Scientific Name: Vireo flavifrons
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The Yellow-throated Vireo is a fairly common breeding species in deciduous forests
throughout the eastern United States. Its range extends north to southern Ontario and
southern New England, south to the Gulf Coast and Florida, and west to Minnesota, Iowa,
Missouri, eastern Oklahoma and eastern Texas (DeGraaf et al. 1991). It is a summer
resident throughout most of Minnesota except in the northeast and southwest regions. The
spring migration period extends from late April through early June, with peak numbers
arriving in early to mid-May. In fall, most individuals leave the state by late August or early
September (Janssen 1987). This species is a long distance migrant, wintering from
eastern Mexico south to Columbia and northern Venezuela (Ehrlich et al. 1988). A few
individuals may be found in winter along the Gulf Coast and in Florida (Peterson 1980).
This species is found in relatively open mature woodlands, tall deciduous floodplain
forests, groves of shade trees, and occasionally in mixed deciduous-coniferous forests
(Bushman and Therres 1988). In a study conducted in Missouri, the most consistent
characteristics of vegetation around 32 song perches were a high canopy (>16 m, never
<15), intermediate to nearly complete canopy closure (70-90%, never <55%), and
intermediate to nearly closed subcanopy (50-90%, never <35%) (Kahl et al.1985). The
Yellow-throated Vireo seldom nests in dense forests, and rarely in conifers. The species
was therefore classified as dependent upon mature, deciduous trees.
This vireo forages and nests in the upper canopy. Its diet consists almost entirely of
insects, although berries may also be consumed, especially in the fall (Ehrlich et al. 1988).
Its nest is typically a deep cup, suspended from a forked branch greater than 6 m high
(Harrison 1975). It lays three to five eggs (Ehrlich et al. 1988), and probably raises only
one brood per season.
Although USFWS Breeding Bird Surveys indicate that regional and continental
populations are stable (Robbins et al 1986), marked declines in numbers of Yellow-throated Vireos have been noted by observers in the eastern United States (Whitcomb et
al. 1979, Robbins 1979). In Minnesota, its distribution has been apparently increasing in
recent years to the north and west (Janssen 1987). United States Fish and Wildlife Service
roadside count data, however, indicate no trends in the population since 1966 (Janssen
1990).
Numerous studies provide evidence suggesting that the Yellow-throated Vireo is an
area sensitive species. Bond (1957) was the first to report that some species of small
songbirds were apparently dependent on large forest tracts. In the course of his study of
upland forest habitats in southern Wisconsin, he found that the Yellow-throated Vireo was
50% more common in tracts larger than 80 ac (>32 ha) compared to tracts of less than 40
acres. According to Robbins (1979) the Yellow-throated Vireo has disappeared from areas
in Maryland where it previously nested. The decrease in numbers is apparently correlated
with increased fragmentation of the forests of that region.
The number of Yellow-throated Vireos detected at 500 Breeding Bird Survey stops
in central and eastern Maryland declined sharply when contiguous forest adjacent to the
stop was less than 250 acres (Robbins 1979). Whitcomb et al. (1979) detected this
species only in the largest forest fragments (>175 acres) they censused in central
Maryland. In central Illinois, Blake and Karr (1984) detected Yellow-throated Vireos on only
two forest islands of less than 295 acres. These were a 16 and 40 acre islands. Lynch and
Whigham (1984) found a significant negative correlation between the occurrence of Yellow-Throated Vireos and the degree of isolation of a forest patch. Robbins et al. (1989) found
a significant correlation between the occurrence of this species and percent forested area
within 2 km.
Contradictory data has been presented on the tolerance of this species to selective
cutting and to minimum area requirements of contiguous habitat (Bushman and Therres
1988). Nevertheless, evidence suggests that the extent of mature deciduous forest may be
a limiting factor for this species. The species was therefore categorized as a forest interior
species.
