Avian Conservation and Ecology (Dec 2018)

Prothonotary Warbler demography and nest site selection in natural and artificial cavities in bottomland forests of Arkansas, USA

  • Morgan C. Slevin,
  • Alix E. Matthews,
  • Than J. Boves

DOI
https://doi.org/10.5751/ACE-01235-130205
Journal volume & issue
Vol. 13, no. 2
p. 5

Abstract

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Anthropogenic alterations to bottomland forests in the United States that occurred post-European settlement likely negatively affected many avian species. The Prothonotary Warbler (Protonotaria citrea), a secondary cavity nester that breeds predominantly in these forests, has steadily declined over the past 60 years, and our ability to mitigate this trend is partially limited by a lack of basic biological data. Although much research has been devoted to Prothonotary Warblers, most studies have focused on local breeding populations that use nest boxes; we lack information about habitat selection behavior and demographic parameters of individuals that use natural cavities, which includes the vast majority of the global population. We studied warblers nesting both in boxes and natural cavities in central Arkansas, USA. We aimed to evaluate: (1) microhabitat features important for nest site selection, (2) relationships between these features and nest survival, and (3) demographic parameters of individuals breeding in natural cavities versus nest boxes. We hypothesized (1) selected nest site characteristics are associated with nest survival, and (2) natural cavities and nest boxes provide similar nest features related to clutch size and number fledged, but that predation protection differs. We found that warblers preferred nesting in dead trees with cavities that were higher and shallower than available random cavities, and that canopy cover within 5 m of nests was inversely related to nest survival. Demographic parameters did not differ between natural cavities and nest boxes; however, when excluding flooded nests, boxes experienced lower rates of nest depredation. We believe that forest management strategies that increase the number of suitable dead nest trees and restore the natural hydrology of these ecosystems would create and improve habitat for this iconic species. We advocate multiscale experimental canopy cover manipulation to explore the causal mechanism(s) of the relationship we found between canopy cover and nest survival.

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