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Juvenile prospecting, or exploratory behavior for gleaning information about areas or events, can have profound effects on the selection of future breeding habitat, particularly for birds with high site fidelity whose initial choice of breeding habitat could represent a lifetime investment in fitness. We present data from a 10-yr study of Piping Plovers (Charadrius melodus) on the Missouri River, USA, to determine whether postfledging, hatch-year (HY) prospecting movements inform second-year (SY) nest site choices. First, we compared the home ranges of HY and adult (after-hatch-year; AHY) plovers to investigate whether differences in habitat use existed between HY and AHY plovers. Second, we evaluated the effects of prospecting, nest density, reproductive success, and nesting and foraging habitat availability on SY plover nest site selection. Lastly, we evaluated the potential reproductive benefits of nesting in prospected areas by comparing the nest success and fledging success of SY plovers tha...

We describe Laniarius willardi, a new species of boubou shrike (Malaconotidae) from the Albertine Rift of Africa. The most conspicuous, distinguishing morphological feature of the species is a gray to blue-gray iris. This and external morphometric data indicate that L. willardi is diagnosable from other black or sooty boubous. Further, L. willardi is genetically diagnosable, and its closest relative is the Mountain Sooty Boubou (L. poensis camerunensis) from Cameroon. The Crimson-breasted Bush-shrike (L. atrococcineus) and the Lowland Sooty Boubou (L. leucorhynchus) are together the sister clade to L. willardi—L.p. camerunensis. Laniarius willardi and the geographically codistributed L. p. holomelas differ by 11.5% in uncorrected sequence divergence, and elevational data taken from museum specimens suggest the possibility of elevational segregation of the species at ∼2,000 m, with L. willardi occurring at lower elevations. Our broad sampling of black and sooty boubou taxa indicate that (1) races...

The double-collared sunbirds of the Eastern Arc Mountains of Tanzania and southeastern Kenya are characterized by regional variation in morphology and plumage. That variation has resulted in considerable dispute over their taxonomic status and delineation of range boundaries. It has been suggested that Moreau's Sunbird (Nectarinia Moreaui) is an atypical phenotype that has arisen from a hybridization event between the more widely distributed Eastern Double-collared Sunbird (N. mediocris) and the narrowly distributed Loveridge's Sunbird (N. loveridgei). A discriminant analysis of six standard morphological characters indicates that Moreau's Sunbird is intermediate in shape and size between the Eastern Double-collared and Loveridge's sunbirds. There is greater overlap between female Moreau's and Eastern Double-collared sunbirds than between males; Loveridge's Sunbird shows little overlap with the other taxa. Discrete plumage characters separate all three taxa. Molecular analyses of 728 base pairs of mitochondrial DNA (NADH3 and control region) suggest that Moreau's Sunbird is a valid taxon and the sister species to Loveridge's Sunbird. Eastern Double-collared Sunbird haplotypes can be divided into three distinct clades, separated from each other by substantial genetic divergence (approximately 8–10% sequence divergence). We propose species status for each of those clades and suggest the following three taxa: N. mediocris Shelley 1855, N. usambarica Gröte 1922, and N. fuelleborni Reichenow 1899. Finally, we propose a biogeographical hypothesis of speciation events within the N. mediocris species complex.

A new intergeneric hybrid manakin is characterized using morphological characters and mitochondrial and nuclear DNA sequences. Many morphological traits suggest the bird is intermediate between Ilicura militaris and Chiroxiphia caudata. Sequences of the maternally inherited mitochondrial ND2 gene demonstrate the female parent to be Chiroxiphia caudata, and the nuclear beta-fibrinogen intron 5 sequences can not eliminate Chiroxiphia and Ilicura as parents. Therefore, DNA sequence data lead to the conclusion that Ilicura is the male parent of this unusual bird. This study is important because it highlights the significance of using multiple character systems in diagnosing unusual bird specimens.

We assessed levels of genetic differentiation based on mitochondrial DNA sequences (portions of the cytochrome-b and ND2 genes) at several taxonomic levels in thamnophilid antbirds. Our focus was to investigate genetic differentiation among populations of two species in the genus Drymophila and to identify the sister genus to Drymophila. In addition, we present evidence of high levels of population subdivision in Hypocnemis cantator (Warbling Antbird). This widespread Amazonian taxon co-occurs, on a local scale, with D. devillei (Striated Antbird). Sequence divergences among populations of D. devillei and D. caudata (Long-tailed Antbird), two bamboo-specialists, often exceeded 2% between populations. Divergences within H. cantator, a species with more generalized habitat requirements and a more continuous distribution, were even higher, including 5.7% divergence between samples separated by 350 km of apparently continuous Amazonian forest. At higher taxonomic levels, genetic distances suggest that antbird genera and biological species are old. Genetic divergence between the two species that comprise the genus Hypocnemis was 9.3%, and divergence between D. devillei and D. caudata averaged 7.2%. Weighted parsimony and maximum-likelihood analyses supported Hypocnemis as the sister taxon to Drymophila; the genus Myrmotherula was not monophyletic, supporting previous allozyme analyses. In addition to the protein-coding sequences, we found that spacer regions between genes also provided phylogenetically informative characters from the level of suboscine families to within the biological species that we studied. Received 31 March 1998, accepted 7 April 1999.

Observations of mate guarding by males and robbing of nest material by fe- males suggest the hypothesis that dominance should be related to reproductive success in the Mexican Jay (Aphelocoma ultramarina). We analyzed the probability of successful reproduction in this plural-breeding, group-territorial species with respect to variation in social rank, sex, age, flock territory, and year. We examined the correlates of dominance rank at two stages of nesting, early (before and during laying) and late (after laying). The correlates of rank differed between the sexes and nesting stages. In the early or prelaying stage, success in getting a mate and initiating laying was correlated with rank in males but not in females, and with age in both females and males. In the late stage, given that a bird had a nest with eggs, fledging success was not significantly related to rank overall. In females, however, a significant inter- action was found between rank and age such that top rank was associated with greater suc- cess in older but not younger females. These effects of dominance at two stages of the nesting cycle (i.e. before and after egg laying) are consistent with the mate-guarding behavior of males and the nest-robbing behavior of females during nesting. Received 30 January 1996, accepted 19 December 1996.