AUSTRALIAN 180 BIRD WATCHER AUSTRALIAN BIRD WATCHER 1991, 14, 180-189 Vocal Mimicry of Larger Honeyeaters by the Regent Honeyeater Xanthomyw phrygia by PHILIP A. VEERMAN, 24 Castley Circuit, Kambah, A.C.T. 2902 Summary This paper presents evidence of solitary Regent Honeyeaters Xanthomyza phrygia associating with a variety of larger honeyeaters and mimicking the calls of those other species. The significance of this behaviour is discussed along with a summary of other aspects of the Regent Honeyeater's vocal behaviour. It may be a unique case of vocal mimicry used for deception. Introduction Avian vocal mimicry usually involves a mimic copying calls of a fairly wide though random range of model species, that are neither closely related to nor have similar niche requirements to that of the mimicking species. An example has come to light which differs markedly from this trend. Solitary Regent Honeyeaters Xo.nthomyza phrygia apparently associate with and mimic the calls of larger members of their own family (Meliphagidae) exclusively. Although most ornithological textbooks mention vocal mimicry, I have not been able to find similar behaviour described for any other species. This behaviour may relate to the decline in population status of the Regent Honeyeater. It may have adaptive value as a deceptive ploy, either assisting in defence of food supply or reducing aggression by promoting social cohesion with larger species. Either option would be an unusual (perhaps unprecedented) use of vocal mimicry by birds and it may simply be a behavioural quirk of no adaptive significance. Usual calls as described in the literature I begin with a summary of the usual calls of the Regent Honeyeater if only to demonstrate that they are very different from the calls of those which it mimics. The usual calls have been variously described in the literature. I point out that several of the following descriptions use the calls of better-known species as comparisons or aids to memory; I do not suggest these to be references to mimicry. Campbell (1901) described the 'peculiar plaintive song, accompanied with the bowing of the head, [is] very agreeable'. Mellor (1919) described 'scores of these birds indulging in foliage bathing (see Veerman 1988a for comments on that), making a 'remarkably sweet and continuous song [being] a flute-like warble, of silvery liquid notes, not unlike the song of the oriole [presumably Oriolus sagittatus], but more lively and continuous'. He also described it as ventriloquial. Collison (1959) mentioned that, from a breeding pair 'the only sound heard was a soft gurgling note and a scolding sound when the birds were attacking others. No ringing call was heard at any time.' Allan (1989) mentioned that 'the call... was clear, moderately prominent, and to the anthropomorphically minded, somewhat worried, often consisting of five notes, the third of which was of a higher pitch than the rest. The birds engaged in hectic activity, frequent pursuit of one another and inflight clicking noises.' Ley (1990) described calls consistent with those of Pizzey (1980) as did Bounds & Lepschi (1988) with regard to the mewing call. It is noteworthy that in an aggressive encounter whilst defending a feeding site against a Red Wattlebird Anthochaera carunculata, a display was used in conjunction with a call 'similar to but more agitated than the commonly uttered and apparently territorial call' and not mimicry (Franklin & Robinson 1989). VOL. 14 (5) MARCH 1992 Vocal Mimicry by Regent Honeyeater 181 Among the field guides, Officer (1964) and Frith (1976) mention a rather metallic clink, the head being bowed at the same time, with a clattering call in flight; Cayley (1966) 'a rich bell-like note, interspersed with clicking sound'; Macdonald (1973) 'tinkling notes like Bell Miner [Manorina melanophrys] but softer and less explosive, often tink, tink-tink, the rapid double note being lower in tone'. Likewise, the call was described as simply 'bell-like' by Incoll (1981) and Ryan (1981). Longmore (1991) described the voice as 'varied, soft metallic tinkling notes; loud rolling phrases; or a rapid double note'. Pizzey's (1980) description appears the most complete: 'Not specially noisy, but calls very distinctive when breeding. Common call is anvil-like ringing chink-chink-chink, somewhat like Magpie-lark [Grallina cyanoleuca], slow mellow quippa-plonk-quip, quip-kik or quicker quip-quip, also liquid cloop-cloop­ cloop, mewing or turkey-like[? Meleagris gallopavo]; calls accompanied by bowing or uttered in flight; subsong reported'. Most other field guides have descriptions, if any, along similar lines. Of the above descriptions, Pizzey's quippa-plonk-quip fits best part of one call on the recording made by Bill Flentje and Alan Gibb (Figure la). Another recording contains a call which can be interpreted as the metallic ringing or anvil call (Figure lc). New descriptions of calls, not involving mimicry Unpublished information obtained on the species' behaviour included mention of normal and mimicked calls. For both types, I point out that most, if not all, of these are independent reports widely separated in time and place, as follows: Andrew Ley (pers. comm.) advised that, in perhaps 100+ hours of being within hearing range near their nests, he has noted only three calls: a bell like ding-ding-ding, a liquid bubbling and 'presumably the call described by others as "mewing", being a high-pitched double syllable reminiscent of the complaining crying of a young puppy. These all share a remote ethereal quality and when calling the birds appear to put in much more effort than is justified by the amount of sound produced. Because of this, it has been suggested that there may be an ultrasonic component in the calls.' Brief reports include: 'Perched bird moved its head up and down in the manner of a bird making a vocalization, all that was discernible was a very soft warbling' (Charles Silveira). 'Two birds were seen doing bobbing and stretching actions toward [one] another. Beaks were slightly open, necks stretched and a soft melodious call was given' (E. Collins). 'Clapping of beak 2-5 times like a Common Starling [Sturnus vulgaris] followed by a single call with a trill in it, tryw, whilst putting its head forward, call short, melodious, thrush-like' (J. Brouwer). 'It has three notes, ascends slightly and reminds me of the quiet almost bell-like communication call of Crimson Rosellas [Pla~ elegans]' (D. Franklin). 'Five syllables, like "it's for the teacher" with the emphasis and highest pitch on "tea", the fourth syllable' (Graeme Chapman pers. comm.). 'A very firm piping call' (C. Hawley). 'A rollicking whistle' (A.K. Morris). It is difficult to describe bird calls in text and although these descriptions possess similarities, they appear more diverse than most field-guide descriptions of calls of other species. Certainly these descriptions suggest the calls are generally pleasant, delivered at quite a range of levels of volume and clarity. The bell-like notes appear separate from the rather intricate song phrase. The descriptions and recordings indicate that the species performs exaggerated body movements when calling. This bowing and neck-stretching display appears to be related to territory establishment and maintenance and is always given in conjunction with a call (P. Menkhorst pers. comm.). It also indulges in bill snapping as a part of its sound repertoire, a habit that would appear to be well established among honeyeaters (Prendergast 1987, 1990). AUSTRALIAN 182 VEERMAN BIRD WATCHER Calls of juveniles Some descriptions of the juvenile begging calls are as follows: Incoll (1981) mentioned 'two young ones in adjacent trees, each making slight husky chirping sounds as they were being constantly fed'. Franklin (pers. comm.) says 'the call of the young is a kwit slightly reminiscent of a White-naped Honeyeater [Melithreptus lunatus]'. Ley (1990) described dependent young giving soft buzzing food-begging calls like those of a young Red Wattlebird and (pers. comm.) says that he has heard a version of this given by a nestling when it was as young as one week. P. Menkhorst (pers. comm.) agrees; 'begging calls of fledglings sound very similar to those of a fledgling Red Wattlebird; a rasping zweet zweet repeated about once per second and more frequently when a parent approaches'. On this basis, I suggest the similarity of this juvenile call as attributable to relationship, rather than mimicry. It was commented that J. Courtney, on the basis of this similarity of juvenile begging calls, had first suggested the relationship of these birds (the 'ontogeny recapitulates phylogeny' concept). Evidence and reports of calls involving mimicry On the overcast afternoon of 3 September 1974, I went to Blackburn Lake (a reserve in suburban Melbourne) to find and photograph the one Regent Honeyeater that had been reported from the site (in later years they bred there). I found the bird feeding alone in tangled bushes and in the twenty minutes or so that I watched it, at about two to four metres from me, the only calls made were on four occasions a call almost identical to the typical kwock-ay-ock call of the Red Wattlebird. It threw its head back when calling exactly as the Wattlebird does. The only detectable difference was that the call was less loud or harsh than the Red Wattlebird's. Had I not been watching, I would have been unhesitating in attributing it to a more distant Red Wattlebird; in fact the larger species was abundant in the area and at least one was low in the adjacent tree, although there was no obvious interaction between them. This has been reported before (Veerman 1988b). I had assumed that this was the bird's normal call. Harold Crouch (pers. comm.) compiled a report of one Regent Honeyeater inhabiting creek-bank vegetation at Rostrevor (suburban Adelaide).