Sounds and Vocal Behavior

The Northern Flicker is very vocal in spring during which its long call (kick, kick, kick, kick, kick...) and drumming may be heard from more than a kilometer away. Homeowners sometimes express annoyance at individuals who take to hammering on metal chimneys and gates early in the morning, but fortunately this territorial advertisement only lasts for a few weeks in spring. Besides these common sounds it has a complex array of additional vocalizations emitted in specific contexts.

Development

Nestling buzzing develops shortly after hatching and persists until hatchlings are nearly fully feathered but still in the nest. Peah develops before fledging and is persistently given in episodes from nest by whichever nestling controls the cavity opening. Nothing is known about when other vocalizations are first uttered. Nothing is known about vocal learning, but it would be surprising if it occurred.

Vocal Array

Long Call. The most familiar vocalization , commonly heard in spring during pair formation and territory establishment. Comprised of a sustained series of frequency modulated pulses that appear as inverted U-shaped notes in sonograms (Figure 4A; 11 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close ). Pulses occur at a rate of approximately 7 notes/s (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ), range 7–11 (11 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close ), with average duration of 5.3 s and maximum recorded of 19.6 s (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ); strongest frequency range is 2.0–3.5 kHz. Call is variably described as swik-wik-wik... or kick, kick, kick....

Peah. A single note with multiple energy peaks over a frequency range of approximately 1–8 kHz; duration 0.2–0.5 s. Note is frequency modulated with a parallel decline in frequencies of energy peaks (Figure 4B). Given by adults, nestlings a few days before fledging, and fledglings.

Wicka. The most complex and variable vocalization. A relatively quiet, close-interaction vocalization given in unison by pairs, trios, and sometimes quartets of adults engaged in close territorial and courtship “dances.” It comprises a rhythmic series of two alternating notes , which are variously modulated and emphasized, and lasts up to 4 s; variously described a swik-a, wik-a, wik-a..., ta-week, ta-week, ta-week..., cha-week-a, cha-week-a, cha-week-a..., wik-up, wik-up, wik-up... (97 Short, L. L. (1972). Systematics and behavior of South American flickers (Aves, Colaptes). Bulletin of the American Museum of Natural History 149:1–109. Close , 11 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close ). The following description is based on Figure 1.4 in Duncan (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). One note rises in frequency at varying rates for a duration of 0.02–0.35 s or more and appears as parallel frequency bands in sonograms (Figure 4C). Another note drops sharply in frequency, comprises same frequency bands, but is of shorter duration, 0.01–0.04 s. Alternating notes are fairly regularly spaced and separated by a gap of approximately 0.17 s. The fundamental and lower harmonics are strongest; fundamental harmonic is in the range of 1.25–3.5 kHz.

Abbreviated Wicka. A vocalization between members of a pair near to each other. Much quieter than the Wicka and usually consists of only the first rising note wiik. Given in different contexts than the Wicka and not accompanied by "dance" movements (KLW).

Whurdle. The least-known and least-heard vocalization. Indeed, the mechanism of its production still needs to be established. Kilham (172 Kilham, L. (1959). Early reproductive behavior of flickers. Wilson Bulletin 71:323–336. Close ) thought it was produced mechanically in flight by the wings, but others (e.g., 132 Burns, F. L. (1900). Monograph of the flicker. Wilson Bulletin 7:1–82. Close , 97 Short, L. L. (1972). Systematics and behavior of South American flickers (Aves, Colaptes). Bulletin of the American Museum of Natural History 149:1–109. Close , 11 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close , 146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ) considered it a vocalization. Whurdle is a soft sound that has been described as a “gurgling almost involuntary chur-r-r-r-r” (132 Burns, F. L. (1900). Monograph of the flicker. Wilson Bulletin 7:1–82. Close ) given on the wing. Figure 4D is a rare recording of Whurdle. It comprises short bursts of a few (3–6) low-frequency (0.5–2.1 kHz), closely spaced pulses; pulse duration approximately 55 ms; interpulse duration 5–20 ms; spacing between bursts variable.

Abbreviated Long Call. A shortened version of the Long Call; 3–6 bursts, usually emitted at a slower pace and softer was identified by Short (97 Short, L. L. (1972). Systematics and behavior of South American flickers (Aves, Colaptes). Bulletin of the American Museum of Natural History 149:1–109. Close ) and Duncan (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ), but this needs more study as it is not certain whether it differs from the Long Call.

Nestling Buzzing. Produced in unison by nestlings when the nest opening is suddenly darkened, e.g., by a parent returning to feed nestlings. Buzzing chorus has a frequency and energy spectrum remarkably similar to that of an agitated swarm of honeybees (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ; see below).

Distress Scream. May be given by adults when captured or in the hand while being banded. A series of extremely loud screaming pulses, probably similar in form to fright screams of other species.

Geographic Variation

Poorly studied and more information needed. Extent of geographic variation between auratus and cafer groups, as well as Caribbean populations, is unknown and thus is an important area for research, particularly with regard to hybrid zones.

The vocalizations of mexicanoides have been described as "quite different than the notes of the northern species" (173 Wetmore, A. (1941). Notes on birds of the Guatemalan highlands. Proceedings of the United States National Museum 89:523–581. Close ), and most of their vocalizations do appear to average slightly higher pitched and perhaps faster, but a detailed analysis is needed to quantify such differences. Most striking is the apparent lack of the Peah call in mexicanoides, with no examples of such a call in online repositories (n = 98 available recordings). Conversely, a commonly heard call consisting of series of short, single notes that resemble a single note of the long call, but given in loose series with some variation in pitch is unlike anything regularly heard from birds further north; this perhaps what is referred to as "high-pitched, chattering, and laughing calls" by Wetmore (173 Wetmore, A. (1941). Notes on birds of the Guatemalan highlands. Proceedings of the United States National Museum 89:523–581. Close ).

Phenology

Most vocalization and drumming is associated with territorial and breeding seasons (134 Royall, W. C., Jr., and O. E. Bray (1980). A study of radio-equipped flickers. North American Bird Bander 5(2):47–50. Close , 171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ) but Long Calls and Peah may be heard all year. Long-calling increases in frequency just prior to the breeding season and extends to fall migration, when family groups break up (11 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close ). Frequency with which Long Call and Peah (and drumming) varies over nesting season. Long Call is given most frequently during territorial establishment; declines during nest excavation and is rarely given from onset of egg-laying until nestlings are ready to fledge (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Long Call is often abbreviated in the postnesting period (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Peah has similar bimodal phenology with frequent calls in early spring, a hiatus through much of the nesting phase, but resumes and peaks just before fledging (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ).

Daily Patterns of Vocalizing

Few data; no salient pattern of daily variation. Not heard at night.

Places of Vocalizing

Less prone to establish fixed drumming and calling posts than other woodpecker species (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ). Long Call is usually given from a high perch; since the call is often alternated with drumming, the perch is often a dead branch or snag. Wicka occurs wherever courtship bouts occur. Whurdle is given only on the wing.

Sex Differences

All vocalizations, as well as drumming and tapping (see Nonvocal Sounds), are produced by both sexes. Long Call and drumming are given more often by males than by females (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Unknown whether other calls are produced by one sex more frequently than the other. Long Calls and Peah differ among individuals (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ) and sexual dimorphism in the Long Call is detectable by discriminant function analysis, if not by ear (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Unknown whether other calls can be separated statistically according to sex.

Repertoire and Delivery of Songs

Long Call and Peah can serve as “signatures” to identify individual birds (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ), and there appears to be little variation in these calls within individuals, but this needs to be more thoroughly studied. No data on variation within and between individuals for other vocalizations.

Social Context and Presumed Functions of Vocalizations

Long Call. Functions in territorial defense and courtship (as does drumming, see below; 97 Short, L. L. (1972). Systematics and behavior of South American flickers (Aves, Colaptes). Bulletin of the American Museum of Natural History 149:1–109. Close , 11 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close , 171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Territorial defense and courtship are integrated in flickers, and it is difficult to tease the two activities apart. Birds vigorously defend an area around the nest but not a feeding territory (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close , 167 Elchuk, C. L., and K. L. Wiebe (2003). Ephemeral food resources and high conspecific densities as factors explaining lack of feeding territories in Northern Flickers (Colaptes auratus). Auk 120(1):187–193. Close ). Although acknowledging that Long Call functions in both mate attraction and territorial defense, 171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close inferred that its primary function is mate attraction. This inference was based on the set of observations that males Long-call most intensely when they do not have a mate (also noticed by WSM and KLW), that males give Long Call more and drum less when the female is away from territory, and that individuals approach playbacks of recorded Long Calls more frequently prior to pair formation than after.

Peah. Function has been debated. Short (97 Short, L. L. (1972). Systematics and behavior of South American flickers (Aves, Colaptes). Bulletin of the American Museum of Natural History 149:1–109. Close , 11 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close ) and Kilham (133 Kilham, L. (1983). Life history studies of woodpeckers of eastern North America. Publications of the Nuttall Ornithological Club 20, Cambridge, MA, USA. Close ) considered it an alarm call, but others (e.g., 132 Burns, F. L. (1900). Monograph of the flicker. Wilson Bulletin 7:1–82. Close , 146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close , 171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ) believed it is used to maintain contact among individuals, either between mates or between parent and offspring. Short (97 Short, L. L. (1972). Systematics and behavior of South American flickers (Aves, Colaptes). Bulletin of the American Museum of Natural History 149:1–109. Close ) reported that captive flickers respond to a stranger entering an aviary by emitting a “loud alarm peah,” but Lawrence (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ) stated that the klee-yer (Peah) is a self-announcing call and her notes give no evidence that it is used as an alarm call.

Peah is sometimes used to call the mate to the nest site. After one parent has had a long incubation or brooding bout, it may emerge from nest, and give a loud Peah from a nearby perch or sometimes from the cavity entrance. Often the mate then appears almost immediately to switch nest duties (WSM, KLW). Other times, a parent may Peah when mobbing a potential predator, such as a squirrel, near the nest (KLW). The call may function then not so much as an alarm per se, but as a way to call in the mate to help with nest defense.

Peah is the first “adult-call” to develop and is given almost incessantly by individual nestlings perched with their heads protruding from the nest opening, the last few days before fledging. At this same time, parents frequently emit Peah in the vicinity of the nest. Duncan (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ) argued tentatively, but reasonably, that Peah functions as an individual “signature” call that enables adults and fledglings to recognize each other and locate each other postfledging.

Wicka. Always given in a social context and usually in conjunction with highly animated courtship/agonistic dancing behaviors which have been appropriately described as “wick-up” bouts. Most commonly this involves a trio, but also duos or quartets. In trios, usually two birds of the same sex engage in a wick-up bout while a bird of opposite sex looks on, i.e., perhaps assessing the actors. Short (97 Short, L. L. (1972). Systematics and behavior of South American flickers (Aves, Colaptes). Bulletin of the American Museum of Natural History 149:1–109. Close ) suggested that the two note types that alternate in the Wicka convey a distinct meaning: the rising note conveys submissive behavior and the falling note strong threat behavior and that variation in emphasis and modulation of these notes conveys mood and social status. However, variation of this interesting vocalization is poorly understood, and a quantitative study of this behavior with integrated video and audio recording equipment would be valuable.

Abbreviated Wicka. A very quiet call sometimes given by an isolated bird but usually between members of a mated pair at close range (1‒10 m from each other). I have only heard these calls in the immediate vicinity of the nest tree in two contexts (KLW). The first when the bird encounters something novel such as a net or trap placed near the entrance hole in which case the soft vocalization seems to express a mix of confusion, curiosity, and apprehension. The second context occurs between the male and female while switching incubation duties in which case it may function as a formal exchange of responsibility for the nest site.

Whurdle. Short (97 Short, L. L. (1972). Systematics and behavior of South American flickers (Aves, Colaptes). Bulletin of the American Museum of Natural History 149:1–109. Close ) characterized it as a soft “anxiety” vocalization and Lawrence (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ) considered it a “low-intensity alert note.” These contexts are consistent with our observations (WSM, KLW). For example, Northern Flickers may Whurdle as they fly towards their nest after perceiving a conspecific intruder or another (e.g., human or predator) intruder. It may also occur as a response to a recorded playback.

Nestling Buzzing. A loud, frenzied buzzing, produced as nestlings crane their heads and gaping mouths toward a parent. Duncan (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ) made the interesting and persuasive argument that this is Batesian mimicry that protects nestlings from some predators (red squirrels) by conveying the false impression that nest cavity is occupied by a honeybee colony.

Fright Scream. Given when the individual is physically constrained or handled. As in other species, presumably functions as an anti-predator strategy (see Koenig et al. [174 Koenig, W. D., M. T. Stanback, P. N. Hooge, and R. L. Mumme (1991). Distress calls in the Acorn Woodpecker. Condor 93:637–643. Close ]).

Two nonvocal sounds are produced: drumming and ritualized tapping.

Drumming

Figure 5. The drumming of the Northern Flicker has been described as “a miniature pneumatic drill” (172 Kilham, L. (1959). Early reproductive behavior of flickers. Wilson Bulletin 71:323–336. Close ). It drums in conjunction with territorial defense, as is characteristic of all woodpeckers. Drumming is produced by rapid, even beating of the tip of the bill on a resonating object, usually a dead tree limb or branch, sometimes a metal surface. One Northern Flicker near Wheatland, Wyoming had a favorite “drum” that was the cowling of an abandoned farm tractor; the extraordinarily loud staccato beat could be heard 800 m away (WSM). In Wisconsin, Duncan (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ) reported a mean duration of drum roll 1.07 s, mean total beats in drum roll 25.01, mean beat rate 23.29 Hz, mean interbeat duration 44.9 ms which could be distinguished from the drums of Downy Woodpecker (Dryobates pubescens) by discriminant function analyses. To the ear, the Northern Flicker drums also sound different from those of Pileated Woodpecker (Dryocopus pileatus) and Yellow-bellied Sapsucker (Sphyrapicus varius). However, Stark et al. (175 Stark, R. D., D. J. Dodenhoff, and E. V. Johnson (1998). A quantitative analysis of woodpecker drumming. Condor 100:350–356. Close ) found that drumming of flickers was not very distinct from four other woodpecker species in California so species identification solely based on drumming is not always reliable. It is not known whether drumming patterns of subspecies of Northern Flicker are distinctive.

Drumming usually occurs in conjunction with the Long Call, and both sexes drum (and give the Long Call). Females drum near the nest (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close , 171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Males in spring drum more when a female is in the vicinity and calling (171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Both sexes drum at established posts around the breeding territory, presumably selected on the basis of resonance. Although it is difficult to separate functions of the Long Call and drumming (and indeed they probably serve the same functions to a varying extent), it is reasonable to infer that drumming has more to do with territorial defense, especially of the area associated with nest site, and that Long Calling has more to do with mate attraction at a distance.

Ritualized Tapping

The Northern Flicker makes a variety of tapping sounds, many of which are incidental to nest excavation. More generally, woodpeckers engage in a variety of tapping activities that include food-tapping, hole-boring, displacement-tapping, and ritual tapping (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ). There seem to be no published reports of food-tapping or displacement-tapping in the Northern Flicker. Ritualized tapping, in contrast, is a rare but easily recognized behavior in this species (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ). It is a rhythmic burst of typically 3–5 taps (up to 20 reported [172 Kilham, L. (1959). Early reproductive behavior of flickers. Wilson Bulletin 71:323–336. Close ]), but it is much slower than drumming and occurs only during nest excavation. When one member of a pair is at the nest excavation site and the other returns; the occupant taps the short, slow, rhythmic burst on the lip of the cavity from outside, or inside, the cavity, while the arriving bird looks on. The occupant usually flies away and may return a few minutes later, at which time the tapping ritual may be repeated but with roles reversed.