Based on the description provided, it sounds like you are asking about the Yellow-rumped Warbler, which is a small gray bird with yellow patches on its rump. The Yellow-rumped Warbler (Setophaga coronata) is a common sight in North America and gets its name from the distinctive colorful patches on its rear. Let’s dive deeper into identifying details and facts about this little bird.
Identifying Details
The Yellow-rumped Warbler is a small songbird that grows to be 4.7-5.5 inches in length and weighs just 0.3-0.5 ounces. Here are some key identifying features of this species:
- Gray back and crown
- White underside and throat
- Yellow patches on sides of breast and rump
- Black streaks on flanks
- White wingbars
- Dark eyeline and eyelore
- Thin pointed bill
The male and female Yellow-rumped Warblers look very similar. The males may have slightly brighter yellow patches, but otherwise it is difficult to distinguish between the two sexes by appearance alone.
In flight, these warblers display white outer tail feathers that are visible when their tail is fanned. Their wings are short and rounded. Their flight style consists of a mix of fluttering and gliding.
Range and Habitat
The Yellow-rumped Warbler has an extremely large range extending across much of North America. This species breeds predominantly in Canada and the western United States, as far north as Alaska and the Yukon Territory.
In the fall, they migrate south to overwinter in Central America, the Caribbean, and the southern United States. Some individuals may remain year-round in parts of California, the Pacific Northwest, and the Appalachian Mountains if food sources allow.
These warblers occupy a wide variety of habitats during the breeding season, including both wet coniferous and mixed forests. They are also found in areas with plentiful shrubs and smaller trees, such as forest edges, parks, and suburban yards.
On their wintering grounds, they move into more open woodlands, shade-coffee plantations, and mangroves. A key factor in their habitat selection seems to be the presence of suitable nesting sites and insect prey.
Diet
The diet of the Yellow-rumped Warbler consists predominantly of insects and spiders. Its insect prey includes flies, beetles, moths, butterflies, treehoppers, and ants. These birds forage actively in trees and shrubs, gleaning insects from leaves and twigs.
They have the unique ability among warblers to digest waxes found in bayberries and wax myrtle. This allows them to supplement their diet with the waxy fruit from these plants when insect food sources are scarce.
The Yellow-rumped Warbler employs a variety of foraging techniques to capture prey. These include hovering, probing, leaf-gleaning, flycatching, and bark-gleaning. They sometimes beat their wings against vegetation to stir up hidden insects.
Nesting and Reproduction
Yellow-rumped Warblers begin breeding in late April or May, depending on their northern latitude. The males establish nesting territories and attract females through singing and display flights.
The female chooses the nest site, typically located in a conifer tree 5-15 feet above the ground. The nest is an open cup built from twigs, bark strips, grass, moss, and pine needles. It is then lined with soft materials like hair, down, and fine grasses.
A clutch contains 3-6 eggs which are creamy white with brown speckles. The female incubates the eggs for 12-13 days before they hatch. The nestlings are cared for by both parents and fledge the nest at 9-12 days old. The young birds become independent a few weeks after fledging.
These birds are prone to brood parasitism by Brown-headed Cowbirds in some parts of their range. If the warbler parents raise a cowbird chick, it often results in lower success for their own young. Yellow-rumped Warblers may produce two broods per season, especially in southern areas.
Migration
One of the Yellow-rumped Warbler’s most remarkable traits is its ability to digest bayberries and wax myrtles. This allows them to make use of fruit resources not available to other warblers and gives them an advantage on their migratory journeys.
These warblers are among the first to migrate south in the fall, starting as early as late August. They migrate by night in loose flocks, feeding on wax myrtle berries during the day to fuel up. Their wintering grounds often contain good supplies of these high-energy fruits.
In the spring, the Yellow-rumped Warblers again rely on wax myrtle and bayberry fruits to fuel their return migration north. They start arriving on the breeding grounds by early April. Males arrive first to establish nesting territories before the females follow several weeks later.
These birds fly remarkably long distances, covering 2500 miles or more between their breeding and wintering areas. Their ability to eat waxy fruits helps sustain them on these lengthy migratory journeys.
Conservation Status
The Yellow-rumped Warbler has a large global population estimated at 72 million individuals. Their numbers actually grew over the last 50 years as they adapted well to human changes in the environment, including forest management practices.
They are not currently considered threatened or endangered. However, potential threats could include loss of wintering habitat and collisions with human structures during migration. Overall, the Yellow-rumped Warbler remains widespread and common throughout its broad range.
Fun Facts
Here are a few interesting facts about the Yellow-rumped Warbler:
- Its scientific name Setophaga coronata means “crowned moth-eater”.
- Yellow-rumped Warblers sunbathe, facing into the sun and fluffing their feathers.
- They sometimes steal feathers from other birds to line their own nests.
- Their song is a buzzy “tseet” sound.
- They were once called “Myrtle Warblers” and “Butter-butts”.
- Yellow pigments in their feathers come from carotenoids in their diet.
Conclusion
The Yellow-rumped Warbler is easily identified by its gray and white plumage accented by yellow rump patches and wingbars. This common songbird breeds across northern forests and migrates long distances to and from its wintering grounds farther south. It has adapted well to human changes, allowing its widespread population to remain stable. The Yellow-rumped Warbler’s unique ability to eat waxy fruits provides it with an important migratory advantage over other warbler species. So the next time you see a flash of yellow in the trees, listen and look closely – it may just be one of these hardy little warblers!