Just northeast of Denver and northwest of DIA, Barr Lake is the focus of the eponymous state park and home to the Rocky Mountain Bird Observatory. Bird records for the park go back well over a century, making this historically the best-studied birding site in Colorado. In that time, Barr has added at least eighteen species to the state list. The lake is almost completely surrounded by mature cottonwoods, often several deep with considerable undergrowth, making this an excellent place to find migrant landbirds and riparian breeders.