by Alex Forsythe
"The Yellow Warbler is one of our best known and most abundant summer residents. It arrives as the buds on the apple trees are bursting into bloom. It is no unusual thing to awaken a warm spring morning, after a few days of cold weather, and find that in the night the grass has grown markedly, the naked limbs of the apple trees are clothed in green and decked in flowers. One can almost see things grow. While gazing upon the changed scene, a bit of bright yellow flits among the apple boughs and says 'we-chee, chee, chee, chee-wee'. It is the Yellow Warbler. The warm spell has quickened his movements and brought back a friend of other days." (W. S. Blatchley, State Geologist, Indiana Department of Geology and Natural Resources 22nd Annual Report, 1897).
Yellow Warblers are little rays of sunshine that gleefully herald the arrival of spring. With their golden plumage and tendency to perch and sing to you at eye level, they are one of the easiest warblers to see and identify. However, if you go birding in Central or South America, in the Caribbean, or in the southernmost portion of Texas, you may encounter Yellow Warblers with an extra splash of color: a chestnut crown or head. In these areas, these subspecies are called the "Golden" or "Mangrove" Warbler.
Although Brown-headed Cowbirds will lay their eggs in the Yellow Warbler's nest (40% of the Warbler's nests are parasitized), the Warbler has been known to spot the deception and build a new nest on top of the Cowbird's egg. In the process, the Warbler covers and abandons her own eggs and will lay a new clutch. In 1955, researcher A. J. Berger reported that a Yellow Warbler nest he had been studying in Remus, Michigan had been rebuilt 5 times, covering up 11 Brown-headed Cowbird eggs, in one breeding season! In Berger's study, only 8% of the 75 Cowbird eggs laid in 126 Yellow Warbler nests produced fledglings (Wilson Bulletin, June 1963).
Despite the predation, populations of Yellow Warblers have remained steady. The Breeding Bird Survey Data from the Indiana Dunes bears this out: from 14 nesting birds spotted in 1993, to 26 nesting birds spotted in 2005. With a wide nesting range (from the northern part of South America to Newfoundland and Alaska), their nesting range naturally includes Indiana. According to the U.S.G.S. Interactive Breeding Bird Atlas Species Map (http://www.pwrc.usgs.gov/bba/index.cfm?fa=bba.MapViewer), Yellow Warbler nests have been confirmed throughout our state.
The Yellow Warbler is one of the first warblers to arrive in the spring, but they are also one of the first to leave in late summer. Blatchley noted in his report that their disappearance in the fall is so gradual as to go unnoticed, and that "no more unsatisfactory records are at hand of the fall migration of any birds than of this one."