Development of song in the wood thrush (Hylocichla mustelina), with notes on a technique for hand-rearing passerines from the egg. American Museum novitates ; no. 2666

27 p. : ill. ; 26 cm.Includes bibliographical references (p. 27)."Two wood thrushes (Hylocichla mustelina), reared from the egg in isolation from experienced conspecifics, developed song that is remarkably species-specific, but lacking in certain characteristics of the central phrases. Wild wood thrushes failed to respond to the playback of the isolates' songs, which suggests that features of the central phrase, normally learned from experienced conspecifics during the first 10 months of age, may transmit information required for species-recognition in this species. Am unusually detailed account updates the author's technique for hand-rearing passerines from the egg, including simplification of equipment and diet"--p. [1]

Flycatcher

7 p. : ill. ; 24 cm.Includes bibliographical references (p. 6-7)

Warblers

18 p. : ill. ; 24 cm.Includes bibliographical references (p. 17-18)."A spectrographic analysis of tape recordings of Blue-winged Warblers at one locality on Long Island, New York, revealed the limits of individual and intrapopulational variation in the song of that species in an area where the closely related Golden-winged Warbler does not breed. Intrapopulational variation consisted of different combinations and sequences of four basic components. Individual variation involved minor alterations in the duration and configuration of these components but did not include changes in their combination or sequence. Each male had a repertoire of only two distinct song patterns. The significance of these findings is discussed with reference to reports that some Blue-winged Warblers have a greater variability in song in areas where the Golden-winged Warbler also occurs"--P. 17

Hybridization in meadowlarks. Bulletin of the AMNH ; v. 134, article 1

25 p., 8 p. of plates : ill. (some col.) ; 27 cm.Includes bibliographical references (p. 24-25)."Previous studies of the comparative biology of the eastern meadowlark (Sturnella magna) and the western meadowlark (S. neglecta) have revealed that these sibling species are virtually, if not completely, isolated throughout a rather narrow zone of sympatry from central Mexico to the Great Lakes region of the United States. A case of hybridization of the two species in New York is fully substantiated by the capture of both adults and their hybrid offspring, and by the subsequent analysis of the morphology and vocalizations of the captive birds. Another hybrid, from Quebec, was also raised in captivity and is included in this analysis. A total of six hybrids are reported on here, all of which represent the first generation of hybrids produced by crossings in the wild of neglecta males with nominate magna females. No data are currently available on the reciprocal cross or on populations of magna other than the nominate race. Attempts to breed and to hybridize these captive individuals have failed. Morphologically, the first generation of hybrids of this particular cross are phenotypically indistinguishable from the magna parent with respect to those characters that depend on the intensity of melanic and carotenoid pigmentation, but are intermediate between the parental types with respect to the sexually dimorphic characters, including cheek color and mensural characteristics. Mensural characters are useless as indices of hybridization except for the elimination of 'extreme' specimens. All hybrid males from this cross should be identifiable by the concordance of a prominent yellow area on the cheek with an overall dark plumage coloration. The same characters must be used for females, but with considerably less confidence. The size of the repertoire of primary song patterns shows some promise as a clue for the field identification of hybrid males, but the actual patterns of primary song are meaningless for this purpose. Conflicting evidence on the call notes of hybrids necessitates further experimentation in this area and, at present, precludes their use for the identification of hybrids in the field. The results of this study make it clear that hybrid meadowlarks can be identified with accuracy and authority only on the basis of a prior knowledge of the phenotypic recombinations of specific characters in hybrids of known parentage"--P. 24

Revision and probable evolution of the Myiarchus flycatchers of the West Indies. Bulletin of the AMNH ; v. 136, article 6

p. 331-370, [15] p. of plates : ill., maps. ; 28 cm.Includes bibliographical references (p. 368-370)."The extent of morphological and vocal divergence among West Indian populations of Myiarchus is documented, and a key to the identification of these flycatchers is included. Of the 12 recognizable taxa, seven species (all endemic) are admitted. No new forms are recognized, but substantial changes in specific limits are recommended, based principally on the response of territorial males to the playback of vocal repertoires: four monotypic species, including two on Jamaica (M. validus and M. barbirostris), one on Puerto Rico (M. antillarum), and one in the southern Lesser Antilles (M. nugator); three polytypic species, including one on Cuba, Grand Cayman, and the Bahamas (M. sagrae), one on Jamaica and Hispaniola (M. stolidus), and one in the northern Lesser Antilles (M. oberi). An attempt is made to reconstruct the evolution of these species as newly constituted, and to determine their relative ages, origins, and paths of entry into the West Indian region. It is postulated that Myiarchus entered the West Indies by four primary invasions: three by way of Jamaica, from the Honduran-Nicaraguan bulge, and one via Grenada from Venezuela. The oldest invasion, perhaps by an obscure species in the late Tertiary avifauna of Middle America, led to the development of M. stolidus on Jamaica and Hispaniola. Subsequent range expansions from Hispaniola led to the evolution of M. sagrae and M. antillarum in the Greater Antilles and, more recently, to the polytypic M. oberi in the Lesser Antilles. In order not to obscure the relationships between these species, which are thought to have been derived from stolidus of Jamaica, it is recommended that they be considered a superspecies. After the submergence of the Greater Antillean land masses in the early Pleistocene, a second invasion of Jamaica by a Middle American Myiarchus, now obscure, resulted in the endemic M. validus. A third invasion of Jamaica, probably in the mid or late Pleistocene, by a representative of M. tuberculifer of Middle America, produced another endemic, M. barbirostris. The fourth invasion, no earlier than late Pleistocene, involved the range extension of M. tyrannulus from Venezuela into Grenada. With subsequent isolation this population evolved into M. nugator. Its expansion north of St. Vincent was blocked by a water barrier and competition with a congener already established on St. Lucia. This study of insular populations supports evidence, gained previously from continental species of this genus, that suggests a relative plasticity of morphology in contrast to the conservativeness of certain vocal characters. It has also demonstrated the efficacy of using the behavioral responses of territorial males to experimental playback of vocal repertoires for determining the specific limits of allopatric populations of Myiarchus"--P. 368

A phylogeny of the thirty-two genera in the Elaenia assemblage of tyrant flycatchers. American Museum novitates ; ; no. 2914.

57 p. : ill. ; 26 cm.Bibliography: p. 49-52

Experiments on species discrimination in Myiarchus flycatchers. American Museum novitates ; no. 2126

16 p. : ill. ; 24 cm.Includes bibliographical references (p. 16)."Field experiments were conducted on one species in New York (Myiarchus crinitus) and three species in Arizona (M. tyrannulus, M. cinerascens, M. tuberculifer) to test the hypothesis that differences in vocalizations function as the basis for species discrimination by these birds. 2. The response of territorial birds to various combinations of audio signals afforded by playback of prepared tapes of five species of Myiarchus, and to visual signals provided by mounted specimens of Myiarchus and non-Myiarchus species, was observed and photographed. 3. Each of the four species demonstrated an ability to discriminate between the vocal repertoires of five species of Myiarchus and reacted positively only to that repertoire representative of its own species. 4. Each of the four species reacted aggressively and even attacked mounted specimens, irrespective of species, providing these specimens were associated experimentally with playback of the vocal repertoire characteristic of the species being tested. 5. There was no evidence of discrimination by experimental birds between the visual signals presented by the various Myiarchus mounts used, but Myiarchus mounts appeared to have more stimulus value than mounts of non-Myiarchus species. 6. These results support the hypothesis that differences in vocalizations do function as the basis for species discrimination by these birds. They also lend weight to the use of species-specific vocal patterns as legitimate taxonomic characters, when considered in conjunction with more conventional morphological characters, in the establishment of specific limits and relationships within this difficult genus"--P. 15-16

Specific limits of the Yucatan flycatcher, Myiarchus yucatanensis. American Museum novitates ; no. 2229

12 p. : ill. ; 24 cm.Includes bibliographical references (p. 11-12)

Breeding birds on fallow farmland

60 p. : ill., maps ; 26 cm.Includes bibliographical references (p. 57-58)."A combination of both the horizontal and vertical approaches to the study of avian succession was applied over a 20-year period in research on the breeding birds of fallow farmland in Long Island, New York. Eight fields, representing stages in secondary plant succession from bare soil to a field 45 years old, varied in size from 0.41 to 1.88 hectares. Botanical data on average cover of herbaceous species and upright woody species, and on the density of trees by height class and by diameter characterize the vegetation of each study area. Breeding bird censuses were counts of all individuals, not indices to or estimates of population size. Particular attention was given to nest location and construction and to light readings taken at the nests to provide an index of relative nest cover. The sequence in which bird species became established in these fields was: red-winged blackbird, song sparrow, field sparrow, indigo bunting, common yellowthroat, blue-winged warbler, gray catbird, brown thrasher, and rufous-sided towhee. This is the same sequence of species derived by an arrangement in order of increasing cover at the nest. Likewise, this is the order in which these same species disappear from the continuum of communities that characterizes old field succession on Long Island. The concordance among these three sequences suggests that species-specific requirements with respect to cover at the nest plays an important role in determining which stages of old field succession a species finds attractive for nesting. There was a rapid increase in species diversity with an increase in age of the fields, and a leveling-off in numbers of territorial species from about 15 years (open shrubland) to 40 years (dense shrubby woodland) after cultivation. A more mature oak woodland in the same region (60 years after clear-cutting) had a greater species diversity than that of any earlier stage of old field succession. This progressive increase in species diversity with succession from herbaceous fields to mature forest is consistent with the findings of others. The density of breeding birds continued to increase beyond that age at which species diversity began to level off (about 15 years after cultivation) and did not reach peak density until another 15 years had elapsed. Density within the more mature oak woodland was significantly less than that of the 30- to 40-year old shrubby woodland. Whether or not there is a decline in density of breeding birds as succession approaches climax probably is determined by the relative availability of moisture. Other investigators have confirmed that in the more xeric successions, such as described in this study, a decline in density is the rule. In the more mesic successions, density is higher in the forest than in the intermediate shrubland stage. Species diversity and density were significantly lower in study areas where succession was arrested than in those permitted to revegetate naturally"--P. 5

The phylogenetic affinities of the flycatcher genera Myiobius Darwin and Terenotriccus Ridgway. American Museum novitates ; ; no. 2915.

11 p. : ill. ; 26 cm.Bibliography: p. 10