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Cited by 62Animal Vocal Communication and BehaviorAvian ecology and behaviorAnimal Behavior and Reproduction

Directional acoustic radiation in the strut display of male sage grouse Centrocercus urophasianus

Dantzker, Marc S., Deane, Grant B., Bradbury, Jack W.·1999·Journal of Experimental Biology
DOI 10.1242/jeb.202.21.2893
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Abstract

We present evidence that the acoustic component of the strut display of male sage grouse Centrocercus urophasianus is highly directional and that the nature of this directionality is unique among measured vertebrates. Where vertebrate acoustic signals have been found to be directional, they are most intense anteriorly and are bilaterally symmetrical. Our results show that sage grouse acoustic radiation (beam) patterns are often asymmetric about the birds’ anterior–posterior axis. The beam pattern of the ‘whistle’ note is actually strikingly bilobate with a deep null directly in front of the displaying bird. While the sage grouse display serves to attract potential mates, male sage grouse rarely face females head on when they call. The results of this study suggest that males may reach females with a high-intensity signal despite their preference for an oblique display posture relative to those females. We characterized these patterns using a novel technique that allowed us to map acoustic radiation patterns of unrestrained animals calling in the wild. Using an eight-microphone array, our technique integrates acoustic localization with synchronous pressure-field measurements while controlling for small-scale environmental variation in sound propagation.

AI snapshot

Written from the paper’s full text.

TL;DR

Male sage grouse strut displays radiate sound directionally, with beam patterns that are often asymmetric and, for the whistle, bilobate with a deep null directly in front of the bird. The authors used an eight-microphone field array with acoustic localization and path-specific transmission-loss corrections to map these patterns in unrestrained wild males.

Key findings

  • Across 39 vocalizations from three males (30 from male A, 7 from male B, 2 from male C), coos were directional and usually loudest in front and quietest at the sides, with maxima rotated up to 45° to either side. All-male coo 1 had a beam-pattern range of 8.6±2.4 dB and DI of 3.3±1.1 dB; coo 2 had 9.4±2.3 dB and DI 3.6±1.0 dB. Rayleigh tests for coo maxima forward and minima sideways were significant for all males combined (P<0.001).
  • Whistles showed a deep anterior null at least part of the time, with modal minima in front and modal maxima to the sides or behind. All-male whistle mean range was 14.0±2.3 dB and DI 4.4±0.5 dB; at its most directional time slice, the average whistle was 22.9±3.4 dB less intense in front than at the sides (DI 6.7±0.7 dB).
  • Pop 1 was strongly directional but its angular distribution of maxima/minima was not distinguishable from random (combined Rayleigh test, N=39, P>0.1); all-male range was 9.7±3.8 dB and DI 3.8±1.3 dB. Pop 2 was much less directional (range 5.2±1.4 dB, DI 2.5±0.7 dB), often falling below the 4 dB noise floor; when significantly directional, it tended to be louder in front and quieter behind.
  • Transmission loss was stable from 22:30 to 07:30 h. Below 1.2 kHz, repeated measurements differed by a mean of 1.1±0.5 dB (N=5); from 1.2 to 5.0 kHz, variation was 3.7±1.8 dB (N=5). Estimated beam-pattern measurement error was ±2 dB below 1200 Hz and ±4 dB above 1200 Hz.

Methods

  • Recorded three male sage grouse at lek 8 in Long Valley, Mono County, California, USA, from 4 to 21 April 1997, using circular eight-microphone arrays with microphones at approximately 20 cm height, plus synchronous video. Transmission-loss measurements were made at night (23:00–03:30 h) when birds were absent.
  • Used least-squares acoustic localization with multiple reference microphones to identify calls produced within 1.5 m of calibrated sites; bird orientation was estimated from synchronous video. Computed band-averaged and time-averaged beam patterns from Fourier-transformed pressure data corrected with empirically measured transmission loss for each propagation path.
  • Compared beam patterns using angle of maximum lobe, angle of minimum, beam-pattern range in dB, and directivity index; used Rayleigh tests on angular distributions of maxima and minima.

Limitations

  • Stated: the sample was skewed toward male A (30 of 39 vocalizations), and no tests were conducted for male C because sample size was insufficient. The authors note future studies should use an omnidirectional speaker to calibrate more sites and achieve sample sizes sufficient for comparisons between males.
  • Stated: orientation could not be determined acoustically and was estimated from video; many pop 2 beam-pattern ranges fell below the 4 dB noise floor; measurement error was ±2 dB below 1200 Hz and ±4 dB above 1200 Hz; no extant acoustic model sufficiently explained the observed propagation heterogeneity.
  • Evident: only three males at one lek in one season were sampled, only the horizontal plane was characterized, and the data do not reveal the adaptive significance of the unusual radiation patterns.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1242/jeb.202.21.2893

Cites

60 of 60 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

2 of 51 cited sources checked · 0 supported · 0 flagged · accuracy not yet measured

  • Findingown data
    § Environmental acoustics · p. 7

    The higher-frequency whistle spans a less reliable frequency band from 0.6 to 3.2 kHz.

    “In contrast, the higher-frequency whistle spans a less reliable frequency band from 0.6 to 3.2 kHz (Fig. 2).”
    Quote in the paperSubstantial claim
  • Findingown data
    § Beam pattern and the directional factor · p. 4

    Preliminary examination of sound propagation over the lek revealed that homogeneous geometric spreading models were insufficient for this environment.

    “Our preliminary examination of sound propagation over the lek revealed that models such as this were insufficient for this environment.”
    Quote in the paperSubstantial claim
  • Findingown data
    § Summary · p. 2

    Sage grouse acoustic radiation (beam) patterns are often asymmetric about the birds' anterior-posterior axis.

    “Our results show that sage grouse acoustic radiation (beam) patterns are often asymmetric about the birds' anterior-posterior axis.”
    • Also stated in: § Introduction · p. 3 · plain
      “Our results show that sage grouse beam patterns are variably asymmetric about the animal's anterior-posterior axis.”
    Quote in the paperSubstantial claim
  • Findingown data
    § Summary · p. 2

    The beam pattern of the 'whistle' note has a deep null directly in front of the displaying bird.

    “The beam pattern of the 'whistle' note is actually strikingly bilobate with a deep null directly in front of the displaying bird.”
    • Also stated in: § Introduction · p. 3 · plain
      “The beam pattern of one of the call elements, the 'whistle', has a deep minimum (null) directly in front of the displaying bird”
    Quote in the paperSubstantial claim
  • Findingown data
    § Environmental acoustics · p. 7

    The low-frequency components of the sage grouse display (coos and pop 2) have most of their energy in this well-propagated frequency range.

    “The low-frequency components of the sage grouse display (coos and pop 2) have most of their energy in this well-propagated frequency range (Fig. 2).”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 50
  • May combine two claims. 44
  • The quote only partly states this claim. 2

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    A model of the vocal apparatus as a vibrating piston suspended in a baffle has adequately explained the basic patterns observed in birds, bats, cetaceans and humans.

    “A model of the vocal apparatus as a vibrating piston suspended in a baffle has adequately explained the basic patterns observed in birds, bats, cetaceans and humans (Flanagan, 1972; Hartley and Suthers, 1989, 1990; Hunter et al., 1986; Larsen and Dabelsteen, 1990; Mogensen and Møhl, 1979; Pilleri, 1990; Stevens, 1997; Strother and Mogus, 1970).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Flanagan, 1972 source
    • cites Hartley and Suthers, 1989 source
    • cites Hunter et al., 1986 source

      The Introduction (page unavailable) models avian sound directionality using a circular vibrating piston set in a sphere representing the bird’s head or body. This supports the claim’s basic modeling point for birds, but the cited passages do not establish that this model explains patterns in bats, cetaceans, or humans; they also describe a sphere rather than a baffle. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation
    § Directionality, display posture and the study of mate choice · p. 14

    If the receiver can perceive the vocalization's directionality, then appropriate posture might also help to specify the intended recipient of the signal.

    “If the receiver can perceive the vocalization's directionality, then appropriate posture might also help to specify the intended recipient of the signal (McGregor and Krebs, 1984; Richards, 1981).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites McGregor and Krebs, 1984 source
    • cites Richards, 1981 source

      The introduction describes how Carolina wrens may use acoustic degradation to judge a singer’s distance, and the Methods describe near- and far-song playbacks. Neither addresses whether a receiver perceives vocal directionality or whether the singer’s posture specifies an intended recipient (searched: directionality, orientation, posture, receiver). (LLM, conf=0.76)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data
    § Environmental acoustics · p. 7

    At low frequencies, sound propagation was reliable across paths and less acoustic pressure was lost in transmission than in free-field spherical spreading.

    “At these low frequencies, sound propagation was reliable across paths and less acoustic pressure was lost in transmission than in free-field spherical spreading.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Environmental acoustics · p. 7

    Transmission loss fluctuated with time of day but was stable from 22:30 to 07:30h.

    “Transmission loss fluctuated with time of day but was stable from 22:30 to 07:30h (Fig. 4).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Beam patterns · p. 9

    Pop 1 was strongly directional, but the angular distribution of its beam pattern maxima and minima was not distinguishable from random.

    “Pop 1 was strongly directional (Table 1) but the angular distribution of the beam pattern maxima and minima was not distinguishable from random (Rayleigh test: combined data set, N =39, P &gt;0.1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Environmental acoustics · p. 7

    Shorter paths show shallower notches and a concomitant decrease in the frequency-dependence of propagation.

    “Shorter paths show shallower notches and a concomitant decrease in the frequency-dependence of propagation (Fig. 5D,E).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Beam patterns · p. 9

    The orientations of the major lobes of the coo beam patterns were variable with respect to the anterior-posterior axis of the birds, with the maximum lobe rotated by up to 45 degrees to either side of the bird.

    “The orientations of the major lobes of the coo beam patterns were variable with respect to the anterior-posterior axis of the birds.”
    • Also stated in: § Beam patterns · p. 9 · plain
      “In many vocalizations, the maximum lobe was rotated by up to 45° to either side of the bird, and in some examples the posterior lobe was actually slightly louder than the anterior lobe.”
    • Also stated in: § Bioacoustic conclusions · p. 13 · plain
      “This maximal lobe rotated up to 45 ° to either side between vocalizations.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Acoustic localization · p. 7

    The sample is skewed towards a single individual, but the range of directionality exhibited by male A subsumes the range of values exhibited by the other two males.

    “Although this sample is skewed towards a single individual, the range of directionality exhibited by male A subsumes the range of values exhibited by the other two males.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Beam patterns · p. 9

    The coo notes had directional beam patterns that were consistent between the two coos of a single call but variable between vocalizations.

    “The coo notes had directional beam patterns (Table 1) which were consistent between the two coos of a single call but variable between vocalizations (Fig. 6).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Beam patterns · p. 9

    On average, the whistle was highly directional and extremely variable.

    “On average, the whistle was highly directional and extremely variable (Table 3).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Beam patterns · p. 9

    The two pops showed markedly different beam patterns from the coos and from each other.

    “The two pops showed markedly different beam patterns from the coos and from each other.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Acoustic localization · p. 7

    The study identified 39 vocalizations produced within 1.5 m of calibration sites: 30 from male A, seven from male B, and two from male C.

    “We identified 39 vocalizations produced within 1.5 m of our calibration sites: 30 vocalizations from male A, seven from male B and two from male C.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Bioacoustic conclusions · p. 13

    Pop 1 was strongly directional but highly variable in its orientation, whereas pop 2 had a much lower magnitude of directionality but was fairly stable in its directional pattern.

    “Pop 1 was strongly directional but highly variable in its orientation, whereas pop 2 had a much lower magnitude of directionality but was fairly stable in its directional pattern.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Beam patterns · p. 9

    The directionality showed high between-note variability in all measured vocalizations, and the beam patterns for each call note vary between vocalizations.

    “This directionality showed high between-note variability in all measured vocalizations.”
    • Also stated in: § Advantages of synchronous recordings · p. 11 · plain
      “Our results show that the beam patterns for each call note vary between vocalizations.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Beam patterns · p. 9

    The beam patterns of the coos tended to be loudest to the front and quietest at the sides, with a variable amount of energy radiated behind the displaying bird; the coos were always intense in front and sometimes intense behind, and least intense to either side.

    “The beam patterns of the coos tended to be loudest to the front and quietest at the sides, with a variable amount of energy radiated behind the displaying bird.”
    • Also stated in: § Bioacoustic conclusions · p. 13 · plain
      “First, the coos were always intense in front of the animal and sometimes intense behind as well. The coos were least intense to either side.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Environmental acoustics · p. 7

    The exact position of this notch is variable between paths but is always between 1 and 2 kHz.

    “The exact position of this notch is variable between paths but is always between 1 and 2 kHz.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Beam patterns · p. 9

    The anterior null was not present for the entire whistle but was always present for at least part of it.

    “This null was not present for the entire whistle but was always present for at least part of it.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The lower frequencies of the whistle, 500-1400 Hz, often exhibited the deepest anterior nulls and the strongest directionality.

    “Also, the lower frequencies of the whistle, 500-1400 Hz, often exhibited the deepest anterior nulls and the strongest directionality.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation
    § Directionality, display posture and the study of mate choice · p. 14

    Sage grouse males do not face females head on; while males rotate to different directions for successive calls, they rarely face a female head on.

    “Sage grouse males do not face females head on.”
    • Also stated in: § Directionality, display posture and the study of mate choice · p. 14 · plain
      “Indeed, while males rotate to different directions for successive calls, they rarely face a female head on (J. W. Bradbury and M. S. Dantzker, personal observation).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given
    § Comparisons with the directionality of other vertebrate vocalizations · p. 14

    The shape of the beam patterns for the coos and pops superficially resemble some of these patterns.

    “The shape of the beam patterns for the coos and pops superficially resemble some of these patterns.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The expectation that lower-frequency sounds would be less directional than higher-frequency sounds held generally true in sage grouse because the whistle contains energy principally in wavelengths shorter than those of the less-directional coo and pop notes.

    “This held generally true in sage grouse since the whistle contains energy principally in wavelengths shorter than those of the less-directional coo and pop notes.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingnone given
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The two most surprising results are the deep anterior null in the radiation pattern of the whistle and the bilateral asymmetry and variable direction of the peak in the radiation pattern of the coos and pop 1.

    “The two most surprising results are the deep anterior null in the radiation pattern of the whistle and the bilateral asymmetry and variable direction of the peak in the radiation pattern of the coos and pop 1.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Appendix C: the directivity index · p. 16

    The simulation of the dipole radiation pattern yielded a range of DI values (median 2.84 dB; range 2.32 dB<DI<3.01 dB), with no values exceeding the analytically calculated value.

    “This yielded a range of values (median 2.84 dB; range 2.32 dB&lt;DI&lt;3.01dB). No values exceed the value calculated analytically above.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingreasoning
    § Appendix C: the directivity index · p. 16

    For a pulsating sphere, DI=0 dB; for a hemispherical source mounted on a rigid baffle, DI=3.01 dB; for a simple dipole radiation pattern, DI=3.01 dB.

    “For a pulsating sphere where H ( q )=0, we find that DI=0 dB. A hemispherical source mounted on a rigid baffle where H ( q )=0 for 0&lt; q &lt; p and H ( q )=0 for p &lt; q &lt; 2 p then has DI=3.01 dB. For a simple dipole radiation pattern where H ( q )=cos 2 q , we find an equivalent DI=3.01dB.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given
    § Summary · p. 2

    Where vertebrate acoustic signals have been found to be directional, they are most intense anteriorly and are bilaterally symmetrical.

    “Where vertebrate acoustic signals have been found to be directional, they are most intense anteriorly and are bilaterally symmetrical.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Introduction · p. 2

    The strut display of male sage grouse is highly stereotyped and elaborate.

    “The strut display of the male sage grouse is highly stereotyped and elaborate (Hjorth, 1970; Honess and Allred, 1942; Wiley, 1973a; Young et al., 1994).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Hjorth, 1970

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Honess and Allred, 1942

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Wiley, 1973a

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Study design and conductreasoning
    § Acoustic localization · p. 6

    Both near-source location and complete encirclement by receivers were true of the experimental design.

    “Both were true of our experimental design.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The localization method assumes that the speed of sound is known, that there is little wind, and that receiver positions are accurately known.

  • Classified as probably not a substantial claim.

    Premisecitation
    § Advantages of synchronous recordings · p. 11

    Previous studies have made detailed beam pattern maps using two microphones by repeatedly repositioning a single receiver while another remains fixed to correct for fluctuations in overall amplitude.

    “Previous studies have made detailed beam pattern maps using two microphones by repeatedly repositioning a single receiver at various angles while another remains in a fixed position to correct for fluctuations in overall amplitude.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data
    § Advantages of synchronous recordings · p. 11

    The assumption that beam patterns remain constant between vocalizations may be inappropriate for some organisms, and synchronous recording is therefore preferred.

    “Therefore, this assumption may be inappropriate for some organisms, and synchronous recording is therefore preferred (Gerhardt, 1998).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Gerhardt, 1998 source

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Study design and conductnone given
    § Acoustic localization · p. 6

    Receiver positions were definitely fixed and precisely known.

    “Receiver positions were definitely fixed and precisely known.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductreasoning
    § Advantages of explicit environmental measures · p. 11

    The paper measured the precise transmission loss curve for each measurement path and explicitly corrected for propagation heterogeneity in frequency and space.

    “Instead, we measured the precise transmission loss curve for each measurement path and explicitly corrected for propagation heterogeneity in frequency and space.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning
    § Environmental acoustics · p. 7

    Long-distance communication in the whistle frequency range is very unreliable, suggesting that the whistle component of the call might be an exclusively close-range component of sage grouse communication.

    “Long-distance communication in this frequency range is very unreliable, suggesting that the whistle component of the call might be an exclusively close-range component of sage grouse communication.”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Study design and conductreasoning
    § Acoustic localization · p. 6

    The additional step allowed the authors to identify and purge vocalizations with disparate location estimates from the data set.

    “This additional step allowed us to identify and purge these vocalizations from the data set.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    This is consistent with models of single-site acoustic radiation.

    “This is consistent with models of single-site acoustic radiation.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    Most frog vocalizations are much less directional and some exhibit a nearly omnidirectional pattern, DI approximately 0.

    “Most frogs vocalizations are much less directional and some have been found to exhibit a nearly omnidirectional pattern, DI ≈ 0 (Gerhardt, 1975; Passmore, 1981; Prestwich et al., 1989).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Gerhardt, 1975 source
    • cites Passmore, 1981

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Prestwich et al., 1989 source

  • Classified as probably not a substantial claim.

    Study design and conductreasoning
    § Advantages of synchronous recordings · p. 11

    The tradeoff associated with synchronous recording is that the spatial resolution of radiation maps is limited by the number of receivers deployed.

    “The tradeoff associated with synchronous recording is that the spatial resolution of radiation maps is limited by the number of receivers deployed.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning
    § Discussion · p. 10

    The paper had to develop a new method for measuring acoustic directionality in the field to measure and map these patterns accurately.

    “To measure these patterns and map them accurately, we had to develop a new method for the measurement of acoustic directionality in the field.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Premisereasoning
    § Advantages of explicit environmental measures · p. 11

    Field studies must account for the complexities of propagation in natural environments.

    “Field studies must account for the complexities of propagation in natural environments.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given
    § Acoustic localization · p. 6

    The orientation of the male relative to the receiver array could not be determined acoustically and was therefore estimated from synchronous video recordings.

    “The orientation could not be determined acoustically and was therefore estimated from the synchronous video recordings.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The most directional measured frog call has a beam pattern that ranges 6 dB from front to back (DI approximately 1.5).

    “the most directional of the measured frog calls has a beam pattern which ranges 6 dB from front to back (DI ≈ 1.5) (Gerhardt, 1975).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Gerhardt, 1975 source

  • Classified as probably not a substantial claim.

    Premisereasoning
    § Advantages of explicit environmental measures · p. 11

    Field study allows for the measurement of acoustic directionality in the context of natural display behavior.

    “Field study also allows for the measurement of acoustic directionality in the context of natural display behavior.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The acoustic radiation patterns of a number of other vertebrate vocalizations have been measured and conform to a general theme.

    “The acoustic radiation patterns of a number of other vertebrate vocalizations have been measured and they conform to a general theme.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The most directional vocalizations, with approximately 20-36 dB in beam pattern range, are the echolocation pulses of bats and toothed whales.

    “The most directional vocalizations, with approximately 20-36dB in beam pattern range, are the echolocation pulses of bats and of toothed whales (Au et al., 1995; Fuzessery et al., 1992; Hartley and Suthers, 1987, 1989, 1990; Pilleri et al., 1976; Purves and Pilleri, 1983; Schnitzler and Henson, 1980; Wotton et al., 1997).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Au et al., 1995

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Fuzessery et al., 1992 source
    • cites Hartley and Suthers, 1987 source

  • Classified as probably not a substantial claim. May combine two claims.

    Premisenone given
    § Advantages of explicit environmental measures · p. 11

    These simplifications may be appropriate when measurement propagation paths are very short, when there are no nearby surface boundaries, and when all paths are free from heterogeneous features.

    “These simplifications may be appropriate (a) when the measurement propagation paths are very short, (b) when there are no nearby surface boundaries, and (c) when all paths are free from heterogeneous features.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    Intermediate directionality, with beam pattern ranges of 6-15 dB and DI between 2.0 and 3.5 depending on frequency, has been found in human speech and blackbird vocalizations.

    “Intermediate directionality, with beam pattern ranges of 6-15 dB and DI between 2.0 and 3.5 depending on frequency, has been found in human speech and blackbird vocalizations (Flanagan, 1972; Larsen and Dabelsteen, 1990).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Flanagan, 1972 source
    • cites Larsen and Dabelsteen, 1990 source

  • Classified as probably not a substantial claim.

    Premisenone given
    § Advantages of synchronous recordings · p. 11

    Using asynchronous measures to reconstruct radiation patterns assumes that beam patterns remain constant between vocalizations of the same type.

    “In addition, using asynchronous measures to reconstruct radiation patterns assumes that beam patterns remain constant between vocalizations of the same type.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given
    § Advantages of explicit environmental measures · p. 11

    Anechoic recording chambers obviate detailed environmental calibration because measures of the acoustic field are direct measures of the emission field.

    “Anechoic recording chambers obviate detailed environmental calibration since the measures of the acoustic field are direct measures of the emission field.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisenone given
    § Advantages of synchronous recordings · p. 11

    The asynchronous method can only be used when the focal animal's position is fixed by behavior or design and the same vocalization can be coaxed or induced for repeated measures.

    “However, this method can only be used when the focal animal's position is fixed by behavior or design and the same vocalization can be coaxed or induced for repeated measures.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning
    § Measurement summary · p. 4

    The authors could then calculate beam patterns generated only by the directional properties of the source.

    “We could then calculate beam patterns generated only by the directional properties of the source.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning
    § Acoustic localization · p. 6

    Only calls that showed a high correspondence between all eight location estimates were used in these analyses.

    “In addition, only calls that showed a high correspondence between all eight location estimates were used in these analyses.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisenone given
    § Advantages of explicit environmental measures · p. 11

    Previous field studies of acoustic directionality have dealt with the environment by assuming or demonstrating that sound propagation is not frequency-dependent over the measurement distance and that environmental effects are homogeneous across measurement paths.

    “Previous field studies of acoustic directionality have dealt with the environment by either assuming or demonstrating (a) that sound propagation is not frequency-dependent over the measurement distance and (b) that environmental effects are homogeneous across the measurement paths.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisereasoning
    § Advantages of explicit environmental measures · p. 11

    These simplifications allow the treatment of field measurements as if they were conducted in an anechoic chamber and thus require no explicit corrections for propagation effects.

    “These simplifications allow the treatment of field measurements as if they were conducted in an anechoic chamber and thus require no explicit corrections for propagation effects.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § Advantages of synchronous recordings · p. 11

    The asynchronous, two-microphone method allows for fine spatial resolution in mapping acoustic fields and has been used to reconstruct complicated radiation patterns.

    “This asynchronous, two-microphone method allows for fine spatial resolution in the mapping of acoustic fields and has been used to reconstruct some very complicated radiation patterns (Au et al., 1995; Bennet-Clark, 1987; Forrest, 1991; Hartley and Suthers, 1987, 1989, 1990; Hunter et al., 1986; Larsen and Dabelsteen, 1990).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Au et al., 1995

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Bennet-Clark, 1987 source
    • cites Forrest, 1991 source

  • Classified as probably not a substantial claim.

    Study design and conductown data
    § Acoustic localization · p. 6

    Concurrent wind measurement allowed the authors to exclude data recorded during periods of wind in excess of 3 km h−1.

    “Concurrent wind measurement allowed us to exclude data recorded during periods of wind in excess of 3kmh -1 .”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The degree to which these fields are directional varies from a narrow beam to nearly or completely omnidirectional.

    “The degree to which these fields are directional varies from a narrow beam to nearly or completely omnidirectional.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based).

    Premisenone given
    § Advantages of explicit environmental measures · p. 11

    For many organisms, laboratory study is impossible or impractical and measures must be made in the field.

    “For many organisms, laboratory study is impossible or impractical and measures must be made in the field.”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Study design and conductreasoning
    § Advantages of synchronous recordings · p. 11

    The paper's synchronous recording technique allowed testing of the assumption that beam patterns remain constant between vocalizations.

    “Our synchronous recording technique allowed us to test this assumption in sage grouse.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisereasoning
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    Few of the above studies resolved these patterns beyond the forward-facing 180 degrees, so these range values are estimates and it would be inappropriate to estimate DIs.

    “Few of the above studies resolved these patterns beyond the forward-facing 180°, so these range values are estimates and it would be inappropriate to estimate DIs.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data
    § Appendix A: calibration of the acoustic system · p. 15

    The spherical spreading relationship between source and microphone was tested and found to hold true by measuring source spreading loss at three ranges, verifying that calibration measurements were not made in the near field of the source and were free from multi-path effects.

    “This relationship was tested and found to hold true by measuring the source spreading loss at three ranges, verifying that the calibration measurements were not made in the near field of the source and were free from multi-path effects.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § Directionality, display posture and the study of mate choice · p. 14

    In situations where the intended receiver's position is unknown, an omnidirectional vocalization may be favored.

    “In situations like this, an omnidirectional vocalization may be favored.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationreasoning
    § Directionality, display posture and the study of mate choice · p. 14

    The directionality of vertebrate vocalizations is likely to be tuned to the social and environmental context of the display, and display posture is likely to reflect the degree and nature of that directionality.

    “The directionality of vertebrate vocalizations is likely to be tuned to the social and environmental context of the display, and display posture is likely to reflect the degree and nature of that directionality.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    Bufo americanus radiates sound in two equally intense lobes 180 degrees apart, one in front and one behind, separated by a notch of approximately 3-4 dB.

    “One species of toad, Bufo americanus , radiates sound in two equally intense lobes 180 ° apart, one in front and one behind, separated by a notch of approximately 3-4dB (Gerhardt, 1975).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Gerhardt, 1975 source

  • Classified as probably not a substantial claim.

    Premisecitation
    § Appendix A: calibration of the acoustic system · p. 15

    The ground-induced interference structure depends sensitively on the composition of the ground and ground relief.

    “The ground-induced interference structure depends sensitively on the composition of the ground (Embleton et al., 1983) and ground relief.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Embleton et al., 1983 source

  • Classified as probably not a substantial claim.

    Premisecitation
    § Directionality, display posture and the study of mate choice · p. 14

    Amplitude is likely to be an important determinant of mate attraction.

    “While amplitude is likely to be an important determinant of mate attraction (Forrest and Raspet, 1994)”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Forrest and Raspet, 1994 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    One dual-site radiation model argued that emission through a paired structure could lead to an increase in directionality for bats that call through their noses.

    “One dual-site radiation model argued that emission through a paired structure could lead to an increase in directionality for bats that call through their noses (Möhres, 1967; Sokolov and Makarov, 1971).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Möhres, 1967

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Sokolov and Makarov, 1971

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    Alternative models of single-site radiation have come closer to explaining the smaller side lobes in the acoustic field of bats.

    “Alternative models of single-site radiation have come closer to explaining the smaller side lobes in the acoustic field of bats (Hartley and Suthers, 1989, 1990).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Hartley and Suthers, 1989, 1990

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Premisecitation
    § Directionality, display posture and the study of mate choice · p. 14

    Directionality is a defining component of an acoustic signal's active space, although it is often overlooked.

    “Directionality is a defining component of an acoustic signal's active space, although it is often overlooked (e.g. Brenowitz, 1982).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Brenowitz, 1982 source

  • May combine two claims.

    Interpretationown data
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The sage grouse coos and pop 1 show the level of directionality commonly found in the communication signals of larger vertebrates, while pop 2 is more similar to the omnidirectional sounds of frogs.

    “The sage grouse coos and pop 1 show the level of directionality commonly found in the communication signals of larger vertebrates, while pop 2 is more similar to the omnidirectional sounds of frogs.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    Since the Cacosternum boettgeri study did not account for propagation effects, it is possible that the skew was environmentally induced.

    “In addition, since this study did not account for propagation effects, it is possible that the skew was environmentally induced.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning
    § Appendix A: calibration of the acoustic system · p. 15

    Rotation of the speaker allowed calibration of the system with an effectively omni-directional source.

    “however, the rotation of the speaker allowed us to calibrate our system with an effectively omni-directional source.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The Kudelski speaker is directional.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    There are only two previously reported minor exceptions to the vertebrate theme that vocalizations are loudest in front and quieter behind.

    “To our knowledge, there are only two previously reported minor exceptions to the vertebrate theme that vocalizations are loudest in front and quieter behind.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The call of Cacosternum boettgeri was reported to be 1-1.5 dB louder directly posterior.

    “Also, the call of the African frog Cacosternum boettgeri was reported to be 1-1.5dB louder directly posterior (Passmore, 1981).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Passmore, 1981

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § Appendix C: the directivity index · p. 16

    The directivity index does not inform us as to the shape of the radiation pattern, only the degree to which the acoustic power is concentrated.

    “This illustrates that the directivity index does not inform us as to the shape of the radiation pattern, only the degree to which the acoustic power is concentrated.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation
    § Directionality, display posture and the study of mate choice · p. 14

    Directionality and heterogeneous transmission loss also stymie efforts to measure the amplitude of other species' acoustic displays.

    “These same factors, directionality and heterogeneous transmission loss, also stymie efforts to measure the amplitude of other species' acoustic displays (Gerhardt, 1998).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Gerhardt, 1998 source

  • May combine two claims.

    Interpretationreasoning
    § Directionality, display posture and the study of mate choice · p. 14

    Even directionality as low as 3-6 dB is likely to be behaviorally relevant because, given spherical spreading, this translates to a 40-100% greater distance of propagation in the direction of the maximum lobe before the signal is lost.

    “Even directionality as low as 3-6dB is likely to be behaviorally relevant because, given spherical spreading, this translates to a 40-100 % greater distance of propagation in the direction of the maximum lobe before the signal is lost.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    The effect in Cacosternum boettgeri was extremely small, within the range of likely measurement error for field work.

    “This effect was extremely small, within the range of likely measurement error for working in the field.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given
    § Comparisons with the directionality of other vertebrate vocalizations · p. 13

    Previous attempts to understand patterns generated by vertebrate vocalization have used simple acoustic models of single-source radiation to estimate radiation mechanisms.

    “Previous attempts to understand the patterns generated by vertebrate vocalization have used simple acoustic models of single-source radiation to arrive at a realistic estimate of radiation mechanisms.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning
    § Appendix A: calibration of the acoustic system · p. 15

    As the ground relief varied considerably along the transmission paths studied, the transmission loss along each path needed to be measured.

    “As the ground relief varied considerably along the transmission paths studied, the transmission loss along each path needed to be measured.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data
    § Directionality, display posture and the study of mate choice · p. 14

    These data do not reveal the adaptive significance of the unusual radiation patterns described.

    “Beyond this, however, these data do not reveal the adaptive significance of the unusual radiation patterns we have described.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Directionality, display posture and the study of mate choice · p. 14

    Lekking sage grouse are under intense sexual selection driven by female choice.

    “We now know that lekking sage grouse are under intense sexual selection driven by female choice (Gibson and Bradbury, 1985; Hartzler, 1972; Hjorth, 1970; Lumsden, 1968; Patterson, 1952; Scott, 1942; Wiley, 1973b).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Gibson and Bradbury, 1985 source
    • cites Hartzler, 1972
    • cites Hjorth, 1970

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Appendix A: calibration of the acoustic system · p. 15

    Acoustic transmissions close to the ground are characterized by frequency-dependent structure in the transmission loss caused by interference between airborne and ground-reflected arrivals.

    “Acoustic transmissions close to the ground are characterized by frequency-dependent structure in the transmission loss caused by interference between airborne and ground-reflected arrivals.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Embleton et al., 1983 source
81 of 81

  • The authors state this as an assumption.

    The localization method assumes that the speed of sound is known, that there is little wind, and that receiver positions are accurately known.

    “The method assumes that the speed of sound is known, that there is little wind and that receiver positions are accurately known (Spiesberger and Fristrup, 1990).”

  • The paper relies on this without support.

    The explosive use of dual anterior air sacs is unique to the Centrocercus grouse strut display.

    “this explosive use of dual anterior air sacs is unique to the Centrocercus grouse strut display.”

  • The paper relies on this without support.

    During the whistle, the air-sac geometry changes extensively.

    “During the duration of the whistle, both the dominant frequency and the air-sac geometry change extensively.”

  • The authors state this as an assumption.

    All time variables have been Fourier-transformed so that we are dealing with the steady-state response of the system.

    “In what follows, we will assume that all time variables have been Fourier-transformed so that we are dealing with the steady-state response of the system.”

  • The paper relies on this without support.

    The Kudelski speaker is directional.

    “Like most loudspeakers, the Kudelski speaker is directional”
5 of 5

Cites

Flagged first, then by citations

1 of the 61 references couldn’t be matched to a known paper.

Research works printed but not linked: 10

  1. Hjorth, 1970, Reproductive behavior in Tetranidae, with special reference to males, Viltrevy, 7, 183
  2. Honess, 1942, Structure and function of the neck muscles in inflation and deflation of the esophagus in the sage cock, 5
  3. Lumsden, 1968, The displays of the sage grouse, Ontario Department of Lands and Forests Reseach Report (Wildlife), 83, 1
  4. MathWorks, 1998, MATLAB. Natick, MA: Math Works Inc
  5. Möhres, 1967, Ultrasonic orientation in megadermatic bats, Animal Sonar Systems: Biology and Bionics, 1, 115
  6. Narins, 1982, The relationship between call intensity and function in the Puerto Rican coqui (Anura: Leptodactylidae), Herpetologica, 38, 287
  7. Passmore, 1981, Sound levels of mating calls of some African frogs, Herpetologica, 37, 166
  8. Pilleri, 1976, Sonar clicks, directionality of the emission field and echolocating behaviour of the Indus River Dolphin (Platanista indi Blyth, 1859), 157
  9. Shure, 1997, XCORR Cross-Correlation Function Estimates
  10. Sokolov, 1971, Direction of the ultrasonic radiation and role of the nasal leaf in Rhinolophus ferrumequinum, Biologicheskie Nauki, 7, 37

Cited by

Sorted by citations

Related

Authors
Dantzker, M. S., Deane, G. B., & Bradbury, J. W.
Affiliations
  • University of California San Diego (US)
  • Scripps Institution of Oceanography (US)
ORCID
Venue
Journal of Experimental Biology
Publisher
The Company of Biologists
Published
1999-11-01
Volume
202
Issue
21
Pages
2893-2909
ISSN
  • 0022-0949 (ISSN-L)
  • 1477-9145
DOI
10.1242/jeb.202.21.2893
OpenAlex
W2102241073
Cited by
62
References
61
Citations by year
2026: 3 · 2025: 1 · 2023: 2 · 2022: 1 · 2021: 4 · 2020: 2 · 2019: 1 · 2018: 3 · 2017: 3 · 2016: 2 · 2015: 1 · 2014: 3 · 2013: 2 · 2012: 6
FWCI
1.02
Type
journal article
Language
en
Open access
closed
Licence
www.biologists.com/user-licence-1-1/ (vor)
Locations
  • Journal of Experimental Biology (publishedVersion)
  • PubMed (publishedVersion)
  • eScholarship (California Digital Library) (submittedVersion)
  • Road Ecology Center
Funders
National Institute of General Medical Sciences (T32 GM07240)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Developmental Biology › Animal Vocal Communication and Behavior
  • Physical Sciences › Environmental Science › Ecology › Avian ecology and behavior
  • Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Animal Behavior and Reproduction
Keywords
sage grouse, Centrocercus urophasianus, sound radiation pattern, sound localization, microphone array, mating display
MeSH terms
Acoustics, Animals, Birds, Male, Posture, Sexual Behavior, Animal, Vocalization, Animal

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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