A seven-year Cornell University study published in 2013 found that "low-level PCB contamination is disrupting the way some birds sing their songs."
You may also search article databases from the SUNY Adirondack Library's webpage using the "Start Your Research Here" box on the library's home page. Off-campus access is limited to the college's students, faculty and staff; community members may visit the library to search them.
Here are selected birding magazines' sites. Full access is usually reserved for members, but non-members can usually see some of the articles, photos and blogs:
These two databases list articles from ornithological periodicals:
Here are other excellent sources for birding research: