MacGillivray’s Warbler – Profile | Facts | Song | Traits | Range

MacGillivray's Warbler

MacGillivray’s Warbler is olive above and shiny yellow under, with distinctive grey hoods extending to its breast. Males’ hoods are darkish charcoal grey, and females’ hoods are lighter grey.

MacGillivray’s Warbler profile

Both sexes have white crescents above and under their eyes. Males have darkish areas in front of their eyes. Immature birds have much less distinct hoods and resemble females.

A furtive songbird of dense brush, MacGillivray’s Warbler is a chic yellow and grey amid green leaves. Males have a sooty grey hood highlighted with hanging white crescents above and under the attention.

Don’t search for this species in open forests, however, search for it as an alternative in virtually any form of dense thicket, shrubbery, willows, or low tangles alongside wooded streams.

In these areas, it forages contained in the vegetation, gleaning bugs from foliage and from the ground.

MacGillivray’s Warbler  Geographic Range

MacGillivray’s warblers breed in western North America as far north as southeastern Alaska and as far south as Central Arizona and elements of southern California.

There have been informed of them nesting as far east because the Cypress Hills of South Dakota, however, they’re more generally discovered within the Rocky Mountains and west to the Pacific Ocean.

MacGillivray’s warblers winter primarily alongside the pacific slope of Central America from northern Mexico to Panama, although they happen as far south as Colombia.

Some birds have been recognized to overwinter as far north as southern California (San Diego), however, that is fairly uncommon.

MacGillivray’s Warbler  Overview

MacGillivray’s warbler (Geothlypis tolmiei) is a species of New World warbler. These birds are sluggish and heavy warblers, preferring to spend most of their time on, or close to the ground, besides when singing.

The MacGillivray’s warbler was named by John James Audubon in honor of Scottish ornithologist William MacGillivray, though the right credit score to its discovery goes to John Kirk Townsend. The particular name was given in honor of William Fraser Tolmie.

Adult MacGillivray’s warblers are an olive-green coloration on their upper parts and boring yellow under. Males have blackheads and breasts, whereas females and immature birds have drab light grey heads; each male and females have damaged white eye-rings.

The song is a sequence of repeated two-note phrases, step by step rising in quantity, ending with two single notes: jeeter jeeter jeeter JEETER JEETER jeet jeet.

MacGillivray’s warblers are similar to their eastern counterpart, the mourning warbler, the first distinction between the 2 species being the mourning warbler’s lack of an eye-ring.


  • Length: 3.9-5.9 in (10-15 cm)
  • Weight: 0.3-0.5 oz (9-13 g)
  • Wingspan: 7.5 in (19 cm)

MacGillivray’s warblers are migratory and spend their summers in temperate forests within the western United States, and in boreal forests of western Canada. In autumn, these birds migrate to Central America, the place they keep in temperate shrublands for the winter.


A compact, small songbird with a full body for a warbler and a thick neck. The bill is straight and skinny general, though heavier than many different warblers’ payments. The tail is medium size and the legs are pretty long.

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MacGillivray’s Warbler Description

MacGillivray’s warblers are small warblers, weighing between 8.6 and 12.6 grams (imply 10.Four g). They are 10 to 15 cm long with an average wingspan of seven.5 cm.

Adult males in alternate plumage exhibit a damaged eye-ring, jet black hood, yellow underparts, distinctive black lores, and an olive back.

There is appreciable sexual dimorphism, as females’ hoods are at all times a light gray with a whitish chin. Juvenile birds seem just like adult females, however, could present slight black lores.

Similar species embody each mourning warbler (Oporornis philadelphia) and Connecticut warblers (Oporornis agilis). Though the damaged eye ring is normally diagnostic, mourning Warblers could have a skinny damaged eye ring.

For definitive identification, a wing size minus tail size worth of lower than 10 mm will distinguish MacGillivray’s warblers from mourning warblers (wing-tail > 19mm).


Adult males are wealthy golden-olive above, shiny yellow under, with a darkish grey hood extending all the way down to the chest. The face has white crescents (arcs) above and under the attention and blackish lores (the world between eye and bill).

Adult females are comparable however duller in coloration. Immatures are largely olive-brown above, with whitish eye arcs and a grayish or brownish model of the hood, damaged up by a pale throat.

MacGillivray’s Warbler Migration

MacGillivray’s warblers are extremely migratory, arriving in California from Central America throughout mid-April and departing for the tropics in mid-August to early October.

Their migration normally follows the Rocky Mountains. On the breeding grounds, males are fairly territorial, singing to promote their presence to possible opponents.

Though males could chase one another, preventing hardly ever happens. Studies of territory size range from 0.Eight to 1.7 hectares.

On their winter grounds, these birds are usually solitary, forming seasonally monogamous pairs solely upon returning to the breeding grounds. Birds are discovered hopping alongside the ground, gleaning bugs from vegetation.

Besides migration, the flight is characterized by quick bursts from one piece of vegetation to a different one.

Little interplay with different species happens, although observations do exist of MacGillivray’s warblers bathing with different warblers.

Richard Hutto noticed some agonistic interplay with different warbler species; nevertheless, such behavior was uncommon.


Hops or flies low in vegetation or on the ground and gleans bugs, usually calling commonly (a particular tsik). Males sing from open or hid perches within the understory. Migrants usually call commonly, in contrast to Mourning Warbler migrants.

MacGillivray’s Warbler  Habitat

MacGillivray’s warblers breed primarily at average elevations (as much as 3000 m) in secondary growth coniferous forests and riparian corridors.

In the north elements of their range, they inhabit some deciduous forests and can generally breed in chaparral.

During migration, they’re present in dense shrubs in mountain ranges. In their wintering range, they’re usually encountered in humid or semiarid second-growth forests.

Nests and forages in dense shrubby vegetation, second growth, and alongside streams with dense underbrush. Migrants usually happen in comparable habitats. Winters in dense habitats in Central America, from coastal mangrove and edges of thorn forest into the cloud forest.


MacGillivray’s warblers are insectivorous, gleaning bugs from bark and different vegetation at decrease ranges within the forest. Food gadgets embody beetles, bees, wasps, ants, true bugs, caterpillars, and weevils. Most foraging is in dense, moist thickets alongside the forest ground.


Most communication happens through vocalization. Males sing throughout the breeding season to outline their territories and decide species identification of different people.

Occasionally, they could emit a flight song as nicely. Singing is most frequent at daybreak and nightfall throughout the breeding season, normally whereas sitting 5 to 7 m off the ground.

In addition to singing, each man and woman could use harsh chip calls to scare intruders away from the nests. Calls could also be vocalized year-round. Nestlings additionally emit noise, utilizing a “buzzy” food-begging call.

macgillivray's warbler macgillivray's warbler song

MacGillivray’s Warbler  Reproduction

MacGillivray’s warblers are regarded as seasonally monogamous and solitary on their winter grounds. Males set up territories and promote for females with song. Currently, little information exists regarding pair constancy.

MacGillivray’s warblers normally breed in secondary growth coniferous forests, alongside riparian corridors, or in clear-cuts. In Oregon, breeding density was calculated to be 0.56 birds per hectare.

Courtship is believed to begin quickly after arrival on the breeding grounds, as soon as males have established territories. Nests are made in dense thickets, with an implied nest height of 46.3 cm off the ground.

They are cup formed, composed of an outer layer of stripped leaves and twigs that fasten the nest to the dense understory and an interior layer of softer grasses. Eggs are laid from May to early June, with a mean laying date of June fifth.

Clutch sizes range from 2 to six eggs, with just one clutch per season. Eggs seem creamy with brown speckles and are normally 17.Eight by 13.6 mm. Incubation begins after the first egg is laid and lasts 11 to 13 days.

Females develop brood patches and are the only real incubators of the clutch. The younger are unfeathered and altrical at the beginning, demanding fixed feeding and care from each the female and male parents.

Hatchlings are left alone for less than quick intervals because the females and males forage for bugs to feed their offspring. Though each sex takes part, analysis signifies that females play a bigger position in acquiring meals for offspring.

Young fledge after Eight to 9 days, although they proceed to forage as a family for a while after. Unfortunately, no information exists as to how long this dependency interval lasts.

Where to search out

Home in on MacGillivray’s Warblers by listening for them in spring and early summer season, when males sing loudly within the early morning.

Some sing from open perches, however many sing from inside thick cover, the place they’re tougher to identify.

Sometimes squeaking or making pishing sounds will convey one into view. When this species will not be singing, pay attention to its sharp, distinctive call word.

MacGillivray’s Warbler  Facts

The ranges of MacGillivray’s Warbler and the intently associated Mourning Warbler come collectively in a small part of the Peace area of British Columbia, Canada, they usually generally kind hybrids there.

MacGillivray’s Warblers nest from close to sea level to as high as 10,000 feet in elevation.

MacGillivray’s Warbler was named by John James Audubon for his pal and editor, William MacGillivray, a Scottish naturalist. Audubon coined this name although John Kirk Townsend had already named the species Tolmie’s Warbler, in honor of surgeon William Fraser Tolmie, who had a long profession as fur dealer, politician, and scientist.

The oldest recorded MacGillivray’s Warbler was a male no less than Four years, 1 month old when it was recaptured and rereleased throughout banding operations in Oregon.


The IUCN evaluated MacGillivray’s warblers as a species of “least concern” in 2004. This classification is justified by the truth that the range is kind of broad (2.6 million kilometers squared), and the worldwide inhabitants are estimated at 5.4 million people.

However, MacGillivray’s warblers are listed as protected below the US Migratory Bird Act Treaty, a chunk of legislating defending all North American migratory bird species.

Surprisingly, since MacGillivray’s warblers usually nest in secondary growth and clear-cuts, proof exists that populations are literally increasing in response to deforestation each within the winter and breeding ranges.

In addition, replanted pine forests, used for logging, usually present appropriate habitat for nesting.

However, the long-term penalties of deforestation could have detrimental impacts on this species, as forest composition finally modifications to unsuitable nesting habitat.

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