British Birds Established 1907; incorporating 'The Zoologist', established 1843 Status and behaviour of the Tenerife Kinglet Hans LohrL, Ellen Thaler and David A. Christie ABSTRACT The Tenerife Kinglet Regulus teneriffae appears to be a little-studied taxon, despite the fact that its taxonomic status has given rise to much debate. This paper summarises our knowledge of this attractive bird. Over the years, the small kinglet Regulus which is endemic to the Canary Islands has been treated both as a subspecies of the Goldcrest R. regulus (e.g. Hartert 1932-38; Bannerman 1922, 1963; Cramp 1992) and as a subspecies of the Firecrest R. ignkapittus (e.g. Seebohm 1883; Vols0e 1951; Vaurie 1954, 1959; Etchecopar & Hue 1967), the latter view being followed also, though with some reservation, by Nicolai & Wolters (1971), Mauersberger & Stubs (1971) and Niethammer & Wolters (1972). More recently, A. van Loon (in Cramp 1992) and Beaman (1994) included it as an island race of Goldcrest, though both admit that their decision is not incontrovertible, whereas Sibley & Monroe (1990) considered that these two forms were better treated as allospecies. The current treatment by British Birds (86: 1-2) follows that of Sibley & Monroe (1990), the Canary Islands species being given the English name of Tenerife Kinglet Regulus teneriffae. This view is adhered to below, but the situation is by no means fully clarified. Despite the interest in the taxonomy of this delightful little bird, very little appears to have been published on the species in the last few decades. Indeed, the only major paper of which we are aware is that by Lohrl & Thaler (1980), which detailed observations made on Tenerife and of a captive female. The present paper is largely a summary of that work. {Brit. Birds 89: 379-386, September 1996] © British Birds Ltd 1996 379 380 Lohrt, Thaler & Christie: Tenerife Kinglet General appearance The immediate impression given by Tenerife Kinglet is that of a Goldcrest, but with a broad black band on the upper forehead joining the two black stripes that border the central crown, and with narrower pale tips to the tertials. It shares with Goldcrest a prominent, very broad pale surround to the eye and does, in fact, bear little resemblance to Firecrest, lacking that species' bold pale supercilium, black eye-stripe and obvious bronzy 'shoulder' patch. Distribution The Tenerife Kinglet is restricted to the outer islands of the Canaries: Tenerife, La Palma, La Gomera and Hierro. It appears to be not uncommon, at least in the Anaga mountains in the northeast of Tenerife, where it occurs in the region of the former laurel (Lauraceae) forests. This area is today dominated by the tree-heaths Erica arborea and E. scoparia, which would seem to be essential for nesting purposes. It becomes rare in the pine Pinus forest, where it occurs only in areas with tree-heath. Not unexpectedly, the species appears to be wholly resident. Nevertheless, it is interesting to note that a female reared in captivity demonstrated migratory restlessness, largely coinciding with the timing of autumn and spring passage periods of central European Goldcrests and Firecrests; its nocturnal unrest was less intense than that of Firecrest, but more continuous than that of Goldcrest. To what extent this single captive reflects the migratory disposition of a Tenerife Kinglet population remains to be seen. A more or less pronounced migratory disposition has, however, been confirmed also for Blackcaps Sylvia atricapilla living in the same area (Berthold 1978). Voice Volsoe (1951) interpreted Lack & Southern's (1949) description of the Tenerife Kinglet's song as being typical of Firecrest, although he was probably unfamiliar with the latter's song. In playback experiments in Germany, however, Becker (1978) found that both Firecrests and Goldcrests showed little, if any, reaction to the song of Tenerife Kinglet, although Goldcrest reacted well to the kinglet's excitement call; the song was similar in structure to that of Goldcrest, though somewhat more variable. Sonagrams showed the calls of the captive female Tenerife Kinglet to be Goldcrest-like, though somewhat lower in pitch; 63 Goldcrests and 18 Firecrests showed hardly any recognisable individual variations (Thaler 1979). A clear difference exists, however, in the use of the 'short alarm-call'. This call, used very frequently by Goldcrests and Firecrests, apparently indicates low-intensity alarm when danger is not immediately threatening, and is given by both sexes in various other situations as an excitement call (Thaler 1979). In a densely occupied breeding area on Tenerife, males (apparently only males?) uttered it frequently at the start of the breeding season during territorial disputes, the call in this case probably having the function of deterring rivals ('rival-call': see Thielcke 1970). It seems that Tenerife Kinglets (especially females?) require a much stronger stimulus to utter the short alarm, which is clearly of lower threshold level in the cases of Goldcrest and Firecrest. British Birds, vol. 89, no. 9, September 1996 381 Plate 139. Captive female Tenerife Kinglet Regulus teneriffae, October 1983 (Ellen Thaler). Plumage of male is identical unless the crown feathers are raised. Plate 140. Aggressive display by captive female Tenerife Kinglet Regulus teneriffae, March 1981 (Ellen Thaler). Male would show more orange in crown. Plate 141. Captive female Tenerife Kinglet Regulus teneriffae wing-flicking while foraging on snow, January 1981 (Ellen Thaler). Note taxon's diagnostically broad black stripe on forecrown. 382 Lohrl, Thaler & Christie: Tenerife Kinglet Breeding Pre-laying period At one site 725 m above sea level, a female was carrying nest material on 1st March; the following day, a completed nest was found. If nest-building takes 15-20 days (Thaler 1976), construction must have started no later than mid February, bearing in mind that building activity ceases in wet and cool weather (which at this time of the year is frequent in the breeding area). Another pair had fledged young on 7th April, which means that eggs were laid in the first few days of March. The breeding season is doubtless later at higher altitudes. As with Goldcrest, the male shares in nest-building. During 1979-80, a captive female Tenerife Kinglet paired with a male Goldcrest was observed nest-building: all building activities were typical for Goldcrest, and the male prepared most of the foundation; the rapid 'vibrating' of the material that is characteristic of Firecrest (Thaler 1976: 135) was lacking, and the nest hollow was not arched over by a rim of inward-pointing feathers. The female kinglet spent a total of 4.5 days on the lining, somewhat shorter than observed among Goldcrests (minimum 5.5 days) and Firecrests (minimum 5 days), though this may be due to the smaller clutch (five, incubation from third egg); she used only 121 feathers, whereas captive Goldcrests used at least 1,151 and captive Firecrests at least 673 feathers. Several nests, including two freshly built ones, were located on Tenerife, all suspended 4-7 m above ground in thin horizontal branches of tree-heath. Although tree-heath facilitates the construction of suspended nests in the same way as spruce Picea does, it offers little protection against rain; in addition, the nests are more visible. Completed nests are ball-shaped and, as with all Regulus nests, the entrance is at the top and not, as Bannerman (1963) suggested, at the side. Both fresh nests were collected after use. One was still fully intact, and its attachment to the branches could be examined: two stronger branches (diameter 2-5 mm) passed along the interior of the nest wall for lengths of 50 and 70 mm respectively, and a further 17 twigs barely 1 mm thick were woven more or less horizontally into the wall. Both were true 'suspended nests', ideally adapted to the growth habit of the tree-heath. In their horizontal suspension they differed clearly from Goldcrest and Firecrest nests, which (almost always) are interwoven into vertical side twigs of spruce branches (Palmgren 1932; Thaler 1976). The materials used, however, were very similar: about 80% spiders' web, moss and lichens, 5% other soft vegetable material (grass panicles, rootlets, fibres), and 15% soft lining. They were somewhat lighter (8.9 and 8.6 g) than Goldcrest or Firecrest nests, and contained fewer feathers in the lining (194 and 116 feathers, against average of 1,773 for Goldcrest and average of 618 for Firecrest), but more aerial seeds, especially long, silky thistledown. When the female was at or in the finished nest, the male often sang for 2-4 minutes at a distance of 1-3 m. The song was usually shorter than the territorial song, and always with a highly variable end section or terminal flourish. Sometimes only a few elements preceded this, so that the 'song' consisted almost wholly of the end section. For the Goldcrest, the terminal section plays a major role in 'intimate behaviour' between male and female (Becker 1976; pers. obs.). When foraging during this period, most prey captured were minute insects. On British Birds, vol. 89, no. 9, September 1996 383 one occasion, one of the kinglets spent much time searching moss-covered branches and narrow trunks in a high-lying misty area. Incubation and fledging periods During 41 minutes' observation on 18th March, incubation stints lasted for 12 and 11 minutes, with intervals of 10 and 8 minutes; and, on the foEowing day, for 3, 10, 20 and 12 minutes, with breaks of 7, 13 and 10 minutes. On 21st March, after heavy showers, the female returned very hesitantly to the sodden nest: between 10.53 and 12.05 hours, she incubated for 11 and 24 minutes, with intervals of 13, 16 and 8 minutes. During the incubation period, the male no longer sang near the nest, but always some distance away.