Ornis Hungarica 2021. 29(1): 98–107.
DOI: 10.2478/orhu-2021-0007

The instrumental signals of the Eurasian
Wryneck (Jynx torquilla)
Kyle Turner1 & Gerard Gorman2*
Received: February 21, 2021 – Revised: April 12, 2021 – Accepted: April 14, 2021
Turner, K. & Gorman, G. 2021. The instrumental signals of the Eurasian Wryneck (Jynx
torquilla). – Ornis Hungarica 29 (1): 98–107. DOI: 10.2478/orhu-2021-0007
Abstract In a study of acoustic communication at seven nest cavities of Eurasian Wrynecks, sound recordings
were made of ninety-one separate bursts of tapping. From Hungary in the east, and France in the west, tapping
was heard both from inside cavities and at their entrances. Analysis of the tapping rhythms indicated two
forms corresponding to different observed behaviour. They were never loud and were used exclusively incommunication between breeding pairs. No functional significance was found in the only two brief examples oftapping fast enough to be described structurally as drumming.
Keywords: communication, tapping, drumming, nest cavities, wryneck, woodpeckers, spectrogramÖsszefoglalás Ebben az akusztikus kommunikációval foglalkozó kutatásban hét nyaktekercs fészekodúnál 91 különálló kopogás egységről készült hangfelvétel. Keleten (Magyarország) és nyugaton (Franciaország) a kopogást
az üregek belsejéből és a bejáratnál is lehetett hallani. A kopogás ritmusának analízise két formát mutatott ki, amelyek különböző megfigyelt viselkedéseknek feleltek meg. Sosem voltak hangosak, és kizárólag a költő pár közötti
kommunikációban használták azokat. Nem találtunk funkcionális jelentőséget a csupán két rövid példa esetében,amikor a kopogás olyan gyors volt, hogy szerkezetileg dobolásként lehetett leírni.
Kulcsszavak: kommunikáció, kopogás, dobolás, fészekodúk, nyaktekercs, harkályok, spektogram
Independent Bio-acoustics Researcher, St. Andrews Farm, Woodbridge Lane, Bedchester, Shaftesbury, Dorset,
SP7 0BF. United Kingdom
2
Independent Picidae Researcher, Hungarian Woodpecker Working Group, MME/Birdlife Hungary, 1121, Budapest, Költő utca 21, Hungary* corresponding author, e-mail: picidae.gerard@gmail.com
1

Introduction
The Eurasian Wryneck (Jynx torquilla) is often regarded as an aberrant woodpecker, as inseveral aspects of its anatomy and morphology, it is the least typical of the eleven species
in the Picidae family that breed in Europe. It is the only member, for example, that is truly
migratory (most European breeding populations winter in sub-Saharan Africa), to havecryptic colouration, to have a relatively small head and long tail, to perch rather than climb,
and to have a weak, passerine-like bill (Goodge 1972). Indeed, this species lacks many of
the structural features typical of true woodpeckers (Picinae) that facilitate a physical ability
to bore deep into wood to find invertebrate prey and fully excavate a nest cavity. The species
is not sexually dimorphic and in most cases males and females are inseparable.
The Eurasian Wryneck has an exclusively Old-World distribution, occurring in parts ofEurope, Asia and Africa (Gorman 2014). It is polytypic, with taxonomists recognising from fourK. Turner & G. Gorman99

to seven subspecies (Winkler et al. 1995, del Hoyo & Collar 2014, Clements et al. 2019, Gill et
al. 2020). Although the overall global population is suspected to be in decline, the species is notconsidered to be vulnerable or seriously threatened as it occurs over a vast range. Therefore, in
the IUCN’s Red List of species, it is categorised as Least Concern (BirdLife 2021).
Ringing recoveries in Europe suggest two probable migration routes, with birds fromthe north and west passing through Iberia and birds from further east travelling through
Italy and the Balkans (Reichlin et al. 2009). The return to breeding areas in spring marksa peak of vocal activity, while both males and females seek potential nest sites. Persistent
advertising, in the form of song, leads to the inspection of cavities by both birds and tocourtship, which is accompanied by a range of soft, intimate calls (Ruge 1971). At this stage,
although they do not excavate a complete cavity, birds may undertake some light, peripheral
improvement of an existing one.
Some previous observers have suggested an instrumental function to tapping at the cavity
entrance, such as when showing a potential nest site and when birds arrive for nest relief.
Short (1982), referencing Witherby et al. (1938), wrote that the species sometimes drums‘woodpeckerlike, but weakly, slowly, and not audible at any distance’, and ‘drums weakly
and infrequently in slow series’ (1988). ‘Drumming’ inside the cavity as birds preparedto nest is mentioned by Puhlmann (1914). Tapping and ‘drumming’ on cavity walls andat the entrance are mentioned as taking place, when birds inspect and modify cavities, by
Glutz von Blotzheim and Bauer (1994). The same authors also mention tapping with arhythmic start that ends in a uniform roll on a branch away from the nest, but this behaviour
is seldom observed and unpredictable (Gorman 2004). Wimmer and Zahner (2010) refer
to soft ‘tapping and drumming’ when showing a nest cavity. More specifically, Schneider(1961) described four rolls ranging from six to ten strikes given by a bird at the entrance toa nest box in response to the arrival of a second bird.
Ruge (1971), however, defines such sounds as ‘demonstrative tapping’ or ‘rhythmic tapping’.
Due to the lack of any recorded examples, Eurasian Wryneck was not included in statisticalcomparisons of drumming by European woodpeckers (Zabka 1980, Florentin et al. 2016). In
addition, Menzel (1968), Winkler et al. (1995) and González et al. (2002) do not detail any
instrumental sounds for the species in their works. Whereas instrumental tapping has been
described in all of the European Picidae (Cramp 1985), a behavioural comparison using measured
examples, including Eurasian Wryneck, has yet to be published (Florentin et al. in prep.).
The aim of this paper was to analyse recent sound recordings of the instrumental signals
produced by Eurasian Wrynecks with their bills, and to establish a better understandingof their structure and function. In addition, we sought to clarify the terminology used byprevious authors on this subject, which in some cases is ambiguous.

Method and Materials
The recordings used in this study were made in two areas of Europe, Hungary and France.
In Hungary, pairs were observed in the remnants of orchards bordering villages in the Bükk
National Park (48.048°N 20.528°E). In France, pairs were observed in old false acacia

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ORNIS HUNGARICA 2021. 29(1)(Ro­bi­nia pseudoacacia) scrub on a sheep grazed limestone plateau in the Parc Naturel
Régional des Causses du Quercy (44.385°N, 1.342°E). Recordings were made in bothareas from April to June covering the period of pair establishment and breeding. We placed
microphones close to potential nest sites because this is the only reliable method of collecting
instrumental sounds from this species. No examples of instrumental recordings for Eurasian
Wryneck were found by searching other resources, such as the internet site xeno-canto.org.
The only examples available came from a wide-ranging study of the acoustic signals ofEuropean woodpeckers (Turner unpub.).
We used a range of equipment: a pair of Sennheiser MKH 105 omnidirectional condenser
microphones in an Atherstone 50×13cm parabolic reflector into a Kenwood DMC-G7R
Minidisc recorder @ 44.1kHz/16bit (Atrac 4.5) and a pair of Sennheiser MKH 60 (shortgun) condenser microphones into a Sound Devices 722 file recorder @ 44.1kHz/16bit.
Reflector recordings were made at a distance of approximately seven metres and the open
microphones were placed at about four metres from the nest cavity. Behaviour was observed
though binoculars from between seven and ten metres. Sound editing was carried out using
Cool Edit Pro II software, with spectrograms produced on Raven Lite (Cornell). Strikecounts were extracted manually from spectrograms and average strike interval lengths were
measured to the nearest millisecond, as employed in studies of drum-roll patterns (Zabka
1980, Florentin et al. 2016), using Microsoft Excel 2016.
We employed the following terms: ‘instrumental’ to mean a non-vocal sound used as asignal, ‘rhythmical’ to mean evenly spaced or smoothly accelerating/decelerating, ‘strike’ tomean an individual acoustic impact showing as a spike on a spectrogram, ‘burst’ to mean adistinct grouping of similarly spaced strikes having an average interval of more than 90ms,‘roll’ to mean a distinct grouping of similarly spaced strikes having an average interval ofless than 90ms. An average strike speed slower than this falls outside the range for drumrolls encountered among European woodpeckers (Zabka 1980, Florentin et al. 2016, Turner2020), and is therefore treated as instrumental tapping.
Gaps separating bursts of tapping were set at a minimum of 200 milliseconds, beyond
which there was an audible pause in the tapping rhythm. Slower tapping speeds wereassociated with cavity modification. Sounds resulting from this activity typically had a more
erratic strike rate in both rhythm and strength coupled with angled strikes sounding more
like tearing, which resulted in double spikes on spectrograms. These sounds, parallelingthose of excavation in other woodpeckers, were not treated as instrumental signals and werethus disregarded.

Results
Twenty-three recordings of sequences containing instrumental tapping were made, at fivenest sites in France and two in Hungary, between 2001 and 2013 (Table 1). Twelve of thesewere made at one nest in Hungary during a concentrated effort of 14 hours over seven daysat the start of June 2007. Tapping bursts, consisting of the evenly or smoothly spaced strikes
typical of instrumental signals, were given when both members of the pair were present:

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101

Dates and regions in which recordings of the Fast and Slow tapping rhythms were made.
Number of bursts in brackets. In total, forty-two bursts of fast tapping were recorded atfive nests and fifty of slow tapping at four nests, with both forms occurring at two nests
1. táblázat Gyors és lassú ritmusú kopogás felvételeinek dátuma és régiója. Az egységek száma
zárójelben szerepel. Összesen negyvenkét egységről készült felvétel, gyors kopogás
esetében öt fészeknél és ötven lassú kopogás esetében négy fészeknél, mindkét forma 2
fészeknél fordult elő

Table 1.

Year

2001

Fast
Hungary
FastFranceSlow
Hungary

2003

2004

2006

6 May
(3)
8/13 May(14)

20/21 April
(3)

2007

2013

2/3 June(15)
12/18 April
(5)

6 May
(2)

Slow
FranceFigure 1. Average strike interval lengths (ms)1. ábra Átlagos csapások közötti intervallumok
hossza (ms)28 May(2)
2/3 June(47)
12 May(1)

Figure 2. Average number of strikes per burst
Fast tapping (n=42). Slow tapping(n=50). One exceptionally long burstof 65 strikes of fast tapping has been
omitted2. ábra A csapások átlagos száma egységenként
Gyors kopogás (n=42). Lassú kopogás(n=50). Egy kivételesen hosszú, gyors
kopogás-egységet, amely 65 csapásból
állt, kihagytunk

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ORNIS HUNGARICA 2021. 29(1)Figure 3. Burst of 18 strikes of fast tapping just inside the cavity, with a very regular interval length of
140 ms. Seven bursts were given in the sequence. France, 13th May 2001
3. ábra 18 csapásból álló gyors kopogás-egység az odú belsejéből, nagyon szabályos 140 ms
intervallum hosszúsággal. Hét egység volt egymás után. Franciaország, 2001. május 13.

Figure 4. Short burst of slower tapping (5 strikes coloured blue, from 0.75 to 1.41 secs.) with average intervals of 162 ms given by one bird outside the cavity entrance during a song duet. The tapping
coincides with the mate’s song, heard from inside the nest cavity (8 elements, coloured red) andis immediately followed by the first bird’s song (4 elements, coloured blue). This combinationof slow taps and song came during a nine-minute recording that contained eighteen slow tapping bursts intermixed with thirty-five of excavation by the bird at the nest entrance. In the duet, this bird sang forty-two times and the bird inside fourteen times. Occasional ‘vet’ calls were
given by both birds and one exceptionally soft roll was heard from inside towards the end
4. ábra Rövid egység lassú kopogásból (5 csapás, 0,75–1,41 s) 162 ms átlagos intervallum hosszal,
egy madártól az odú bejáratán kívül egy duett során. A kopogás egybeesik a pár énekével,amit az odú belsejéből lehet hallani (8 elem, 0,6–1,44 s), amit azonnal követ az első madáréneke (4 elem, 1,8–2,7 s). Ez a kombinációja a lassú kopogásnak és éneknek egy kilenc perces
felvételen szerepelt, amely tizennyolc lassú kopogás egységet tartalmazott összekeveredve
harmincöt, az odú bejáratánál végzett vájással. A duett során ez a madár negyvenkétszerénekelt, míg a bent lévő madár tizennégyszer. Alkalmi „vet” hívóhangokat mindkét madár
kiadott, és egy nagyon halk, dobpergés-szerű hang volt hallható belülről a vége feléK. Turner & G. Gorman

103

Figure 5. Soft roll, 4 strikes (from 1.3 to 1.52 secs) with average intervals of 69 ms. Given by a bird
inside the cavity (from the same sequence as Figure 4 Hungary, 3rd June 2007). Later in themorning, the first nestling calls were heard. This roll was one of only two recorded, bothhaving only four strikes, with average interval lengths of 69 ms and 72 ms
5. ábra Halk dobpergés-szerű hang, 4 ütés (1,3–1,52 s) 69 ms átlagos intervallummal. Egy odúbanlévő madár adta ki (ugyanabból a sorozatból, amelyikből a 4. ábra. Magyarország, 2007.
június 3). A délelőtt során később lehetett hallani az első fióka hangokat. Ez a dobpergésszerű hang az egyike volt a csupán kettő felvettnek, mindkettőben csak négy csapás volt,
69 ms és 72 ms intervallum hosszúsággal

Figure 6. One bird tapping at the nest entrance (2 bursts - 4 & 6 strikes, coloured blue) at average strikeintervals of 179 ms, while the mate replies with faster taps (15, coloured red) from inside thecavity at 126 ms. Hungary 3rd June 2007. The relationship between the structural difference offast and slow tapping with the functional significance, one form given inside the cavity andthe other outside, was clearly illustrated during a ‘tapping-duet’ where the bursts overlapped
6. ábra Egy madár kopácsol az odú bejáratánál (2 sorozat - 4 és 6 csapás, kék szín), a csapások
közötti intervallum átlagosan 179 ms volt, míg a párja gyorsabb kopogással válaszolt (15,piros szín) az odú belsejéből 126 ms-mal. Magyarország, 2007. június 3. A gyors és lassú
kopogás szerkezeti különbségének és funkcionális jelentőségének kapcsolata, az egyik az
odú belsejéből, a másik kívülről leadva, világosan illusztrálva lett a „kopogás-duett” során,ahol a sorozatok átfedtek

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ORNIS HUNGARICA 2021. 29(1)close to the cavity entrance, at the edge of the entrance, and inside the nest cavity. Twotapping speeds were identified (Figures 1, 2).
Bursts of tapping were faster and longer when the pair were close to each other, forming
a component of a courtship ceremony together with soft ‘vet’ and ‘graeb’ calls, and short,
muted versions of the typical song of the species. Most of these fast bursts were given fromdeep within the nest chamber, with both birds present inside. However, one sequence wasgiven by a bird just inside the entrance (Figure 3).
Nineteen recordings of courtship were made at the seven nest sites between April andJune. Of these, twelve, from five of the sites, included fast tapping. In Hungary, a recordingof a courtship sequence made at the time of egg-laying in mid-May, contained no tapping.
However, in early June as eggs were starting to hatch, five sequences with tapping wererecorded. By contrast, in France, five out of seven courtship sequences that contained
tapping were recorded in the middle of April, possibly before eggs were laid. Overall,fourteen sequences containing bursts of fast tapping were recorded, eight in France and six
in Hungary, of which five were at the nest in 2007.
All other examples of rhythmical tapping were given externally, by the nest entrance, inshorter, slower bursts. These appeared to signal the presence of the bird in the following
situations: as the second bird was moving closer, to its mate already inside the nest (Figures4, 6), to its mate which had emerged, or following the ‘sgissgissgiss’ call when the mate
did not respond. This call has been described as given in annoyance when a mate failed toappear for nest relief (Bussmann 1941). Nine sequences containing bursts of slower tapping
were recorded, one at a nest in France and eight in Hungary, with seven at the nest in 2007.
An analysis of average strike intervals and number of strikes per burst enabled a comparisonof relative speed and burst length for the two tapping rhythms (see Figures 1, 2).
Double or triple taps were regularly heard but did not appear to have a different significancefrom the slower form and were frequently incorporated into longer sequences, with similar
strike interval lengths to the longer bursts. One example of a double tap was given on exiting
the cavity after feeding newly hatched young, and a triple tap was given in immediate
response to its mate’s song.

Discussion
We found that breeding pairs of Wryneck used tapping as a means of communication atnest sites. Two speeds were observed, with a faster form given by one bird inside the cavity
during courtship and a slower form given at the entrance. The statistics for strikes per burst
from fast tapping inside the nest cavity may not fully reflect the length of the bursts, as these
may have been shortened where some strikes were just too soft to hear or were obscured
by sounds of other birds outside. Also, some ambiguity remains regarding the separationof slow tapping intended as a signal, from the generally looser pecking involved when
Wrynecks modify a cavity entrance. That is, when they are combined in one sequence. This
combination is not untypical of other woodpeckers, but the continuation right through tohatching was unexpected, except where it may have been a form of comfort behaviour.

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105

In most European woodpeckers, instrumental tapping has been identified in two
behavioural contexts; to signal either a potential nest site or, when a cavity is in use,readiness to changeover during excavation, incubation or brooding. Such communication ismost ritualised in Black Woodpecker (Dryocopus martius) (Blume 1996), which taps rapidly
inside the cavity during nest relief. For Eurasian Wryneck, the present study indicates thatit uses the fast form as a component of a courtship ceremony, which may be performed at
any time from early mating through to egg hatching and also occurs inside the nest. The
slower form, given in short bursts, has a parallel with the ‘nest showing’ signals of so-called
pied woodpeckers (Winkler & Short 1978, Blume & Tiefenbach 1997). The differences inobserved behaviour confirm the significance of a functional separation of the two forms
resulting from structural analysis (Zabka 1980) and see Figures 5, 6 above. This is supportedby the lack of any examples of slow tapping heard from inside the cavity.
It is interesting to speculate on the similarities between Eurasian Wryneck and the true
(Picinae) woodpeckers regarding their evolutionary divergence. The theory that instrumental
signals, including eventually drumming, may have evolved from the action of excavation(see for example, discussion in Zabka 1980) would suggest that separation occurred after
the development of a strong bill and associated muscles. In this case, Eurasian Wryneck
would be evolving away from a common, strong-billed ancestor. And yet, many similarities
with the ‘true woodpeckers’ remain, as with some members of the Melanerpes genus of theAmericas where mutual tapping, with one bird inside the cavity and one outside, is typical(Winkler & Christie 2002).
No substantive evidence was found of the use of drumming, either structurally fastenough to be considered drum-rolls, or functionally serving as signals. The two short rolls
heard, barely matched our definition of the term and deviate from the relationship between
structure and function associated with most other European woodpeckers (Turner 2020).
One hypothetical explanation for the four-strike roll given inside the cavity could be as an
intimate ‘celebration’ of egg hatching (as is done far more loudly, for example, by Black
Woodpecker). While Eurasian Wryneck is capable of producing drum-rolls of sorts, weconsider that with its fine-tipped, weak bill, it is not equipped to perform ‘drumming’in the true sense, to loudly advertise territory as other woodpeckers do. Rather, it ‘taps
energetically with the bill within and around the nesting cavity’ (Gorman 2004). We agreewith Ruge et al. (1988) that Eurasian Wrynecks do not genuinely ‘drum’ and that the
instrumental signals of this species are more accurately described as ‘demonstrative’ or‘rhythmical tapping’.

Conclusion
With statistical reliability limited by the available data, we believe that this study has
nevertheless presented clear evidence of two tapping speeds performed by Eurasian
Wrynecks at their nest sites. Both speeds were found to occur in the two distant areas ofEurope where observations were made. The faster form, given inside the cavity during
courtship, also had on average three times more strikes per burst than the slower form,

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ORNIS HUNGARICA 2021. 29(1)given to signal presence at the entrance. Our close observations established that all of theexamples recorded were given in communication between breeding pairs. One recording
captured a pair tapping simultaneously, one at the faster speed inside and one at the slower
speed outside. Two exceptionally soft and short rolls did not establish any clear behaviouralsignificance and hardly justified the use of the term ‘drumming’ in the discussion of acoustic
signals for this species. A better understanding of the function of instrumental tappingused by Eurasian Wryneck, and indeed other woodpecker species, would require a more
continuous observation of one or more pairs throughout their breeding cycle.

Acknowledgements
We would like to thank Danny Alder for his constructive comments and advice and Joanna
Guske for help with translations. We also thank anonymous reviewers for their comments.
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