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Species: Common Yellowthroat Geothlypis trichas

Description:

The Common Yellowthroat is widespread and common in a wide variety of weedy, brushy and marshy habitats but are also found in drier upland habitats as long as there is abundant and dense undergrowth for foraging and nesting. Yellowthroats eat primarily insects, gleaned from low vegetation or on the ground. The familiar song of the male varies between individuals and localities, but has a characteristic rhythm and form. Typically, three to four repetitions of a three or four note phrase are sung with one note sharply accented: “Wichity, wichity, wichity, witch” or “witch-a-wee-o, witch-a-wee-o, witch-a-wee-o.” The low harsh alarm call is also distinctive. They are abundant breeders in North America, ranging from southern Canada to central Mexico. Northern races are migratory, wintering in the southern parts of the breeding range, Central America and the West Indies
Active and inquisitive with wren-like habits they are often flushed from low, grassy, weedy areas. To foil predators, parents drop down into the thick of grasses, secretly approaching the well hidden nest, deliver the food, then depart by another route. The bulky nest made up of woven plant material with linings of fine grasses is hidden in weeds or grasses on or near ground level and usually contains 3-5 white eggs with markings on the larger end.

Identification:

General: They are of small size, stocky, with a short necked crouching posture, plain olive upper side and rounded tail. They measure 11-15 cm with wing span approx 17cm and weight approx 10 gm.
The belly is white and the undertail coverts yellow. They have no white wing bars or tail corners.

Adult Male: Identified by its black mask edged toward the crown with white the coloration vary slightly in appearance among populations
Interior western: pale and greyish with less yellow on throat and whitish frontal band.
Pacific Variation: small and dark brown above with whitish frontal band and extensive yellow on underside.
Southwestern Variation: relatively large bright olive sometimes with entirely yellow underside and with yellow tinged frontal band and yellow on throat wrapping around behind cheek.

Adult female: Females lack the mask, are brownish olive above, buffy below with some yellow especially on the throat. They have a faint buffy eye ring.

Juvenile: Very non-descript with the throat often buffy and sides brownish, males may show a trace of a black mask.

Similar Species: Female Common Yellowthroats resemble female Connecticut and Mourning warblers, except they have dusky or grayish hoods and entirely yellow underparts.

Behavior:  Male Common Yellowthroats perform song flight displays, especially during the late afternoon. The male gradually ascends into the air, calling to a height of 20 feet or higher, whereupon he utters a number of short sputtering notes, followed by song. He then drops back to the ground.

Habitat: The breeding habitats of these birds are mashes and other wet areas with dense shrub and other low vegetation. They may also be found in other areas with dense shrub or thick vegetation from prairie habitat to pine forests. Frequently found near water these birds are less common in dry areas.

Information:

Due to their size Common Yellowthroats are vulnerable to a large number of bird-eating predators, such as Sharp-shinned hawks, Merlins and Shrikes. They have also been recorded as predated by largemouth bass probably taken as the bird foraged on low reed stems.
Within a breeding season the Common Yellowthroat is monogamous although females show no fidelity to their mates and will often try to attract other males with their calls.

Conservation Status:

Although the destruction of wetlands has eliminated habitat in many areas, Common Yellowthroats are one of the most widely distributed and common warblers in North America. Populations in the Pacific Northwest have actually increased in recent years, and Breeding Bird Survey data show a significant increase in Washington since 1966. Common Yellowthroats are common hosts for parasitic Brown-headed Cowbirds, but this does not appear to be a major factor in the Northwest. Conservation status is listed as least Concern (LC).
 
Capture Rates


Common in high numbers at Colony Farm, Common Yellowthroat capture rate (2010-2012; standardized as birds captured per 100 net hours) peaks from July through September corresponding to juvenile dispersal. Yellowthroats migrate south for the winter as indicated by zero capture rates from November - March.

 

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