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130 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 119, No. 1, March 2007 The Wilson Journal ofOrnithology 1 19(1):130—133, 2007 Differences in Song Rate in Two Populations of Yellow Warblers C. Morgan Wilson* ^’"^ and Rebecca L. Holberton' -'* — ABSTRACT The Yellow Warbler (Dendroicape- duced endocrine response to stress during techia) has a mating system characterized by monog- nestling provisioning (when compared to tem- daimsytriabnudtiboinpaorfentaanlycaDree,ndarnodichaasstpheeciberso.adWeshtebnreefdaicnegd perate-breeding males) to help optimize the with a short breeding season and unpredictable con- tradeoff between individual risk and short- ditions at high latitude, they display physiological re- term reproductive success (Wilson and Hol- sponses to help optimize the tradeoffbetween individ- berton 2004). In the present study, we inves- ual risk and reproductive success. Because these cir- tigated whether corresponding behavioral cumstances may also affect behavior, we measuredthe plasticity occurs in the time- and energy-de- song rates (songs/hr) of subArctic- and temperate- manding behavior of singing. We predicted breeding males during the nestling period. Temperate males sangathigherrates whencomparedtosubArctic that subArctic-breeding males would spend males. Maintainingahigh song ratewhileprovisioning less time singing during the nestling period nestlings may be advantageous if a second brood is when compared to their temperate counter- attempted. Our results suggest behavioral plasticity as parts, particularly late in the nestling period, a result ofdiffering constraints on time and reproduc- when energetic demands of their growing tion. Received3April2006. Accepted28August2006. nestlings are highest. Temperate-breeding males also have demanding nestlings during this stage, but we predicted they would be less The Yellow Warbler {Dendroica petechia) constrained by parental care and more likely has the broadest breeding distribution of any to continue defending territories and females Dendroica species (Dunn and Garrett 1997, in preparation for a possible second breeding Lowther et al. 1999) and occurs in high den- attempt. sity over much ofits range (Sauer et al. 2001 ). This species’ mating system is characterized METHODS by monogamy and biparental care, but extra- We found Yellow Warbler nests along the pair mating (Yezerinac and Weatherhead Churchill River near Churchill, Manitoba 1997, Yezerinac et al. 1999) and polygyny (58° 37' N, 94° 13' W) in early June 1999, and have been documented (Ford 1983, 1996; in areas immediately around Jennings Ran- DellaSala 1986; Reid and Sealy 1986; Spector dolph Lake (JRL; 39° 24' N, 79°07'W) in 1991). Such deviations from the typical mat- Garrett County, Maryland and Mineral Coun- ing system may occur mainly al lower lati- ty, West Virginia in May 2000 and 2001. The tudes, because the briefnorthern breeding sea- male ofeach nest was captured after the onset son enforces increased nesting synchrony and of incubation by the female but prior to hatch reduces opportunities for extra-pair interac- of the eggs. Birds were marked with a USGS tions when compared to more temperate pop- aluminum leg band and a unique combination ulaWtieonsear(lBireirskdieemo1n9s9t5,raYteezdertihnatacmeatleals. b1r9e9e9d).- of colored leg bands. The nestling period was divided a priori into early (days 1-3), middle ing at high latitude display a signihcantly re- (days 4-6), and late (days 7-9) stages. Each male’s song rate (songs/hr) was expressed as ' Department of Biology, University of Mississippi, the number of songs during focal, 1-hr-long University, MS 38677 USA. observation periods on days 2, 5, and 8. Ob- -Current address; Department of Biology, Hollins servations were conducted between 0500 and University, Roanoke. VA 24020 USA. 0900 hrs CDT at Churchill and between 0700 es, UCnuirvreernstitayddorfesMsa:inDee.paOrrtomneon,tMofEBi0o4l4og6i9caUlSSAc.ienc- and 1 100 hrs EDT at JRL (within 1-4 hrs fol- Corresponding author; e-mail: mwilson@hollins. lowing sunrise at each location). Each color edu marked male was confirmed as the male ofthe SHORT COMMUNICATIONS 131 120 JRL (8) Churchill(11) Day2 Day5 Day8 Nestling stage FIG. 1. Song rates ofmale Yellow Warblers during the nestling period were higher in a temperate study site (JRL; Maryland and West Virginia) than at a subArctic site (near Churchill, Manitoba) and did not change over the nestling period at each site. Sample size shown in parentheses. Bars represent the mean ± SE. An asterisk represents a significant difference {P = 0.01, 0.04, and < 0.001 for days 2, 5, and 8, respectively). territory by observing him provisioning nest- RESULTS lings. The breeding density of Yellow Warblers at Seventeen or more nests were found at each Churchill was almost three times as high as at study site, but only 1 1 (Churchill) and 8 (JRL) JRL (—3.6 vs. —1.3 pairs/ha). However, JRL remained intact throughout the study period. males sang at higher (Fj = 25.28, P < Data were normally distributed and statistical 17 0.001) rates than did Churchill males overall analyses were performed using StatView ver- and at each nestling stage (song rates ± SE CsiAo,n U4S.A51).(AAbsaicnugsle-Cfoanccteorptrse,peaIntce.d, mBeearskulreeys, o±n1d6a.y51s,25,9.5,38an±d 183,.8r2e,sp9e3c.ti5v0el±y:12J.R4L7,; C7h5u.r5-0 analysis of variance (ANOVA) was used to chill, 29.18 ± 7.80, 25.64 ± 8.10, 14.36 ± examine song rate at each site, with nestling 3.68; Fig. 1). There was a significant song rate sptoangeent.comAprtiwsoi-nfgactthoerrreeppeeaatteedd mmeeaassuurreecAoNm-- X site interaction (F2,7 = 3.64, P = 0.04), but OVA was used to test for differences in song sliinngcepseorniogdraatteseidtihdernostitvear(yChaucrrchoislslthFe nest=- rate between the sites, with nestling stage 1.74, P = 0.10; JRL: F,j = 1.74, P =20j.o21; comprising the repeated measure component. Fig. 1), this interaction may be a statistical Fisher’s protected least significant difference (PLSD) was used for post hoc analyses. artifact. Breeding density at each site was calculated DISCUSSION by dividing the number of nests by the esti- mated total area ofnesting habitat studied, us- The higher breeding density ofYellow War- ing distinct habitat edges (e.g., waterbody and blers at Churchill might have been expected forest edges) to define this area. to lead to a high rate of singing behavior, but 132 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. J19, No. 1, March 2007 this was not the case; JRL males sang at much (Master Permit 22616), approved by University of higher rates. The difference between sites may Mississippi Institutional Animal Care and Use Com- reflect differences in territory size, food avail- mittee, and conducted in accordance with the Guide- lines for the Use of Wild Birds in Research, a report ability, and/or other ecological factors, or dif- ofthe American Ornithologists’ Union. ferences between the subspecies that occur at the sites {D. p. parkesi and D. p. aestivcp re- LITERATURE CITED spectively; Browning 1994). However, we Bart, J. and A. Tornes. 1989. Importance ofmonog- suggest the difference may also reflect differ- amous male birds in determining reproductive ences in breeding biology. Under harsh and/ success: evidence for House Wrens and a review or unpredictable conditions, paternal care may of male-removal studies. Behavioral Ecology and be crucial to reproductive success (Bart and Sociobiology 24:109-1 16. Tomes 1989, Lynn and Wingfield 2003). Briskie, J. V. 1995. Nesting biology of the Yellow Thus, Churchill males may invest more in pa- JWoaurrbnlaelroaft tFhieelndorOtrhneirtnhollimoigtyo6f6i:ts53b1r-e5e4d3i.ngrange. rental care and less in singing. Following Browning, M. R. 1994. A taxonomic review ofDen- brood-rearing (median hatch date at Churchill, droica petechia (Yellow Warbler) (Aves: Paruli- 27 Jun), males must transition quickly from nae). Proceedings of the Biological Society of reproduction to molt to prepare for migration Washington 107:27-51. by mid August (Jehl 2004). Therefore, second DellaSala, D. a. 1986. Polygyny in the Yellow War- bler. Wilson Bulletin 98:152-154. broods are highly unlikely because of time Dunn, J. L. and K. L. Garrett. 1997. A held guide constraints (Briskie 1995, Dunn and Garret to warblers of North America. Houghton Mifflin 1997, Jehl 2004). In contrast, while paternal Company, New York, USA. care may also be important to reproductive Ford, N. L. 1983. Variation in mate fldelity in mo- success in temperate populations, the higher nogamous birds. Current Ornithology 1:329-356. song rate of temperate males may help main- Ford, N. L. 1996. Polyterritorial polygyny in North American passerines.JournalofFieldOrnithology tain territories and retain mates if a second 67:10-16. brood is attempted. The frequency of second Goossen, J. P. and S. G. Sealy. 1982. Production of broods in temperate populations of Yellow young in a den.se nesting population of Yellow Warblers remains unclear, as they have been Warblers, Dendroica petechia, in Manitoba. Ca- reported as both common (Dunn and Garrett nadian Field-Naturalist 96:189-199. 1997) and rare (Goossen and Sealy 1982). Jehl, Jr., J. R. 2004. Birdlife ofthe Churchill Region: Second brood attempts were not studied at the status, history, biology. Trafford Publishing, Vic- JRL site. If attempted, the timing of the nest- Lowtthoerira,, PB.riEt.,isCh.CCoelluamdbai,a,N.CaKn.adKlae.in,C. C. Rimmer, ing cycle (median hatch date of 25 May) AND D. A. Spector. 1999. Yellow Warbler [Den- would likely result in a second clutch in mid droica petechia). The birds of North Ameri- to late June. Identifying the factor(s) that in- ca. Number 454. http://bna.birds.cornell.edu/BNA/ fluence song rate in these two populations re- account/Yellow_Warbler/ (accessed 14 August 2006). quires further study, but our results suggest behavioral plasticity ofmales ofthe same spe- Lynnn,utS-.coEl.laarnedd LJ.onCg.spWuirnsgfiareelde.ss2e0nt0i3a.lMfaolreneCshtelsitn-g cies faced with potentially different con- survival: a removal study. Condor 105:154-158. straints on time and reproduction. Reid, M. L. and S. G. Sealy. 1986. Behavior of a polygynous yearling Yellow Warbler. Wilson Bul- ACKNOWLEDGMENTS letin 98:315-317. Sauer, J. R., J. E. Hines, and J. Fallon. 2001. The This research was funded by the Churchill Northern North American breeding bird survey, results and Studies Centre, the American Ornithologists' Union, analysis 1966-2000. Version 2001.2. USGS, Pa- and the National Science Foundation (IBN 9873852). tuxent Wildlife Research Center, Laurel, Mary- We thank C. E. Braun, R. D. Godard. D. A. Spector, land. USA. and anonymous reviewers for their helpful comments. Spector. D. A. 1991. The singingbehaviourofYellow We also thank Gary Aronhalt, Jr.. Andrew Campbell, Warblers. Behaviour 117:29-52. C. W. Cordell. Kevin Dodge, Jeffery Kruys. R. H. Wilson, C. M. and R. L. Holberton. 2004. Individual Lemlin, J. P. Wilson. D. W. Wilson, and J. H. Wilson risk versus immediate reproductive success: a ba- for held assistance, and the U. S. Army Corps of En- sis for latitudinal differences in the adrenocortical gineers and the Mountain Top Hunt Club for allowing response to stress in Yellow Warblers {Dendroica us to conduct research on their lands. Research was petechia). Auk 121:1238—1249. conducted under USGS and CWS Banding Permits Yezerinac, S. M. and P. J. We.atherhead. 1997. Re- SHORT COMMUNICATIONS 133 productive synchrony and extra-pair mating strat- TAM, AND R. Montgomerie. 1999. Extrapair pa- egy in a socially monogamous bird, Dendroica ternity in a farnorthern population ofYellow War- petechia. Animal Behaviour 54:1393-1403. blers, Dendroica petechia. Journal of Avian Bi- Yezerinac, S. M., H. L. Gibbs, J. V. Briskie, R. Whit- ology 30:234-237. The Wilson Journal ofOrnithology 119(1):133-134, 2007 Red-breasted Sapsuckers Nest in Utility Pole Steven R. Helm' — ABSTRACT. A pair of Red-breasted Sapsuckers of the pole was characterized by a vineyard (Sphyrapicus ruber) was observed nesting in an elec- and farm with Christmas trees and scattered tric distribution, creosote-treated, wood utility pole in orchard trees to the west and mature riparian the Willamette Valley, Oregon during spring 2006. To the author’s knowledge, this is the first published ac- mixed forest, along the Tualatin River, to the countofa sapsuckernesting in a utility pole. Received east. Branches of an approximately 25-m tall 5 July 2006. Accepted4 August 2006. Douglas-fir (Psuedotsuga menziesii) contacted the west side of the pole. Red-breasted Sapsuckers, although known A pair of Red-breasted Sapsuckers {Sphyr- to drum on utility poles (Bent 1939), typically apicus ruber) was observed nesting in an elec- excavate nest cavities in large snags or live tric distribution, creosote-treated, wood utility trees with decayed interiors (Howell 1952, Joy pole from 29 May through 4 June 2006 in the 2000, Walters et al. 2002). Nests in western Willamette Valley, Clackamas County, Oregon are associated with dense midstory Oregon (T2S, RIE, S28). The approximately and understory cover in close proximity to 12-m tall pole was installed in 1969 and was water (Nelson 1988). New nest cavities are heavily damaged. The nest hole was at a excavated each year, often in the same tree height of 3.0 m, while four similar sized nest used in previous years (Howell 1952), and holes and numerous non-nest excavations eggs are deposited on fine wood chips that are were evident higher on the pole. On 8 June retained in the cavity (Bent 1939). Other spe- 2006, an adult was found dead on the pole. cies ofwoodpeckers are known to nest in util- The bird’s leg had become tangled in fine, ity poles causing significant damage (Dennis black, plastic netting material that was present 1964, Harness and Walters 2004). Lower nest in the nest cavity. Apparently, the bird could success occurs in recently installed, treated not free itself as it flew from the pole. It is poles compared to more weathered, older (15 unknown whether the netting was used by the to 20 years), treated poles (Rumsey 1970). pair as a nest liner or placed by someone to None of the four currently recognized spe- cause nest failure. Nestlings were heard at the cies ofsapsuckers (AOU 1998) has previously time the adult was removed but perished, as been reported, to the author’s knowledge, to the nest was abandoned by the other adult. nest in utility poles. This account departs from Red-breasted Sapsuckers had nested in this published literature on nesting habitat of sap- pole for several consecutive years according suckers in general, and suggests that Red- to local residents. breasted Sapsuckers are more opportunistic The pole was along a lightly traveled road than previously thought. Photographic docu- in a semi-rural area and the nest hole faced mentation of the nesting pair was submitted east, toward the road. Habitat in the vicinity with the manuscript. LITERATURE CITED ' U.S. Army Corps of Engineers, R O. Box 2946 AmericanOrnithologists’ Union. 1998.Check-listof (CENWP-PM-E), Portland, OR 97208, USA; e-mail: North American birds. Seventh Edition. American [email protected] Ornithologists’ Union, Washington, D.C., USA.