117 Behavioural evidence of the systematic relationships of the Patagonian Crested Duck Lophonetta specularioides specularioides A.N.P. Stevens1, H.G. Young2 & F. McKinney3 1A.N.P. Stevens, Mount Ida College,777 Dedham Street, Newton, MA 02459,USA. Email: [email protected] 2H.G. Young, Durrell Wildlife Conservation Trust,Les Augrès Manor, Trinity,Jersey JE3 5BP,UK. Email: [email protected] 3F. McKinney, Deceased Despite recent advances in phylogenetic analysis, relationships among species of dabbling ducks remain uncertain. In particular, the placement of the Crested Duck Lophonetta specularioides remains in question. Although most researchers have placed the Crested Duck within the tribe Anatini, its placement within the tribe varies from study to study. A study was carried out to determine whether social displays used by the Patagonian Crested Duck Lophonetta specularioides specularioides could inform the phylogenetic debate. Detailed analyses of behavioural displays indicate that although many displays used by the Crested Duck are superficially similar to those of other dabbling ducks (genus Anas) they probably arose via convergent evolution. Such homoplasy provides evidence in support of mitochondrial DNA sequencing studies that place the Crested Duck in a position basal to the rest of the dabbling ducks and suggests that this species lacks close relatives. Key Words: dabbling ducks, Lophonetta, phylogeny, Anatini, social display © Wildfowl & Wetlands Trust Wildfowl (2005) 55: 119-134 118 Patagonian Crested Duck displays The systematic relationships of the results similar to those of Johnson and Crested Duck Lophonetta specularioides Sorenson (1999) in a broader study of are still uncertain, although most the Anseriformes. evidence indicates that it is closely If the phylogeny presented by related to the dabbling ducks (tribe Johnson and Sorenson (1999) is Anatini) and that it is the sister- correct in aligning Lophonetta with species of the Bronze-winged Duck the silver teal/blue-winged duck Speculanas specularis. Delacour & branch of the Anatini, it follows that Mayr (1945) allied Crested Duck with some behavioural traits could be shelducks (tribe Tadornini) because of shared with this group. Either the shelduck-like aggressiveness, other display repertoire of Lophonetta could reproductive behaviour and duckling be unique (reflecting the absence of coloration, separating it from Bronze- very close relatives) or it might share winged Duck, which they placed within some homologous features with the Anatini. Johnsgard (1965, 1978) later silver teal/blue-winged duck clade. placed both species within the genus Furthermore, if Lophonetta exhibits Anas; however, most systematists displays that resemble those of the continue to give them separate generic mallard/teal/pintail/wigeon clades, it status. Based on a cladistic analysis may be possible to infer that these have of morphological characters, Livezey evolved through convergent evolution. (1991) placed the Crested Duck and Indeed, such convergence was inferred Bronze-winged Duck in one supergenus by Kaltenhauser (1971) with respect to calling them the ‘Proto-dabbling the Grunt-whistle (GW) display of typical Ducks’. In Livezey’s (1991) phylogenetic dabbling ducks and the superficially tree, Lophonetta and Speculanas similar display of Lophonetta. represent a separate branch, basal to Two races of Lophonetta all the true dabbling ducks. specularioides are recognised (see Molecular techniques have below). In this paper the authors advanced knowledge of the ancestry describe the displays of L. s. of these two species by establishing specularioides, the Patagonian Crested their membership in a larger clade Duck, based on videotapes of captive with the Brazilian Teal Amazonetta birds, and compare them with the brasiliensis and four species of Steamer displays of other Anatini. Although Ducks Tachyeres. In an extensive captive birds may not perform mitochondrial DNA sequencing study displays at the frequency that might be of dabbling ducks, Johnson and observed in wild birds, the form of the Sorenson (1999) placed Amazonetta, displays is unlikely to differ between Tachyeres, Speculanas and Lophonetta the two groups, and the authors feel together in a group of ‘South American that the displays described here Ducks’ in a basal position to one of the reflect the overall behaviour of this two major branches of dabbling ducks subspecies. The objective of this study that includes the silver teal and blue- is to identify similarities of displays of winged ducks. More recently, Donne- L. s. specularioides and dabbling ducks Goussé and colleagues (2002) found and assess whether these represent Patagonian Crested Duck displays 119 homologies or convergently evolved above 4,000 m, from northern Peru and traits. Such detailed comparison of Bolivia to northern Chile and Argentina. display features has been shown to be The Patagonian Crested Duck effective in illuminating behavioural inhabits lower altitudes in southern homologies and homoplasies in other Chile, Argentinian Patagonia and the species (Wenzel 1992). Falkland Islands and may migrate to the coast in winter, often forming large Methods flocks outside the breeding season (Johnsgard 1978). They feed by dabbling Ten hours of video tape were analysed or head-under in shallow water and for this study. Four hours were recorded are usually in habitats devoid of aquatic at Cedar Creek Natural History Area, vegetation and much cover (these birds Anoka County, Minnesota (two pairs apparently do not rely on being able to recorded in 2000); six additional hours escape detection by hiding). They are were recorded at the Wildfowl & carnivorous, feeding on crustaceans, Wetlands Trust at Slimbridge, England invertebrate larvae, clams (Weller (two pairs recorded in 1999 and a 1972), and adult insects (F. McKinney, mixed-sex flock of five males and four personal observation). Breeding birds females in 2001). Crested Ducks were are territorial and both sexes are very filmed from a hide at both locations. aggressive, chasing conspecifics and Film of the birds in courting parties other, often larger, wildfowl species and in pairs was consistent with many (Buitron & Nuechterlein 1989; Weller of the displays described by other 1972). Pair bonds are strong, and researchers. mates cooperate in caring for ducklings All figures presented here were (Buitron & Nuechterlein 1989). High traced from film projected onto a levels of vigilance, co-operation screen using a Sharp Notevision PG by both adults and aggressiveness A1OX projector. Crested Duck displays allow Crested Ducks to nest in close were traced from an NTSC-format VHS proximity with predatory birds such as copy (30 frames per second) of the gulls Larus spp. and skuas Catharacta original PAL video; all other displays spp. (Young 2005). were traced from Digital8 video (30 Many of the displays of this frames per second). species are conspicuous and striking, and females have loud calls. Male Results courtship displays have pronounced orientation components with respect to General characteristics of the target female. The long tail is often social behaviour conspicuously raised, exposing the black undertail coverts, and the male’s The natural habitats used by this species crest is often erected during displays. are generally open lakes, creeks or Displays are described below; those sea shores. One race, Andean Crested performed with ‘broadside orientation’ Duck L. s. alticola, is resident in the occur with one side of the male’s body high Andean lakes, nesting primarily directed towards the target female 120 Patagonian Crested Duck displays (as opposed to facing towards or away without lateral head movements (see from the target). Display durations are Bill-up Call below). reported as mean (± s.d.). Displays Head-flick: (n = 64) This display, described in this paper were consistent involving a rotary movement of the across all birds observed; however, head, differs in form from the Head- due to the small sample size, additional shake. The male lowers the bill close variations in the displays may exist. to the ground or water’s surface when beginning this display, rolling the head Male displays from side to side as he brings the bill closer to the breast and neck. The Head-shake: (n = 286) This is a ritualised Head-flick ends with the crest erect, Head-shake; the basically lateral forming a peak above the male’s nape, movements of the head are easily seen which is similar to crest position at the in slow-motion video but are tricky to end of a body-shake. This display differs differentiate from a rotary head-flick from the Head-flick of Anas in that the without video enhancement because bill is not lifted above horizontal, as the bill is pointed upwards during the it is at the culmination of displays by head movement. (This upward bill- Anas (McKinney 1965). The duration of pointing component occurs in other a Head-flick is almost double that of displays of Crested Duck, e.g. Bill-Up a Head-shake: 0.956 (± 0.144) s. Used Call, Decrescendo). McKinney (1965) much less frequently than Head-shake, noted that L. s. alticola performs similar Head-flick precedes a ‘major’ display (n head-shaking movements, which differ = 10) just as often as it occurs following from those of Anas in the uptilting of such a display (n = 11). the bill. The Head-shake is a very rapid Body-shake: (n = 25) This is a typical movement, lasting an average of 0.504 ritualised swimming-shake, with a (± 0.088) s, and it may be repeated up to prolonged tail-wag at the start and seven times preceding a display (mean: head held low to the water’s surface. 3.04 ± 1.46). It appears in introductory Obvious rotary movements of the head context at start of a display bout, initiate the full Body-shake; as with but is probably better regarded as a Head-flick, these rolling movements preliminary to individual displays. end with the crest erect and the bill Kaltenhauser (1971) reported that brought close to the breast. (This males utter a single-note vocalisation shake is reminiscent of Wood Duck Aix during the Head-shake, and Jones sponsa; it is quite different from the (1948) noted similar behaviour in L.