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Given Harper

Articles 1 - 11 of 11

Full-Text Articles in Life Sciences

Corrosion Casts: A Novel Application Of A Polyurethane Resin (Pu4ii) For Visualizing Eggshell Pore Morphology, Given Harper, Jason P. Murphy, Mark T. Swanson, William B. Jaeckle Dec 2014

Corrosion Casts: A Novel Application Of A Polyurethane Resin (Pu4ii) For Visualizing Eggshell Pore Morphology, Given Harper, Jason P. Murphy, Mark T. Swanson, William B. Jaeckle

Given Harper

Avian eggshells serve the dual purposes of protecting the developing embryo from the external environment while also facilitating the loss of water vapor and the required exchange of CO2 and O2 gases. Pores that span the eggshell enable the loss of water and trans-shell gas exchange. Although knowledge of the geometry of these spaces is necessary to generate accurate estimates of the rate of gas diffusion across the shell, few techniques exist to obtain these data. Estimates of gas conductance across eggshells are typically calculated from eggshell thickness and the size and number of the pores on the exterior eggshell …

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Influence Of Latitude On The Winter Abundance Of Red-Tailed Hawks (Buteo Jamaicensis) And American Kestrels (Falco Sparverius) In Illinois, Given Harper, Anna Groves, Vic Berardi, Paul Sweet, Jance Sweet, Angelo P. Capparella Dec 2012

Influence Of Latitude On The Winter Abundance Of Red-Tailed Hawks (Buteo Jamaicensis) And American Kestrels (Falco Sparverius) In Illinois, Given Harper, Anna Groves, Vic Berardi, Paul Sweet, Jance Sweet, Angelo P. Capparella

Given Harper

We use five years of data from 18 routes surveyed to determine the temporal stability of a first reported 100 years pattern, and reconfirmed that the abundance of winter 50 years ago tailed Hawk and American Kestrel decreases with increasing latitude, being more high in the central regions of Illinos in the northern regions. Trained volunteers conducted sampling ( n  = 143) a month driving along selected routes from December to February, from 2004-2005 to 2008-2009. We found significant increases in the abundance of both species from the northern regions to the central regions of Illinois. No significant effects of …

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Why Are Incubation Periods Longer In The Tropics? A Common-Garden Experiment With House Wrens Reveals It Is All In The Egg, Given Harper, W. Douglas Robinson, John D. Styrsky, Brian J. Payne, Charles F. Thompson Mar 2008

Why Are Incubation Periods Longer In The Tropics? A Common-Garden Experiment With House Wrens Reveals It Is All In The Egg, Given Harper, W. Douglas Robinson, John D. Styrsky, Brian J. Payne, Charles F. Thompson

Given Harper

Incubation periods of Neotropical birds are often longer than those of related species at temperate latitudes. We conducted a common-garden experiment to test the hypothesis that longer tropical incubation periods result from longer embryo development times rather than from different patterns of parental incubation behavior. House wrens, one of few species whose geographic range includes tropical equatorial and temperate high latitudes, have incubation periods averaging 1.2 days longer at tropical latitudes. We incubated eggs of house wrens in Illinois and Panama under identical conditions in mechanical incubators. Even after factoring out differences in egg size, tropical house wrens still required …

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Lack Of Widespread Organochlorine Pesticide Contamination In South American Resident Passerines, Given Harper, A. P. Capparella, J. A. Klemens, J. A. Frick Mar 2003

Lack Of Widespread Organochlorine Pesticide Contamination In South American Resident Passerines, Given Harper, A. P. Capparella, J. A. Klemens, J. A. Frick

Given Harper

Recent studies have documented the existence of organochlorine (OC) pesticides and metabolites— notably p,p'-DDE, dieldrin and heptachlor epoxide—in the nglg range in many species of Neotropical migrant passerines that breed in the Nearctic region and winter in the Neotropics (e.g., Kannan 1991; Harper et al. 1996; Klemens et al. 2000; Bartuszevige et al. 2002). This is despite the banning and/or restricted use of OC pesticides in the United States and Canada in the 1970s and the observed decline in DDT residues in migratory songbirds seen in the 1970s (Johnston 1974). Apparently, these relatively short-lived birds are still being exposed to …

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Use Of Elisa For Determination Of Plasma Prolactin Levels In The House Wren, Given Harper, Sharon M. Sintich, Michelle K. Keagle, Ian G. Welsford Oct 1995

Use Of Elisa For Determination Of Plasma Prolactin Levels In The House Wren, Given Harper, Sharon M. Sintich, Michelle K. Keagle, Ian G. Welsford

Given Harper

Prolactin concentrations in avian plasma have been traditionally quantified using a radioimmunoassay (RIA) procedure. RIA is useful for such studies due to its sensitivity and specificity (e.g., Follett et al. 1972, Wingfield and Farner 1975, McNeilly et al. 1978, Burke and Papkoff 1980, Schwabl 1993). For example, the heterologous RIA for detecting prolactin in turkeys, developed by McNeilly et al. (1978), recovered 98% of a prolactin standard added to a turkey plasma sample and exhibited less than 0.1% cross reactivity with other plasma hormones. In an homologous RIA developed by Burke and Papkoff (1980), detection limits of approximately 0.42 ± …

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Intrapopulation Variation In Hatching Synchrony In House Wrens: Test Of The Individual-Optimization Hypothesis, Given Harper, Steven A. Juliano, Charles F. Thompson Jun 1994

Intrapopulation Variation In Hatching Synchrony In House Wrens: Test Of The Individual-Optimization Hypothesis, Given Harper, Steven A. Juliano, Charles F. Thompson

Given Harper

Intrapopulation variation in hatching synchrony has been documented in several avian species, although little attention has been paid to this phenomenon. We experimentally reversed some synchronously and asynchronously hatched broods to test an individual-optimization hypothesis to explain variation in hatching synchrony in a population of House Wrens (Troglodytes aedon) in central Illinois. Contrary to expectation, the number and quality (as measured by mass) of fledglings produced in reversed broods was the same as that for unmanipulated broods, as were recapture rates of juveniles and offspring recruitment to subsequent breeding populations. Thus, the results do not support the individual-optimization hypothesis as …

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Avian Hatching Asynchrony: Brood Classification Based On Discriminant Function Analysis Of Nestling Masses, Given Harper, Steven A. Juliano, Charles F. Thompson May 1993

Avian Hatching Asynchrony: Brood Classification Based On Discriminant Function Analysis Of Nestling Masses, Given Harper, Steven A. Juliano, Charles F. Thompson

Given Harper

Studies of hatching asynchrony in altricial birds have used several methods to determine if a brood hatches synchronously or asynchronously. The most commonly used methods include making frequent nest visits during the time of hatching and using nestling mass or other measures of size on a given day to estimate nestling age or to describe the extent of the size hierarchy within broods. We made daily nest visits to determine if House Wren (Troglodytes aedon) broods hatched synchronously or asynchronously, and then compared classification of these broods based on discriminant function analysis with that based on mass differences of nestlings. …

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Effects Of Predator Size And Female Receptivity On Courtship Behavior Of Captive-Bred Male Guppies, Given Harper, Kristin Braun Dec 1992

Effects Of Predator Size And Female Receptivity On Courtship Behavior Of Captive-Bred Male Guppies, Given Harper, Kristin Braun

Given Harper

The effects of predator size and female receptivity on the courtship behavior of captivebred male guppies (Poecilia reticulata) were investigated. Male guppies exhibited riskreckless courtship behavior in that they did not decrease the amount of time spent performing visually conspicuous sigmoid displays and increase the frequency of attempted forced copulations when large predatory fish were present. Female receptivity (i.e., virgin or non-virgin females) also had no effect on male courtship behavior.

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Red-Bellied Woodpecker Predation On Nestling House Wrens, Given Harper, Andrew J. Neill Jul 1990

Red-Bellied Woodpecker Predation On Nestling House Wrens, Given Harper, Andrew J. Neill

Given Harper

No abstract provided.

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Nonfish Prey Of Wintering Bald Eagles In Lilinois, Given Harper, D. Scott Hopkins, Thomas C. Dunston Nov 1988

Nonfish Prey Of Wintering Bald Eagles In Lilinois, Given Harper, D. Scott Hopkins, Thomas C. Dunston

Given Harper

Many Bald Eagles (Haliaeetus leucocephalus) winter in Illinois (Fawks 1979), where they feed primarily on fish (e.g., Southern 1966, Fischer 1982, Harper 1983). However, few reports have been published documenting their use of mammalian and avian prey in the midwestern United States (Lingle and Krapu 1986, Stalmaster 1987). This paper describes the almost exclusive use of nonfish prey in an upland population of Bald Eagles, and discusses related management implications.

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Live Northern Harrier Entrapped In Ice, Given Harper, Thomas C. Dunstan Dec 1982

Live Northern Harrier Entrapped In Ice, Given Harper, Thomas C. Dunstan

Given Harper

No abstract provided.

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