Ornithology Commons^™

Low Activities Of Digestive Enzymes In The Guts Of Herbivorous Grouse (Aves: Tetraoninae), Jennifer Sorensen Forbey

Biology Faculty Publications and Presentations

Avian herbivores face the exceptional challenge of digesting recalcitrant plant material while under the selective pressure to reduce gut mass as an adaptation for fight. One mechanism by which avian herbivores may overcome this challenge is to maintain high activities of intestinal enzymes that facilitate the digestion and absorption of nutrients. However, previous studies in herbivorous animals provide equivocal evidence as to how activities of digestive enzymes may be adapted to herbivorous diets. For example, “rate-maximizing” herbivores generally exhibit rapid digesta transit times and high activities of digestive enzymes. Conversely, “yield-maximizing” herbivores utilize long gut retention times and express lower …

Long‐Distance Natal Dispersal Is Relatively Frequent And Correlated With Environmental Factors In A Widespread Raptor, Hanna M. Mccaslin, T. Trevor Caughlin, Julie A. Heath

Biology Faculty Publications and Presentations

1. Dispersal is a critical process influencing population dynamics and responses to global change. Long‐distance dispersal (LDD) can be especially important for gene flow and adaptability, although little is known about the factors influencing LDD because studying large‐scale movements is challenging and LDD tends to be observed less frequently than shorter‐distance dispersal (SDD).
2. We sought to understand patterns of natal dispersal at a large scale, specifically aiming to understand the relative frequency of LDD compared to SDD and correlates of dispersal distances.
3. We used bird banding and encounter data for American kestrels (Falco sparverius) to investigate the effects of …

Prevalence Of Anticoagulant Rodenticides In Ferruginous Hawk Nestlings And Evaluation Of A Novel Method To Rapidly Assess Exposure, Ariana Joyce Dickson

Boise State University Theses and Dissertations

Anticoagulant rodenticides (ARs) are compounds commonly used to control rodent pests by inhibiting an enzyme critical for synthesis of clotting factors in their blood. Secondary and tertiary poisoning of non-target species frequently occur, especially of predators that consume rodents, including many species of raptors. Although raptor exposure to ARs has been documented on at least three continents, patterns, pathways and the sub-lethal effects of exposure are not well studied. This has created a substantial need to monitor the effects of ARs in free-living populations. I evaluated the prevalence of secondary, non-target exposure to anticoagulant rodenticides experienced by a predatory raptor, …

Movements Of White-Headed And White-Backed Vultures, Teague K. Scott

Boise State University Theses and Dissertations

Vultures are the only obligate vertebrate scavengers, and as such provide crucial services as keystone species and support the health and function of ecosystems in which they live. African vultures are a diverse group, with nine species found throughout Sub-Saharan Africa, many with overlapping distributions. Unfortunately, African vultures are faced with numerous threats throughout their range that have led to significant population declines, some greater than 90%, in only three generations. Four of these species are currently listed as critically endangered, and three as endangered.

Despite the significant perils faced by African vultures, there are still significant knowledge gaps and, …

How Water Level And Irrigation Practices Affect Waterbird Community, Nesting, And Foraging Habitat Use On The Duck Valley Indian Reservation, Jamie L. Burke

Boise State University Theses and Dissertations

Loss of habitat continues to threaten all bird populations. Despite efforts for conservation of wetlands, waterbirds continue to face habitat threats especially in western North America where water resources are limited across the landscape. The White-faced Ibis (Plegadis chihi) is a colonial nesting waterbird of conservation concern that builds nests in emergent vegetation of freshwater wetlands throughout the western United States. An ibis breeding colony site located at the Blue Creek Wetland complex on Duck Valley Indian Reservation may face habitat threats in the future due to plans intended to increase irrigation water use efficiency. Plans include manipulation …

Old Enemies With New Problems?: Investigating The Ecological Relationship Between Ridgway’S Hawk And The Parasitic Nest Fly Philornis Pici, Christine Deegear Hayes

Boise State University Theses and Dissertations

Modern conservation efforts tend not to focus on individual species, but rather on the entire ecosystem of a species in peril. Many ecological factors can affect a species’ ability to maintain healthy populations. Parasites, which derive nutrients at the expense of their hosts, can reduce host fitness and limit population growth, acting as biological controls in healthy ecosystems. The negative impacts of parasites on their hosts can be exacerbated by climate change and anthropogenic land-use practices in ways that may limit recovery or drive host species to extinction. Introduced parasitic nest flies in the genus Philornis (Diptera: Muscidae) are threatening …

Long-Billed Curlew Nest Site Selection And Success In The Intermountain West, Stephanie E. Coates, Benjamin W. Wright, Jay D. Carlisle

Intermountain Bird Observatory Publications and Presentations

Grassland birds have experienced steeper population declines between 1966 and 2015 than any other bird group on the North American continent, and migratory grassland birds may face threats in all stages of their annual cycle. The grassland‐associated long‐billed curlew (Numenius americanus) is experiencing population declines in regional and local portions of their North American breeding range. The nesting period is an important portion of the annual cycle when curlews may face demographic rate limitations from a suite of threats including predators and anthropogenic disturbance. We compared nest sites to random sites within breeding territories to examine nest site …

Using Motion-Activated Trail Cameras To Study Diet And Productivity Of Cliff-Nesting Golden Eagles, Jordan T. Harrison, Michael N. Kochert, Benjamin P. Pauli, Julie A. Heath

Raptor Research Center Publications and Presentations

Studies of cliff-nesting raptors can be challenging because direct observations of nest contents are difficult. Our goals were to develop a protocol for installing motion-activated trail cameras at Golden Eagle (Aquila chrysaetos) nests to record diet information and productivity, and to estimate prey detection probability using different diet study methods. In 2014 and 2015, we installed cameras at 12 Golden Eagle nests with 18–42-d-old nestlings. Following installation, we monitored adult behavior using direct observation and post-installation image review. At two nests, adult eagles did not return to nests or exhibited behaviors suggesting avoidance of the cameras, but returned …

Sex Determination By Morphological Measurements Of Young Rockhopper Penguins (Eudyptes Chrysocome) During The Crèche Phase, Virginia Morandini, Miguel Ferrer, Lynelle Perry, Marc Bechard

Raptor Research Center Publications and Presentations

To provide an easy and reliable work tool to identify the sex of Rockhopper Penguin (Eudyptes chrysocome) chicks, we weighed and measured 95 nestlings in the crèche phase during 24-31 January 2017 on the Falkland Islands, Argentina. Sex was subsequently determined using DNA analyses of blood from the same individuals. Significant differences were found in bill length (exposed culmen), bill depth and width, flipper length, and diagonal tarsus, but stepwise discriminant analysis showed bill length to be the best predictor for sex determination. Our model correctly classified 82.7% of males and 90.2% of females (overall correct classification 86.2%). …

Flushing Responses Of Golden Eagles (Aquila Chrysaetos) In Response To Recreation, Robert J. Spaul, Julie A. Heath

Biology Faculty Publications and Presentations

Disturbance because of human activity, including recreation on wildlands, can affect bird behavior which in turn can reduce breeding success, an important consideration for species of management concern. We observed Golden Eagles (Aquila chysaetos) during the breeding season to determine whether the probability of flushing was affected by the type of recreationist, distance to encounter, eagle nest attendance, or date. We monitored eagles in 23 nesting territories from distant (600-1,200 m) observation points and recorded recreation activity within 1,200 m of eagles in the Owyhee Front of southwestern Idaho. In most (86%, n = 270) encounters, eagles did …

Barn Owls (Tyto Alba) Crossing The Road - Examining The Interplay Among Occupancy, Behavior, Habitat Selection, And Roadway Mortality In Southern Idaho, Tempe Regan

Boise State University Theses and Dissertations

Barn Owls (Tyto alba) are killed by vehicle collisions in greater numbers than any other North American bird of prey. Interstate-84 (I-84) in southern Idaho, USA has among the world’s highest known rates of Barn Owl-vehicle collisions. Little is known about Barn Owl occupancy in this region, so it is unclear if owls are killed in proportion to their abundance, or if they are equally abundant in segments with lower mortality and somehow escape collisions. Furthermore, studies of Barn Owl movements and behavior are limited. I was interested in understanding (1) factors that affect Barn Owl occupancy in …

Earlier Nesting By A Predatory Bird Is Associated With Human Adaptations To Climate Change, Shawn Heath Smith

Boise State University Theses and Dissertations

Advancing growing seasons and prey abundance drive earlier breeding in dietary specialists because, ultimately, consumers benefit by timing their reproduction to coincide with peak prey abundance. The selective pressure to breed earlier may be lower for species that forage on diverse prey items that vary in abundance both spatially and temporally. The selective pressure may be reduced further if predators have access to a mosaic of habitats, each of which having different shifts in growing seasons. We studied whether earlier breeding of a predatory generalist, the American kestrel (Falco sparverius) nesting in a mosaic of habitat types was …

Pheomelanin Pigment Is Not An Indicator Of Feather Corticosterone Content In Diurnal Migratory Raptors In Idaho, Christopher Porterfield

Boise State University Theses and Dissertations

In some cases, pigmentation can be used as an indicator of measures of condition. In this study, I tested the relationship between reddish pheomelanin pigmentation and the amount of corticosterone, a hormone associated with stress, sequestered in the feathers. I predicted that with higher corticosterone in feathers individuals would exhibit increased brightness and reduced saturation of pheomelanin pigments in their feathers. I collected spectral data from feathers from American Kestrels (Falco sparverius), Cooper’s Hawks (Accipiter cooperii), and Sharp-shinned Hawks (A. striatus) during migration in southwestern Idaho over two years (2010-2011). After extracting corticosterone from …

Wintering Bald Eagle Count Trends In The Conterminous United States, 1986-2010, Wade L. Eakle, Laura Bond, Mark R. Fuller, Richard A. Fischer, Karen Steenhof

Biomedical Research Institute Publications and Presentations

We analyzed counts from the annual Midwinter Bald Eagle Survey to examine state, regional, and national trends in counts of wintering Bald Eagles (Haliaeetus leucocephalus) within the conterminous 48 United States from 1986 to 2010. Using hierarchical mixed model methods, we report trends in counts from 11 729 surveys along 844 routes in 44 states. Nationwide Bald Eagle counts increased 0.6% per yr over the 25-yr period, compared to an estimate of 1.9% per yr from 1986 to 2000. Trend estimates for Bald Eagles were significant (P ≤ 0.05) and positive in the northeastern and northwestern U.S. …

Barn Owl Sex Determination, Lillian Mckinley

College of Arts and Sciences Presentations

The goal of the study is to develop this model of sex determination in Barn Owls. The sex of birds of prey is usually determined using one of two methods: plumage or size. Plumage is often the most obvious way to tell the difference between male and female birds, because male birds often have bright and colorful plumage and female birds generally have drab and dull colored plumage. In species that do not have plumage variation, size difference is used for sex determination. The most common measurement of size is body mass, but other measurements can also be used including: …

See No, Smell No, Taste No Evil: How Sage-Grouse Detect Toxic Sagebrush, K. Gehlken, B. Robb, S. Agafonov, J. Forbey

College of Arts and Sciences Poster Presentations

There is increasing evidence that sage-grouse selectively consume individual and species of sagebrush that have the lowest concentrations of chemical defenses, or toxins. We propose that this selection requires the ability to see, smell or taste specific chemicals or groups of chemicals that vary quantitatively and qualitatively in sagebrush available throughout the winter range of sage-grouse. We are developing methods to determine if and how selected and avoided sagebrush may differ in color, smell and taste. We used ultraviolet and near infrared detectors to determine the variation in the "color" of phenolics in sagebrush. We used gas chromatography to determine …

Yolk Androgens And Development In American Kestrel Nestlings, Melanie Dawn Berg

Boise State University Theses and Dissertations

Maternally derived yolk androgens affect many aspects of phenotypic development. To explore this phenomenon I injected clutches of American kestrels (Falco sparverius) with one of three different dosages of testosterone + androstenedione or with vehicle. Morphological measurements taken from nestlings 26 days after hatching showed no significant treatment effect. In 2007, nestlings with more yolk androgens had lower hatching mass and higher hematocrit levels 15 days after hatching than nestlings with less yolk androgens, but the effects disappeared by day 26. In 2008, there were no effects of androgens on mass or hematocrit. Because the results were not …

Diet And Behavior Of Ferruginous Hawks Nesting In Two Grasslands In New Mexico With Differing Anthropogenic Alteration, William Hanlon Keeley

Boise State University Theses and Dissertations

I analyzed regurgitated pellets, prey remains, and video recordings to describe Ferruginous Hawk (Buteo regalis) diet in two grasslands in New Mexico, USA, the Estancia Valley and the Plains of San Agustin, that differed in anthropogenic alteration. Video monitoring revealed Ferruginous Hawks provisioned nestlings with more biomass than pellet analysis estimates from the same nests. Three mammalian prey species, Botta’s pocket gopher (Thomomys bottae), Gunnison’s prairie dog (Cynomys gunnisoni), and desert cottontail (Sylvilagus audubonii)contributed similar proportions to Ferruginous Hawk diet in percent biomass while Botta's pocket gopher dominated diet in percent frequency. …