Identifying the composition of avian diets is a critical step in characterizing the roles of birds within ecosystems. However, because birds are a diverse taxonomic group with equally diverse dietary habits, gaining an accurate and thorough understanding of avian diet can be difficult. In addition to overcoming the inherent difficulties of studying birds, the field is advancing rapidly, and researchers are challenged with a myriad of methods to study avian diet, a task that has only become more difficult with the introduction of laboratory techniques to dietary studies. Because methodology drives inference, it is important that researchers are aware of the capabilities and limitations of each method to ensure the results of their study are interpreted correctly. However, few reviews exist which detail each of the traditional and laboratory techniques used in dietary studies, with even fewer framing these methods through a bird-specific lens. Here, we discuss the strengths and limitations of morphological prey identification, DNA-based techniques, stable isotope analysis, and the tracing of dietary biomolecules throughout food webs. We identify areas of improvement for each method, provide instances in which the combination of techniques can yield the most comprehensive findings, introduce potential avenues for combining results from each technique within a unified framework, and present recommendations for the future focus of avian dietary research.

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ABSTRACT. Prescribed burning maintains marsh habitat, but its impact on breeding King Rails (Rallus elegans) is poorly understood. This practice may serve as a means to enhance populations of a species whose numbers are declining in the southeastern United States. We used call-broadcast surveys and nest searches to categorize the state of occupied plots by the presence or non-presence of nesting activity in the Back Bay region, North Carolina and Virginia, in 2010. We also used nest video surveillance to estimate nest survival in 2009 and 2010. The probabilities that a surveyed plot was occupied ( 1 ) and contained an active nest ( 2 ) were higher in recently burned marsh plots (0-1 year-since-burn [YSB]) than in plots with ≥2 YSB at Mackay Island and Back Bay National Wildlife Refuges (NWRs). Highest probabilities were recorded in 0-1 YSB plots at Mackay Island NWR ( 1 = 0.96 ± 0.04, 2 = 0.75 ± 0.18), and the lowest in ≥2 YSB plots at Back Bay NWR ( 1 = 0.21 ± 0.10, 2 = 0.03 ± 0.04). Nest survival from egg laying to hatching (31 d) was 0.48 (95% confidence interval [CI] = 0.06-0.83), with an estimated 0.79 (95% CI = 0.29-0.96) survival rate for the incubation stage (21 d). These nest survival estimates for King Rails in fire-managed marshes were similar to estimates for other populations. Measures of vegetation cover, proxies for concealment, did not differ between nest sites and unused sites, even within recently burned marshes. This lack of differences in vegetation structure suggests that regrowth occurs rapidly during the period between burning (winter months) and the onset of reproduction (late April). Thus, recently burned marshes may benefit nesting King Rails by providing nest concealment. In addition, burned marshes may enhance availability of many invertebrates. Although we found that the probability that surveyed plots contained active nests was higher in recently burned marsh plots, estimates of fledging success are needed before marsh burns can be considered an effective means of fostering population growth. RESUMEN. Ocurrencia de nidos y supervivencia del Rascón real en pantanos costeros con manejo de fuego en Carolina del Norte y VirginiaLos incendios controlados ayudan a mantener los pantanos, pero su impacto en la reproducción del Rascón real (Rallus elegans) está poco estudiado. Esta práctica puede servir como un medio de incrementar poblaciones de una especie cuyos números han declinado en el sudeste de Estados Unidos. Usamos censos con playback y búsqueda de nidos a fin de categorizar el estado de ocupación de parcelas por la presencia o ausencia de actividad de nido en la región de Back Bay, en Carolina del Norte y Virginia, en 2010. Utilizamos también monitoreo por video de nidos para estimar la supervivencia de nido en 2009 y 2010. Las probabilidades de que una parcela censada se encontrara ocupado ( 1 ) y de que contuviese nidos activos ( 2 ) fueron más altos en pantanos recientemente incendiados (0-1 años desde quema [ADQ]) que en parcelas con ≥2 ADQ en Isla Mackay y en el Refugio Nacion...

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