F. Gill

PHYLOGENY OF TITMICE (PARIDAE): II. SPECIES RELATIONSHIPS BASED ON SEQUENCES OF THE MITOCHONDRIAL CYTOCHROME-B GENE

Abstract We present a phylogenetic hypothesis for 40 species in the bird family Paridae, based on comparisons of nucleotide sequences of the mitochondrial cytochrome-b gene. Parids, including tits and chickadees, are an older group than their morphological stereotypy suggests. The longest cytochrome-b distances between species reach 12% in uncorrected divergence. With the exception of one thrasher-like terrestrial tit species of the Tibetan plateau (Pseudopodoces humilis), morphological and ecological stasis have prevailed since the initial parid radiation in the Old World during the mid-Tertiary. All trees support monophyly of the family Paridae, which includes Parus (sensu lato) and the monotypic Oriental genera Sylviparus, Melanochlora, and Pseudopodoces. Within the clade of chickadees and gray tits (Parus, subgenus Poecile), three Old World species, Parus lugubris of the eastern Mediterranean and Balkan regions, P. superciliosus of high elevations in the Himalayas of western China, and P. varius of the Orient are sisters to all other species. The Eurasian crested titmice (subgenus Lophophanes) and North American crested titmice (subgenus Baeolophus) are sister groups. Our data suggest two colonizations of the New World by parids in the late Tertiary. The ancestor of modern Baeolophus colonized North America 4 mya, and the ancestor of all North American chickadees colonized North America 3.5 mya. Phylogénie chez la mésange (Paridés): II. Relations entre les espèces basées sur des séquences du gène mitochondrial cytochrome-b

Speciation in North American chickadees. I: Patterns of mtDNA genetic divergence

We surveyed mitochondrial DNA haplotype divergence within and between populations of six species of North American chickadees (Parus, Subgenus Poecile) with the following results. (1) Genotype diversities (range 0.3 to 0.7) and low nucleotide diversities (range 3 to 27 × 10−4) within populations were typical of known vertebrates. (2) The two widespread, northern species (atricapillus and hudsonicus) exhibit little mtDNA genetic differentiation throughout their previously glaciated continental distributions, most likely because of recent, postglacial range expansions. (3) Newfoundland populations of atricapillus and maritime province (Newfoundland plus Nova Scotia) populations of hudsonicus have distinct mtDNA haplotypes which differ from continental haplotypes by single restriction site changes. (4) Haplotypes of the southeastern U.S. species P. carolinensis divide into eastern and western sets which have diverged by three percent. This heretofore unrecognized, divided population structure may correspond to the Tombigbee River/ Mobile Bay disjunction known in some other vertebrate taxa. (5) Allopatric populations of the southwestern species sclateri and gambeli exhibit divergences of one and three percent respectively. (6) Prevailing interspecific divergence distances of three to seven percent suggest speciation early in the Pleistocene rather than during late (e.g., Wisconsin) glaciations. (7) Phylogenetic analyses suggest that North American taxa include two clades, hudsonicus‐rufescens‐sclateri versus carolinensis‐atricapillus‐gambeli and that carolinensis and atricapillus are not sister species.

LOCAL CYTONUCLEAR EXTINCTION OF THE GOLDEN-WINGED WARBLER

I compared the mtDNA compositions of two adjacent populations of Vermivora chrysoptera (golden‐winged warbler) at different stages of transient hybridization with its sister species V. pinus (blue‐winged warbler). Pinus mtDNA introgresses asymmetrically and perhaps rapidly into chrysoptera phenotypes without comparable reverse introgression of chrysoptera mtDNA into replacing pinus populations. Pinus mtDNA was virtually fixed (98%) in an actively hybridizing lowland population with varied phenotypes. Pinus mtDNA increased from 27% (n = 11) in 1988 to 70% (n = 10) in 1992 in successive samples of a highland population in the initial stages of hybridization. This population comprised mostly pure and slightly introgressed chrysoptera phenotypes. The rapid pace of asymmetrical introgression may be the result of initial invasion of chrysoptera populations by pioneering female pinus and/or an unknown competitive advantage of pinus females and their daughters over chrysoptera females.

DNA-DNA HYBRIDIZATION EVIDENCE OF PHYLOGENETIC-RELATIONSHIPS AMONG MAJOR LINEAGES OF PARUS

DNA-DNA hybrids were formed among 2 outgroups and 12 taxa of titmice and chickadees to estimate the genealogical relationships of the main Parus lineages. A complete matrix of reciprocal comparisons among seven parids and the Verdin (Auriparus flaviceps) indicated that the Blue Tit (P. caeruleus) and Great Tit (P. major) together form the sister group of the rest of the genus, and that the Bridled Titmouse (P. wollweberi) is more closely related to North American titmice than to the Old World crested tits. The DNA-hybridization data complement information from allozyme and mtDNA studies of closely related parids and provide historical insight into patterns of tit behavior.

DISCRIMINATION BEHAVIOR AND HYBRIDIZATION OF THE BLUE-WINGED AND GOLDEN-WINGED WARBLERS

Closely-related, sympatric species differ in one or more characters that have been identified as premating isolating mechanisms. These may be morphological, behavioral, physiological, or ecological. Theoretically, premating isolating mechanisms evolve as divergent characters in allopatric populations or as specific adaptations that reduce the frequency of those mixed matings that result in inferior hybrids in sympatric populations. Thus, studies of hybridizing populations are of evolutionary interest in that they provide an opportunity to test this theory. One of the more thoroughly studied cases of avian hybridization is between the Bluewinged and Golden-winged warblers (Vermivora pinus and V. chrysoptera). These species differ strikingly in plumage coloration, sing distinct songs, and produce distinctive hybrid forms, the Brewsters and Lawrences warblers (see Parkes, 1951). Short (1963) has analyzed the extent of introgression in representative populations, and Ficken and Ficken (1967 to 1970) have reported their field work on various aspects of behavior and ecology from populations in the eastern United States. Despite an extensive literature, understanding of the status of the Blue-winged and Golden-winged warblers is not complete. In this paper we summarize and discuss the results of our studies on the morphology and behavior of sympatric, hybridizing populations of the Blue-winged and Goldenwinged warblers in southern Michigan,

Yellow-billed Cuckoo (Coccyzus americanus)

STATUS AND RANK COMMENTS Yellow billed Cuckoo (Coccyzus americanus) populations west of the Continental Divide were first proposed for protection under the Federal Endangered Species Act (ESA) in 1986 . Following several warranted but precluded findings, western Yellow-billed Cuckoos were proposed for listing as a Threatened Distinct Population Segment (DPS) by the U.S. Fish and Wildlife Service in 2013 . In 2014, the Yellow-billed Cuckoo western DPS was officially designated as Threatened under the ESA . In this context it is important to note that the species occurs on both sides of the Continental Divide in Wyoming (see Distribution and Range, below), but the ESA status applies only to individuals occurring west of the Divide.

Phylogeny of titmice (Paridae): I. Estimate of relationships among subgenera based on DNA-DNA hybridization

The phylogenetic relationships of titmice and chickadees (Passeriformes: Paridae) were estimated by DNA-DNA hybridization. Fifteen species of parids (representing all six subgenera) and two outgroups, Penduline Tit Remiz pendulinus and Whitebreasted Nuthatch Sitta carolinensis, were radiolabeled and compared pairwise to produce a complete reciprocal set of distance measures. The resulting phylogeny supported the traditional allocation of species to subgenera, except that Parus wollweberi clustered with the North American crested tits (subgenus Baeolophus) rather than the Old World crested tits (Lophophanes). The interrelationships of most subgenera remained unresolved. Nevertheless, a major subdivision in the family was strongly indicated: i.e., the great tits (subgenus Parus) and the blue tits (subgenus Cyanistes) formed a clade that is the sister taxon of the rest of the family. This bifurcation has important ecological, physiological, and morphological ramifications, as it correlates exactly with seed-caching and flocking habits, hippocampal development, and leg-muscle character distributions. These DNA-hybridization results corroborate or complement the phylogenetic relationships among parids supported by other molecular data sets (viz., allozyme, restriction site, and preliminary DNA hybridization analyses).

ECOLOGY AND EVOLUTION OF THE SYMPATRIC MASCARENE WHITE-EYES, ZOSTEROPS BORBONICA AND ZOSTEROPS OLIVACEA

THE Zosteropidae, or white-eyes, are a small paleotropical group of generalized passerines that have colonized more oceanic islands than any other passerine family (Moreau, 1964). While two species of Zosterops rarely coexist in mainland avifaunas, multiple invasions of small islands have resulted in several cases of bona fide sympatry. One such case involves the endemic Mascarene white-eyes, Z. borbonica and Z. olivacea, which are sympatric on Mauritius and Reunion Islands in the western Indian Ocean. Whereas niche expansion in a reduced competitive environment seems to be frequent in island coloinists (Mac Arthur and Wilson, 1967; Keast, 1968), studies of the Mascarene white-eyes, here reported, suggest that the first white-eye to colonize the Mascarene islands became more specialized, rather than more generalized, in the absence of competitors. A second successful colonization by a generalized white-eye and subsequent sustained coexistence of the two species was apparently facilitated by the specialization of the first arrival. THE MASCARENE ISLANDS

Great Blue Heron (Ardea herodias)

Three subspecies of the Great Blue Heron are recognized in North America, two of which occur in British Columbia: A. herodias herodias, which occurs across most of North America, and A. herodias fannini, which occurs only on the Pacific coast from Washington to Alaska (Payne 1979; Hancock and Kushlan 1984; Cannings 1998). The separation of these subspecies is based on differences in plumage, morphology, and migratory behaviour (Hancock and Elliott 1978; Payne 1979).

Experiments on Species Discrimination in Blue-Winged Warblers

DISCRIMINATION of species by birds may be dependent upon appropriate visual and auditory stimuli. Lacks study (1943) of the Robin (Erithacus rubecula) demonstrated the importance of a visual stimulus, the red breast. Other more recent studies (Dilger, 1956; Stein, 1958, 1963; Lanyon, 1963) have demonstrated the lack of importance of morphology and the reliance on auditory signals in certain species. Wood warblers (Parulidae) possess complex species-specific plumage patterns and vocalizations and might therefore rely on both types of stimuli. Species discrimination within the Blue-winged Warbler (Vermivora pinus) and Golden-winged Warbler (V. chrysoptera) complex is of particular interest because of the frequent hybridization of these birds in some areas of sympatry (Carter, 1944; Parkes, 1951; Berger, 1958; Short, 1963). The experiments discussed in this paper were designed to determine the basis for species discrimination in a population of Blue-winged Warblers on Long Island, New York, an area in which the Golden-winged Warbler is rarely found breeding. Morphologically, specimens from this population exhibit little evidence of introgression (Short, 1963).