 frames per second and then project the film at regular speed. This results in motion appearing faster than it actually was recorded. Such a method of photography can be carried out with a movie camera which will take one frame at a time. The purpose of this paper is to present construction plans of a device which will trip the camera shutter at timed intervals. With a little time and effort the results obtained are satisfying and yet inexpensive. Three principal parts of the apparatus are: timer; light control mechanism, and camera tripping device (Fig. 1). The light control and tripping device depend on the timer and do not operate simultaneously; i.e., the camera shutter is tripped after the lights are on. The apparatus operates by the following sequence: the clock completes the relay circuit, the relay turns off all lights except the floodlights which are turned on, the floodlights activate the photoelectric relay, the relay completes the solenoid circuit, and the solenoid trips the camera shutter. One picture is taken and the next will not be taken until the clock again closes the relay circuit. The timing mechanism consists of a 6 volt relay using an electric clock to complete or break the circuit (Fig. 2). This is done by running one side of the 6 volt circuit through the clock proper and through one of the hands which makes contact with the other side of the circuit. The clock, the lights, the photoelectric relay, and the solenoid require 110-volt current and are connected by a common line. The switching part of the relay and the lights make up the light control mechanism. The relay will complete one circuit at the same time that it breaks another. The photo floodlights are on one of the circuits. The other circuit is used to operate lights not involved in the actual picture taking; for example, lights used for growing plants and room lights. The advantage of two separate