Elick, Jennifer, Earth and Environmental Sciences, Susquehanna University, 514 University Ave., Selinsgrove, PA, 17870, elick@susqu.edu; Dickinson, Emma, Mary, Earth and Environmental Sciences, Susquehanna University, 514 University Ave , Selinsgrove, PA, 17870, dickinson@susqu.edu.
In central Pennsylvania, the spring arrival of the Baltimore Oriole (Icterus galbula), their choice of nest location, and nest building materials appear to be strongly influenced by climate change and anthropogenic activities. For the last 12 years, data provided by residents of the Isle of Que (Selinsgrove, Pennsylvania) documents an earlier arrival time for the orioles. In this study, before the leafing-out of trees, historical oriole nests were mapped throughout the Isle of Que and Boy Scout Island using the Arc GIS Field Maps app. These islands are located along the Susquehanna River. There were 56 nests located on the Isle of Que and 2 nests observed on Boy Scout Island. Additionally, nests were examined using binoculars and a Mavic Pro 3 drone to determine if they contained anthropogenic materials like yarn or plastics.
On the Isle, most of the nests were located along Front Street or around houses in developed areas. The abundance of nests near residents over forested spaces (33%) seemed inconsistent with oriole habitat suitability, which prompted us to examine why they chose to live near people. In comparison, Boy Scout Island, which is completely forested, contained very few nests. The dominance of agriculture (58%) and development (9%) on the Isle of Que, in comparison to the Boy Scout Island, which is mostly forested (~100%), caused us to question why the birds preferred living on the Isle of Que near people. On major difference is in the occurrence of flowering vegetation. Flowering trees and bushes (entomophilous plants) were mapped the day after the arrival of the first oriole (April 26, 2025). This study found that early blooming vegetation used in residential landscaping like flowering dogwood, lilac, Japanese Cherry, and apple trees attract insects that represent an important dietary requirement for orioles. Boy Scout Island did not contain the same kinds of flowering vegetation. Insects provide protein for reproduction; other fruit and berry resources become abundant in forested areas and along the riparian buffer after the young have hatched. Though orioles are known to occupy open woodlands, the forest environment in this area is dominated by woodpeckers, which may offer greater competition for food resources in the forest. Nearly all the oriole nests (99%) were also found to be constructed with some form of plastic. The plastic consists of monofilament fishing line, degraded strands of tarp, bail binding, plastic zip ties, polyester yarn, plastic twine, and polyester batting. Most of the nests were in mature deciduous trees (sycamore and maple) in the residential/developed region of the Isle of Que.
The mapping of historic nests reveals a possible explanation for the preferred habitats (and possible changing behaviors) of orioles. The durability of man-made plastics causes the nests to be longer-lasting and resistant to weather and decomposition. Global climate change, the use of plastics and other man-made materials, and the nest location preference demonstrates the influence of our changing world on oriole populations in central Pennsylvania.
Baltimore orioles , Isle of Que , Anthropogenic , climate change