Yellow-rumped Warbler (Setophaga coronata)

Spring is time for things to renew. Life shakes off the frost and begins anew. I think its time we shake off the winter and start anew here at NerdBirders as well. We have a new look. We are adding new things every day. Today, we wish to bring back the Bird of the Week. Starting today we will post a new bird each week. Feel free to make suggestions or just enjoy! I hope to see you all around more often. Without further ado, let me introduce you to this week’s Bird of the Week

Yellow-rumped Warbler

The Yellow-rumped Warbler, Setophaga coronata, also nicknamed the butter butt bird. How cute is that? Perfect for this woodland beauty. It is a hardy species in the passerine family–which is made up of perching birds, as well as songbirds (the difference between the two seen in the feet — alas, that is for another post). This little bird can be seen all over my state, Washington State, and the entire Northwest of the United States downward South into Mexico and South America and Northward through Canada and beyond. It also spreads out into the Southern parts of the U.S. and the Northern Parts across the U.S. as well (see distribution map below).

yellow indicates summer-only range; blue, winter-only range; and green, year-round range (Source: Wikipedia)

yellow indicates summer-only range; blue, winter-only range; and green, year-round range (Source: Wikipedia)

The yellow-rumped warbler is a survivor. Of the migratory birds, the butter butt bird is one of the last birds to migrate South in the Winter and one of the first to return in the Spring. It owes its hardiness and its ability to travel at leisure to its main food source: the myrtle (Myrica cerifera) or here in the Pacific Northwest (Myrica californica). A waxy berry sustains these birds. According to Garrett Lowe and Russell Greenburg,

The trick is that the yellow-rumped warbler, referred to as the myrtle Warbler in the Eastern U.S., dines on the fat-filled fruits of its namesake, the wax myrtles (and bayberries) of the genus Myrica, which pump it full of energy to survive the harsh temperate winters. So strong is their dependence that its winter range corresponds largely, if not entirely, with Myrica. The southern edge of the winter distribution, Panama, is also the southern extent of Myrica in Latin America. The disjunct population of warblers wintering along coastal California, Oregon and Washington coincides with a west coast distribution of Myrica as well.  So profound is their dependence on Myrica berries, that myrtle warblers are thought to be one of the few vertebrates that can digest wax—a major constituent of wax myrtle and bayberries (used during colonial times for candles).

This is a local myrica plant:


Myrica Californica

Some Fun Facts from All About Birds regarding the Yellow-rumped Warbler:1

The Yellow-rumped Warbler is the ONLY warbler able to digest the waxes found in bayberries and wax myrtles. They are versatile foragers who can find insects in a tree, in seaweed, skimming along rivers and the ocean, from spiderwebs and even getting them from a pile of manure! Now that’s resourceful! When Yellow-rumped Warblers find themselves foraging with other warbler species, they typically let Palm, Magnolia and Black-throated Green warblers do as they wish, but they don’t take kindly to the Pine and Blackburian warblers. And the males forage higher than the females. Maybe the ladies want to stay closer to their nests or perhaps they like to socialize? And finally, the oldest known Yellow-rumped Warbler of the myrtle race was 8 years 9 months old. The oldest known individual of the “Audubon’s” race was 10 years old. So, this hardy little bird lives a long time, in comparison with other birds such as the Western Meadowlark whose average life expectancy is 6 years, 6 months.

While the myrtle berry helps them survive harsher seasons and migrate leisurely, these bright bummed birds are mostly insectivores. They like to eat bugs. They commonly eat caterpillars and other larvae, leaf beetles, bark beetles, weevils, ants, scale insects, aphids, grasshoppers, caddisflies, craneflies, and gnats, as well as spiders. They also eat spruce budworm, a serious forest pest, during outbreaks.2 They also eat other types of fruits and plants such as grapes, greenbrier, poison oak, Virginia creep, dogwood and even poision ivy. In addition, they eat wild seeds such as from beach grasses and goldenrod, and they may come to feeders, where they’ll take sunflower seeds, raisins, peanut butter, and suet. On their wintering grounds in Mexico they’ve been seen sipping the sweet honeydew liquid excreted by aphids.3

They like to live in the mixed woodlands, specifically in coniferous trees (hemlock spruce, white cedar, pine, Douglas-fir, larch or tamarack, etc.). The females build the nest but males help bring them materials at times. This process usually takes about 10 days. They usually nest at great range of heights, anywhere from 3.9 feet to 49 feet high. Their nest is a cup of twigs, pine needles, grasses and rootlets. Sometimes, it has moose, horse or deer hair as well as moss and lichens. The nest is lined with fine hair and feathers, “sometimes woven into the nest in such a way that they curl up and over the eggs.”4 Once she lays eggs, she cares for them for about 12 to 13 days while they incubate. Once hatched, the male and female provide them with food and warmth for about two weeks before they fledge. Two weeks! Birds are so amazing, really.

These lovely mid-sized birds (in comparison to other wood birds) are worth finding. Check in your local area to find where you can see them, you won’t regret it. I will leave you with a link to their songs and calls: click here.

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