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Aspects of the ecology of the common raven in Harney Basin, OregonStiehl, Richard B. 01 January 1978 (has links)
Common Ravens (Corvus corax L.) have been implicated as significant predators on the eggs of waterfowl and shorebirds on Malheur National Wildlife Refuge. Malheur Refuge, located in southeastern Oregon on the northern edge of the Great Basin, is one of the largest waterfowl refuges in the United States and is an important breeding area for waterfowl. In order to provide fundamental information on which a sound raven management plan could be based, research was conducted from 1975-1977 on aspects of population density, brood phenology, nesting success, seasonal use of the study area, roosting behavior, and food habits of ravens on and near the refuge. Nesting density was determined to be one pair per approximately 25 km2 . Most nests occurred in rimrocks, but trees and abandoned human structures were also used. Investigation of 87 nests revealed that the incubation period was 21 + 1 days. Incubation began with the laying of the first egg; hatching was asynchronous. Nesting period was 41 + 3 days. An original method of age-classing ravens is described. A total of 266 ravens was marked with patagial tags. Observation of marked individuals as far as 480 km from the study area suggests considerable mobility in the population. Population numbers vary seasonally, peaking in the winter. The Harney Basin is the location of an exceptionally large winter roost for ravens. Analysis of food remains, collected from 34 nests, indicates that ravens have varied diets and that there are significant differences in the diets of ravens nesting in different habitats. A correlation exists between the proportion of the diet that is avian material and the proximity of the raven nest to waterfowl production areas. Based on these findings, suggestions are offered for a management plan for Common Ravens on Malheur National Wildlife Refuge.
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Avian Affairs: A Study of the Occurrence and Benefits of Extra-pair Breeding Behavior in Eastern Kingbirds (Tyrannus Tyrannus)Dolan, Amy Catherine 01 June 2006 (has links)
Over three consecutive breeding seasons I examined the breeding system of Eastern Kingbirds in Malheur National Wildlife Refuge in SE, Oregon. To assess genetic paternity, I optimized seven microsatellite markers and determined that extra pair paternity was common. Extra-pair young were present in approximately 60% of nests, representing 47% of young. I examined implications of extra-pair paternity from three perspectives.
First, I examined the impact of extra-pair paternity on the opportunity for sexual selection within a socially monogamous system and identified correlates of male reproductive success. Some males were successful at the expense of others, and 24% of males did not sire any young. Thus, variance in male reproductive success was more than nine times greater than female variance, indicating that sexual selection operates strongly in this system. Extra-pair success was positively related to tarsus length and inversely dependent upon dawn song start time. Within-pair success was positively related to nest defense intensity during the incubation period.
Second, I assessed the four genetic hypotheses proposed to explain female cooperation in extra-pair copulations. Extra-pair young were not distributed randomly among broods. Cuckolded within-pair males were not more closely related to females than were extra-pair sires. Pair wise comparisons indicated males with specific song and morphological traits were chosen as sires. Brood success (proportion of brood to fledge and recruit) was unrelated to thenumber of males who sired young in the brood. Extra-pair young were larger and heavier than their within-pair half-siblings. These results unambiguously support the 'good genes' hypothesis of female extra-pair mating.
Last, I examined the influence of breeding date and parental condition (mother, social father and genetic sire) on offspring sex ratio. Given that male variance in reproductive success is much greater than that of females, I predicted the characters of genetic sires would be the most important factor influencing offspring sex ratio. Contrary to my prediction, male traits did not influence offspring sex ratio. However, more males hatched early in the season and females in better condition produced more sons. I also found that male nestling survival to the next breeding season was inversely related to date.
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Determination of the value to planners of incorporating ecotourist needs data in the interpretive planning processMasberg, Barbara Ann 15 October 1992 (has links)
The purpose of this study was to answer the following question: What was the
perceived value to planners of incorporating information from ecotourists about their
perceived needs in the standard system presently being used to plan interpretation?
The Ecotourist Needs Assessment (ETNA) process was proposed as an external needs
assessment. To exemplify this process, an instrument called Ecotourist Needs Assessment
Instrument (ETNAI) was developed to collect input from ecotourists who visited
the Malheur National Wildlife Refuge. A case resulted from the process. The
ETNAI case was used to obtain planners' opinions about whether ETNA had value in
the context of data collection and inventory in interpretive planning.
The ETNAI case included developing and validating the ETNAI and
providing a procedure for implementing ETNAI. Upon completion of the ETNAI
case, an interview guide was developed and administered to interpretive planners.
Interpretive planners were asked how they currently plan interpretation and collect
information to decide interpretive topics. Other questions dealt with their feelings
regarding the usefulness of the ETNA and the data collected using the ETNA.
The interpretive planners described the current system and provided
information about the proposed system (ETNA). Currently, decisions involving
interpretation are based on three factors: 1) money, 2) mandates/missions, and/or 3)
management. The interpretive planner chose outside (external) groups except during
a master planning process when the general public provided input. The outside
groups included: professionals, the public, and recreation providers. The current
methods used to collect information were informal or considered casual. When
contrasted with the proposed method, the interpretive planners felt the ETNA had
value. This was reflected in their suggestions for use:
As an evaluation tool after an interpretive program is given to a specific
audience.
As a method to assess the interpretive needs of visitors and specific
audiences for interpretation.
As a technique to access visitors and the public, both general and
specific.
As a mechanism to collect data at public meetings.
As a systematic routine to develop interpretation, to provide feedback
for further development, and to evaluate interpretation embedded in the
site system.
As a method to effectively determine the distribution of funds. / Graduation date: 1993
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