Jeff Marr

Submarine slope stability on high-latitude glaciated Svalbard–Barents Sea margin

Abstract Slope stability is evaluated at two locations on high latitude, deep sea fans along the Svalbard–Barents Sea margin, based on available samples and using an “infinite slope” analysis. The stability evaluation uses the Mohr–Coulomb failure criterion, and a semi-analytical approach based on Gibsons formulation for determining the excess pore pressure build-up due to sedimentation. The main results are presented in the form of contour plots of slope safety factors in a diagram with axes of time and thickness of deposit. The results show that during rapid sedimentation, which mostly takes place during periods of maximum glaciation with the ice front located along the shelf edge, slope failure will occur with a frequency varying between 95 and 170 years. Only part of the upper sedimented layer will be mobilised (10–30 m), while the remaining thickness (40–70 m) will remain at the initial sedimentation site. These results may explain why the continental slope is characterised by relatively uniform sediment thickness from upper to lower slope.

Calls of the bald eagle (Haliaeetus leucocephalus)

Injury and mortality statistics suggest that bald eagles entering the air space of wind energy facilities face considerable risk. To mitigate the hazard, acoustic deterrent systems designed to discourage entry into such hazardous air spaces are under consideration. In this study, the acoustic properties of a collection of call types within the eagle vocal repertoire are reported as a first step in a larger program of study designed to assess the deterrent capacity of the bird’s natural vocal utterances. To that end, calls were recorded from bald eagles housed in the Raptor Center at the University of Minnesota. Based on preliminary acoustic analyses, at least five calls were identified and are referred to here as peal/scream, chatter/cackle, snort, squeal and grunt. With the exception of the low frequency grunt, calls were uniformly high pitched, tonal in nature, exhibited harmonic spectral structure, and they were generally complex, exhibiting distinct nonlinear characteristics. In this presentation, the spectrotemporal properties of each call type will be described with the goal of generating an acoustic repository to enable the consistent classification of calls to be tested for their potential as deterrence signals. [This work was supported by Department of Energy grant #DE-EE0007881.]Injury and mortality statistics suggest that bald eagles entering the air space of wind energy facilities face considerable risk. To mitigate the hazard, acoustic deterrent systems designed to discourage entry into such hazardous air spaces are under consideration. In this study, the acoustic properties of a collection of call types within the eagle vocal repertoire are reported as a first step in a larger program of study designed to assess the deterrent capacity of the bird’s natural vocal utterances. To that end, calls were recorded from bald eagles housed in the Raptor Center at the University of Minnesota. Based on preliminary acoustic analyses, at least five calls were identified and are referred to here as peal/scream, chatter/cackle, snort, squeal and grunt. With the exception of the low frequency grunt, calls were uniformly high pitched, tonal in nature, exhibited harmonic spectral structure, and they were generally complex, exhibiting distinct nonlinear characteristics. In this presentation, the...

The auditory attributes of Golden Eagles: Do Golden (Aquila chrysaetos) and Bald Eagles (Haliaeetus leucocephalus) share the same auditory space?

According to the U.S. Fish and Wildlife Service (2018), fatalities associated with wind turbine collisions have been reported for more than 200 bird species. Furthermore, based on statistical models of industry growth it has been suggested that as many as 1.4 million bird fatalities/year could be realized if the Department of Energy (DOE) wind energy goals are achieved; i.e., wind energy supplying 20% of total U.S. energy needs by 2030. Although passerine bird fatalities are most commonly reported, raptors that hunt by day, including bald and golden eagles, are the second most frequent casualties of turbine collisions. To address this concern, deterrence protocols designed to discourage eagles from encroaching into wind energy facility air spaces and thereby constrain the degree of risk to which birds are exposed are under investigation. As part of an effort to guide development of acoustic deterrence protocols, we report that the responsive frequency range of golden eagles is similar to that reported for bald eagles; upper and lower frequency limits of hearing are approximately 6.0 and 0.3 kHz, respectively. Suprathreshold response profiles measured in golden eagles exhibit standard features that will be compared with those of bald eagles. [Work supported by DOE grant #DE-EE0007881.] According to the U.S. Fish and Wildlife Service (2018), fatalities associated with wind turbine collisions have been reported for more than 200 bird species. Furthermore, based on statistical models of industry growth it has been suggested that as many as 1.4 million bird fatalities/year could be realized if the Department of Energy (DOE) wind energy goals are achieved; i.e., wind energy supplying 20% of total U.S. energy needs by 2030. Although passerine bird fatalities are most commonly reported, raptors that hunt by day, including bald and golden eagles, are the second most frequent casualties of turbine collisions. To address this concern, deterrence protocols designed to discourage eagles from encroaching into wind energy facility air spaces and thereby constrain the degree of risk to which birds are exposed are under investigation. As part of an effort to guide development of acoustic deterrence protocols, we report that the responsive frequency range of golden eagles is similar to that reported for...