Original description: Junco insularis Ridgway 1876
Taxonomic history in AOU/AOS Check-list
AOU 1 (1886): Guadalupe Junco, Junco insularis
AOU 2 (1895): Guadalupe Junco, Junco insularis
AOU 3 (1910): Guadalupe Junco, Junco insularis
AOU 4 (1931): Guadalupe Junco, Junco insularis
AOU 5 (1957): Guadalupe Junco, Junco insularis
AOU 6 (1983): Dark-eyed Junco, Junco hyemalis [insularis group, Guadalupe Junco]
AOU 7 (1998): Dark-eyed Junco, Junco hyemalis [insularis group, Guadalupe Junco]
IUCN Conservation Status: Endangered
The Guadalupe Junco is critically endangered, inhabiting a total range of only some 500 acres in its native island’s north. By 1970, the population of introduced goats recorded by Bryant had increased to more than 35,000, and their aggressive browsing, along with the trees’ old age, reduced the cypress forest to a small, narrow grove. Goats were eradicated from the island in 2007, but a fire the following year delayed the forest’s regeneration, reducing the junco’s prime habitat by more than half.
“Feral cats and mice still plague the island, so that long-term survival of juncos is anything but guaranteed. Targeted conservation efforts are urgently needed….”
Habitat: Guadalupe Juncos occur from sea level to the island’s highest elevations in pine, oak, and cypress forests; they also make use of the introduced tree tobacco, a plant scorned by browsing livestock and thus available to the juncos and other birds even before goats were removed from the island in 2007. Howell suggested that breeding efforts were more successful in the native cypress groves than in tree tobacco thickets.
Behavior: The Guadalupe Junco provides a prime illustration of “island tameness,” fearlessly approaching humans and even entering dwellings in search of food. It is possible that the decades of cautionary experience with human collectors has made the birds somewhat less tame:
“In June 1953 the juncos showed no alarm unless approached within about 6 feet, but the birds moved away at closer range and could not have been caught in a butterfly net or struck with a stick.”
The juncos spend most of their time on the ground or in low vegetation, feeding on seeds and insects gathered from loose soil and crevices.
Voice: Bryant claimed that the song of the Guadalupe Junco was, like that of most of the dark-eyed juncos, a simple loose trill resembling that of a Chipping Sparrow. In fact, the island bird’s song is considerably more complex and considerably more variable; one song type may be repeated several times before the singer switches to a second, finally returning to the first. The songs comprise several different syllable types uttered in varying combinations; they may include a trill, a buzz, and a selection of bright, whistled syllables. One simple song type begins with a cheerful series of slurred notes, chiptewee, followed by a medium-slow trill.
Detailed description and measurements drawn from standard reference works
Adult: Medium-length tail short for a junco. Inner three pairs of tail feathers slaty blackish. Rectrix 4 usually mostly or entirely blackish on outer web, mixed black and white on inner; rectrix 5 usually mostly or entirely blackish on outer web, mixed black and white—white usually predominating—on inner; rectrix 6 usually mostly or entirely white on outer web, entirely or mostly white on inner web. Upper tail coverts and rump dull fairly pale slaty. Back and scapulars brown. Wing short. Primaries and secondaries blackish with narrow grayer edges. Tertials blackish with gray-brown edges. Greater and median coverts mostly blackish on inner webs, broadly edged brown on outer webs; brown of coverts flows into brown of scapulars. Wing coverts without whitish tips. Nape soft gray, distinctly set off from brown back.
Under tail coverts dusky with dirty white edges. Vent and center of belly white, bordered by broad pinkish cinnamon flanks. Breast and throat pale slaty gray, blacker at base of lower mandible.
Crown pale slaty gray, with variable faint brownish wash especially in female. Broad black patch on lore, encompassing entire eye and base of lower mandible.
Tarsus and long toes dusky flesh-pink. Eye brown. Bill deep at base and very long; lower mandible dark dull pinkish gray, upper mandible darker bluish horn at base and along culmen.
Juvenile: Medium-length tail short for a junco. Inner three pairs of tail feathers slaty blackish. Rectrix 4 usually mostly or entirely blackish on outer web, mixed black and white on inner; rectrix 5 usually mostly or entirely blackish on outer web, mixed black and white—white usually predominating—on inner; rectrix 6 usually mostly or entirely white on outer web, entirely or mostly white on inner web. Upper tail coverts and rump dull fairly pale slaty with fine scattered streaks. Back and scapulars dusty brown with fine darker shaft streaks. Wing short. Primaries and secondaries blackish with narrow grayer edges. Tertials blackish with gray-brown edges. Greater and median coverts mostly gray on inner webs, broadly edged dusty brown on outer webs; brown of coverts flows into brown of scapulars. Wing coverts sometimes with small brown or buffy tips. Nape brownish gray with narrow streaks, rather indistinctly set off from brown back.
Under tail coverts dusky with dirty white edges. Vent and center of belly off-white with scant fine streaking; flanks buffy gray with dusky streaking, breast sides pinker. Breast buffy gray with coarse dusky streaking. Throat pale buffy gray, streaked dusky where it meets breast.
Crown deep brownish gray with dusky streaks. Ear coverts and neck sides dull gray to brownish gray with fine, faint streaks.
Eye brown. Bill deep at base and long; lower mandible light brown at base and dusky at bip, upper mandible darker.
Length 136-144 mm (5.4-5.7 inches)
Wing chord 66-69 mm (2.6-2.7 inches)
Tail 59-63 mm (2.3-2.5 inches)
W:T 1.09
