The pre-reproductive period in a tropical bird: parental care, dispersal, survival, and avian life histories

The period between offspring birth and recruitment into the breeding population is considered one of the least understood components of animal life histories. Yet, examining this period is essential for studies of parental care, dispersal, demography, and life histories. Studies of the pre-reproductive period are particularly few in tropical regions, where the organization of life histories are predicted to differ compared to northern hemisphere species. For my dissertation I used radio-telemetry, mark-resighting, and field observations to study the pre-reproductive period in a Neotropical bird, the western slaty-antshrike (Thamnophilus atrinucha), in Panama. First, I found that parental care after offspring left the nest (the post-fledging period) was greater than care during the nestling period. Prolonged care resulted in a clear trade-off for parents as they did not nest again until fledglings from the first brood were independent. Parents fed offspring for a prolonged duration during the post-fledging period and higher post-fledging survival was observed compared to many northern hemisphere species. Second, I observed that offspring that remained with parents for longer periods on the natal territory had higher survival both while on the natal territory and after dispersal compared to those dispersing earlier. Parental aggression towards offspring increased with offspring age and offspring dispersed earlier when parents renested. Contrary to other family living species, only a small proportion of antshrike offspring remained on the natal territory until the following year and all dispersed to float. Floating is when juveniles wander within other breeding pairs’ territories. These results suggest that the benefits of delayed dispersal declined with offspring age and with renesting by parents. Third, I observed that survival during the dependent period and first year was greater in slaty antshrikes compared to that of northern hemisphere species. Pre-reproductive survival relative to adult survival was equal or greater than that observed in northern hemisphere species. The date offspring left the nest, mass, and age at dispersal influenced offspring survival, whereas offspring sex and year did not. Relatively high survival during the pre-reproductive period coupled with comparatively low annual productivity clarifies how many tropical species achieve replacement. High juvenile survival appears to obtain from extended post-fledging parental care, delayed dispersal, low costs of dispersal, and a less seasonal environment. Lastly, I experimentally manipulated begging at the nest to examine changes in parental behavior. Under elevated begging, parents increased provisioning rates and reduced the time between arrival to the nest and feeding of nestlings, potentially to reduce begging sounds. Furthermore, parents switched to preferentially feed the closest offspring during the begging treatment. This suggests parents either allowed sibling competition to influence feeding decisions, or feeding the closer nestling increased the efficiency of provisioning. In summary, I found that slaty antshrikes have delayed age at reproduction, higher post-fledging and first year survival, extended post-fledging parental care, equal or greater pre-reproductive survival relative to adult survival, and delayed dispersal compared to many northern hemisphere passerines. These results suggest that this tropical species has a strategy of high investment into few offspring. Furthermore, reproductive effort is equal or greater at least in slaty antshrikes compared to northern hemisphere species, suggesting that the latitudinal gradient in clutch size is not explained by a gradient in reproductive effort.

A "Greater Britain": colonial kin in fictions of settlement, 1850-1890

This dissertation traces the ways in which nineteenth-century fictional narratives of white settlement represent “family” as, on the one hand, an abstract theoretical model for a unified and relatively homogenous British settler empire and on the other, a fundamental challenge to ideas about imperial integrity and transnational Anglo-Saxon racial identification. I argue that representations of transoceanic white families in nineteenth-century fictions about Australian settler colonialism negotiate the tension between the bounded domesticity of an insular English nation and the kind of kinship that spans oceans and continents as a result of mass emigration from the British isles to the United States, Canada, New Zealand, and the Australian colonies. As such, these fictions construct productive analogies between the familial metaphors and affective language in the political discourse of “Greater Britain”—-a transoceanic imagined community of British settler colonies and their “mother country” united by race and language—-and ideas of family, gender, and domesticity as they operate within specific bourgeois families. Concerns over the disruption of transoceanic families bear testament to contradictions between the idea of a unified imperial identity (both British and Anglo-Saxon), the proliferation of fractured local identities (such as settlers’ English, Irish Catholic, and Australian nationalisms), and the conspicuous absence of indigenous families from narratives of settlement. I intervene at the intersection of postcolonial literary criticism and gender theory by examining the strategic deployments of heteronormative kinship metaphors and metonymies in the rhetorical consolidation of settler colonial space. Settler colonialism was distinct from the “civilizing” domination of subject peoples in South Asia in that it depended on the rhetorical construction of colonial territory as empty space or as land occupied by nearly extinct “primitive” races. This dissertation argues that political rhetoric, travel narratives, and fiction used the image of white female bourgeois reproductive power and sentimental attachment as a technology for settler colonial success, embodying this technology both in the benevolent figure of the metropolitan “mother country” (the paternalistic female counter to the material realities of patriarchal and violent settler colonial practices) and in fictional juxtapositions of happy white settler fecund families with the solitary self-extinguishing figure of the black aboriginal “savage.” Yet even in the narratives where the continuity and coherence of families across imperial space is questioned—-and “Greater Britain” itself—-domesticity and heteronormative familial relations effectively rewrite settler space as white, Anglo-Saxon and bourgeois, and the sentimentalism of troubled European families masks the presence and genocide of indigenous aboriginal peoples. I analyze a range of novels and political texts, canonical and non-canonical, metropolitan and colonial. My introductory first chapter examines the discourse on a “Greater Britain” in the travel narratives of J.A. Froude, Charles Wentworth Dilke, and Anthony Trollope and in the Oxbridge lectures of Herman Merivale and J.R. Seeley. These writers make arguments for an imperial economy of affect circulating between Britain and the settler colonies that reinforces political connections, and at times surpasses the limits of political possibility by relying on the language of sentiment and feeling to build a transoceanic “Greater British” community. Subsequent chapters show how metropolitan and colonial fiction writers, including Charles Dickens, Anthony Trollope, Marcus Clarke, Henry Kingsley, and Catherine Helen Spence, test the viability of this “Greater British” economy of affect by presenting transoceanic family connections and structures straining under the weight of forces including the vast distances between colonies and the “mother country,” settler violence, and the transportation system.