It's not often that a bird's back side becomes its defining feature but that's the case with this bird, the yellow-rumped warbler, Setophaga coronata as it's known in the world of science.
That back patch just above the tail is its signature mark. In the spring and summer, this bird becomes brightly plumed, with sharp blacks and whites and a shade of yellow that approaches orange. But in the winter, when we're most likely to see it down here in Florida, it becomes much duller, the yellow tramp stamp being this warbler's one remaining colorful flare.
The yellow-rumped warbler ranges over most of North and Central America, breeding in the summer throughout most of the Rocky Mountains and along the far northern reaches of the continent. Come fall, it migrates in huge numbers, flying south to Florida and warm spots beyond. Not all yellow-rumps make the trip, however. Their ability to eat and digest certain wax-covered fruit allows them to spend the winter as far north as New England or even into Canada.
Yellow-rumps are rather large as warblers go, meaning it's still on the small side in the greater scheme of things, but bigger than its cousins. It's body length can approach six inches, it's wingspan can exceed nine. Both males and females are about the same size; like with most birds, females are duller in appearance than the guys.
There are two distinct forms of the yellow-rumped warbler, the wax myrtle, predominant in the east, and Audubon's, which tends to hang in the Rockies and is rarely seen in the east. Myrtles, however, will winter along the Pacific Coast. They've also been known to roam as far as Alaska, Siberia and Europe.
In the summer, conifer forests are the main habitat for yellow-rumps; in winter, they prefer open areas where fruit is available. They do eat a wide variety of fruit, including the berries of poison ivy and poison oak.
Other times of the year, however, bugs, including beetles, ants, larvae and scale insects, are on the menu. They will hover to pick them off leaves, strike through the air or forage on the ground for a meal.
They tend to build their nests in conifers, either out on the edges of branches or in the crook of a branch along the main trunk. They can be high, or near the ground.
A pair can have one or two broods a year, each between one to six eggs each. Eggs incubate for about two weeks, with the females doing most of the sitting. The young fledge in another two weeks. Both parents do the feeding.
Yellow-rumps are members of Parulidae, the wood warbler family.
Arthur R. Marshall Loxahatchee National Wildlife Refuge