Sayornis phoebeeastern phoebe

Geographic Range

The breeding range of the Eastern Phoebe extends from northern Canada down into the southeastern U.S. It winters primarily in the southeastern U.S., with especially heavy concentrations in Texas and Florida. The winter range can also reach well into Mexico. It has only been recorded twice outside of North America, both times in 1987 in Great Britain (Weeks, 1994).

Habitat

The Eastern Phoebe occurs in woodlands and in woody vegetation. They seem to prefer deciduous woodlands, and perhaps edge forest, and open habitats rather than mature or closed forests. There is some evidence that they prefer to be near water, but the availability of suitable nesting habitat limits them more often than preference (Weeks, 1994).

Physical Description

The Eastern Phoebe is medium-sized flycatcher, dull in coloration to blend in with its surrounding woodland habitat. It ranges from 142-168 mm, and the male is generally larger than the female. The plumage of the male also tends to be darker, but neither of these characteristics is a failsafe means of determining the bird's sex. The upperparts of the adults are olive or grayish-brown, and the underparts tend to be pale buff. Juveniles have white bars on their wings. The bill is black (Terres, 1980; Weeks, 1994).

  • Average mass
    21.6 g
    0.76 oz
    AnAge
  • Average basal metabolic rate
    0.3449 W
    AnAge

Reproduction

The Eastern Phoebe is monogamous and usually double-brooded. Pair formation occurs quickly after they arrive on the breeding grounds in spring. No recurrent courtship displays have been documented. The female always initiates copulation, usually in the mornings only, during the male's pre-dawn song. After pairs are formed, nest-building begins immediately, which helps them to establish territory. The female chooses the nest site. She alone builds it, though the male is with her continuously while she builds, most likely guarding his mate. The nests are made of mud, moss, some leaves, and lined with fine grass, stems and hair. Phoebes often reuse nests, of their own species or another species, though never without renovating them first. They also often build over old eggs or dead young. The nests are always built with cover overhead. Suitable nesting habitat for Eastern Phoebes is limited, so there is strong site attachment in this species. Often the same pair will breed at the same site for several successive years. Eastern phoebes keep the same nest and same mate for both broods. The laying of the first clutch usually begins 7-14 days after the nest is complete. The clutch can be 2-6, but usually 5 eggs are laid. The eggs are white with little gloss, and they sometimes have a few reddish-brown dots on one end. Incubation lasts about 16 days, less for the second brood which occurs in summer. Incubation is carried out solely by the female, and the male does not feed her while she sits. Most eggs hatch within a 24-hour period, and the female removes the eggshells from the nest immediately afterwards. Though the chicks are able to fly by day 15, they usually do not fledge until day 16 or 18. Both males and females feed the young. The young are capable of breeding in their first year.

The Eastern Phoebe is strongly parasitized by the Brown-headed Cowbird. Cowbird females often remove phoebe eggs in the process of leaving their own, and the egg is rarely rejected by the phoebe female. In most of these nests only the cowbird egg hatches, but if the phoebe egg does hatch, it will do so a few days later and the phoebe chick will usually starve. The fledgling success of cowbirds in parasitized phoebe nests is about 60-70%, about the same rate of success as phoebes in unparasitized nests (Weeks, 1994).

  • Average eggs per season
    5
    AnAge
  • Average time to hatching
    16 days
    AnAge

Lifespan/Longevity

Behavior

The most distinctive behavior attributed to the Eastern Phoebe is the 'tail-wag,' in which the bird sweeps its tail widely up and down and then side to side when alighted on a perch. One of the most important factors in the spread of the phoebe into the U.S. is its growing habit of building nests on human structures or under bridges, giving it the nickname 'bridge pewee.' Its migrations follow the insect emergence northward in spring and frost-induced insect decline southward in fall. Most of the birds' activities are carried out solitarily, including roosting, with the exception of the breeding season. Even at this time, contact is usually only made during copulation. At other times, the male may attempt contact but is aggressively rebuffed by the female. There are only 2 different song forms which the adult males regularly sing. Females sing rarely and briefly. Males use these vocalizations to announce territory, but more often to attract a mate. Territorial disputes, involving vocalizations and chases but rarely physical contact, frequently break out in the breeding season. The Eastern Phoebe is highly territorial (Terres, 1980; Weeks, 1994).

Communication and Perception

Food Habits

The Eastern Phoebe is predominantly insectivorous, consuming mostly flying insects such as wasps, ants, flies and wild bees. Invertebrates such as grasshoppers, airborn spiders, hairworms from the water and even small fishes from shallow water round out their diet. It has been observed that it can survive on fruit when insects are unavailable. Flycatching is its main means of obtaining food, usually done from a perch less than 10 meters off the ground. It also occasionally chases flying insects to the ground, pounces on insects on the ground, and picks insects from trees while hovering. Its most active foraging period occurs in the morning (Terres, 1980; Weeks, 1994).

Economic Importance for Humans: Positive

Phoebes feed on some species of insects that are harmful.

Economic Importance for Humans: Negative

Phoebes sometimes nest near man-made structures, and it is sometimes necessary to remove their nests due to potential health problems associated with mites in the nests and droppings beneath the nest (Weeks).

Conservation Status

The Eastern phoebe is very tolerant of human presence. The growing use of man-made structures as substitute nest sites has greatly facilitated their expansion across North America (Weeks).

Contributors

Alicia Ivory (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

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

acoustic

uses sound to communicate

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.

chemical

uses smells or other chemicals to communicate

endothermic

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.

forest

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

iteroparous

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).

motile

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.

oviparous

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

sexual

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

tactile

uses touch to communicate

visual

uses sight to communicate

References

Terres, J. The Audubon Society Encyclopedia of North American Birds. Alfred A. Knopf, New York, 1980.

Weeks, H.P., Jr. 1994. Eastern Phoebe (Sayornis phoebe). In The Birds of North America, No. 94 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.