|Species: MacGillivray's Warbler
Warbler is the close western counterpart of the Mourning Warbler. It
is a skulking bird that spends much time low, well within dense
brush and thickets. Its major physical distinction is the prominent
white eye arcs above and below each eye.
John K. Townsend first named this warbler Tolmie’s warbler after Dr.
W.T.Tolmie, an ornithologist, surgeon and entrepreneur with the
Hudson’s Bay Co. Later, however, J.J.Audubon renamed the species
MacGillivray’s in honour of a close friendship with Dr.
W.MacGillivary, a Scottish ornithologist.
This wood warbler is found over much of the west from southeastern
Alaska to New Mexico and as far east as western Nebraska. The first
breeding birds arrive on territory in coastal B.C. in late April to
early May. Its winter range is from Central Mexico to Panama.
This is a medium size warbler with prominent white eye-arcs above
and below each eye witch is present in all plumages. It has a weakly
bi-coloured bill and pink legs. It is 13 cm long and weighs 10.5 g.
Gray hood; black lores; white arcs above and below the eyes and
variable dark slate mottling on lower throat. Olive upperparts and
bright yellow below.
Similar to male but hood and throat paler; chin whitish and
yellow below slightly paler than male.
Gray of forehead, crown and nape slightly tinged with olive-brown.
Chin and throat very pale gray, becoming darker gray; slightly
mottled on the lower throat forming a hood border. Juveniles have
either a broken or complete white eye ring.
The Orange Crowned Warbler with yellowish underparts,
particularly birds of the race ‘orestera’ are very similar. The
Mourning Warbler lacks the white eye arcs, but otherwise is very
difficult to distinguish from Oporonis tolmiei.
This warbler haunts dense thickets, where it forages by hopping
along the ground or among lower twigs of shrubs and trees for
insects. It is timid and elusive.
Prefers cut-over or fire-swept areas of second-growth woodland, dead
and fallen trees, brushy areas near low moist ground; brushy dry
hillsides not far from water, thicketed draws and canyons as well as
dense willows along stream bottoms.
season the male becomes bolder and often sings, alternating between
thickets and a treetop perch throwing back its head and putting much
effort into its liquid song.
This species hybridizes with its eastern equivalent, the Mourning
Warbler where ranges overlap.
The nest is between upright stems of shrubbery 2-5ft above ground in
dense, moist places and is loosely built of weed stalks, straws,
dried grasses lined with fine materials. The nest usually contains 4
white or cream-white, brown speckled eggs.
Populations appear to be stable, and the species’ acceptance of
brushy habitats, which are successional to logging, suggests that
widespread declines are unlikely. Populations at the southern limit
of the range in coastal central California, the mountains of
southern California, and in Mexico are a small and fragmented, and
could be vulnerable.
Capture of MacGillivray's Warbler occurs from spring through
the summer and early fall (April - September). Capture rates
(2010-2012; standardized as birds captured per 100 net
hours) however are at their highest in spring into early
summer (May and June). MacGillivray's Warblers are medium to
long distance migrants, moving south for the winter as seen
by our zero capture rate between October - March.