Bijdragen tot de Dierkunde, 55 (2): 219-232 — 1985 Observations on the behaviour of the Scarlet Ibis, Eudocimus ruber, in Artis Zoo, Amsterdam by H. Albrecht R.E. Spil M.W. van Walstijn & Royal Zoological Society "Natura Artis Magistra", Plantage Kerklaan 38, 1018 CZ Amsterdam, The Netherlands & Department of Animal Behaviour, University of Amsterdam, The Netherlands Abstract without overt signs of aggression. The hierarchy was not linear but could be subdivided into three groupings. The The Scarlet Ibis, Eudocimus ruber (Linnaeus), fam. of bird correlated with status a was sex-dependent, weight Threskiornithidae, is the closest relative ofthe White Ibis, and of but length the bill, not with nest-ownership or age. Eudocimus albus (Linnaeus). The two species live in adjoin- The breeding behaviour of the Scarlet Ibis and the is known about the ing geographical areas. Nothing White Ibis seems to be so similar that, bearing in mind Scarlet Ibis’s in the wild and little breeding biology only the be their similarity in morphology, question may posed about its breeding biology in captivity. A better under- whether they are conspecific. standing of the breeding of this species in captivity should its and also elucidate its help to improve management to Zusammenfassung relationship with its much better known counterpart, the White Ibis. Der Rote Sichler, Eudocimus ruber (Linnaeus), Fam. Three of behaviour in types display are recognized Threskiornithidae, ist der vikariierende nächste Verwand- the the and courtship: snap display, dipping snap display te des Weißen Sichlers, Eudocimus albus (Linnaeus). Von also in The latter occurs greeting ceremonies, twig pulling. der Brutbiologie des Roten Sichlers ist aus Freiland und together with the up-down display, and as a precopulatory Ein besseres Gefangenschaft nur wenig bekannt. stable for activity. Breeding pairs are one breeding cycle, Verständnis dieser empfindlichen Art soil dazu beitragen, but occasionally promiscuous matings can be observed. Of sie besser zu schützen und die Beziehungen zum Weißen 16 birds in 1982, 12 bred in all with a breeding again 1983, Sichler zu klären. different partner. Bei der Balz können drei Verhaltensweisen is of Egg laying preceded by a period increasing ap- unterschieden werden: Schnabelschnappen, Beugeschnap- of both members of the the pearance couple on und Letzteres ist auch beim together pen Zweigschütteln. Begrüßen where copulation takes place. Nests contain 2-3 nest, eggs, und, zusammen mit dem Ab-auf, beim Paarungsvorspiel which are incubated for 21-23 is indicated beobachten. Während eines sind Männchen days. Hatching zu Brutzyklus failure a sudden decrease in incubation. Hatching can by und Weibchen fest verpaart, gelegentlich konnten Fremd- be succeeded the of clutches. by laying replacement beobachtet werden. Von 16 die in paarungen Vögeln, Nesting failures were due to destruction of nests or wählten alle in 1983 young, 1982 verpaart waren, Brutvögel (12 often resulting from disturbances humans or domestic by Vögel) einen neuenPartner. cats. One incubated for 4 months without pair over ap- Vor dem Eierlegen sind die Brutpartner regelmäßig zu- interruption, without being parent probably eggs present sammen am Nest, wo auch die Paarungen stattfinden. Ein for of the time. most Gelege (2-3 Eier) wird 21-23 Tage bebrütet. Nach dem than males. Nest Females spend more time incubating Schlüpfen werden die Jungen zunächst gehudert. Streu- reliefs much 1 than in occur at a higher rate (ca. per hour) nende Katzen oder auch menschliche Störungen können the wild 2 For to 3 weeks after (ca. per day). up hatching, den Brutprozeß leicht stören. Mißlingt ein Gelege, wird the almost one parent bird stays at nest continuously. oft sogleich mit einem folgenden begonnen. Ein Paar brü- visited other Unattended nests are quickly by birds, über 4 Monate ohne vermutlich tete Unterbrechung, sogar males. One the predominantly parent, mostly male, ohne Eier. almost chases intruder varia- immediately an away. Slight Weibchen brüten mehr als Männchen. Brutablösungen tions in behaviour could not be correlated with in viel öfter 1 breeding treten Gefangenschaft auf (ca. pro Stunde) breeding success. als im Freiland Bis 3 Wochen nach (ca. 2 pro Tag). etwa A dominance hierarchy could be distinguished between dem Schlüpfen ist ein Elternteil beinahe konstant am Nest. adult birds. Aggressive encounters consisted of three dif- Unbewachte Nester werden schnell durch fremde Vögel behaviour threat ferent patterns: fighting, forward and (meist Männchen) besucht. Diese werden sogleich verjagt, stab-and-counter stab. Often bird another meist Männchen. Aus dem Verhalten eines festen one gave way to vom 220 R. E. SPIL ET AL. - BEHAVIOUR OF SCARLET IBIS 1. Distribution of the Scarlet Ibis in South America of Ch. Its northwestern Fig. (courtesy Luthin). counterpart, the White this the Ibis, overlaps range only near border of Colombia and Venezuela (Luthin, pers. comm.). Brutpaares ließen sich keine Rückschlüße ziehen, ob sein geographical distribution is restricted to Bruterfolg gut oder schlecht sein würde. and inundated in the mangrove swamps plains Adulte Vögel lassen eine Rangordnung erkennen. Bei northern part of South America (fig. 1). The agonistischen Begegnungen lassen sich drei Verhaltens- birds live in often mixed with weisen unterscheiden: Kämpfen, Drohen und Schnabel- large colonies, of the Ciconiiformes fechten. Oft gibt ein Vogel seine Über- oder Unterlegen- other members order heit durch oder Ausweichen erkennen. nur Verdrängen zu (herons, spoonbills). The number of Scarlet Die Hierarchie ist nicht strikt lineär. Drei Ranggruppen Ibises is decreasing rapidly, as the birds are konnten unterschieden werden, innerhalb deren sich auch very sensitive to human disturbance and Dreiecksverhältnisse oder andere komplizierte Beziehun- limited in their choice of habitat erkennen ließen. Der eines (ffrench & gen Rang Vogels hängtab von In French Geschlecht, Gewicht und Schnabellänge, jedoch nicht von Haverschmidt, 1970; Spaans, 1982). Alter oder Nestbesitz. Guiana, intensive hunting takes place for the Das Brutverhalten des Roten und Weißen Sichlers zeigt feathers which are then used in imitation so viele Übereinstimmungen, daß die Frage berechtigt ist, flowers (Betlem & De Jong, 1983). ob wir es mit zwei Arten oder nur mit einer Art zu tun ha- Little behavioural research has been ben. done on the Scarlet Ibis. Some behaviour in the field has been described by ffrench & Haverschmidt INTRODUCTION (1970); Risdon (1969) and De Tarzo Zuquim Antas (1979) mention some breeding records in The The Scarlet Ibis, Eudocimus ruber (Linnaeus, zoos. White Ibis, Eudocimus albus (Lin- is of the coloured has been the of extensive 1766), one most strikingly naeus, 1766), subject members of the family Threskiornithidae. Its ecological and ethological research by Kushlan - 1985 221 BIJDRAGEN TOT DE DIERKUNDE, 55 (2) Fig. 2. The old aviary in Artis Zoo, built in 1863-1866 (cf. Anon., 1867). Reproduced from an engraving after a drawing 1868 in “Geillustreerde medaille Natura Artis Amsterdam”. A by W. Hekking Jr., published ca. van Magistra te nearly identical lithograph, drawn by the same artist, has been published in the yearbook of the Royal Zoological Society “Natura Artis for the 1869. the round in the middle is the summer residence of the Magistra” year Nowadays, cage Scarlet Ibises. (1973, 1976, 1977 and 1978) and Rudegeair records from some other zoos have also been (1975). taken into account. Cross breeding between Scarlet and White Ibises has occurred in Florida, where the Scarlet Ibis in 1961 THE COLONY IN ARTIS ZOO was introduced (Zahl, 1967) and in the northern part of South America where the distribution of Scarlet and The Scarlet Ibis has been in Artis Zoo range kept Ibis White overlaps slightly (Ramo & Busto, since 1916 in separate summer and winter The residence is of 1982; Luthin, pers. comm.). quarters. summer a cage ap- 6 7 back The present study has been carried out in the proximately 4J4 x x m (fig. 2). The of Artis Zoo under the auspices of the University the cage is a brick wall covered with ivy. Seven of Amsterdam and the Royal Zoological Society prefabricated nests are placed in the ivy at "Natura Artis Magistra", Amsterdam. Obser- heights varying from 2.5-5 m (fig. 3). More concentrated loose material added the vations were on breeding nesting is on ground. and social interactions. several behaviour Breeding The cage contains branches, some 222 R. E. SPIL ET AL. - BEHAVIOUR OF SCARLET IBIS 3. Ibises with artificial sometimes build 30-40 Artis A. F. Nord- Fig. nest platforms, which they up cm high (photo: Zoo, heim). bushes and a small pond. From our observation last 6 years has varied from 2-9 young (mean The birds be point it was not possible to look into the nests. 4.7). can recognized individually In 1983 the consisted of 27 birds. coloured both May group by rings worn on legs. The ibises varied in from 1 20 age to years. died Three birds during the breeding season, of probably as a result disturbance caused by METHODS OF OBSERVATION domestic cats. Two birds suffered from a broken bill from some earlier mishap. They, On April 26th, 1983, the birds were transferred and did in the winter observa- 12 others, not participate from their quarters, where no breeding process. Fledging success during the tions could be made, to the summer aviary. - 223 BIJDRAGEN TOT DE DIERKUNDE, 55 (2) 1985 1983 made From 28 April up to 31 August we 30 minutes observations, spread throughout the day, totalling 134.5 hours. Initial observations of had been made in the summer 1982. all birds of behaviour For on nests three types recorded: were standing, incubating or reliev- ing partner. Incubating birds were identified by the of the recording ringing combination part- elsewhere in the Each ner off duty aviary. brood scored for duration and of relief was variety behaviour. Besides also followed activities at the nest, we agonistic encounters, foraging and resting. Apart from these quantitative observations, of behaviour qualitative descriptions were made such and patterns as courtship, copulation greeting.