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Articles 631 - 660 of 662
Full-Text Articles in Biology
Peregrine Falcon Eggs: Egg Size, Hatchling Sex, And Clutch Sex Ratios, William Burnham, Calvin Sandfort, James R. Belthoff
Peregrine Falcon Eggs: Egg Size, Hatchling Sex, And Clutch Sex Ratios, William Burnham, Calvin Sandfort, James R. Belthoff
Biology Faculty Publications and Presentations
Eggs (n = 367) collected from wild Peregrine Falcon (Falco peregrinus anatum) nests between 1976 and 1990 in Colorado and New Mexico were artificially incubated and hatched. We retrospectively examined these data for variation in egg length, breadth, and initial mass of hatchlings to resolve questions about relationships among egg size, chick size, and sex; and egg size related to first and second clutches and years. Egg length and breadth were significantly related to chick mass at hatching. Neither egg size nor hatchling mass were related to sex. Egg breadth slightly increased and then decreased over the years eggs were …
Comparative Studies Of Evolutionary Responses To Light Environments In Arabidopsis, Massimo Pigliucci, Heidi Pollard, Mitchell B. Cruzan
Comparative Studies Of Evolutionary Responses To Light Environments In Arabidopsis, Massimo Pigliucci, Heidi Pollard, Mitchell B. Cruzan
Biology Faculty Publications and Presentations
In this article, we compare the reaction norms to foliage shade (changes in light quality, spatially fine-grained environmental variation) and photoperiod (day length, spatially coarse-grained environmental variation) in several haplotypes of Arabidopsis thaliana from Scandinavia. We found that both across-environment means and phenotypic plasticities evolved continuously and very rapidly within this group. Both character means and trait plasticities were highly integrated, in part as predicted by the adaptive plasticity hypothesis for response to foliage shade (the so-called shade-avoidance syndrome). We found that a significant but small fraction of the variance in across-treatment trait means and plasticities in response to one …
Avian Population Trends Within The Evolving Agricultural Landscape Of The Eastern And Central United States, Michael T. Murphy
Avian Population Trends Within The Evolving Agricultural Landscape Of The Eastern And Central United States, Michael T. Murphy
Biology Faculty Publications and Presentations
State-level Breeding Bird Survey (1980-1998) and U.S. Department of Agriculture statistics were used to test the hypothesis that changes in agricultural land use within the eastern and central U.S. have driven population trends of grassland and shrub habitat birds over the past two decades. The degree to which population trends differed between grassland and shrub habitats was evaluated with respect to migratory and nesting behavior. Grassland birds declined significantly between 1980 and 1999, but, on average, shrub habitat species did not. Grassland-breeding, long-distance migrants exhibited the strongest negative trends. Most species (78%; n = 63) exhibited at least one significant …
Genetic Differentiation Of Rare And Common Varieties Of Eriogonum Shockleyi (Polygonaceae) In Idaho Using Issr Variability, James F. Smith
Genetic Differentiation Of Rare And Common Varieties Of Eriogonum Shockleyi (Polygonaceae) In Idaho Using Issr Variability, James F. Smith
Biology Faculty Publications and Presentations
Idaho populations of Eriogonum shockleyi are divided taxonomically into 2 varieties: E. shockleyi var. packardae , which is endemic to Idaho, and the typical variety, which is widespread in the western United States. Recent morphological investigations of E. shockleyi in Idaho have identified potentially reliable morphological characters for field identification of the subspecific taxa. This paper investigates the genetic basis for the separation of the 2 varieties of E. shockleyi using inter simple-sequence repeats (ISSR) markers. Although we found some morphological differences between the populations that correlated with the 2 varieties, we identified no molecular markers in this study to …
Nest-Site Characteristics Of Burrowing Owls (Athene Cunicularia) In The Snake River Birds Of Prey National Conservation Area, Idaho, And Application To Artificial Burrow Installation, James R. Belthoff, R. Andrew King
Nest-Site Characteristics Of Burrowing Owls (Athene Cunicularia) In The Snake River Birds Of Prey National Conservation Area, Idaho, And Application To Artificial Burrow Installation, James R. Belthoff, R. Andrew King
Biology Faculty Publications and Presentations
Burrowing Owl (Athene cunicularia) populations are declining in many portions of their range, and research and management efforts into stemming declines are underway. One tool with promise is the artificial burrow, which can supplement nesting opportunities and play a role in research, mitigation, translocation, and reintroduction studies. However, few studies directly assess important burrow and surrounding topographic features upon which owls choose sites and then construct and install artificial burrows accordingly. In this study we (1) measure physical, vegetative, and topographic characteristics of Burrowing Owl nest sites in the Snake River Birds of Prey National Conservation Area (SRBPNCA); …
High Frequency Of Extra-Pair Paternity In Eastern Kingbirds, Diane L. Rowe, Michael T. Murphy, Robert C. Fleischer, Paul G. Wolf
High Frequency Of Extra-Pair Paternity In Eastern Kingbirds, Diane L. Rowe, Michael T. Murphy, Robert C. Fleischer, Paul G. Wolf
Biology Faculty Publications and Presentations
Genetic parentage in the socially monogamous and territorial Eastern Kingbird( Tyrannust tyrannus) was examined in a central New York population by multilocus DNA fingerprinting. Extra-pair young were identified in 60% (12 of 20) of nests. Of the 64 nestlings profiled, 42% were sired by extra-pair males, but no cases of conspecific brood parasitism were detected. These results are markedly different from a previous electrophoretic study of the same species in a Michigan population, which reported 39% of nestlings were unrelated to one (typically the mother, quasiparasitismo)r both (conspecificb roodp arasitism) of the putative parents. In the New York population, extra-pairp …
Bounce And Double Trill Songs Of Male And Female Western Screech-Owls: Characterization And Usefulness For Classification Of Sex, Brian L. Herting, James R. Belthoff
Bounce And Double Trill Songs Of Male And Female Western Screech-Owls: Characterization And Usefulness For Classification Of Sex, Brian L. Herting, James R. Belthoff
Biology Faculty Publications and Presentations
Both sexes of adult Western Screech-Owls (Otus kennicottii) sing in response to playback of conspecific song within their territories. Two primary songs are the bounce and double trill. Using sonographic analysis of tape-recorded vocalizations, our study quantified characterstics of bounce and double trill songs uttered by individuals within a population of Western Screech-Owls inhabiting riparian woodlands in southwestern Idaho. We asked if songs of males and females differed and, if so, how accurately could songs be classified by sex. On average, male bounce songs were ∼30% lower in frequency than bounce songs of females, but song duration, note duration, number …
High Species Diversity In Fleshy-Fruited Tropical Understory Plants, James F. Smith
High Species Diversity In Fleshy-Fruited Tropical Understory Plants, James F. Smith
Biology Faculty Publications and Presentations
Key innovations may increase the number of taxa in a clade that possesses the proposed innovation in comparison to its sister group that lacks the trait through either increased speciation or reduced extinction rates. Comparing sister clades across several independent lineages provides statistical support that the trait has increased species diversity. Previous studies have indicated that there may not be a relationship between biotic dispersal and higher species diversity, but only a few of these studies specified habit, habitat, or type of disperser. No previous study has specified all of the above parameters and used a phylogenetic approach. This article …
Post-Fledging Dispersal Of Burrowing Owls In Southwestern Idaho: Characterization Of Movements And Use Of Satellite Burrows, R. Andrew King, James R. Belthoff
Post-Fledging Dispersal Of Burrowing Owls In Southwestern Idaho: Characterization Of Movements And Use Of Satellite Burrows, R. Andrew King, James R. Belthoff
Biology Faculty Publications and Presentations
Using radiotelemetry, we monitored dispersing juvenile Western Burrowing Owls (Athene cunicularia hypugaea) within a migratory population in southwestern Idaho during 1994 and 1995. Owls remained within natal areas for an average (± SE) of 58 ± 3.4 days post-hatching before moving permanently beyond 300 m, which was our operational cutoff for dispersal from the natal area. On average, owls dispersed on 27 July (range: 15 July to 22 August), which was approximately 4 weeks after fledging. After initiating dispersal, juveniles continued moving farther away from their natal burrows and, by 61-65 days post-hatching, they had moved 0.6 ± …
The Phylogenetic Relationships Of Lembocarpus And Goyazia (Gesneriaceae) Based On NdhF Sequences, James F. Smith
The Phylogenetic Relationships Of Lembocarpus And Goyazia (Gesneriaceae) Based On NdhF Sequences, James F. Smith
Biology Faculty Publications and Presentations
The phylogenetic relationships of Goyazia and Lembocarpus are investigated based on cladistic analysis of ndhF sequences. Both genera are currently classified in the tribe Gloxinieae, but both are poorly known. Based on its floral morphology, the classification of Goyazia in Gloxinieae is not controversial. Lembocarpus may be placed in Gloxinieae, Episcieae, or Sinningieae. The acaulescent, tuberous nature of Lembocarpus limits the number of characters available for a morphological analysis and has made its classification and phylogenetic relationships difficult to resolve. Phylogenetic analyses of ndhF sequences place both genera in Gloxinieae. Although the affinities within the tribe are ambiguous …
Is Reproduction By Tree Swallows (Tachycineta Bicolor) Cost-Free?, Michael T. Murphy
Is Reproduction By Tree Swallows (Tachycineta Bicolor) Cost-Free?, Michael T. Murphy
Biology Faculty Publications and Presentations
We manipulated brood sizes of Tree Swallows (Tachycineta bicolor) in 1996 and 1997 to test for the existence of intra- and intergenerational costs of reproduction. Modal clutch size was six eggs, but experimental brood sizes ranged from two to nine young. Nestling starvation was higher in 1996 (and dependent on brood size) than in 1997, but in both years enlargement of brood size resulted in increased productivity. Nestling mass near fledging was negatively correlated with brood size, but tarsus length and wing chord were not. Food deliveries by parents increased steadily between broods of two to six young but then …
Cullin-3 Targets Cyclin E For Ubiquitination And Controls S Phase In Mammalian Cells, Jeffrey D. Singer, Mark Gurian-West, Bruce Clurman, James M. Roberts
Cullin-3 Targets Cyclin E For Ubiquitination And Controls S Phase In Mammalian Cells, Jeffrey D. Singer, Mark Gurian-West, Bruce Clurman, James M. Roberts
Biology Faculty Publications and Presentations
Cyclin E is an unstable protein that is degraded in a ubiquitin- and proteasome- dependent pathway. Two factors stimulate cyclin E ubiquitination in vivo: when it is free of its CDK partner, and when it is phosphorylated on threonine 380. We pursued the first of these pathways by using a two-hybrid screen to identify proteins that could bind only to free cyclin E. This resulted in the isolation of human Cul-3, a member of the cullin family of E3 ubiquitin–protein ligases. We found that Cul-3 was bound to cyclin E but not to cyclin E-Cdk2 complexes in mammalian cells, and …
Spatial Learning Of An Escape Task By Young Corn Snakes, Elaphe Guttata Guttata, David A. Holtzman, Terrence W. Haris, Guillermo Aranguren, Elizabeth Bostock
Spatial Learning Of An Escape Task By Young Corn Snakes, Elaphe Guttata Guttata, David A. Holtzman, Terrence W. Haris, Guillermo Aranguren, Elizabeth Bostock
Biology Faculty Publications and Presentations
Spatial learning is critical to most animals for many behaviours necessary to survival. In vertebrates, most studies on spatial learning and memory have been conducted in mammalian and avian species with few studies on reptiles. We examined spatial learning in the corn snake, Elaphe guttata guttata by training 17 young snakes to find the one open shelter in an eight-hole arena, where the entrance was not visible from the arena surface. Over a 16-trial, 4-day training period, snakes showed (1) a significant decrease in the mean latency to the goal, (2) a significant decrease in the mean total distance travelled, …
Breeding Birds At The Idaho National Engineering And Environmental Laboratory, 1985 - 1991, James R. Belthoff, Leon R. Powers, Timothy D. Reynolds
Breeding Birds At The Idaho National Engineering And Environmental Laboratory, 1985 - 1991, James R. Belthoff, Leon R. Powers, Timothy D. Reynolds
Biology Faculty Publications and Presentations
During the summers of 1985-1991, bird censuses were conducted along 13 permanent routes located at the 2315-km2 Idaho National Engineering and Environmental laboratory (INEEL, formerly INEL) in southeastern Idaho. The objectives of the surveys were to (1) compare avifauna in and near facility complex sites with remote, relatively undisturbed habitats, (2) identify trends in populations of sagebrush-obligate species and other common shrug-steppe species, and (3) determine the presence, abundance, and population status of species of special concern. Five routes were official U.S. Geological Survey, Biological Resources Division 40.0-km Breeding Bird Survey (BBS) routes (formerly administered by the U.S. Fish …
A Cladistic Analysis Of NdhF Sequences From Representative Species Of Saintpaulia And Streptocarpus Subgenera And Streptocarpella (Gesneriaceae), James F. Smith, M. E. Kresge, M. Möller, Q. C. B. Cronk
A Cladistic Analysis Of NdhF Sequences From Representative Species Of Saintpaulia And Streptocarpus Subgenera And Streptocarpella (Gesneriaceae), James F. Smith, M. E. Kresge, M. Möller, Q. C. B. Cronk
Biology Faculty Publications and Presentations
Two African genera of the Gesneriaceae, Saintpaulia and Streptocarpus, are similar in many respects. Both genera have blue to purple flowers, pollen of similar shape and exine sculpting, embryos with one-celled uninucleate chalazal haustoria, shared vegetative structures among some species, and are among the few genera in the Gesneriaceae which include species with chromosome count of n=15. Similarity of these features has indicated that the two genera are likely to be closely related. This study examines the sequences of the chloroplast gene ndhF among several representative Saintpaulia and representatives of Streptocarpus subgenera Streptocarpella and Streptocarpus. The …
Body Condition And The Adrenal Stress Response In Captive American Kestrel Juveniles, Julie A. Heath, Alfred M. Dufty Jr.
Body Condition And The Adrenal Stress Response In Captive American Kestrel Juveniles, Julie A. Heath, Alfred M. Dufty Jr.
Biology Faculty Publications and Presentations
We examined the adrenal response to handling stress of birds in different body conditions. In order to affect the birds’ body condition, young (73-d old) female American kestrels (Falco sparverius) were maintained for 6 wk on one of three diets: a control diet (fed ad lib.) and two calorically restricted diets. To invoke a stress response, we removed birds from their cages and took repeated blood samples over the course of an hour. All birds responded to handling stress with an increase in plasma corticosterone, but control birds (in good body condition) showed a more rapid increase to …
Corticosterone Levels During Nest Departure Of Juvenile American Kestrels, Julie Heath
Corticosterone Levels During Nest Departure Of Juvenile American Kestrels, Julie Heath
Biology Faculty Publications and Presentations
Many avian behavior patterns, such as breeding, migration and territoriality, are correlated with changes in hormone levels. Elevated levels of corticosterone, an adrenal steroid hormone, are associated with increased foraging and increased activity levels in birds. Young birds about to take their first flight may benefit from elevated plasma corticosterone levels that facilitate locomotor activity and foraging behavior while they are developing flight and hunting skills. I examined the relationship between corticosterone levels and the timing of nest departure in nestling American Kestrels (Falco sparverius). American Kestrels are cavity nesters and typically depart from the nest between 25-30 …
Corticosterone And The Stress Response In Young Western Screech-Owls: Effects Of Captivity, Gender, And Activity Period, Alfred M. Dufty Jr., James R. Belthoff
Corticosterone And The Stress Response In Young Western Screech-Owls: Effects Of Captivity, Gender, And Activity Period, Alfred M. Dufty Jr., James R. Belthoff
Biology Faculty Publications and Presentations
We used a standard handling protocol to examine the stress response of captive young western screech-owls during their active (nighttime) and inactive (daytime) periods and to compare the stress responses of captive and free-living owls. Circulating corticosterone levels were significantly higher during the inactive period than in the active period in this nocturnal species. This suggests that the daily pattern of corticosterone secretion is reversed in nocturnal birds and is correlated with activity period rather than with the light/dark cycle. Young (ca. 4-5 mo old) screech-owls of both sexes showed increases in plasma corticosterone up to 30 min after capture, …
Tribal Relationships In The Gesneriaceae: Evidence From Dna Sequences Of The Chloroplast Gene NdhF, James F. Smith, J. C. Wolfram, K. D. Brown, Cynthia L. Carroll, D. S. Denton
Tribal Relationships In The Gesneriaceae: Evidence From Dna Sequences Of The Chloroplast Gene NdhF, James F. Smith, J. C. Wolfram, K. D. Brown, Cynthia L. Carroll, D. S. Denton
Biology Faculty Publications and Presentations
The tribal relationships of the Gesneriaceae are investigated using ndhF sequences. A full analysis of 70 taxa including 16 species from the Scrophulariaceae, Bigoniaceae, and Acanthaceae as outgroups, resulted in two most-parsimonious trees of 5610 steps each. In all trees the Gesneriaceae were a monophyletic group and Paulownia was the closest single-species outgroup for the analysis. Further analyses eliminated all but the members of the Gesneriaceae and Paulownia in order to better asses relationships within the family. The smaller analysis resulted in a single most-parsimonious tree of 4613 steps. The Klugieae are identified as the sister to the remainder …
Plumage Variation, Plasma Steroids And Social Dominance In Male House Finches, James R. Belthoff, Alfred M. Dufty Jr., Sidney A. Gauthreaux Jr.
Plumage Variation, Plasma Steroids And Social Dominance In Male House Finches, James R. Belthoff, Alfred M. Dufty Jr., Sidney A. Gauthreaux Jr.
Biology Faculty Publications and Presentations
In male House Finches (Carpodacusm exicanus), the extent and color of plumage varies depending on access to carotenoid pigments. "Colorful" males exhibit extensive red pigmentation, while less colorful (i.e., "drab") males exhibit carotenoid pigmentation over a smaller percentage of their plumage, pigmentation of a color besides red (e.g., yellow, gold, orange, or pink), or both. One explanation for maintenance of plumage variation is that it reliably reflects social status, allowing males to correctly assess their status in relation to others and avoid or minimize costly fights. Social relationships may also be related to endogenous factors, such as circulating levels of …
Breeding Patterns Of Eastern Phoebes In Kansas: Adaptive Strategies Or Physiological Constraint?, Michael T. Murphy
Breeding Patterns Of Eastern Phoebes In Kansas: Adaptive Strategies Or Physiological Constraint?, Michael T. Murphy
Biology Faculty Publications and Presentations
Data were collected on annual (1980-1983) and seasonal (spring vs. summer) variation in reproduction by the double-brooded Eastern Phoebe (Sayornis phoebe) to test the proposal that phoebes modify reproductive patterns on a seasonal basis and switch from being brood survivalists in spring to brood reductionists in summer. Clutch size did not differ between spring and summer broods nor among years, but spring nests fledged one more nestling than summer nests. In 1981 breeding began earlier, eggs were larger, and nestlings grew faster than in all other years. Clutch size and egg mass within spring clutches increased seasonally. Egg mass was …
Thorn-Like Prickles And Heterophylly In Cyanea: Adaptations To Extinct Avian Browsers On Hawaii?, T. J. Givnish, K. J. Sytsma, James F. Smith, W. J. Hahn
Thorn-Like Prickles And Heterophylly In Cyanea: Adaptations To Extinct Avian Browsers On Hawaii?, T. J. Givnish, K. J. Sytsma, James F. Smith, W. J. Hahn
Biology Faculty Publications and Presentations
The evolution of thorn-like structures in plants on oceanic islands that lack mammalian and reptilian herbivores is puzzling, as is their tendency toward juvenile-adult leaf dimorphism. We propose that these traits arose in Cyanea (Campanul) on Hawaii as mechanical and visual defenses against herbivory by flightless geese and goose-like ducks that were extirpated by Polynesians within the last 1600 years. A chloroplast DNA phylogeny indicates that thorn-like prickles evolved at least four times and leaf dimorphism at least three times during the last 3.7 million years. The incidence of both traits increases from Oahu eastward toward younger islands, paralleling the …
Phylogenetics Of Seed Plants: An Analysis Of Nucleotide Sequences From The Plastid Gene RbcL, James F. Smith
Phylogenetics Of Seed Plants: An Analysis Of Nucleotide Sequences From The Plastid Gene RbcL, James F. Smith
Biology Faculty Publications and Presentations
We present the results of two exploratory parsimony analyses of DNA sequences from 475 and 499 species of seed plants. respectively, representing all major taxonomic groups. The data are exclusively from the chloroplast gene rbcL, which codes for the large subunit of ribulose-l .5-bisphosphate carboxylase/ oxygenase (RuBisCO or RuBPCase). We used two different state-transformation assumptions resulting in two sets of cladograms: (i) equal-weighting for the 499-taxon analysis; and (ii) a procedure that differentially weights transversions over transitions within characters and codon positions among characters for the 475-taxon analysis. The degree of congruence between these results and other molecular. as …
Phylogenetic Analysis Of The Zingiberales Based On RbcL Sequences, James F. Smith, W. John Kress, Elizabeth A. Zimmer
Phylogenetic Analysis Of The Zingiberales Based On RbcL Sequences, James F. Smith, W. John Kress, Elizabeth A. Zimmer
Biology Faculty Publications and Presentations
Morphological data have been used previously to construct phylogenies of the eight families of the Zingiberales one of the most widely accepted monophyletic groups of flowering plants. To provide additional support for phylogenetic relationships within the order, and placement of the order among monocots, we present a parsimony analysis of DNA sequences from the chloroplast-encoded gene, rbcL, for 21 species of Zingiberales and proposed relatives. Five analyses with equal, and differential weights were performed. All analyses resulted in the same most parsimonious tree for taxa within the Zingiberales and the immediate outgroup. The closest sister group to the Zingiberales …
Phylogenetic Hypotheses For The Monocotyledons Constructed From RbcL Sequence Data, James F. Smith
Phylogenetic Hypotheses For The Monocotyledons Constructed From RbcL Sequence Data, James F. Smith
Biology Faculty Publications and Presentations
DNA sequences for the plastid locus that encodes the large subunit if ribulose 1.5 bisphosphate carboxylase/oxygenase (rbcL) were determined for 18 species of monocotyledons in 15 families. These data were analyzed together with sequences for 60 other monocot species in a total of 52 families by the maximum likelihood method producing one, presumably optimal, topology. An additional 26 species were added (104 total monocot species) and analyzed by the parsimony method with an outgroup of 18 dicot species producing 109 trees of 3,932 steps. The rbcL data show at least moderate support for seven lineages corresponding to …
Temporal Patterns Of Nectar And Pollen Production In Aralia Hispida: Implications For Reproductive Success, James D. Thomas, Mary A. Mckenna, Mitchell B. Cruzan
Temporal Patterns Of Nectar And Pollen Production In Aralia Hispida: Implications For Reproductive Success, James D. Thomas, Mary A. Mckenna, Mitchell B. Cruzan
Biology Faculty Publications and Presentations
Large plants of Aralia hispida present their pollen and nectar in hundreds of small flowers than open sequentially over 2—3 wk in a pattern of synchronized protandry that alternates male and female phases. The primary pollinators, bumble bees, are able to discover individual plants with elevated levels of either nectar or pollen, and to return to them more often than to less rewarding plants. Both pollen and nectar are presented gradually over time in such a way as to favor traplining behavior by the bees, with many, frequent visits. In controlled environments, lifetime sugar production per flower varies among plants, …
The Impact Of Weather On Kingbird Foraging Behavior, Michael T. Murphy
The Impact Of Weather On Kingbird Foraging Behavior, Michael T. Murphy
Biology Faculty Publications and Presentations
Foraging data on Eastern Kingbirds (Tyrannus tyrannus) were collected during the early breeding season in eastern Kansas to test the hypothesis that foraging rate and other aspects of foraging behavior vary with weather. Foraging characteristics of five additional kingbird species were also examined to assess Fitzpatrick's (1980) generalization that kingbirds (Tyrannus spp.) are aerial hawking specialists. In Eastern Kingbirds, total foraging rate was independent of air temperature, cloud cover, wind speed, and time of day, but the rate of aerial hawking varied directly with air temperature and inversely with cloud cover (both P < 0.05). Effects of the two variables were additive. The percentage of foraging movements that were aerial hawks also increased with temperature and declined with cloud cover, and, hover-gleaning and perch-to-ground sallying were observed mainly during cloudy weather. Sally (i.e., foraging flight) distance correlated directly with perch height and air temperature, and large insects were captured almost exclusively in long upward or horizontal flights. I interpret these data to indicate that foraging behavior and the capture of large, flying insects depends on weather because of how it affects the activity of insect prey. Foraging data on kingbirds support Fitzpatrick's generalization, but the relative use of aerial hawking varies considerably among species. Resident Tropical Kingbirds( T. melancholicus) are the most specialized foragers, whereas the migrant and widely distributed Eastern Kingbird appears to be the most generalized. Certain habitats also appear to favor the use of particular foraging methods (e.g., outward striking in grasslands and perch-to-ground sallying in drier, open habitats).
Body Size, Nest Predation, And Reproductive Patterns In Brown Thrashers And Other Mimids, Michael T. Murphy, Robert C. Fleischer
Body Size, Nest Predation, And Reproductive Patterns In Brown Thrashers And Other Mimids, Michael T. Murphy, Robert C. Fleischer
Biology Faculty Publications and Presentations
We describe the breeding biology of Brown Thrashers (Toxostoma rufum) in Kansas, and combine this with data from other temperate-zone breeding Mimidae to characterize reproductive patterns in this group. Brown Thrashers produced clutches of 3 to 6 eggs, but clutches of 4 predominated. Most pairs raised 2 broods per year. Incubation required between 13 and 14 days, and hatching was usually asynchronous. Though sample size was small, asynchrony appeared to increase in frequency towards the end of the breeding season. Nestlings grew rapidly, and in 10 days or less most pre-fledgingg rowthw as completed. Young fledgedn ormallya t 11 days …
Body Size And Condition, Timing Of Breeding, And Aspects Of Egg Production In Eastern Kingbirds, Michael T. Murphy
Body Size And Condition, Timing Of Breeding, And Aspects Of Egg Production In Eastern Kingbirds, Michael T. Murphy
Biology Faculty Publications and Presentations
Variation in timing of breeding in Eastern Kingbirds (Tyrannus tyrannus) was correlated only weakly with external morphological characters, but was correlated positively and significantly with estimates of body size based on measurements of skeletons and muscle weights. Small females apparently held a reproductive advantage in being able to mobilize resources for reproduction before large females. Egg weight was independent of all measures of female size, but was directly and significantly (P = 0.03) correlated with standard flight muscle weight, a relative index of body condition. Egg size was thus a function more of female body condition than size. On average, …
Brood Parasitism Of Eastern Kingbirds By Brown-Headed Cowbirds, Michael T. Murphy
Brood Parasitism Of Eastern Kingbirds By Brown-Headed Cowbirds, Michael T. Murphy
Biology Faculty Publications and Presentations
Understanding why brood parasites lay eggs in the nests of hosts that reject eggs is hampered by insuf-ficient data on the frequency with which parasites lay in rejecter nests, and by ignorance of which in-dividuals practice this seemingly inappropriate be-havior. Parasitism rates of rejecters can be deter-mined only when host nests are observed during egg laying because most parasite eggs are rejected rapidly (e.g. Scott 1977). Even then, however, a certain per-centage of parasitized nests may go undetected. De-termining the selective value of host defense mech-anisms also depends on knowledge of the frequency of parasitism, and the amount of reproductive …