Annual abundance of northern bobwhite (Colinus virginianus) and scaled quail (Callipepla squamata) fluctuates drastically in Texas, which complicates a quail manager’s ability to forecast quail abundance for the ensuing hunting season. The Texas Quail Index (TQI) was a 5-year citizen-science project that evaluated several indices of quail abundance and habitat parameters as predictors of quail abundance during the ensuing fall. I found that spring cock-call counts explained 41% of the variation in fall covey-call counts for all study sites in year 1–4, and 89% of the variation in year 5. Further investigation revealed that year 5 was a drought year and had a significantly lower percentage of juveniles in the hunter’s bag. These results suggest that during drought years, fall quail abundance is more predictable than during non-drought years and that low breeding success may be the reason. If these data are correct, quail managers should have a better ability to predict the declines of their fall quail abundance in the dry years. The TQI relied on citizen scientists (cooperators) to collect data. Since most (66.1%) cooperators dropped out of the program, and <8% of all data sets were complete, I surveyed the cooperators by mail to determine the rate and cause of cooperator decline and to identify characteristics of a reliable cooperator (i.e., one that did not drop out of the study). I found that cooperator participation declined earlier each year for year 1–4, and that year 5 demonstrated a steady trend with the least amount of cooperators. Most respondents who dropped out (61.5%) reported their motive for leaving was that it was too time consuming. I found no difference in mean cooperator demographics, satisfaction, or landownership goals between those respondents who dropped out and those that did not. However, 38% of those who dropped out were not completely satisfied with communication from TQI coordinators compared to only 15% of those who did not drop out, indicating that communication, or perhaps overall volunteer management, might have been improved. Future studies should maintain better communication with participants, require less time, and provide an incentive for retention.

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Craniofacial development requires orchestrated and complex interactions between multiple tissues of different origins. Cranial neural crest stem cells migrate from the dorsal neural tube into the frontonasal process and branchial arches where they ultimately form most of the skeletal structures and connective tissue of the craniofacial complex, as well as contributing neurons and glia to cranial ganglia. The timing and mechanism by which cranial neural crest cells progressively differentiate from multipotent stem cells into lineage restricted and terminally differentiating cell types has previously not been investigated. In addition, there are many deficits in our knowledge of the molecular controls regulating early development of neural crest cells within the branchial arches. Spatial and temporal changes in migratory and lineage potential in neural crest populations contributing to the developing first branchial arch and trigeminal ganglia were examined by back-transplanting cells from quail into chick embryos. Neural crest cells that had barely entered the first branchial arch had largely lost both the ability to localise to the trigeminal ganglia and neurogenic differentiation capacity but were still capable of long-distance migration. However, after a further 12 hours residence in the branchial arch, neural crest cells had lost long-distance migratory ability.

The common gecko, Hoplodactylus pacificus (Gray, in McCann (1955) ), is widely distributed throughout New Zealand. As yet no specific ecological study of this lizard has been published, though Sharell (1966) mentions habitat preferences and hibernation behaviour, and Whitaker (1968) has published some data for H. pacificus on Poor Knights Islands (mentioned in this report) and describes their observed foraging behaviour. In this study, carried out from late March through to May 1970, I have recorded information on snout-vent lengths, weights, individual movements, and habitat preference, and have also estimated the population density. This particular lizard does not seem to be active during the Autumn months and no observations of food preferences and foraging behaviour were able to be made.

Recent studies have established that yolk hormones of maternal origin have significant effects on the physiology and behavior of offspring in birds. Herrington (2012) demonstrated that an elevation of progesterone in yolk elevates emotional reactivity in bobwhite quail neonates. Chicks that hatched from progesterone treated eggs displayed increased latency in tonic immobility and did not emerge as quickly from a covered location into an open field compared to control groups. For the present study, three experimental groups were formed: chicks hatched from eggs with artificially elevated progesterone (P), chicks hatched from an oil-vehicle control group (V), and chicks hatched from a non-manipulated control group (C). Experiment 1 examined levels of progesterone with High Performance Liquid Chromatography/tandem Mass Spectroscopy (HPLC/MS) from prenatal day 1 to prenatal day 17 in bobwhite quail egg yolk. In Experiment 2, bobwhite quail embryos were passively exposed to an individual maternal assembly call for 24 hours prior to hatching. Chicks were then tested individually for their preference between the familiarized call and a novel call at 24 and 48 hours following hatching. For Experiment 3, newly hatched chicks were exposed to an individual maternal assembly call for 24-hrs. Chicks were then tested for their preference for the familiarized call at 24 and 48-hrs after hatch. Results of Experiment 1 showed that yolk progesterone levels were significantly elevated in treated eggs and were present in the egg yolk longer into prenatal development than the two control groups. Results from Experiment 2 indicated that chicks from the P group failed to demonstrate a preference for the familiar bobwhite maternal assembly call at 24 or 48-hrs after hatch following 24-hrs of prenatal exposure. In contrast, chicks from the C and V groups demonstrated a significant preference for the familiarized call. In Experiment 3, chicks from the P group showed an enhanced preference for the familiarized bobwhite maternal call compared to chicks from the C and V groups at 24 and 48-hrs after hatch. The results of these experiments suggest that elevated maternal yolk hormone levels in pre-incubated bobwhite quail eggs can influence auditory perceptual learning in embryos and neonates.

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Appetite is a complex behavior which can be influenced by factors within the animal's body as well as the environment around it. Internal factors include hormonal and nutrient concentrations found in the blood stream and subsequent neuropeptide and neurotransmitter signaling in the hypothalamus. External factors, such as high ambient temperature (HAT), can indirectly affect appetite regulation through other neuroendocrine systems such as the hypothalamo-pituitary-adrenal (HPA) axis. Understanding the physiological responses to endogenous factors and HAT exposure in birds will have implications in both the agricultural and biomedical fields. Thus, the purpose of this dissertation research was to explore the hypothalamic molecular mechanisms associated with food intake in broiler type chickens and Japanese quail, and the effect of HAT exposure on food intake in broiler type chickens. Broiler type chickens have undergone intense artificial selection for traits that promote rapid growth, consequently driving them to consume feed incessantly. It is hypothesized that broiler type chickens lack a mechanism that signals satiety, causing them to eat significantly more than layer type chickens. Selection for rapid growth of meat (muscle tissue) has made the broiler more susceptible to the deficits associated with HAT exposure, as animals composed primarily of muscle dissipate less heat while also producing more heat than those composed of fat. The Japanese quail have undergone relatively minor artificial selection compared to the chicken, suggesting that use of this model may provide insight into the mechanisms of appetite regulation in wild-type bird species. This research involved administrating appetite associated factors into the avian brain via an intracerebroventricular (ICV) injection including gastrin releasing peptide, vasoactive intestinal polypeptide, neuropeptide AF, and prostaglandin D2. Additionally, I explored the effects of HAT on food intake, and on the efficacy of several ICV administered appetite associated factors including neuropeptide Y, corticotropin releasing factor and α-melanocyte stimulating hormone. After treatment administration, I measured changes in food intake and behavior, activation of hypothalamic nuclei including the arcuate nucleus, dorsomedial nucleus, lateral hypothalamus, paraventricular nucleus, and the ventromedial nucleus, and the nucleus of the hippocampal commissure. I then measured changes in gene expression in both whole hypothalamic samples and specific hypothalamic nuclei. The data from non-HAT associated studies provided information on the hypothalamic nuclei which respond to the various appetite associated factors and the molecular mechanisms mediating changes in appetite. The data from the HAT study provided information on the hypothalamic nuclei involved in the avian response to HAT exposure, and the molecular mechanisms involved in the effect on food intake. Overall, these data provide insight on the mechanisms associated with short-term regulation of appetite, and pathways associated with stress and food intake. / Doctor of Philosophy / Appetite regulation can be affected by factors both in the body and out in the environment. Understanding how both internal and external factors affect appetite regulation can have positive implications in both the agriculture industry as well as the biomedical field. In agriculture, animals exposed to high ambient temperatures often exhibit several deficits including immunosuppression, decreased body weight, and ultimately an increased risk of mortality. It is hypothesized that the factor linking negative wellbeing to heat exposure is a reduction in food intake. Animals aside, the prevalence of eating disorders has doubled worldwide every 6 years since the year 2000. These numbers have increased even more during the recent COVID-19 pandemic. In order to improve the wellbeing of both humans and animals exposed to stressing stimuli, it is imperative we understand how individual appetite associated factors affect food intake, and how external stressors can impact the normal physiology of the hypothalamus. Thus, the purpose of this dissertation was to elucidate the hypothalamic mechanisms mediating appetite regulation using broiler type chickens and Japanese quail as models. Related pathways and molecular mechanisms were explored for several appetite associated factors including gastrin releasing peptide, vasoactive intestinal polypeptide, neuropeptide AF, and prostaglandin D2. Additionally, the effect of high ambient temperature on food intake, on the efficacy of several appetite associated factors including neuropeptide Y, corticotropin releasing factor and α-melanocyte stimulating hormone, and the hypothalamic pathways and molecular mechanisms mediating heat-induced anorexia were assessed.