| dc.description.abstract | Ecosystem engineers influence other organisms by altering and modifying the local environment. Woodpeckers act as ecosystem engineers by excavating, and then abandoning multiple cavities in dead and live trees throughout their lifetime. These cavities can be crucial to secondary cavity nesting (SCN) birds that are otherwise limited by the availability of naturally occurring cavities. Additionally, woodpeckers have been known to select sites with high resource availability. Thus, secondary cavity nesting birds that are drawn to the area due to increased cavities may reap additional benefits from higher than normal insect loads. To investigate the influence woodpeckers had on the avian assemblages, I located and monitored 55 active Golden-fronted Woodpecker nests in 2019 in south Texas and evaluated the influence of cavity characteristics on nest survival using logistic regression and model averaging. I conducted insect surveys on a subset of these nests and compared overall avian species richness and relative abundance using point counts. Within all sites I conducted nest searches for the four most common SCN species and again used model averaging to predict successful nests. The results of the insect surveys suggest that biomasses of Coleoptera, Hymenoptera, and Coleoptera were strongly correlated with woodpecker site selection and home-range size. Model averaging indicated that woodpeckers had higher nest success in trees with increased cover and lower levels of decay, while SCN birds had higher levels of nesting success in abandoned woodpecker cavities opposed to naturally occurring ones. Additionally, some species had higher success in live trees, contrary to current literature which suggests that cavity nesting species prefer dead and decaying wood. My results suggest that SCNs may be drawn to areas with woodpecker activity due to increased cavity availability, and may reap additional benefits from higher than normal insect loads. Considering that many SCN birds are in decline, understanding the relationship between SCNs, the sources of their cavities, and potential relationships with foraging resources will be crucial to maintaining their populations. | en |
