Oporornis philadelphiamourning warbler

Geographic Range

Mourning warblers occur in Neartic and Neotropical regions. Their breeding range is in the Neartic region and their winter range is in the Neotropical region. The breeding range extends through Alberta and to northern North Dakota. In Canada, they are found in Alberta, Saskatchewan, Manitoba, Ontario, Quebec, Newfoundland, and Nova Scotia. In the United States, they are found in portions of North Dakota, Minnesota, Wisconsin, Michigan, Pennsylvania, New York, West Virginia, and Massachusetts. In the southern part of their range they only breed in higher elevations. The winter range extends from southern Nicaragua to Colombia, western Venezuela, and northern Ecuador. Their migration route is through Central America. They migrate relatively late in spring, leaving their winter range around March and April, but return from their breeding range early in August. (Cox, 1960; Cox, 1960)


Mourning warblers are found in a variety of different habitats. While they are in their breeding range they are found in brushy woodland clearings, forest edges, brushy edges of marshes and bogs, and dense second growth. Males are found in a variety of vegetation types including pure stands of red, white, or jack pine, to stands of maple-basswood, spruce-fir, aspen, and aspen-birch. These vegetation types were almost always associated with edge type conditions like roads, logging trails, clearings, or open woods. Female nesting sites are usually found in briers or weedy growths in thickets. The nest will usually be 15 to 50 cm off the ground. While mourning warblers are in their wintering range they are found in lowland areas from sea level to about 152 m. They are sometimes found as high as 1219 m but it is most common to find them at 914 m. They are generally found in edge areas with dense brush or tall grass. (Chapman, 1917; Cox, 1960)

  • Range elevation
    152 to 1219 m
    498.69 to 3999.34 ft
  • Average elevation
    914 m
    2998.69 ft

Physical Description

Mourning warblers are identifiable by their gray head, neck, and chest, yellow underparts, and olive-green wings and back. These warblers are sexual dimorphic, and change their coloration during the year usually between summer and fall. Also, the juveniles have a different appearance from the adults. Every mourning warbler beaks, irises, feet, and legs are uniform in coloration. The upper part of the beak is brownish-black in color. The bottom part of the beak is pale brown. The iris is brown. The legs and feet are flesh color.

Adult males in spring/summer: Their head and neck are a gray color which then will become a darker grayish-black on their pileum, hindneck, chin, and throat, and they have a black chest. Their underparts are bright yellow. The bright yellow changes into olive-green on its sides and flanks. Their upper parts are then all olive-green edged with white.

Adult males in fall/winter: Their plumage is the same as their summer plumage except the feathers on the throat and chest have gray tips, and the black on their chest is a broken patch. Also, they will have a white-broken eye ring.

Adult females in spring/summer: Females look like the adult male in spring/summer but they will have no black on the chin, throat, or chest. Their chin and throat will be a light gray sometimes a brownish-white color. The color on their pileum and hindneck are duller and are tinged with either more or less olive coloration. Also, their yellow on their under parts are duller.

Young females in first fall/winter: They look like the adult female but they do not have any gray on their head, neck, or chest. Their pileum and hindneck are olive-brownish color. The side of the head and neck are similar but duller. Their eyelids are a dull yellow color. Their chin, throat, and chest are yellowish but duller than the underparts of the body, and is tinged with olive or gray.

Nestlings: Their upper parts are a dark olive-brown color. Their sides and breast are a more yellow brown color. Their belly is a buff yellowish color. Their median and greater wing-coverts are tipped with cinnamon-brown.

An average adult male length is 12.1 cm. The average wingspan 6.15 cm in length. The average tail length is 4.9 cm. An average adult female length is 12.0 cm. The average wingspan is 5.89 cm. The average tail length is 4.67 cm. The average bill length for both male and female is 1.1 cm. The average weight for both male and female is 13 grams. (Chapman, 1917; Knight, 1908)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • male more colorful
  • Average mass
    13 g
    0.46 oz
  • Range length
    11.15 to 13.38 cm
    4.39 to 5.27 in
  • Average length
    12 cm
    4.72 in
  • Range wingspan
    5.46 to 6.5 cm
    2.15 to 2.56 in
  • Average wingspan
    6 cm
    2.36 in


There is little known about the mourning warbler mating system. However, members of the wood warbler family (Phylloscopidae) can be monogamous or poly-territorial polygynous. (Temrin and Jakobsson, 1988)

Mourning warbler breeding range is in the neartic region as far north as Alberta and as far south as North Dakota. They migrate back to their breeding range anywhere from March to April. Therefore, the breeding season takes place in summer, usually from late-April to early-July. The females will find a suitable nest site to lay her eggs and then will incubate them once they are laid. Sometimes she will start incubating them before they are all laid. Suitable nesting sites are usually found on the ground or close to the ground in dense herbaceous or shrubby vegetation. These nests are usually found near edge areas. The nests are made up of leaves, weed stalks, pieces of bark, grasses, sedges, and are lined with fine rootlets, grasses, or hair and they are usually bulky. Eggs may be laid as early as the end of May or as late as the middle of July. Clutch size can vary from 2 to 5 eggs, with an average of 4 eggs. The incubation period for mourning warblers are usually 12 days. The nestling period for mourning warblers are 8-9 days. (Cox, 1960)

  • Breeding season
  • Range eggs per season
    2 to 5
  • Average eggs per season
  • Average time to hatching
    12 days
  • Range fledging age
    8 to 9 days
  • Average time to independence
    3 weeks

Both male and female mourning warblers help with parental care. The brooding is done by the females. While the female is incubating the eggs the male will feed her either on the nest or away from the nest. Once the eggs hatch the female will usually continue to brood to protect the hatchlings and the males will bring the food to the nest for the female and the hatchlings. When the male brings the food back to the nest he will do one of three things. (1) He will feed the hatchlings himself. (2) He will give the food to the female and she will feed the hatchlings. (3) He will give half to the female and they will both feed the hatchlings. Sometimes when the eggs first hatch the female will leave the nest and get food for the hatchlings. After the nestlings fledged the family group stays together for three weeks, until the fledglings become more independent and can forage for themselves. (Cox, 1960)


There is little known on mourning warbler lifespan and longevity. One male individual bird that was banded in Port Huron, Michigan had an estimated age of 7. The main mortality is due to predation on nestlings and fledglings. (Cox, 1960; Klimkiewicz, et al., 1983)

  • Range lifespan
    Status: wild
    7 (high) years


Mourning warblers are diurnal and are a migratory species. Both male and female can be territorial, but males show aggressive behaviors towards interspecific and intraspecific species. These displays include wing and tail flipping with tshirp notes, and sometimes they will chase the other individual. Adult mourning warblers will do two distraction displays to protect their offspring. One of the displays is when the adult will mimic a mouse running through the vegetation, the other display is when the adult will pretend to have a broken wing. Both of these displays are meant to make the predator or threat follow or go after them instead of their offspring. The male mourning warblers will sing and both male and females will do call notes. (Cox, 1960)

  • Range territory size
    6475 to 9713 m^2
  • Average territory size
    7689.03 m^2

Home Range

Male mourning warblers hold territories during breeding season. The size of these territories range from 1.6 to 2.4 acres, with an average of 1.9 acres. The males defend their territories by singing their territorial song and will do more aggressive displays. Some of these displays include: the males hopping from perch to perch rapidly and bobbing their bodies violently, rapidly flipping their wings outward,and open & close their tails, tschrip notes, and short winded chases. (Cox, 1960)

Communication and Perception

Male mourning warblers have two calls; the territorial song and the flight song. Adults will give off two call notes, either in a harsh quality or less harsh quality that is in higher pitch. Although females give call notes, only males sing. The territorial song is loud and ringing with a throaty quality. The paraphrase of this song is whee-o whee-o whee-o, whoo-e whoo-e. The flight song is rapid and begins with a series of chipping notes, followed by a rapid version of the territorial song and ends with a few more chipping notes. The paraphrase of this song is chi-chi-chi-chip-chip-cheery-cheery-chorry-chorry-chi-chip. The first of the two call notes that the adults do is a loud and harsh tshrip. You can hear this if the bird is disturbed away from its nest, this also can be heard from migrating mourning warblers. The second call note is a less harsh and a higher in pitch tsip. It can be heard when the nest or fledglings are approached. It can also be heard when two females have a territorial encounter. (Cox, 1960)

Food Habits

Mourning warblers are insectivores. They eat spiders, beetles, and insects that are found on the ground or low vegetation. Nestlings are fed primarily Lepidoptera larvae but other small insects were fed also. (Cox, 1960)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods


There are many predators of eggs and nestlings of mourning warblers. Some of the predators that are known for taking eggs and nestlings from nests are thirteen-lined ground squirrels, Franklin’s ground squirrels, eastern chipmunks, least chipmunks, and red squirrels. Brown-headed cowbirds are nest parasites. There are two types of anti-predator displays that adult warblers use to protect their offspring. The first display is when a threat or predator is approaching the nest; the adult will dive over the edge quickly and run away through the vegetation, then 20 to 25 feet from the nest it would take flight. This display will make it seem like the adult is a mouse and will confuse the predator. The second display is the “broken wing” display given off by the adult when the young has left the nest. The adult will dash and flop through the vegetation flipping the wings outward of the body and holding them out in a dragging position for short periods of time. (Cox, 1960)

Ecosystem Roles

Mourning warblers are insectivorous birds that impact insect populations in the ecosystems they inhabit. (Cox, 1960)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

Mourning warblers are important members of the ecosystems they inhabit.

Economic Importance for Humans: Negative

There are no known ways that mourning warblers have a negative affect on humans.

Conservation Status

The conservation status of mourning warblers is classified as least concern on the IUCN red list. Their populations are declining but the cause is uncertain and the decline has not been rapid. Mourning warblers are protected under the Migratory Bird Treaty Act. (BirdLife International, 2016; U.S. Fish & Wildlife Service, 2016)

Other Comments

Oporornis philadelphia has also been known by other generic names, including Sylvia philadelphia, Trichas philadelphia, Geothylpis philadelphia, and now Oporornis philadelphia. (Ridgway and Friedmann, 1901)


Mackenzie Purvis (author), University of Wisconsin Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Tanya Dewey (editor), University of Michigan-Ann Arbor.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map


living in the southern part of the New World. In other words, Central and South America.

World Map


uses sound to communicate


living in landscapes dominated by human agriculture.


young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


uses smells or other chemicals to communicate

  1. active during the day, 2. lasting for one day.

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


An animal that eats mainly insects or spiders.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males


marshes are wetland areas often dominated by grasses and reeds.


makes seasonal movements between breeding and wintering grounds


Having one mate at a time.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.


having more than one female as a mate at one time


reproduction that includes combining the genetic contribution of two individuals, a male and a female


living in residential areas on the outskirts of large cities or towns.


uses touch to communicate


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


Living on the ground.


defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


uses sight to communicate


BirdLife International, 2016. "Geothylpis philadelphia" (On-line). The IUCN Red List of Threatened Species. Accessed April 23, 2017 at http://www.iucnredlist.org/details/22721824/0.

Chapman, F. 1917. The warblers of North America. New York: New York :D. Appleton. Accessed April 22, 2017 at http://www.biodiversitylibrary.org/item/116233.

Cox, G. 1960. A life history of the Mourning Warbler.. Wilson Bull, 72: 5-28. Accessed April 22, 2017 at https://sora.unm.edu/sites/default/files/journals/wilson/v072n01/p0005-p0028.pdf.

Klimkiewicz, K., R. Clapp, A. Futcher. 1983. Longevity records of North American birds: Remizidae through Paurlinae.. Journal of Field Ornithology, 54/3: 287-294. Accessed April 23, 2017 at https://www.aphis.usda.gov/wildlife_damage/nwrc/publications/83pubs/klimkiewicz834.pdf.

Knight, O. 1908. The Birds of Maine with key to and description of the various species known to occur or to have occured in the state, an account of their distribution and migration, showing their relative abundance in the various counties of the state as well as other regions, and contributions to their life histories. Maine: Charles H. Glass & Co., Bangor, Mc.. Accessed April 22, 2017 at https://play.google.com/books/reader?id=ZXEaAAAAYAAJ&printsec=frontcover&output=reader&hl=en&pg=GBS.PR4.

Ridgway, R., H. Friedmann. 1901. The birds of North and Middle America : a descriptive catalogue of the higher groups, genera, species, and subspecies of birds known to occur in North America, from the Arctic lands to the Isthmus of Panama, the West Indies and other islands of the Caribbean sea, and the Galapagos Archipelago. Washington: Washington :Govt. Print. Off. Accessed April 22, 2017 at http://www.biodiversitylibrary.org/item/118018.

Temrin, H., S. Jakobsson. 1988. Female reproductive success and nest predation in polyterritorial wood warblers (Phylloscopus sibilatrix). Behavioral Ecology and Sociobiology, 23/4: 225-231.

U.S. Fish & Wildlife Service, 2016. "Migratory Bird Treaty Act Protected Species (10.13 List)" (On-line). Accessed April 23, 2017 at https://www.fws.gov/birds/management/managed-species/migratory-bird-treaty-act-protected-species.php.