Chronic Reproductive Toxicity of Perfluorooctane Sulfonic Acid and a Simple Mixture of Perfluorooctane Sulfonic Acid and Perfluorohexane Sulfonic Acid to Northern Bobwhite Quail (Colinus virginianus).

Per- and poly-fluoroalkyl substances (PFAS) are a broad class of environmentally persistent chemicals that include thousands of potentially toxic synthetic organic molecules. Some PFAS have been shown to cause adverse health effects including decreased total cholesterol, birth weight, and reproductive success in laboratory animals; however, a lack of chronic toxicity data exists for PFAS in avian ecological receptors. The present study reports on the chronic toxicity of perfluorooctane sulfonic acid (PFOS) and a mixture of PFOS and perfluorohexane sulfonic acid (PFHxS) to northern bobwhite quail (Colinus virginianus) via oral exposure from drinking water. Female weight gain was adversely affected at an average daily intake (ADI) of 3.10 × 10-3 ± 0.15 × 10-3 mg PFOS:PFHxS (1.2:1) mixture × kg-1 body weight × d-1 . Successful liberation from the shell once pipped was adversely affected at an ADI of 2.45 × 10-3 ± 0.01 × 10-3 mg PFOS x kg-1 body weight × d-1 . These values are comparatively much lower than the current dietary avian toxicity reference value (TRV) derived from birds that were exposed via feed, suggesting the need for updated avian TRVs. Relationships between test chemical (PFOS) and test substance (PFOS:PFHxS) showed that PFOS and PFHxS have possible interacting effects in avian receptors and likely differing mechanisms of toxicity depending on chemical co-occurrence and dose. Both the single-chemical and mixture exposures produced similar and possibly additive toxicity values. Environ Toxicol Chem 2020;39:1101-1111. © 2020 SETAC.

Prenatal light exposure influences gait performance and body composition in bobwhite quail chicks.

Maternal nesting behavior, which includes periods of patterned inattention, provides key elements essential for avian embryonic development, including regulation of temperature and light. For example, avian research consistently shows the importance of prenatal light exposure for several developmental processes; however, this research has primarily focused on artificial light regimens (i.e. 24 hr, 0 hr light). Comparatively less is known about how exposure to naturally occurring light patterns during incubation influence motor performance, body composition (i.e. body mass, bone length), and developmental age (incubation length). Here we conducted two experiments which investigated the effects of prenatal light exposure on developmental age, body composition, and gait performance in 1-day-old bobwhite quail. Experiment 1 investigated crepuscular light exposure during the last two days of incubation under two light duration treatments (2 hr & 6 hr) compared to a 12 hr continuous light schedule. Results indicated crepuscular prenatal light experience extended the incubation period for 2 hr exposed embryos, but not for 6 hr exposed embryos and negatively influenced postnatal body composition and postnatal gait performance when compared to 12 hr continuous light embryos. Experiment 2 examined the influence of prenatal light duration (2 hr vs 6 hr) and light presentation (crepuscular vs sporadic). Results demonstrated sporadic light presentation improved gait performance in 2 hr exposed hatchlings, but not 6 hr exposed hatchlings, improved body composition in 6 hr exposed hatchlings, but not 2 hr exposed hatchlings, and did not alter incubation length when compared to crepuscular light counterparts. This study provides further evidence for the importance of maternally regulated sensory stimulation during the prenatal period on early postnatal motor development.

Parental Effects and Climate Change: Will Avian Incubation Behavior Shield Embryos from Increasing Environmental Temperatures?

A major driver of wildlife responses to climate change will include non-genomic effects, like those mediated through parental behavior and physiology (i.e., parental effects). Parental effects can influence lifetime reproductive success and survival, and thus population-level processes. However, the extent to which parental effects will contribute to population persistence or declines in response to climate change is not well understood. These effects may be substantial for species that exhibit extensive parental care behaviors, like birds. Environmental temperature is important in shaping avian incubation behavior, and these factors interact to determine the thermal conditions embryos are exposed to during development, and subsequently avian phenotypes and secondary sex ratios. In this article, we argue that incubation behavior may be an important mediator of avian responses to climate change, we compare incubation strategies of two species adapted to different thermal environments nesting in extreme heat, and we present a simple model that estimates changes in egg temperature based on these incubation patterns and predicted increases in maximum daily air temperature. We demonstrate that the predicted increase in air temperature by 2100 in the central USA will increase temperatures that eggs experience during afternoon off-bouts and the proportion of nests exposed to lethal temperatures. To better understand how species and local adaptations and behavioral-plasticity of incubation behavior will contribute to population responses to climate change comparisons are needed across more avian populations, species, and thermal landscapes.

The intersensory redundancy hypothesis: Extending the principle of unimodal facilitation to prenatal development.

Selective attention to different properties of stimulation provides the foundation for perception, learning, and memory. The Intersensory Redundancy Hypothesis (IRH) proposes that early in development information presented redundantly across two or more modalities (multimodal) selectively recruits attention to and enhances perceptual learning of amodal properties, whereas information presented to a single sense modality (unimodal) enhances perceptual learning of modality-specific properties. The present study is the first to assess this principle of unimodal facilitation in non-human animals in prenatal development. We assessed bobwhite quail embryos' prenatal detection of pitch, a modality-specific property, under conditions of unimodal and bimodal (synchronous or asynchronous) exposure. Chicks exposed to prenatal unimodal auditory stimulation or asynchronous bimodal (audiovisual) stimulation preferred the familiarized maternal call over a novel pitch-modified maternal call following hatching, whereas chicks exposed to redundant (synchronous) audiovisual stimulation failed to prefer the familiar call over the pitch-modified call. These results provide further evidence that selective attention is recruited to specific stimulus properties of events in early development and that these biases are evident even during the prenatal period.

Reproductive plasticity and landscape heterogeneity benefit a ground-nesting bird in a fire-prone ecosystem.

Disturbance is critical for the conservation of rangeland ecosystems worldwide and many of these systems are fire dependent. Although it is well established that restoring fire as an ecological process can lead to increased biodiversity in grasslands and shrublands, the underlying mechanisms driving community patterns are poorly understood for fauna in fire-prone landscapes. Much of this uncertainty stems from the paucity of studies that examine the effects of fire at scales relevant to organism life histories. We assessed the response of a non-migratory ground-dwelling bird to disturbance (i.e., prescribed fire) and environmental stochasticity over the course of a 4-yr period, which spanned years of historic drought and record rainfall. Specifically, we investigated the nesting ecology of Northern Bobwhite (Colinus virginianus; hereafter Bobwhite) to illuminate possible avenues by which individuals respond to dynamic landscape patterns during a critical reproductive stage (i.e., nesting) in a mixed-grass shrubland in western Oklahoma, USA. We found that Bobwhites exhibited extreme plasticity in nest substrate use among time since fire categories (TSF) and subsequently maintained high nest survival (e.g., 57-70%). Bobwhites were opportunistic in nest substrate use among TSF categories (i.e., 72% of nest sites in shrubs in 0-12 months post fire compared to 71% in herbaceous vegetation in >36 months post fire), yet nesting decisions were first filtered by similar structural components (i.e., vertical and horizontal cover) within the vicinity of nest sites regardless of TSF category. Despite being a non-migratory and comparatively less mobile ground-nesting bird species, Bobwhites adjusted to dynamic vegetation mosaics on a fire-prone landscape under stochastic climatic conditions that culminated in stable and high nest survival. Broadly, our findings provide a unique depiction of organism response strategies to fire at scales relevant to a critical life-stage, a topic that has been previously understudied and poorly understood. We also demonstrate how doing so can better inform conservation practices aimed at restoring fire regimes on grassland and shrubland landscapes.

Coordinated movement is influenced by prenatal light experience in bobwhite quail chicks (Colinus virginianus).

Sensory-motor development begins early during embryogenesis and is influenced by sensory experience. Little is known about the prenatal factors that influence the development of motor coordination. Here we investigated whether and to what extent prenatal light experience can influence the development of motor coordination in bobwhite quail hatchlings. Quail embryos were incubated under four light conditions: no light (dark), 2h of total light (2HR), 6h of total light (6HR), and diffused sunlight (controls). Hatchlings were video recording walking down a runway at three developmental ages (12, 24, and 48h). Videos were assessed for forward locomotion, a measurement of motor coordination, falls, a measurement of motor instability, and motivation to complete the task. We anticipated a linear decline of coordination with a reduction in prenatal light experience and improved coordination with age. Furthermore, as motor coordination becomes more laborious we anticipated motivation to complete the task would decline. However, our findings revealed hatchlings did not uniformly improve with age as expected, nor did the reduction of light result in a linear reduction in motor coordination. Instead, we found a more complex relationship with 6HR and 2HR hatchlings showing distinct patterns of stability and instability. Similarly, we found a reduction in motivation within the 6HR light condition. It appears that prenatal light exposure influences the development of postnatal motor coordination and we discuss these finding in light of neurodevelopmental processes influenced by light experience.

Elevated yolk progesterone moderates prenatal heart rate and postnatal auditory learning in bobwhite quail (Colinus virginianus).

Previous studies have established that yolk hormones of maternal origin can influence physiology and behavior in birds. However, few studies have examined the effects of maternal gestagens, like progesterone, on chick behavior and physiology. We tested the effects of experimentally elevated egg yolk progesterone on embryonic heart rate and postnatal auditory learning in bobwhite quail hatchlings. Quail chicks were passively exposed to an individual maternal assembly call for 10 min/hr during the 24 hr following hatching. Preference for the familiarized call was tested at 48 hr following hatching in three experimental groups: chicks that received artificially elevated yolk progesterone (P) prior to incubation, vehicle-only controls (V), and non-manipulated controls (C). Resting heart rate of P, V, and C embryos were also measured on prenatal day 17. The resting heart rate of P embryos was significantly higher than both the V and C embryos. Chicks from the P group also showed an enhanced preference for the familiarized bobwhite maternal call when compared to chicks from the C and V groups. Our results indicate that elevated yolk progesterone in pre-incubated bobwhite quail eggs can influence arousal level in bobwhite embryos and postnatal perceptual learning in bobwhite neonates.

Increased yolk progesterone interferes with prenatal auditory learning and elevates emotional reactivity in bobwhite quail (Colinus virginianus) chicks.

Avian eggs contain maternally derived hormones, including testosterone and progesterone. Little is currently known about the effects of these hormones on early behavioral development. We assessed the effects of elevated levels of progesterone levels on prenatal perceptual learning and postnatal emotional reactivity in Northern bobwhite quail. Prior to incubation, eggs received an injection of either progesterone (P) or oil vehicle (V). In P eggs, levels of progesterone were elevated two standard deviations above the mean based on ELISA analysis of progesterone yolk concentrations from a previous study. A third group of eggs served as controls and received no injection (C). Chicks hatched from P eggs displayed elevated levels of emotional reactivity compared to V and C chicks in a tonic immobility task and a hole-in-the-wall emergence task. Chicks from P eggs also failed to demonstrate a preference for a familiarized bobwhite maternal call that had been presented prenatally. In contrast, the V and C chicks demonstrated a significant preference for the familiarized maternal call following hatching, indicating prenatal auditory learning. Our results are consistent with previous findings from precocial birds demonstrating that hormones of maternal origin can influence prenatal perceptual learning as well as emotional reactivity in the period following hatching..

Saving two birds with one stone: using active substance avian acute toxicity data to predict formulated plant protection product toxicity.

Environmental safety assessments for exposure of birds require the provision of acute avian toxicity data for both the pesticidal active substance and formulated products. As an example, testing on the formulated product is waived in Europe using an assessment of data for the constituent active substance(s). This is often not the case globally, because some countries require acute toxicity tests with every formulated product, thereby triggering animal welfare concerns through unnecessary testing. A database of 383 formulated products was compiled from acute toxicity studies conducted with northern bobwhite (Colinus virginianus) or Japanese quail (Coturnix japonica) (unpublished regulatory literature). Of the 383 formulated products studied, 159 contained only active substances considered functionally nontoxic (median lethal dose [LD50] > highest dose tested). Of these, 97% had formulated product LD50 values of >2000 mg formulated product/kg (limit dose), indicating that no new information was obtained in the formulated product study. Furthermore, defined (point estimated) LD50 values for formulated products were compared with LD50 values predicted from toxicity of the active substance(s). This demonstrated that predicted LD50 values were within 2-fold and 5-fold of the measured formulated product LD50 values in 90% and 98% of cases, respectively. This analysis demonstrates that avian acute toxicity testing of formulated products is largely unnecessary and should not be routinely required to assess avian acute toxicity. In particular, when active substances are known to be functionally nontoxic, further formulated product testing adds no further information and unnecessarily increases bird usage in testing. A further analysis highlights the fact that significant reductions (61% in this dataset) could be achieved by using a sequential testing design (Organisation for Economic Co-operation and Development test guideline 223), as opposed to established single-stage designs.

Upper lethal temperatures of Northern Bobwhite embryos and the thermal properties of their eggs.

Northern Bobwhite eggs in the southern United States are often exposed to ambient temperatures in excess of their normal incubation temperature when unattended during their typical extended preincubation period. In drought years, typified by high ambient temperatures, Bobwhite eggs are often exposed to temperatures > 45°C, well-above the upper lethal temperature of most other birds. Because the upper lethal temperature of Bobwhite embryos is not currently known, simulated clutches of eggs were exposed to preincubation temperatures ranging from 39 to 52°C for exposure times of 1, 3, or 6 h. The upper lethal temperatures and the temperatures resulting in ≥ 50% death of Northern Bobwhite embryos were recorded in addition to the time to thermal equilibrium of Bobwhite eggs. The upper lethal temperature for 1, 3, and 6 h of preincubation exposure was 51, 49, and 46°C, respectively. The temperatures resulting in ≥ 50% death were 46, 44, and 40°C for eggs exposed to elevated temperatures for 1, 3, and 6 h, respectively. The mean time for the inner-egg temperature to reach the ambient temperature was 38 ± 1 min (± SE). The thermal tolerances of Northern Bobwhite embryos were much higher than expected, and among the highest reported for birds, indicating an adaptation to the naturally occurring temperature extremes that often occur in the Bobwhite's semi-arid southern range. However, as the temperature increased above the incubation temperature, hatching success declined, showing that increased thermal tolerance has a cost. Although Bobwhite producers, managers, and researchers will find this information useful, it seems most interesting that high temperatures could plausibly have contributed to the population decline observed in the Bobwhite's semi-arid range.

[Reproductive season onset and time invested in territory defense in Colinus leucopogon males (Galliformes: Odontophoridae)]. / Inicio de la epoca reproductiva y tiempo de defensa del territorio en machos de Colinus leucopogon (Galliformes: Odontophoridae).

The factors that determine the onset of the reproductive season and the relationship between territory defense and mating success of Colinus leucopogon males are unknown. Here I report on climatic variables influencing the time of permanence on the territory, and how this affects the species mating success. I also analyze the relationship between the time devoted by males on territory defense and the relationship of song and territorial characteristics. The onset of the reproductive season was determined by an amount of rain greater than 14.3 mm during March, favouring the food availability and nesting places abundance, and also allowed an increase in the reproductive success of Colinus leucopogon. The time invested in territory defense by males was not related with their mating success. Moreover, the duration in territory defense was similar for males that paired, compared with those that did not. In addition, song and territory characteristics were not related with males invested time in their territory defense. Therefore, this could be another reason explaining the lack of a relationship between the duration in the territories by males and pair formation, and suggests that song characteristics strongly influence the formation of pairs in this species.

Biased embryos: Prenatal experience alters the postnatal malleability of auditory preferences in bobwhite quail.

Many precocial birds show a robust preference for the maternal call of their own species before and after hatching. This differential responsiveness to species-specific auditory stimuli by embryos and neonates has been the subject of study for more than four decades, but much remains unknown about the dynamics of this ability. Gottlieb [Gottlieb [1971]. Development of species identification in birds: An enquiry into the prenatal determinants of perception. Chicago/London: University of Chicago Press.] demonstrated that prenatal exposure to embryonic vocalizations serves to canalize the formation of species-specific preferences in ducklings. Apart from this, little is known about the features of the developmental system that serve to canalize such species-typical preferences, on the one hand, and generate novel behavioral phenotypes, on the other. In the current study, we show that briefly exposing bobwhite quail embryos to a heterospecific Japanese quail (JQ) maternal call significantly enhanced their acquisition of a preference for that call when chicks were provided with subsequent postnatal exposure to the same call. This was true whether postnatal exposure involved playback of the maternal call contingent upon chick contact vocalizations or yoked, non-contingent exposure to the call. Chicks that received both passive prenatal and contingent postnatal exposure to the JQ maternal call redirected their species-typical auditory preference, showing a significant preference for JQ call over the call of their own species. In contrast, chicks receiving only prenatal or only postnatal exposure to the JQ call did not show this redirection of their auditory preference. Our results indicate that prenatal sensory stimulation can significantly bias postnatal responsiveness to social stimuli, thereby altering the course of early learning and memory.

Inicio de la época reproductiva y tiempo de defensa del territorio en machos de Colinus leucopogon (Galliformes: Odontophoridae)

Reproductive season onset and time invested in territory defense in Colinus leucopogon males (Galliformes: Odontophoridae). The factors that determine the onset of the reproductive season and the relationship between territory defense and mating success of Colinus leucopogon males are unknown. Here I report on climatic variables influencing the time of permanence on the territory, and how this affects the species mating success. I also analyze the relationship between the time devoted by males on territory defense and the relationship of song and territorial characteristics. The onset of the reproductive season was determined by an amount of rain greater than 14.3mm during March, favouring the food availability and nesting places abundance, and also allowed an increase in the reproductive success of Colinus leucopogon. The time invested in territory defense by males was not related with their mating success. Moreover, the duration in territory defense was similar for males that paired, compared with those that did not. In addition, song and territory characteristics were not related with males invested time in their territory defense. Therefore, this could be another reason explaining the lack of a relationship between the duration in the territories by males and pair formation, and suggests that song characteristics strongly influence the formation of pairs in this species. Rev. Biol. Trop. 59 (1): 363-372. Epub 2011 March 01.

Los factores que determinan el inicio de la época reproductiva, y la relación entre el tiempo que un macho de Colinus leucopogon defiende su territorio con el éxito reproductivo del mismo son desconocidos. Por lo tanto aquí se reporta el efecto de variables climáticas sobre el inicio de la época reproductiva, y el efecto de la duración de los machos en su territorio con el éxito de adquirir pareja. También se analiza la relación entre la duración de los machos en su territorio con las características del canto y el territorio. Precipitaciones superiores a 14.3mm en marzo determinaron el inicio de la época reproductiva. Esto favoreció el incremento de alimento y sitios para anidar, lo que podría incrementar el éxito reproductivo de la especie. La duración de los machos dentro de su territorio no se asoció con la adquisición de pareja, debido a que machos que logran emparejarse duraron un tiempo similar en sus territorios, que machos que no se emparejaron. Las características del canto y el territorio tampoco se relacionaron con la duración del macho dentro de su territorio. Por lo tanto esto puede ser otra causa para que no se haya encontrado una relación entre la duración del macho en su territorio con la formación de parejas, ya que las características del canto son las que más influyen en la formación de parejas en esta especie.

LPLRFamide causes anorexigenic effects in broiler chicks and Bobwhite quail.

Although LPLRFamide was the first member of the RFamide family to be isolated from a vertebrate species, its effects on hunger and satiety-related processes are poorly documented. Thus, we intracerebroventricularly administered LPLRFamide (3.0-15.0 nmol) to both Cobb-500 (a broiler type of Gallus gallus) and Bobwhite quail (Colinus virginianus) chicks and measured their food intake. The threshold of anorexigenic response was 7.0 nmol in Cobb-500 chicks and the effect had diminished by 30 min post-injection. In Bobwhite quail all doses of LPLRFamide tested caused anorexia that remained throughout the 60 min observation period. A comprehensive behavior analysis was conducted and Cobb-500 chicks had increased food pecks early in the observation period and spent a greater amount of time in deep rest. Although food pecks were increased pecking efficiency was decreased. In Bobwhite quail, feeding pecks and the number of jumps were reduced after LPLRFamide treatment. We judged that these behaviors in both species were likely not competitive with ingestion and thus did not secondarily contribute to anorexia. These results demonstrate that LPLRFamide is associated with satiety-related processes in Cobb-500 chicks and Bobwhite quail, while threshold of responses are different.

Increased yolk testosterone facilitates prenatal perceptual learning in Northern bobwhite quail (Colinus virginianus).

Prenatal learning plays an important role in the ontogeny of behavior and birds provide a useful model to explore whether and how prenatal exposure to hormones of maternal origin can influence prenatal learning and the development of behavior. In this study we assessed if prenatal exposure to yolk testosterone can influence auditory learning in embryos of Northern bobwhite quail (Colinus virginianus). We experimentally enhanced testosterone concentrations in bobwhite quail eggs prior to incubation. The embryos from these T-treated eggs as well as control embryos that had received the vehicle-only or were non-treated were exposed to an individual bobwhite hen's maternal call for 120 min over the course of the day prior to hatching. All chicks were tested at 24 h following hatching for their auditory preference between the familiar bobwhite maternal call versus an unfamiliar bobwhite maternal call. T-treated chicks spent significantly more time in proximity to the familiar call compared to the unfamiliar call and also showed shorter latencies to approach the familiar call than control birds. Increased emotional reactivity, i.e. propensity to express fear responses, was also found in T-treated chicks. Baseline heart rates recorded in a second group of T-treated embryos and control embryos did not differ, which suggests no effect of yolk testosterone on baseline arousal level. To our knowledge this is the first demonstration of the influence of prenatal exposure to testosterone on auditory learning.

Neurotoxicogenomic investigations to assess mechanisms of action of the munitions constituents RDX and 2,6-DNT in Northern bobwhite (Colinus virginianus).

Munitions constituents (MCs) including hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), and TNT derivatives are recognized to elicit aberrant neuromuscular responses in many species. The onset of seizures resulting in death was observed in the avian model Northern bobwhite after oral dosing with RDX beginning at 8 mg/kg/day in subacute (14 days) exposures, whereas affective doses of the TNT derivative, 2,6-dinitrotoluene (2,6-DNT), caused gastrointestinal impacts, lethargy, and emaciation in subacute and subchronic (60 days) exposures. To assess and contrast the potential neurotoxicogenomic effects of these MCs, a Northern bobwhite microarray was developed consisting of 4119 complementary DNA (cDNA) features enriched for differentially-expressed brain transcripts from exposures to RDX and 2,6-DNT. RDX affected hundreds of genes in brain tissue, whereas 2,6-DNT affected few (

Mimicking the natural doping of migrant sandpipers in sedentary quails: effects of dietary n-3 fatty acids on muscle membranes and PPAR expression.

Wild semipalmated sandpipers (Calidris pusilla) eat n-3 fatty acids to prime their muscles for long migrations. Sedentary bobwhite quails (Colinus virginianus) were used as a model to investigate the mechanisms for this natural doping. Our goal was to characterize the stimulating effects of n-3 eicosapentaenoic acid (EPA) and n-3 docosahexaenoic acid (DHA) on oxidative capacity. Mechanisms linked to changes in membrane composition and in gene expression for peroxisome proliferator-activated receptors (PPAR) were investigated. Dietary n-3 fatty acids stimulated the activities of oxidative enzymes by 58-90% (citrate synthase, cytochrome oxidase, carnitine palmitoyl transferase and hydroxyacyl dehydrogenase), and sedentary quails showed the same changes in membrane composition as sandpipers preparing for migration. EPA and DHA have the same doping effect. The substitution of n-6 arachidonic acid by n-3 EPA in membrane phospholipids plays an important role in mediating the metabolic effects of the diet, but results provide no significant support for the involvement of PPARs (as determined by changes in gene expression). The fatty acid composition of mitochondrial membranes and sarcoplasmic reticulum can be monitored by measuring total muscle phospholipids because all phospholipids are equally affected by diet. Only extreme regimes of endurance training can lead to increments in oxidative capacity matching those induced here by diet. As they prepare for long migrations, semipalmated sandpipers improve their physical fitness by eating! Choosing n-3 fatty acid doping over endurance training strikes us as a better strategy to boost aerobic capacity when rapid storage of energy is critical.

Developmental species differences in brain cell cycle rates between northern bobwhite quail (Colinus virginianus) and parakeets (Melopsittacus undulatus): implications for mosaic brain evolution.

Adult brains differ among species in the proportional sizes of their major subdivisions. For example, the telencephalon occupies 71% of the entire brain in parakeets (Melopsittacus undulatus) but only 54% in quail (Colinus virginianus). In contrast, the tectum is smaller in parakeets than in quail. To determine whether these differences in brain region size arise because of species differences in cell cycle rates, parakeet and quail embryos were collected at various stages of development (HH24-HH37) and stained with antibodies against proliferating cell nuclear antigen (PCNA), which labels all dividing cells, and phosphorylated histone-3 (pH3), which labels M-phase cells. Analysis of pH3+ cell densities and pH3+/PCNA+ cell ratios were used to compare cell cycle rates across stages and species. Cumulative labeling with bromodeoxyuridine (BrdU) was also used to compare cell cycle rates at stages 24 and 28 in quail. We found that telencephalic cell cycle rates lengthen with age in both species, but that they lengthen significantly later in parakeets than in quail. This species difference in cell cycle rates explains, at least partly, why adult parakeets have a proportionately larger telencephalon. Tectal cell cycle rates also remain elevated for a prolonged period of time in parakeets compared to quail. This seems paradoxical at first, given that the parakeet's adult tectum is relatively small. However, the tectum is initially much smaller but then grows more extensively in parakeets than in quail. Thus, species differences in adult brain proportions can be traced back to species differences in cell cycle kinetics.

Acute and chronic effects of perfluorobutane sulfonate (PFBS) on the mallard and northern bobwhite quail.

Perfluorobutane sulfonate (PFBS) can be a final degradation product of perfluorobutane sulfonyl fluoride (PBSF)-based chemicals. Surfactants based on this chemistry are potential replacements for perfluorooctane sulfonate (PFOS)-related products and have many potential applications in industrial and commercial processes and applications. To evaluate the potential hazard that PFBS may pose to avian species, acute dietary studies with juvenile mallards and northern bobwhite quail, as well as a quail dietary chronic study of reproduction were conducted. In the acute studies, 10-day-old mallards and quail were exposed to nominal dietary concentrations of 1,000, 1,780, 3,160, 5,620 or 10,000 mg PFBS/kg feed, wet weight (ww) for 5 days and the birds were then fed an untreated diet and observed for up to 17 days. No treatment-related mortalities were observed in the study up to 10,000 mg PFBS/kg, ww feed. Body weight gains of quail exposed to 5620 or 10,000 mg PFBS/kg feed were statistically less than that of unexposed controls. Weight gain of mallards exposed to 10,000 mg PFBS/kg feed was statistically less than that of controls. There were no statistically significant effects on feed consumption of either species. In the acute studies, no observed adverse effect concentration (NOAEC) for mallards and quail were 5620 and 3160 mg PFBS/kg, ww feed, respectively. In a reproduction study, adult quail were exposed to nominal dietary concentrations of 100, 300, or 900 mg PFBS/kg, ww feed for up to 21 weeks. There were no treatment-related mortalities or effects on body weight, weight gain, feed consumption, histopathology measures, or reproductive parameters evaluated in the study when compared to the control group. Concentrations of PFBS in blood serum, liver, and eggs were dose-dependent but were less than the administered dose, indicating biodiminution. Based on the results from the quail reproduction study, the dietary NOAEC was 900 mg PFBS/kg, ww feed (equivalent to an ADI of 87.8 mg PFBS/kg bw/d).

Interactive and vicarious acquisition of auditory preferences in Northern bobwhite (Colinus virginianus) chicks.

Studies examining the effects of stimulus contingency on filial imprinting have produced inconsistent findings. In the current study, day-old bobwhite chicks (Colinus virginianus) received individual 5-min sessions in which they were provided contingent, noncontingent, or vicarious exposure to a variant of a bobwhite maternal assembly call. Chicks given contingent exposure to the call showed a significant preference for the familiar call 24 hr following exposure and significantly greater preferences than chicks given noncontingent exposure. Chicks given vicarious exposure to recordings of another chick interacting with the maternal call showed significant deviations from chance responding; however, the direction of chick preference (toward the familiar or unfamiliar) depended on the particular call used. These results indicate that both direct and indirect (vicarious) exposure to stimulus contingency can enhance the acquisition of auditory preferences in precocial avian hatchlings. Precocial avian hatchlings thus likely play a more active role in directing their own perceptual and behavioral development than has typically been thought.