Publications

lyme disease and migrating birds in the saint croix river valley.	during a study of migrating land birds in 1987, we examined over 9,200 individual birds representing 99 species from the saint croix river valley, a lyme disease-endemic area of east central minnesota and northwestern wisconsin. we found that 250 deer tick (ixodes dammini) larvae and nymphs infested 58 birds from 15 migrant species; 56 ticks (22.4%) were positive for the lyme disease spirochete borrelia burgdorferi. five ground-foraging migrant bird species favoring mesic habitats, veery (cathar ...	1989	2782872
bird song syntax: learned intraspecific variation is meaningful.	song syntax, defined as orderly temporal arrangements of acoustic units within a bird song, is a conspicuous feature of the songs of many species of passerine birds. while syntactical features play a role in interspecific song recognition by males of many bird species, syntax variation within species and female responsiveness to song syntax have received little attention. this report demonstrates that differences in naturally occurring learned song syntax within a species whose syntax varies geo ...	1988	3368470
song structure without auditory feedback: emendations of the auditory template hypothesis.	motor patterns of songs of swamp and song sparrows, melospiza georgiana and m. melodia, deafened early in life display a significant degree of species-specific structure. normal songs of the two species differ in the degree to which they are segmented. swamp sparrow song consists of a single segment, and song sparrow songs are multisegmental. song and swamp sparrows were deafened at 17 to 23 days, prior to the onset of song or subsong. the song sparrows developed more segments in their singing t ...	1983	6827307
developmental overproduction and selective attrition: new processes in the epigenesis of birdsong.	all phases of song development from infancy to adulthood were studied intensively in a group of laboratory-reared birds. male swamp sparrows, melospiza georgiana, trained with tape-recorded songs in infancy, developed song some 8 months later, averaging 2.2 song types per bird. analysis of the intermediate stage of plastic song revealed that the birds generated 4 to 5 times more song material than was needed for the species-specific song repertoire. the excess was discarded at the time of full s ...	1982	7106396
kinematics of birdsong: functional correlation of cranial movements and acoustic features in sparrows.	the movements of the head and beak of songbirds may play a functional role in vocal production by influencing the acoustic properties of songs. we investigated this possibility by synchronously measuring the acoustic frequency and amplitude and the kinematics (beak gape and head angle) of singing behavior in the white-throated sparrow (zonotrichia albicollis) and the swamp sparrow (melospiza georgiana). these birds are closely related emberizine sparrows, but their songs differ radically in freq ...	1993	8228778
permissiveness in the learning and development of song syntax in swamp sparrows.	vocal learning in swamp sparrows, melospiza georgiana, is subject to a host of sensory and motor limitations. one such limitation is that young swamp sparrows almost invariably crystallize their songs with a simple trilled syntax, irrespective of the syntax of vocal models from which they learn. a striking exception to this pattern was recently identified by podos (1996, animal behaviour, 51, 1061-1070), who found that large-scale organizational changes in vocal syntax, including the production ...	1999	10413545
tick infestations of birds in coastal georgia and alabama.	mist-netted birds were examined for ticks on jekyll island, glynn co., georgia (32 bird species) in 1996-1998, and at fort morgan, baldwin co., alabama (36 species) in 1998 during fall migration. sixty-two (14.7%) of 423 birds from jekyll island and 22 (13.3%) of 165 birds from fort morgan were infested with ticks. the mean number of ticks per infested bird was 2.0 on jekyll island and 6.3 at fort morgan. ten species of birds were infested with ticks on jekyl1 island where 87% of all ticks were ...	2000	10780541
auditory representation of the vocal repertoire in a songbird with multiple song types.	neural mechanisms for representing complex communication sounds must solve the problem of encoding multiple and potentially overlapping signals. birdsong provides an excellent model for such processing, in that many songbird species produce multiple song types. although auditory song representations in single song type species have been studied, how song is represented in the brains of species that sing multiple song types remains unknown. here we examine song type representations in swamp sparr ...	2001	11675508
causes of reduced clutch size in a tidal marsh endemic.	we tested three hypotheses of clutch size variation in two subspecies of the swamp sparrow (melospiza georgiana georgiana and m. g. nigrescens). swamp sparrows follow the pattern of other estuarine endemics, where clutch size is smaller among tidal salt marsh populations (m. g. nigrescens) than their closest inland relatives (m. g. georgiana). our results support predation risk and temperature, but not adult survival, as explanations of this pattern in swamp sparrows. coastal nests were twice as ...	2008	18825417
swamp sparrows modulate vocal performance in an aggressive context.	vocal performance refers to the proficiency with which a bird sings songs that are challenging to produce, and can be measured in simple trilled songs by their deviation from an upper bound regression of frequency bandwidth on trill rate. here, we show that male swamp sparrows (melospiza georgiana) increase the vocal performance of individual song types in aggressive contexts by increasing both the trill rate and frequency bandwidth. these results are the first to demonstrate flexible modulation ...	2009	19087921
are there species-universal categories in bird song phonology and syntax? a comparative study of chaffinches (fringilla coelebs), zebra finches (taenopygia guttata), and swamp sparrows (melospiza georgiana).	previous studies of learned bird song have suggested the existence of species-universal patterns in song organization: clear clusters in produced songs that do not vary within a species. here the authors combine a computational method of comparing songs with statistical methods of assessing cluster structure to investigate this issue in a more quantitative manner. the authors first analyze song phonology and then examine song syntax at a population level in 3 species with very different song str ...	2010	20175600
what drives variation in the corticosterone stress response between subspecies? a common garden experiment of swamp sparrows (melospiza georgiana).	although differences in the corticosterone stress response have frequently been reported between populations or closely related subspecies, their origin remains unclear. these differences may appear because individuals adjust their corticosterone stress response to the environmental conditions they are experiencing. however, they may also result from selection that has favoured individuals with specific corticosterone stress response or from environmental factors that have affected the developme ...	2011	21443644
mercury in swamp sparrows (melospiza georgiana) from wetland habitats in wisconsin.	wetlands play a major role in the export of methylmercury (mehg) to a watershed. the large contribution of wetlands to watersheds in northern wisconsin, coupled with the acidic environment of this area, makes these habitats especially vulnerable to mercury (hg) accumulation by biota. the purpose of this study was to compare hg accumulation between northern wisconsin wetlands and southern wisconsin wetlands using the swamp sparrow (melospiza georgiana) as a representative species. the swamp sparr ...	2011	21755351
songbirds learn songs least degraded by environmental transmission.	communication depends on accurate reception of signals by receivers, and selection acts on signals to transmit efficiently through the environment. although learnt signals, such as birdsong, vary in their transmission properties through different habitats, few studies have addressed the role of cultural selection in driving acoustic adaptation. here, we present a test of the hypothesis that song-learning birds choose to copy songs that are less degraded by transmission through the environment, u ...	2012	22718954
mercury in wing and tail feathers of hatch-year and adult tidal marsh sparrows.	we estimated mercury exposure and bioaccumulation in sparrow feathers to determine variation among age groups, between sparrow species, and between feather types. results of feather mercury studies in piscivorous birds indicate that mercury concentrations tend to increase with age and differ between feather types; however, data for insectivorous birds are lacking. we estimated mercury exposure of two insectivorous and sympatric tidal marsh sparrows: coastal plain swamp sparrow (melospiza georgia ...	2012	22864586
responses to song playback vary with the vocal performance of both signal senders and receivers.	mating signals of many animal species are difficult to produce and thus should indicate signaler quality. growing evidence suggests that receivers modulate their behaviour in response to signals with varying performance levels, although little is known about if and how responses are affected by receiver attributes. to explore this topic we conducted two experiments with swamp sparrows, melospiza georgiana, in which we challenged territorial males with playback of songs with trill rates that were ...	2013	23945685
experimental support for food limitation of a short-distance migratory bird wintering in the temperate zone.	the winter food limitation hypothesis (wflh) states that winter food abundance is a dominant source of population limitation of migratory birds. evidence is accumulating that long-distance migratory birds wintering in tropical climates have high overwinter survival probabilities and that winter food limitation mainly affects their fitness nonlethally by limiting energetic reserves necessary for successful reproduction. in contrast, the relative roles of direct mortality vs. indirect effects caus ...	2013	24597226
typical versions of learned swamp sparrow song types are more effective signals than are less typical versions.	the learned songs of songbirds often cluster into population-wide types. here, we test the hypothesis that male and female receivers respond differently to songs depending on how typical of those types they are. we used computational methods to cluster a large sample of swamp sparrow (melospiza georgiana) songs into types and to estimate the degree to which individual song exemplars are typical of these types. we then played exemplars to male and female receivers. territorial males responded mor ...	2014	24807252
a neuronal signature of accurate imitative learning in wild-caught songbirds (swamp sparrows, melospiza georgiana).	in humans and other animals, behavioural variation in learning has been associated with variation in neural features like morphology and myelination. by contrast, it is essentially unknown whether cognitive performance scales with electrophysiological properties of individual neurons. birdsong learning offers a rich system to investigate this topic as song acquisition is similar to human language learning. here, we address the interface between behavioural learning and neurophysiology in a cohor ...	2017	29229942
cultural conformity generates extremely stable traditions in bird song.	cultural traditions have been observed in a wide variety of animal species. it remains unclear, however, what is required for social learning to give rise to stable traditions: what level of precision and what learning strategies are required. we address these questions by fitting models of cultural evolution to learned bird song. we recorded 615 swamp sparrow (melospiza georgiana) song repertoires, and compared syllable frequency distributions to the output of individual-based simulations. we f ...	2018	29925831
influence of the agricultural conservation easement program wetland practices on winter occupancy of passerellidae sparrows and avian species richness.	wetlands enrolled in the agricultural conservation easement program (acep) are established as a means of restoring wetland ecosystems and wildlife habitat on private, agricultural land. in west virginia, usa, acep wetlands have never been evaluated to determine how they function as wildlife habitat in comparison to other available wetland habitat in the state. we measured the wintering occupancy of passerellidae species and apparent avian species richness on acep wetlands and a set of reference ...	2019	30677050