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An Unusual Song-like Vocalization Produced by Female Bachman’s Sparrows (Peucaea aestivalis)
James A. Cox, Clark D. Jones, James W. Tucker, Jr., and Gregory F. Budney

Southeastern Naturalist, Volume 13, Issue 2 (2014): N9–N12

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N9 2014 Southeastern Naturalist Notes Vol. 13, No. 2 J.A. Cox, C.D. Jones, J.W. Tucker, Jr., and G.F. Budney An Unusual Song-like Vocalization Produced by Female Bachman’s Sparrows (Peucaea aestivalis) James A. Cox1,*, Clark D. Jones2, James W. Tucker, Jr.1, and Gregory F. Budney3 Abstract - We describe a new female vocalization for Peucaea aestivalis (Bachman’s Sparrow) that may represent a type of female song. The vocalization has characteristics that are similar to the “excited” or “flight” songs that male P. aestivalis produce, and similar song characteristics can be found among other members of the genus, including one congener for which female singing is common. Two marked female P. aestivalis were observed producing the vocalization as well as four unmarked individuals that were paired with territorial males. A recording of one of these unmarked individuals collected in 1989 is similar to the vocalizations observed for marked females. Field notes collected at the time the recording was made suggested the “odd song” was produced by a female, and we provide a sonogram of this new vocalization based on this recording. The vocalization appears to be rare and may be difficult to link to external stimuli and social function . Peucaea aestivalis Lichtenstein (Bachman’s Sparrow) has a widely celebrated song that features elaborate male repertoires and male vocalizations that mimic the songs of other species (Borror 1961, 1971; Mengel 1951; Murray et al. 2004). Bachman’s Sparrows also produce a number of call notes that include: short, simple distress and alarm notes (pseet) given when predators approach nests or fledglings; short chitter and hissing sounds (chay) also given around nests and that may serve to distract potential predators; more-agitated, twittering notes produced during the breeding season when conspecifics encroach on territories; and crepuscular contact notes (including a high-pitched yip) given primarily in winter (Weston 1968). Although female Bachman’s Sparrows have been documented producing all call notes, singing is thought to be restricted to males (Dunning 2006). In this note, we describe an unusual vocalization produced by female Bachman’s Sparrows that differs from the many call notes that have been described (Borror 1971, Dunning 2006) and may represent a form of female singing. Most of our field observations stem from work conducted over the past 10 years with large, marked populations on the Wade Tract in southwest Georgia (30°47'N, 84°04'W; Thomas County; 273 marked individuals), Ft. Benning in west-central Georgia (32°19'N, 84°48'W; Chattahoochee, Muscogee, and Marion counties; 68 marked individuals), and Tall Timbers Research Station in north Florida (30°39'N, 84°14'W; Leon County; 87 marked individuals). The three sites contained mature pine forests that were burned frequently (approximately 2–3-year return intervals), and sex for marked individuals was assigned at capture by the presence of brood patches (females only), cloacal protuberances (males only), and behavioral observations. Although females are elusive, we observed two marked females on the Wade Tract that attracted attention because their vocalizations were much longer in duration and more complex than any of the call notes previously described. The vocalization resembled the complex chattering that can be heard at the close of the “excited” or “flight” song produced by males (Dunning 2006), and one marked female observed in April 2010 produced 1Tall Timbers Research Station and Land Conservancy,13093 Henry Beadel Dr.,Tallahassee, FL 32312. 2D.B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602. 3Macaulay Library, Cornell Lab of Ornithology, 159 Sapsucker Woods Road, Ithaca, NY 14850. *Corresponding author email - jim@ttrs.org. Manuscript Editor: Wylie Barrow Notes of the Southeastern Naturalist, Issue 13/2, 2014 2014 Southeastern Naturalist Notes Vol. 13, No. 2 N10 J.A. Cox, C.D. Jones, J.W. Tucker, Jr., and G.F. Budney the vocalizations uninterrupted for approximately 5 sec. A second marked female produced the vocalization for approximately 3–4 sec in September 2007. Both individuals produced the vocalization from an exposed perch (making their unique color bands easy to read) with their heads tilted in a position similar to that used by males when singing. Dunning (2006) described the male’s excited song as a bubbling, exuberant combination of notes that resembled the songs of a wren or Passerina cyanea L. (Indigo Bunting) produced with unnatural speed. The vocalizations produced by the females that we observed had similar complexity but qualitatively sounded more like the hastened song of Passerina caerulea L. (Blue Grosbeak). One of us (G.F. Budney) recorded an “odd song” of an unmarked individual near Abita Springs, LA, in May 1989 that closely resembled the vocalizations produced by the two marked females as noted here. This individual was paired with another unmarked bird that produced a typical male song, and field notes collected at the time stated the odd vocalization “… appeared to be the female of the pair.” The recording with audible field notes is available on-line (http://macaulaylibrary.org/audio/62939) and was used to produce a sonogram (Fig. 1; segment 0.18–0.22 in the recording). The length of the recorded vocalization is abbreviated compared to the other vocalizations observed in the field but otherwise has all the qualities of the vocalizations observed for the two marked females. We observed similar vocalizations produced by unmarked individuals in the field on three other occasions and believe that these also were female vocalizations because observations occurred near known nests during the early part of the nesting season (April) and males were observed singing typical songs near the putative females that produced the vocalization. Males defend territories vigorously against conspecific males, and an observation of two sparrows together without aggressive interactions is frequently used to assign paired breeding status in this species (Sirman and Cox 2010, Tucker et al. 2006). One of the unmarked females we observed appeared to produce the vocalization in response to playback of a male’s song at Ft. Benning as the male approached the playback device. The male sang as well, while the female continued to produce the vocalization for more than 5 sec. The length and structure of the vocalizations observed for all six individuals differed from chitter and hissing chay calls that females use near nest sites (Dunning 2006, Weston Figure 1. Sonogram of a complex, song-like vocalization produced by a female Bachman’s Sparrow near Abita Springs, LA (available online at http://macaulaylibrary.org/audio/62939; recorded by G.F. Budney). The vocalization begins at 00:18 in the recording and continues for approximately 3 seconds. N11 2014 Southeastern Naturalist Notes Vol. 13, No. 2 J.A. Cox, C.D. Jones, J.W. Tucker, Jr., and G.F. Budney 1968). Although the chitter call contains multiple syllables and might be repeated to form a more lengthy vocalization, it lacks the diversity and range of pitches that we observed and also descends in pitch once initiated (J.A. Cox and C.D. Jones, pers. observ.). The vocalizations we observed ascended in pitch at times, contained more complex rhythms, and were much longer in duration than any of the chitter vocalizations that we have observed. Juvenile Bachman’s Sparrows produce a partial adult song a few months after hatching, but juveniles are easily distinguished from adults until they attain adult plumage toward the end of the breeding season. All observations of unmarked individuals occurred early in the breeding season (April and May) when young birds (if present) would be easy to recognize and lack the capacity to produce partial songs because of their age (J.A. Cox and C.D. Jones, pers. observ.). The single female observed singing late in the breeding season in September, when juveniles have been observed singing, was marked the previous year. In addition, the partial songs we have observed for juveniles seem to be produced by males and include the sustained introductory note that is characteristic of the primary song of adults. There was no introductory note in the female vocalizations we observed. We have difficulties classifying this vocalization definitively as a female song because it could be an unusual type of extended call note. Most of our observations were recorded near nests where agitated call notes would be expected. However, the vocalizations we observed were much longer than any other calls known for this species, and one observation in September was toward the close of the known nesting period for this region (March–September). In addition, in five of the six observations reported (including marked individuals and the individual recorded), the females uncharacteristically perched above ground and did not display the agitated, wren-like bobbing typically performed when disturbed near nest sites (Dunning 2006). Another difficulty in classifying this vocalization stems from the generally limited knowledge we have of female singing (Riebel et al. 2005), which has been documented in several North American sparrows (Arcese et al. 1988, Illes and Yunes-Jimenez 2009). Interspecific variation in the extent to which female singing occurs is great, and the circumstances under which females sing often are rare and limited to specific social and ecological conditions such as shortages of mates or nest sites (Riebel et al. 2005). Interestingly, the genus Peucaea includes at least one member (P. ruficauda Bonaparte [Stripe-headed Sparrow]) in which females sing more frequently than males and produce an extended, complex song (Illes and Yunes-Jimenez 2009). Riebel et al. (2005) suggested that singing in both sexes may be an ancestral condition in birds. This possibility makes classification of this vocalization even more problematic because most members of the Peucaea produce distinctive flight or excited songs that contain the complicated, rhythmic twittering that characterized the vocalizations we observed for female Bachman’s Sparrows (DaCosta et al. 2009). Given the broad occurrence of this type of vocalization among members of this genus, the vocalizations that we observed could be a female song produced under very rare circumstances, a vestigial type of ancestral female singing that is no longer firmly rooted in a specific social function in Bachman’s Sparrows, or an extended type of agitated call. Regardless, we hope additional recordings of this vocalization can be obtained and encourage others studying this species to note the circumstances under which they encounter this newly described female vocalization. Those studying other members of the genus Peucaea also should try to determine whether females produce song-like vocalizations. Acknowledgments. We thank Jeptha H. and Emily V. Wade for establishing the Wade Tract Research Area. Financial support was provided by the Jelks Family Foundation, the Nongame Wildlife Grants Program of the Florida Fish and Wildlife Conservation 2014 Southeastern Naturalist Notes Vol. 13, No. 2 N12 J.A. Cox, C.D. Jones, J.W. Tucker, Jr., and G.F. Budney Commission, the Power of Flight Bird Conservation Program sponsored by the Southern Company and the National Fish and Wildlife Foundation, and the Georgia Department of Natural Resources. Two anonymous reviewers provided helpful comments on an earlier draft of the manuscript. Literature Cited Arcese, P., P.K. Stoddard, and S.M. Hiebert. 1988. The form and function of song in female Song Sparrows. Condor 90:44–50. Borror, D.J. 1961. Intraspecific variation in passerine bird songs. Wilson Bulletin 73:57–78. Borror, D.J. 1971. Songs of Aimophila sparrows occurring in the United States. Wilson Bulletin 83:132–151. DaCosta, J.M., G.M. Spellman, P. Escalante, and J. Klicka. 2009. A molecular systematic revision of two historically problematic songbird clades: Aimophila and Pipilo. Journal of Avian Biology 40:206–216. Dunning, J.B. 2006. Bachman’s Sparrow (Aimophila aestivalis). In A. Poole (Ed.). The Birds of North America. Cornell Lab of Ornithology, Ithaca, NY. Available online at http://bna.birds.cornell.edu/ bna/species/. Accessed July 2013. Illes, A.E., and L. Yunes-Jimenez. 2009. A female songbird out-sings male conspecifics during simulated territorial intrusions. Proceedings of the Royal Society B 276:981–986. Mengel, R.M. 1951. A flight-song of Bachman’s Sparrow. Wilson Bulletin 63:208–209. Murray, R.L., T.P. Stanton, and V.R. Emrick. 2004. Bachman’s Sparrows mimic the vocalizations of the Common Yellowthroat and the Indigo Bunting. Journal of Field Ornithology 75:51–52. Riebel, K., M.L. Hall, and N.E. Langmore. 2005. Female songbirds still struggling to be heard. Trends in Ecology and Evolution 20:419–420. Sirman, A., and J. Cox. 2010. The effects of breeding status on singing frequency in Bachman’s Sparrow. Oriole 75:1–6. Tucker, J.W., W.D. Robinson, and J.B. Grand. 2006. Breeding productivity of Bachman's Sparrows in fire-managed Longleaf Pine forests. Wilson Journal of Ornithology 118:131–137. Weston, F. 1968. Bachman’s Sparrow. Life histories of North American cardinals, grosbeaks, buntings, towhees, finches, sparrows, and allies. Part 2:956–975.