San Diego Management & Monitoring Program


Yellow-breasted chat
Icteria virens

Vertebrata

Vertebrata
Kingdom Phylum Subphylum Class Order Suborder Family

Current distribution rangewide

North America and Central America distribution; the yellow-breasted chat’s range extends north to the southern plains of Canada and south to Central America. During the summer months yellow-breasted chat is distributed over a large area of the eastern United States. The distribution in the west is much more fragmented. Localities include the Cascade Range; central Oregon valleys; southern Idaho; northern Nevada; and portions of California, Utah, western Colorado, and central Arizona [1].


Known Populations in San Diego County

Occurs in MU 1, 2, 3, 6, and 8 in the MSPA. The yellow-breasted chat is a migrant and summer resident, primarily from late March to late September [2].Breeds from late April through early August [1, 2].The yellow-breasted chat breeds primarily in the northern third of the state and is currently scarce in the Central Valley and central and southern California [3]. Populations are known to occur along the Santa Margarita River north of Fallbrook, the San Luis Rey River between Interstate 15 and Pala, the San Pasqual Valley down to Lake Hodges, the lower Pensaquitos Canyon, along the Sweetwater River in the Jamacha area, and in the Tijuana River Valley [2].


List status

Not listed


Habitat affinities

Nesting Chats occupy riparian habitats with well-developed shrub layer and an open canopy [1].Nesting habitat will be in close proximity to borders of streams, creeks and rivers in plants with dense thickets and tangles [3]. The nests are usually placed 1 meter from the ground, but can be up to 2 meters from the ground [4]. Chats will establish and defend territory, but pairs often gather and congregate [1].


Taxonomy and genetics

The yellow-breasted chat is 17-19 cm long, and weighs an average of approximately 26 g. The western subspecies (I. v. auricollis) has a longer tail than the 2 eastern subspecies (I. v. virens), by an average of 6 mm [5, 6, 7]. The maximum recorded age of a wild yellow-breasted chat is 8 years, 11 months [8].


Seasonal activity

Yellow-breasted chats migrate annually between breeding grounds in North America and wintering grounds in Mexico and Central America. For populations breeding in southern California, spring migration from the wintering grounds lasts from mid-April to late May; fall migration from the breeding grounds lasts from mid-July to mid-September [5].


Life history/ reproduction

Similar to the mocking-bird, the song of the yellow-breasted chat consist of a series of repeated whistles, “chacks” and “churrs” , a common characteristic for dense riparian woodland birds [2]. Although spotting one can be difficult, the chat is locally common during summer months. Like many riparian birds, the chat is highly susceptible to brood parasitism by brown-headed cowbirds. Trapping of cowbirds since the mid 1980’s has resulted in a considerable increase in yellow-breasted chat numbers [9]. The breeding season generally begins in late April and can last until August. Males arrive on the breeding grounds shortly before females in April–late May. Pair formation and territory establishment for this species is not well known. Once pair formation is established, females will then initiate nest construction. Eggs are typically laid between May and July. Females lay 3-6 eggs and incubate them for 11–12 days; both parents feed the nestlings until they fledge at approximately 9 days. No data are available on the reproductive success of the California population [1].


Diet and foraging

The yellow-breasted chat eats a variety of arthropods, including beetles and weevils, true bugs, ants, bees, caterpillars, and spiders. In late summer and fall, chats feed to a large extent on small fruits, such as the fruits of honeysuckle, wild strawberry, blackberry, mulberry, chokecherry, sumac, and nightshade [5]. Nestlings are typically fed a diet of soft-bodied orthopterans (e.g., grasshoppers) and larval lepidopterans [10].


Dispersal

Information on juvenile chats and post breeding dispersal is minimal. Data from the eastern United States indicate an extremely low fidelity to breeding sites between years, with many spatially separated breeding sub-populations linked by movement of individuals among short-lived patches of suitable habitat [1]. In southern California, however, the limited amount of available habitat may foster a higher level of breeding site fidelity [1].


Threats

The loss and degradation of riparian woodland with dense understory is a continuing threat to the Central Valley population of yellow-breasted chat, as is brown-headed cowbird brood parasitism. Grazing that degrades suitable habitat has been implicated in local population declines [11].


Special considerations:

The destruction of riparian habitat and invasion of the brown-headed cowbird has simultaneously impacted the yellow breasted chat [9]. Recently, chat populations have successfully rebounded due to the initiation of cowbird trapping along their nesting habitats. Populations where trapping has been implemented appear to have increased in size. Destruction of riparian woodland gained attention and slowed significantly after the least Bell’s vireo was designated as endangered in 1986 leading to a regeneration of suitable habitats for riparian birds [2].


Yellow-breasted chat sources