Masters Theses

Date of Award

8-2006

Degree Type

Thesis

Degree Name

Master of Science

Major

Wildlife and Fisheries Science

Major Professor

David A. Buehler

Committee Members

Frank Van Manen, Roger Tankersley Jr. Joseph R. Robb

Abstract

Cerulean (Dendroica cerulea) nests (n=53) were monitored on Big Oaks National Wildlife Refuge in 2004 and 2005 to assess survival rates and to provide breeding habitat data. Mayfield nest success for ceruleans on the refuge was 22.0 ± 9.6% (2 SE) overall. Fifteen of 53 nests fledged an average of 2.4 ± 0.32 (2SE) fledglings per nests. Three nests (6% of total) were found parasitized by Brown-headed Cowbirds (Molothrus ater), although this should be considered a minimum estimate of parasitism because nests were not checked during incubation. One nest was destroyed during incubation by a Sharp-shinned Hawk (Accipiter striatus).

The mean height of cerulean nests was 17.8 ± 1.2 m (2 SE; range = 6.0 – 31.3m). Nests were built in 12 different species of trees; black walnut (Juglans nigra) and white oak (Quercus alba) were the most common. No habitat characteristics were associated with changes in daily nest survival probability. Daily nest survival also did not differ by temporal characteristics (nest age, stage of nest cycle, or year). Cerulean Warbler breeding habitat differed from random sites. Fewer trees (≥ 3 cm diameter at breast height) and increased woody stem (1-3 cm diameter at breast height) density were associated with cerulean nest sites and nest patches. Nest sites were characterized by having less woody stem density than the nest patch, but tree density did not differ.

Avian nest success, avian consumption of periodic cicadas, and periodic cicada abundance were monitored in 2004 to test the effects of abundant food on nesting ecology. Nests also were monitored in 2005 when periodic cicadas were present in very low numbers. During the 2004 cicada emergence, I estimated that more than 10 million cicadas of 3 different species emerged on the study area and appeared to satiate nest predators from 23 May-10 June. When analyzed together, nests were more likely to survive during the peak of the periodic cicada emergence than at any other time. The same was true of nests build >1 m above ground. The probability of daily survival of ground nests was unaffected by periodic cicada emergence. Analysis of Acadian Flycatcher (Empidonax virescens), Wood Thrush (Hylocichla mustelina), and Cerulean Warbler nests indicated some variation in survival probability over time, but variation in nest survival was not easily distinguishable from a model of constant survival.

Blue Jay (Cyanocitta cristata, nest predator) and Brown-headed Cowbird numbers increased on the study plots the year after the cicada emergence. Brood parasitism rates were consistent between years; Wood Thrush nests were the most affected (19% of nests parasitized).

Although cicada emergence appeared to increase nest survival in 2004, increased nest predator populations in 2005 appeared to decrease nest survival rates to below average levels. As a result, the net effect of cicadas on avian populations may be equivocal.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS