Standardized coefficients for the canonical discriminant functions from song variables.

<p>Discriminant functions DF1 and DF2 account for 96.3% and 3.7% of the total variance, respectively.</p

Discriminant function analysis of song variables for the three junco lineages.

<p><i>J. h. insularis</i> (green squares), <i>J. h. oreganus</i> (blue triangles) and <i>J. phaeonotus</i> (orange circles). Empty circles represent group centroids. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063242#pone-0063242-t005" target="_blank">Table 5</a> for correlation values between discriminant functions and song variables</p

Song spectrograms for representative song types from the three junco lineages.

<p><b>A... </b><i>J. h. oreganus</i>, <b>B... </b><i>J. phaeonotus</i> and <b>C... </b><i>J. h. insularis</i>. Amplitude (y-axis) is given in KHz, and time (x-axis) is in seconds.</p

Differences in morphological trait means among junco lineages.

<p>Bars correspond to 95% confidence intervals. Abbreviations correspond to Guadalupe junco (GUJU), continental dark-eyed juncos (DEJU) and yellow-eyed junco (YEJU). Units of measurement for weight are grams, and wing, tail, tarsus and bill variables are in mm.</p

Mitochondrial DNA haplotype networks of Guadalupe, continental North America and volcano juncos (VOJU).

<p>Shown are median-joining networks for the concatenated CR and COI sequences (<b>A</b>), COI (<b>B</b>) and CR (<b>C</b>). Haplotypes are represented by circles, their size proportional to their frequency in the population. Color patterns are as follows: orange – <i>Junco phaeonotus,</i> blue tones – continental <i>Junco hyemalis</i> (dark: ORJU, light: PSJU, purple: GHJU), green – <i>Junco h. insularis</i>. Each branch represents a single nucleotide change, with additional mutations indicated by bars along branches. Numbers in squares indicate nucleotide changes separating the volcano junco.</p

Genetic diversity and demographic history indices of junco lineages.

<p>Haplotype diversity (<i>h</i>), nucleotide diversity (<i>π</i>) and Fs values for the three junco groups (pooling populations): Continental dark-eyed juncos (DEJU), yellow-eyed juncos (YEJU) and Guadalupe juncos (GUJU). The bottom row shows values obtained when excluding an individual that is likely a recent immigrant to the island (see text). *<i>P</i><0.05.</p

Genetic distances between the three junco lineages.

<p>Genetic distances between the three junco lineages.</p

Photographs of individual males of the five junco morphs included in the study.

<p><b>A.</b> Oregon junco (<i>J. h. oreganus</i>), <b>B.</b> gray-headed junco (<i>J. h. caniceps</i>), <b>C.</b> pink-sided junco (<i>J. h. mearnsi</i>) <b>D.</b> yellow-eyed junco (<i>J. phaeonotus</i>) and <b>E.</b> Guadalupe junco (<i>J. h. insularis</i>). Note the plumage similarity between C and E.</p

Geographic distributions and sampling localities of the different junco populations.

<p><b>A.</b> Distribution map of the genus <i>Junco</i> showing schematics of main plumage morphs. Lineage abbreviations, clockwise from south, are the following: VOJU (volcano junco <i>J. vulcani</i>), YEJU (yellow-eyed junco <i>J. phaeonotus</i>), and the following dark-eyed junco (<i>J. hyemalis</i>) morphs: GUJU (Guadalupe junco <i>J. h. insularis</i>), GHJU (gray-headed junco <i>J. h. caniceps</i>), ORJU (Oregon junco <i>J. h. oreganus</i>), SCJU (slate-colored junco <i>J. h. hyemalis</i>) and PSJU (pink-sided junco <i>J. h. mearnsi</i>). Sampling localities for each morph are marked with colored dots. <b>B.</b> Relative position of Guadalupe island with respect to the California shoreline. Juncos on the island are restricted to patches of cypress forest on the northern central plateau (dark green) and the few pine areas along the northern ridge (brown). Main junco distribution ranges are delimited by light green areas.</p

Mitochondrial DNA haplotype frequencies in junco populations.

<p>Haplotypes for cytochrome <i>c</i> oxidase gene (COI), control region (CR) and the concatenated dataset (CR+COI) are denoted by letters, with the frequency of each indicated in parentheses. Lineage codes correspond to continental dark-eyed forms <i>J. h. oreganus</i> (ORJU), <i>J. h. mearnsi</i> (PSJU) and <i>J. h. caniceps</i> (GHJU), yellow-eyed junco <i>J. phaeonotus</i> (YEJU) and Guadalupe junco <i>J. h. insularis</i> (GUJU).</p