PARENTAL AGGRESSION IN RELATION TO EGG AND NESTLING QUALITY IN EASTERN BLUEBIRDS (SIALIA SIALIS), TREE SWALLOWS (TACHYCINETA BICOLOR), AND HOUSE SPARROWS (PASSER DOMESTICUS)

Author: Marissa Rossi Faculty Mentor: Dr. Michael Butler Department of Biology, Lafayette College 111 Quad Drive, Easton, PA 18042

Birds aggressively defend their offspring from threats to ensure their survival. Many avian species demonstrate biparental care; therefore, aggression levels in both the male and female may be related to how successful the pair is in defending its young. There are two main hypotheses that describe different patterns of aggressive behaviors within pairs: the pair coordination hypothesis (more similarly behaving pairs experience greater nest success, regardless of overall aggression level), and the pair intensity hypothesis (similarly behaving and also more aggressive pairs experience greater nest success). Markers of nest success include clutch size, egg mass, percentage of eggs that hatch, nestling mass, and percentage of nestlings that survive the nestling phase. The goal of this experiment was to evaluate these hypotheses by quantifying both male and female aggression and metrics of nest success. Because European starlings (Sturnus vulgaris) can usurp nests of eastern bluebirds (Sialia sialis), tree swallows (Tachycineta bicolor), and house sparrows (Passer domesticus; all cavity-nesting songbirds), taxidermied starling models were used to elicit aggressive responses during both egg and nestling phases. A total of 43 nests were tested (13 eastern bluebird nests, 16 house sparrow nests, and 14 tree swallow nests), and all aggression trials were recorded on video for future analysis. During video analysis, shy, bold, and aggressive behaviors were quantified. Correlation analyses will determine if males and females are coordinated, and a principal components analysis will consolidate behavioral data into fewer variables. Preliminary results indicate some evidence of parental coordination, with tree swallows and bluebirds being the most aggressive and house sparrows being the least aggressive. These results will indicate if the pair coordination or pair intensity hypothesis is supported.


Additional Abstract Information

Presenter: Marissa Rossi

Institution: Lafayette College

Type: Poster

Subject: Biology

Status: Approved


Time and Location

Session: Poster 2
Date/Time: Thu 12:20pm-1:20pm
Location: University Center Ballroom - Tripod 12 Side C