Swallows Three species of swallow were present at John Heinz National Wildlife Refuge while I was there. The most common were Tree Swallows followed by Northern … Read More Please share!Click to share on Facebook (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Pocket (Opens in new window)Click to share on Pinterest (Opens in new window)Click to share on Twitter (Opens in new window)