Teryl Grubb - Academia.edu (original) (raw)

Papers by Teryl Grubb

We used fixed-wing aircraft to survey the entire shoreline and connecting channels of the five Gr... more We used fixed-wing aircraft to survey the entire shoreline and connecting channels of the five Great Lakes to determine potential nesting habitat for bald eagles (Haliaeetus leucocephalus) during 1992. Habitat was classified as either good, marginal, or unsuitable, based on six habitat attributes: (a) tree cover, (b) proximity and (c) type/amount of human disturbance, (d) potential foraging habitat/shoreline irregularity, and suitable trees for (e) perching and (f) nesting. Of the 10,596 km of shoreline surveyed, we classified 7,006 km (66%) as potentially suitable (i.e. either good or marginal) nesting habitat. We evaluated classification accuracy by comparing surveyed habitat suitability with locations of currently active nest sites; 97% of the 117 active nests along the Great Lakes in 1992 were located in suitable habitat, 82% in good habitat. Bald eagle nests occurred more often in good habitat and less often in unsuitable habitat than expected (X 2 > 35.02, 2 df, P < 0.001). Potential nesting habitat existed along the shoreline of all the Great Lakes, but was most abundant along Lakes Huron and Superior and least along Lakes Ontario and Erie. Habitat availability may limit the nesting population of bald eagles along Lake Erie, which has little unoccupied habitat, the most use of marginal habitat, yet the greatest density of nesting eagles in the Great Lakes.

~~STRACT.-~~ determined food habits of Red-tailed Hawks (Buteo jamaicensis) for comparison with p... more ~~STRACT.-~~ determined food habits of Red-tailed Hawks (Buteo jamaicensis) for comparison with published information for Northern Goshawks (Accipiter gentilis) to evaluate potential competition on the Kaibab Plateau, Arizona. We collected prey remains and pellets from 42 Red-tailed Hawk nests at the end of the nesting season between August-October 1998-2001, and opportunistically from below nest trees during site visits, May-July 2000-01. We identified 478 prey items, including 17 mammal, 7 bird, and 2 reptile species. Prey species frequency did not vary among years (P = 0.3), across habitat types (P = O.8), or by collection technique (P = 0.4). Annual food niche breadth for Red-tailed Hawks averaged 0.57. Published mean niche breadth for Northern Goshawks was 0.32, supporting that Red- tailed Hawks were feeding generalists, while Northern Goshawks were more specialized. However, 48% of Red-tailed Hawk diet on the Kaibab Plateau consisted of species comprising a major portion of th...

Chemosphere, 2010

Monitoring of contaminants in the environment is an important part of understanding the fate of e... more Monitoring of contaminants in the environment is an important part of understanding the fate of ecosystems after a chemical insult. Frequently, such monitoring efforts result in datasets with observations below the detection limit (DL) that are reported as ‘non-detect’ or ‘<DL’ and no value is provided. This study explored the effects of non-detect data and their treatment on summary statistics.

A black and white, circuit-board video camera system with night vision was designed to monitor Me... more A black and white, circuit-board video camera system with night vision was designed to monitor Mexican Spotted Owl (Strix ocddentalis lucida) behavior. A 0.5-Lux infrared camera equipped with a 3.3 mm lens permitted vision up to 3 m in total darkness with the aid of six infrared light-emitting diodes (LEDs). To extend nighttime visibility at selected sites to approximately 6

Trends in Levels and Effects of Persistent Toxic Substances in the Great Lakes, 1998

&STRACT.-~~ used pellets collected from roosts to supplement incidental foraging observations to ... more &STRACT.-~~ used pellets collected from roosts to supplement incidental foraging observations to identify prey species of Bald Eagles (Haliaeetus leucoqbhalus) and to evaluate spatial and temporal trends in their food habits while wintering in northern Arizona between 1994-96. We analyzed 1057 pellets collected from 14 roosts, and identified five mammal and 13 bird species. American Coot (Fulica amen'cana, N = 447) and elk/deer ( C m u s eZuflAus/Odocoileus hemnio7zus, N = 412) were the most common prey remains we identified and they varied annually and inversely with each other (11-58% for coots and 21-'78% for elk/ deer). Diving ducks (92%) were more heavily represented in pe1lel;s with identifiable bird prey ( N = 701) than dabblers (I%), although Christmas Bird Counts indicated 64% divers and 36% dabblers in the study area (N = 18 202; x2 = 46.3, df = 1, P < 0.01). Almost all pellets consisted mostly of mammal or bird remains ( N = 366 and 689, respectively). The overall ratio of mammal to bird pelletx was 59:41, with relative class frequencies varying between years (x2 = 118.29, df = 2, P < 0.01). At roosts <3 km from water (N = 752), 90% of the pellets contained birds; whereas, at roosts >3 km from water (N = 303), 96% of the pellets contained mammals (x2 = 698.54, df = 1, P < 0.01). In three successive winters of varying weather conditions, wintering eagles foraged primarily on mammals, fish, and waterfowl, respectively; but only mammals and waterfowl were accurately represented in pellets.

Bayesian inference facilitated structured interpretation of a nonreplicated, experience-basedsurv... more Bayesian inference facilitated structured interpretation of a nonreplicated, experience-basedsurvey of potential nesting habitat for bald eagles,(Haliaeetus leucocephalus) along the five Great Lakes shorelines. We developed apattern recognition (PATREC) model of our aerial search image with six habitat attributes: (a) tree cover, (b) proximity and (c) type/amount of human disturbance, (d) potential foraging habitat/shoreline irregularity, and suit- able trees for (e) perching and (f) nesting. Tree cover greater than 10 percent, human disturbance more than 0.8 km away, a ratio of total to linear shoreline distance greater than 2.0, and suitable perch and nest trees were pre- requisite for good,eagle habitat (having sufficient physical attributes for bald eagle nesting). The estimated,prob - ability of good habitat was high (96 percent) when all attributes were optimal, and nonexistent (0 percent) when none,of the model,attributes were,present. Of the 117 active bald eagle nests along...

Wildlife Society Bulletin, 2002

... watercraft will be predicted correctly 2 times out of 3. Key words bald eagle, CART modeling,... more ... watercraft will be predicted correctly 2 times out of 3. Key words bald eagle, CART modeling, Haliaeetus leucocephalus, human disturbance, nesting, recreation impacts, watercraft In a review of the effects of human recreation on ...

Journal of …, 1997

We analyzed 3122 observations of military jets, light planes and helicopters for three levels of ... more We analyzed 3122 observations of military jets, light planes and helicopters for three levels of response (none, alert, flight) by breeding Bald Eagles (Haliaeetus leucocephalus) at 13 occupied nests in Arizona and six in Michigan, 1983-85 and 1989-90, respectively. Helicopters elicited the greatest frequency of response (47%), followed by jets (31%) and light planes (26%). Frequency of response (23-61%) and

The Journal of Wildlife Management, 1999

Journal of Wildlife Management, 2010

permit renewal for heli-skiing in the Tri-Canyon Area (TCA) of the Wasatch Mountains, Utah, USA, ... more permit renewal for heli-skiing in the Tri-Canyon Area (TCA) of the Wasatch Mountains, Utah, USA, we recorded 303 helicopter passes between 0 m and 3,000 m (horizontal distance) near L 30 individual golden eagles (Aquila chrysaetos) in 22 nesting territories, through passive observation and active experimentation with civilian and military (Apache AH-64) helicopters. Flight profiles included 800-m, 400-m, 200-m, and 100-m flybys (horizontal distance from cliff nest on parallel course), as well as approaches and popouts where helicopters flew toward, or popped out from behind, adult-occupied cliff nests (0 m, horizontal distance). Between 1981 and 2007, during the only 8 years when nesting in the TCA was confirmed by presence of chicks, WPG annually flew 108-2,836 helicopter flights in the same drainages on 10-37 days between 15 December and 15 April, with no effect on early courtship, nest repair, or subsequent nesting success. Total WPG operating days (x 5 62.4) and helicopter hours (x 5 210.6) fluctuated annually but did not increase 1974-2007 (Cox-Stuart trend test, P 5 0.371, 0.393, respectively). Apache helicopter testing (227 passes) did not reduce golden eagle nesting success or productivity rates within the same year (t 111, 96 5 0.495, 0.782, P 5 0.622, 0.436, respectively), or rates of renewed nesting activity the following year, compared with 81-101 non-manipulated nesting territories. We recorded no response during 66% and only watching during 30% of Apache passes at 0-800 m from nesting golden eagles. No other reactions occurred until after hatching when M 4 golden eagles accounted for 5 flatten and 3 fly behaviors at 3 nest sites. No responding pairs failed to fledge young because of testing. Limited fly responses suggested helicopters only precipitated an imminent departure, rather than causing startled, avoidance reactions. Responsiveness between test weeks 1 and 2 decreased (x 2 2 5 32.167, P M 0.001). Apache helicopters were twice as loud as WPG helicopters at comparable distances. Sound decreased with distance, most rapidly when flights were perpendicular to cliffs or ridges. Eagle ambient behaviors and watching the helicopter occurred randomly throughout recorded sound levels during helicopter testing (76.7-108.8 decibels, unweighted). Much helicopter sound energy is below golden eagles' auditory threshold, thus reducing potential impacts. Neither our observations nor our testing indicated special management restrictions are required for helicopters flying near nesting golden eagles in northern Utah. Our results underscore the necessity for circumstance-specific research, as well as enlightened resource management to accommodate unexpected results.

The Journal of Wildlife Management, 1997

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, a... more JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. . Wiley and Wildlife Society are collaborating with JSTOR to digitize, preserve and extend access to The Journal of Wildlife Management. Abstract: We analyzed variation in canopy closure around 47 Mexican spotted owl (Strix occidentalis lucida) nest sites and 47 random forest sites on the Coconino National Forest in northcentral Arizona. We mapped distinct habitat polygons on 1:15,840 color aerial photographs, assigned each polygon to one of 4 canopy-closure classes (<10, 10-40, 41-70, or >70%), and measured the area in each canopy class within 5 concentric analysis zones with radii of . Landscape composition differed between spotted owl nest and random sites (P < 0.001). Differences were greatest within 0.4 km of nest and random sites but persisted across all analyses zones. Nest sites contained more area in the >70% canopy-closure class and less area in the < 10% class. The most abundant canopy class was 41-70%, except within 0.1 km of nests, where >70% canopy predominated. Nesting spotted owls selected areas with denser canopy than randomly available forest landscapes, but outside the immediate nest area (>0.8 km) canopy closure approached that of the surrounding forest.

The Journal of Wildlife Management, 2013

We recorded 94 sound-response events at 3 adult-occupied northern goshawk (Accipiter gentilis) ne... more We recorded 94 sound-response events at 3 adult-occupied northern goshawk (Accipiter gentilis) nests 78 m, 143 m, and 167 m from the nearest United States Forest Service maintenance level 3, improved gravel road on the Kaibab Plateau in northern Arizona. During 4 test sessions on 7, 8, 10, and 11 June 2010, we recorded 60 experimentally controlled logging trucks; 30 non-experimental, civilian, fixedwinged aircraft; 3 non-experimental, passing cars; and 1 all-terrain vehicle (ATV). Logging truck sound, principally engine and exhaust, was concentrated in the 63 Hz and 80 Hz, 1/3-octave frequency bands. Aircraft sound was concentrated in the 100 Hz and 125 Hz, 1/3-octave frequency bands. Logging truck noise levels varied among nest sites and with distance from roads. At 167 m from the closest road, the logging truck averaged approximately 8 decibels (dB, all decibel levels C-weighted, adjusted, 1 s, equivalent sound level, CLEQ) quieter than aircraft. At 143 m, the logging truck was approximately 3 dB quieter than passing aircraft. Only at 78 m was logging truck noise louder on average than aircraft, by approximately 6 dB. Average aircraft noise levels for each day of testing ranged between 45.6 dB and 67.9 dB and when averaged across the entire study period, varied little among the 3 test sites, 60.1-65.6 dB. On average, our test logging truck (61.9 dB) was no louder than passing aircraft (62.3 dB), which goshawks generally ignored. The logging truck resulted in 27% no response and 73% alert (head turning) response, passing aircraft resulted in 90% no response and only 10% alert response, and the cars and ATV combined resulted in 50% each for no response and alert response. Goshawk alert response rates were inversely proportional to nest distance from the nearest road, decreasing from 91% to 57% alert between 78 m and 167 m. No movements or flushes were associated with either our experimental testing or passive recording of other vehicular noise stimuli. All tested pairs of goshawks successfully fledged young. Because logging truck noise had no effect on northern goshawks nesting along level 3, improved gravel roads on the Kaibab Plateau, restriction of log hauling and other roadbased travel activities on similar roads within post-fledging family areas (PFAs) appears unnecessary based on the type and extent of our testing. Ó 2013 The Wildlife Society.

Journal of Wildlife Management, 2004

We investigated habitat association of sympatric red-tailed hawks (Buteo jamaicensis) and norther... more We investigated habitat association of sympatric red-tailed hawks (Buteo jamaicensis) and northern goshawks (Accipiter gentilis) at 2 spatial scales centered on nest sites: (1) fine-scale patterns of forest structure and topography within 16-m radius circles (0.08 ha), and (2) midscale patterns of forested and nonforested areas, forest fragmentation, and topography within 2,085-m-radius circles (1,367 ha). Nonforested areas were defined as any area lacking >20% canopy closure within a 30 × 30-m cell. At both scales, red-tailed hawk associations were more variable and goshawk associations less variable. At the fine scale, goshawks were consistently associated with open understories, tall trees, and gentle slopes (x -= 9.6°, SD = 6.9) while red-tailed hawks were associated, on average, with steep, north-facing slopes (x -= 17.4°, SD = 8.1) and dense understories. At the midscale, goshawks were consistently associated with patches of continuous forest and level terrain within 645 m of nest sites. Red-tailed hawks were associated with nonforested areas located within 105-645 m of nest sites and steep slopes within 105 m of nest sites. Forest fragmentation was greater around red-tailed hawk nest sites, and forested regions were more aggregated around goshawk nest sites when compared with the other species. These patterns indicate that on the Kaibab Plateau, red-tailed hawks will gain habitat at the midscale and goshawks will lose habitat at both scales if forests are fragmented and mature forest structure is lost.

Journal of Wildlife Management, 2009

Research to determine noise impacts on animals benefits from methodology that adequately describe... more Research to determine noise impacts on animals benefits from methodology that adequately describes the acoustical stimulus as well as the resulting biological responses. We present acoustical considerations and research techniques that we have found to be useful. These include acoustical definitions and noise measurement techniques that conform to standardized acoustical practice and advice for controlled experimentation to supplement behavioral observation. Specific considerations include characteristics of noise stimulus, selection of noise metrics, use of frequency-weighting algorithms tailored to a specific animal species, selection and placement of noise measurement equipment, and methods for documenting animal responses. We also present arguments for measuring the noise stimulus at the location and time of each response observation. Our purpose is to recommend some baseline terminology, metrics, and techniques prerequisite to effective assessment of noise impacts on terrestrial wildlife whenever and wherever potential conflicts arise. ( JOURNAL OF WILDLIFE MANAGEMENT 73 : 788-795; 2009)

The Journal of the Acoustical Society of America, 1995

Page 1. 9:35 4aAB4. The neural mechanism for directional escape in the goldfish. Robert C. Eaton,... more Page 1. 9:35 4aAB4. The neural mechanism for directional escape in the goldfish. Robert C. Eaton, Audrey L. Guzik, and Janet L. Casagrand (Ctr. for Neurosci., EPO Box 334, Univ. of Colorado, Boulder, CO 80309) In response ...

The Journal of the Acoustical Society of America, 1996

The Journal of the Acoustical Society of America, 1999