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At least 73 records · Page 4Linked to original sources
USGS1980

Nest site and colony characteristics of wading birds in selected Atlantic Coast colonies

Nests of 5 species of wading birds were identified and marked during the breeding season at 6 locations from Massachusetts to North Carolina. At the end of the breeding season 12 characteristics of nest-site location were measured. Nest locations were mapped to examine dispersion and nearest neighbor relationships. Multivariate analyses were used to describe and compare sites and species. We found that variations in nest-sites between colonies were greater than between species; colonies differed mainly in the variety and size of vegetation; birds preferred to nest in vegetation that offered relatively stable nest-sites; and the dispersion of nests in the colonies was related to vegetative patterns. The interaction of these factors with the number of bird species and the abundance of birds in the colony seemed to determine whether nest-sites were stratified, segregated or randomly distributed.

The Wilson Bulletin↗
USGS1983

Waterbird mortality from botulism type E in Lake Michigan: An update

Three outbreaks of botulism type E occurring in waterbirds on Lake Michigan since autumn 1976 are discussed. Natural ingestion of food containing type E toxin by Ring-billed Gulls ( Larus delawarensis ) and the presence of type E toxin in blood from moribund gulls were demonstrated. Concurrent presence of type C and type E botulinal toxins was found in a die-off of Common Loons ( Gavia immer ). In combination with previous reported outbreaks, these incidents suggest that this disease is geographically widespread in Lake Michigan, and that environmental conditions conducive to type E botulinal toxin production and consumption occur in both summer and autumn.

Lake Michigan↗
USGS1995

Are red-tailed hawks and great horned owls diurnal-nocturnal dietary counterparts?

Red-tailed Hawks (Buteo jamaicensis) and Great Homed Owls (Bubo virginianus)are common in North America where they occupy a wide range of habitats, often sympatrically. The two species are similar in size and have been portrayed as ecological counterparts, eating the same prey by day and night. We tested the trophic similarity of the two species by comparing published dietary data from across the United States. Both species ate primarily mammals and birds, and mean proportions of those two prey types did not differ significantly between diets of the two raptors. Red-tailed Hawks ate significantly more reptiles, and Great Homed Owls significantly more invertebrates. Dietary diversity was not significantly different at the level of prey taxonomic class, and diet overlap between the two species averaged 91%. At the prey species level, dietary overlap averaged only 50%, and at that level Red-tailed Hawk dietary diversity was significantly greater than that of Great Horned Owls. Mean prey mass of Red-tailed Hawks was significantly greater than that of Great Homed Owls. Populations of the two species in the western United States differed trophically more than did eastern populations. We conclude that, although the two species are generalist predators, they take largely different prey species in the same localities resulting in distinctive trophic characteristics.

The Wilson Bulletin↗
USGS1968

Vegetation used for nesting by the red-winged blackbird in Florida

During the breeding season of 1966, as an adjunct to a taxonomic study of Red-winged Blackbirds in Florida, 177 Redwin g nests were found. The general habitat types were noted, and the plant species harboring nests were listed.....Redwing nests were found in 30 genera of plants. Buttonbush was the primary choice; it was used to support 50 of the 177 nests. Silverling and willow were the next most often used plants. Nests also were found in other shrubs and trees, in assorted herbs and grasses, and in fields of sweet corn and sugarcane. The great degree of nesting adaptability of the Red-winged Blackbird is attested by the diversity of nesting site selections in several habitats.

The Wilson Bulletin↗
USGS1953

A life history study of the yellow throat

Investigations concerning the life history of the Yellow-throat were made in southern Michigan during the spring and summer of 1938. Supplementary information was also obtained at Arlington, Virginia, in 1940 and at the Patuxent Research Refuge, Maryland, in 1947.....Resident males established territories almost immediately upon arrival in spring. In southern Michigan some resident males arrived at least as soon as, if not before, transient males. Most females appeared on their nesting ground about a week later. Adults were engaged in nesting activities from the time of their arrival in spring until the advent of the post-nuptial molt in late summer.....Typical Yellow-throat habitat consists of a mixture of a dense herbaceous vegetation and small woody plants in damp or wet situations. At Ann Arbor, the Yellow-throat was a common breeding species in its restricted suitable habitat. The population density in one area of suitable habitat was about 69 territorial males per 100 acres. Of 11 territorial males that were intensively studied, one was polygamous (with two mates), nine were monogamous, and one was probably monogamous (with at least one mate).....The song of the individual Yellow-throat was heard throughout the breeding season except for the courtship period. Two major types of song were the common song given while perched, and an occasional, more elaborate, flight song. Most males sing in spurts, singing at fairly regular intervals for a considerable period and then abruptly ceasing for another period. The vocabulary of both sexes included several types of call notes that appeared either to have special functions or to represent outward expressions of distinct emotional states of the bird.....Resident males were antagonistic toward each other throughout the breeding season. Most remained on well-established territories during this period. Territories of 10 monogamous males ranged in size from .8 to 1.8 acres but the territory of one polygamous male occupied. 3.4 acres. The behavior of males during inter-territorial encounters was similar in some respects to their behavior when courting females.....While courting females, the males are very attentive and seldom sing for about one week. During the courtship period the female locates the nesting site and builds the nest without assistance from the male.....Nests, constructed of dried plant materials, were situated on or near the ground and were supported on all sides by stems of herbaceous plants or limbs of shrubs. Many nests were composed of three layers with the coarser materials being used in the outer layer.....The full clutch of eggs in 12 nests ranged from 4 to 6 (average, 4.6). Early clutches seem to be larger than later ones. After the first egg is laid, one is laid on each succeeding day until the clutch is complete. Incubation period is about 12 days. Incubation is only by the female. Records of daytime incubation schedules of three females about half way through incubation indicate that the periods spent on and off the nests average about 61 and 16 minutes, respectively.....Young Yellow-throats usually remain in the nest for eight or nine days. During this period they grow and develop rapidly. Their weight quintuples in six days. Both sexes are active in feeding the young and in removing excreta from the nest. Records of feeding at three nests showed a range of one feeding per 5 1/2 minutes to one feeding per 22 minutes, the rate increasing with age of young. Adults care for the young for at least two weeks after the young leave the nest.....Ten of 12 females that were intensively studied were successful in raising young beyond the nestling stage. Only one of these raised two broods, although three females built at least three nests each. In 19 nests, 11 (58 per cent) produced nestlings and 7 (37 per cent) produced fledglings. In total, the 19 nests produced an average of one fledgling Yellow-throat per nest. Of 22 nests that were found near Ann Arbor, 10 (45

The Wilson Bulletin↗
USGS1949

Ecology of a nesting red-shouldered hawk population

An ecological study of a nesting Red-shouldered Hawk population was made over a 185 square mile area on the Coastal Plain of Maryland in 1947. The courting and nesting season extended from late February until late June.....During the nesting season a combination of fairly extensive flood-plain forest with adjacent clearings appears to meet the major ecological requirements of the Red-shouldered Hawk in this region. A total of 51 pairs was found in the study area, occupying about 42 square miles or 23% of the total area studied. The population density on the land that was suitable for this species was about 1 pair per .8 of a square mile, while the density for the entire study area would be only about 1 pair per 3.6 square miles.....Nests were spaced fairly evenly over most of the flood-plain forests, especially in areas where the width.of the flood plain was relatively constant. There was an inverse correlation between the width of the flood plain and the distances between nests in adjacent territories. The nests were all situated in fairly large trees and were from 28 feet to 77 feet above the ground, averaging 50. They were found in 14 different species of trees, all deciduous.....The Barred Owl and Red-shouldered Hawk were commonly associated together in the same lowland habitats. Other raptores were all largely restricted to upland habitats....The average number of young in 47 occupied nests following the hatching period was 2.7 with extremes of 1 and 4. Only 3 out of 52 nests (6%) were found deserted at this time....The food habits of nestling Red-shouldered Hawks are very diversified. They feed on many types of warm-blooded and cold-blooded vertebrates as well as invertebrates.

The Wilson Bulletin↗
USGS1959

Observations on the fulvous tree duck in Louisiana

The Fulvous Tree Duck is a locally common breeding bird of the rice fields of southwestern Louisiana. Observations made in 1955, 1956 and 1957, showed that this species was probably most abundant in the vicinity of Mamou, Evangeline Parish, and Roanoke, Jefferson Davis Parish. Tree ducks arrive in the rice country as the rice is planted in the spring and usually depart following fall harvest. A few winter in the coastal marshes. The nesting period extends from late May well into August. Thirteen and 20 pairs were found nesting in two separate five-square-mile areas. All nests observed were in rice fields. Clutch size in several nests found by John J. Lynch averaged about 13 eggs. A clutch of 23 eggs was probably a dump nest. Several investigators have reported incubation periods varying from 24 to 26 days. Nests were constructed of rice or other plants that occurred in the rice fields; they usually had a canopy and ramp; none was lined with down. Renesting compensated for some first attempt losses. Depredations on rice plantings sometimes occurred in spring in water-planted rice fields. Favorite foods were seeds of grasses and sedges found in rice fields. Flocks totalling 3000 were occasionally seen in the fall on the Lacassine Wildlife Refuge.

The Wilson Bulletin↗
USGS1969

Pre-nesting and nesting behavior of the Swainson's warbler

The Swainson?s Warbler is one of the least known of southern birds. Although fairly common in some parts of its summer range, observations of its breeding biology have been made by very few persons. The present study was conducted mostly at Macon, Georgia; Pendleton Ferry, Arkansas; and Dismal Swamp, Virginia....In central Georgia and east-central Arkansas, Swainson?s Warblers usually arrive on their territories during the first two weeks in April. Territories in several localities ranged in size from 0.3 to 4.8 acres. A color-marked Arkansas male occupied the same territory for at least four months. Hostile encounters between territorial male Swainson?s Warblers usually take place along the boundary of adjacent territories. Paired males were more aggressive than unpaired males. Toward the end of an encounter one of the two males would usually perform a display in which the wing and tail feathers were spread and the tail vibrated. Following boundary encounters males drifted back onto their territories and usually sang unbroken courses of songs for several minutes.....During pre-nesting at Macon, a mated pair spent the day mostly on the ground within 20 feet of each other, often foragin g 3 to 4 feet apart. What may have been a form of courtship display, in which the male flew from a perch down to the female and either pecked her rump or pounced on her, occurred about three times each hour throughout the day. During this period the male sang less than at other times during the breeding season.....First nests are usually built by the first week in May. Although other investigators reported finding nests of this species outside of the defended territory, all nests that I have found were within the territory. The large, bulky nest of this species usually is placed 2-6 feet above the ground. It is built by the female from materials gathered close to the nest site; and takes two or three days to complete.....Three and occasionally four white eggs are laid. The female incubates for 14-15 days. The Cowbird parasitizes nests in some parts of the breeding range of the Swainson?s Warbler.....During incubation the female spends about 78 per cent of daylight time on the nest. Both sexes feed young and clean nest. Young remain in nest from 10-12 days.

The Wilson Bulletin↗
USGS1968

Singing behavior of the Swainson's warbler

Studies of the singing behavior of the Swainson?s Warbler were conducted mainly near Macon, Bibb County, Georgia, and in the Dismal Swamp, Nansemond County, Virginia, during the springs of 1965 and 1966. Singing behavior on the ground and in trees is discussed. Swainson?s Warblers sing vigorously from the time they arrive on the breeding ground until the latter part of June, when the singing of most birds becomes more sporadic. At Macon, Georgia, in mid-April, morning song of one bird began about 20 minutes before sunrise; and evening song of the same bird ceased about 15 minutes after sunset. Songs were delivered at the rate of about 8-9 per minute for the first few minutes of morning song, decreasing to 5-6 per minute for most of the morning. Songs are given in courses or series. The rate of singing is usually faster at the beginning of a course. The number of songs sung by a territorial male in 1 day in the Dismal Swamp, Virginia, 2 June, was 1168. It produced 280 songs the first hour, and sang at a fairly constant rate from 5:00 to 8:00 AM, 192, 194, 198 songs per hour.

The Wilson Bulletin↗
USGS1965

The roosting behavior of the red-winged blackbird in the southern United States

This report concerns the roosting behavior of the Red-winged blackbird and associated species ; and is based on observations made over a 14-year period mainly in the Southern United States....Th e greatest concentrations of Red-winged Blackbirds in the southern states occur in the Coastal Plain Province in or near major grain growing regions.....Roosts are formed during every month of the year. The largest roosts are usually found in winter; the smallest during the breeding season. Composition of roosts may vary from place to place and from season to season.....The general locality in which roosts are found is probably influenced by food supply. The precise location is determined by the character of the habitat. Wetland situations are preferred by Red-winged Blackbirds. Most of the roosts in the Coastal Plain Province are located in marshes and swamps. Rice fields are important in the southern rice producing area. Coniferous stands and bamboo are frequently used in the Piedmont Province.....Blackbirds move out of roosts each morning at about dawn or shortly after, and return in the evening usually before sunset. Some birds may travel 35 miles or more from the starting point in the course of a day?s feeding activity. On cloudy days blackbirds move into the roost earlier than on sunny days. At a Maryland roost subadult male Redwinged Blackbirds were the first to arrive at the roost. Females and then juveniles followed. Adult males were sporadic in their time of arrival. Stratification in a roost flight was observed where birds were flying downstream to a river marsh roost. Bobolinks flew at the greatest elevations; next in order of height were Starlings, Common Grackles, Brown-headed Cowbirds, and Red-winged Blackbirds. The exodus of a large roosting population is usually of shorter duration that the movement into the roost..... In virtually all roosts some segments of the population are segregated. Stratification by species and by sexes of some species has been noted in roosts. Blackbirds may roost on partly submerged vegetation in a marsh, on the ground in grassy fields, in branches of trees, or in various other sites. In deciduous thickets with high bird densities they may roost at elevations of 1 foot to 30 feet or more. In one Arkansas roost Red-winged Blackbirds were roosting along branches at an average of about three birds per foot.

The Wilson Bulletin↗