Thesis (M.S.)--Texas State University-San Marcos, 2007. / Vita. Appendices: leaves 23-75. Includes bibliographical references (leaves 76-79).

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 101-103). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 101-103). Also available on the Internet.

Thesis (M.S.)--Texas State University-San Marcos, 2007. / Vita. Appendices: leaves 23-75. Includes bibliographical references (leaves 76-79).

Thesis (M. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

The ant building activity of the nest represents an important phenomenon, influencing ambient environment. If we want to know, which factors are affecting this process, we will describe its details. This paper aims to detrmine the factors which influence nest building activity, by an experiment using the species of Lasius niger (L.) in the artifical formicaria.

Nest building in birds has long been assumed to be a behaviour that is not learned, despite suggestive evidence to the contrary. In this thesis I investigated the role of learning in nest building in birds. I focused primarily on the choice of nest material made by zebra finches, in particular between two or more colours of nesting material. Using this aspect of behaviour, I found that adult nest building birds changed their preference for a particular colour of nesting material depending on their own nesting and breeding experience: males that built a nest using material of their less preferred colour later preferred that colour following a successful breeding attempt in that nest. In contrast to this role for learning in adults, in two other experiments I found no evidence that juvenile birds learned about the nest from which they had fledged or that birds learned about what material to nest with from conspecifics. Using wild Southern masked weavers, I also addressed variability in a particular aspect of nest building: the attachment of the very first blade of grass knotted onto a branch. I found that birds did not construct the same attachment each time they did it, even when building at the same location, but that males generally used more loops in their attachments as they built more nests, and when using longer pieces of grass. Finally, I tested zebra finches on a nest building ‘task', using a paradigm often used to test cognitive abilities among tool-users. Birds were presented with two lengths of nest material, one of which was more appropriate for one of two sizes of nest box entrance. I found that nesting birds could choose the appropriate length of material and that the birds' handling of material and their choice of material changed with experience. Taking these results together, it seems that there is a greater role for learning in nest construction than is generally acknowledged and that nest building might involve the same underlying cognitive processes as tool manufacture and use.

Male ring doves ( Streptopelia risoria ) held on long days perform more nest-building than birds held on short days. This difference persists even if circulating androgen is maintained at similar levels in both groups by castration and treatment with exogenous testosterone. It therefore appears that daylength can alter nest-building through some means other than changes in gonadal androgen production. The experiments described in this thesis examined three mechanisms which might be responsible for the effect of daylength on male nest-building. The first series of experiments tested the hypothesis that nest-building activity is greater under long days as a result of increased aromatization of testosterone into estrogen. Castrated male doves were implanted with estradiol benzoate, testosterone propionate (TP), or a combination of TP and an aromatase inhibitor, ATD, and exposed to either long or short photoperiods. Males held under long days continued to build more actively, regardless of the type of hormone being used. The results thus indicate that differences in the rate of aromatization cannot account for the effect of photoperiod. In a second series of experiments an attempt was made to determine whether an increase in the production of hypothalamic luteinizing hormone releasing hormone (LHRH) under long daylengths stimulates nest-building, as a result of a synergism with testosterone. Long- and short-day castrated males were treated with exogenous TP or TP and LHRH to see if the influence of short daylengths could be reversed by LHRH. LHRH treatment had no effect on the nesting activity of either short- or long-day birds. Finally, several tests were performed which focussed on the role of the pineal gland. Removal of the pineal caused a decrease in nesting activity in long-day birds, but not in short-day birds. The effect of pinealectomy does not depend on the presence of the gonads, since the birds displayed similar responses following castration and testosterone treatment. In the second test, the ability, of pinealectomy to nullify the stimulatory influence of long daylengths was confirmed. In addition, injections of chicken pineal extract increased nest-building in pinealectomized and in short-day pineal-intact birds, suggesting that the pineal produces a substance which is capable of stimulating nesting activity. The identity of this substance is unknown. Pilot tests using melatonin failed to show any stimulatory effect of this compound on nesting behaviour. However, serotonin, which is also present in the pineal in high concentration, did increase nest-building in short-day pinealectomized males. These results indicate that in response to long daylengths the pineal gland of male doves releases a compound, possibly serotonin, which stimulates nest-building activity. / Science, Faculty of / Zoology, Department of / Graduate

A surge of recent work elucidating a role for learning and memory in avian nest-building behaviour has challenged the long-standing assumption that nest building develops under genetic control. Whereas that work has been addressed at describing the cognitive mechanisms underpinning nest-building behaviour, almost nothing is known about either the neurobiological processes controlling nest building or the selection pressures responsible for the diversity in avian nest-building behaviour. Here, I sought to identify both the neural substrates involved in nest-building behaviour and some of those selection pressures. First, I used expression of the immediate early gene product Fos, an indirect marker of neuronal activity, to identify brain regions activated during nest-building behaviour in the brains of nest-building and control zebra finches (Taeniogypia guttata). I found that neural circuits involved in motor control, social behaviour, and reward were activated during nest building. Furthermore, I found that subpopulations of neurons that signal using the nonapeptides vasotocin and mesotocin and the neurotransmitter dopamine located within some of these neural circuits were also activated during nest building, suggesting these cell-signalling molecules may be involved in controlling nest-building behaviour. Next, I found that variation in the amount of folding in the cerebellum, a brain structure thought to be involved in manipulative skills, increased with increasing nest structural complexity, suggesting that the cerebellum is also involved in nest building. Finally, using evolutionary statistical models, I found support for the hypothesis that nest-site competition off-ground and increased predation pressure on the ground in Old World babblers (Timaliidae) led to the co-evolution of building domed nests on the ground. Here, then, I provide the first evidence of potential neural substrates controlling and selection pressures contributing to variation in nest-building behaviour.

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