DISTRIBUTION

Status of the Glossy Ibis in Mexico

Steve N. G. Howell and Barbara M. de Montes

his paper details the first marshes near Emiliano Zapata, in able experience with both species be­ records of the Glossy Ibis for northern Chiapas. The bird was stud­ fore and after the sighting, Howell is TMexico and summarizes the ied for 20 minutes by the group, most certain that the red irises of a White­ status of Plegadis ibises in Middle of whom were very familiar with faced Ibis would have been apparent America. White-faced Ibis. The bird was at given the views obtained and that the The Glossy Ibis (Plegadis falcinel­ times within 70 meters and observed whitish-bordered loral skin is charac­ lus) is a notoriously nomadic wading through several telescopes in good teristic of the Glossy Ibis. bird widespread in Eurasia, Africa, light. It was an adult, as judged by The flood plain and marshes of the and Australasia (Cramp and Sim­ areas of retained purplish-chestnut Usumacinta River where the sighting mons 1977). In addition, it breeds feathering on the upperparts; other occurred are at the point where either commonly and is increasing in the plumage features, including the white- Plegadis might be expected to occur eastern United States, to which it may streaked head and neck, indicated that from time to time. We know of several have spread from the Old World in the bird was essentially in basic plu­ sightings of Plegadis sp. from the Usu­ the mid- to late 1800s (Palmer 1962). mage. The irises were clearly brown; macinta marshes since the early 1970s In the New World it also occurs lo­ the unfeathered lores appeared slate- including a report of 54 “dark ibis” in cally in the Greater Antilles, Central gray and were bordered both above July 1972 (Sprunt and Knoder 1980), America and northern Venezuela and below by a thin but distinct whi­ suggestive of a breeding colony. (See (A.O.U. 1983), a distribution in ac­ tish line, the upper line broader and below). cord with what one might expect from more striking. The bill and legs ap­ De Montes observed five Plegadis a transAtlantic invader; cf. the early peared grayish. Having had consider­ ibises at Isla Cancún, Quintana Roo, stages of the more spectacular and well-documented spread of the Cattle Egret (Bubulcus ibis) (Crosby 1972). The very similar White-faced Ibis (P chihi) breeds commonly in the Figure 1. Distribution of Plegadis ibises in Mexico and northern Central America. western United States, northern Mex­ ico (see Fig. 1), and locally in South America (A.O.U. 1983). In North America it winters south on the Atlan­ tic slope to eastern Mexico and on the Pacific slope to Guatemala, El Salva­ dor, and possibly Costa Rica (at least formerly). However, vagrant occur­ rences are documented from as far afield as Hawaii, British Columbia, and Massachusetts (DeSante and Pyle 1986) and thus demonstrate a consid­ erable potential for wandering.

Records of Glossy Ibis in Mexico

On November 30, 1985, while lead­ ing a Golden Gate Audubon Society tour, Howell found a lone Plegadis feeding in roadside freshw ater

Volume 43, Number 1 43 on January 30, 1986. They were feed­ ing in mangroves with other wading February 1984: one at a brackish birds including White Ibises (Eudoci­ lagoon on Isla Cozumel, Quintana mus albus), Tricolored Herons Roo (Howell and Peter Pyle). (Egretta tricolor) and Snowy Egrets March 1986: three in freshwater (E. thula). Six birds were noted on marshes near Majahual, Quintana February 2 and March 28 at the same Roo (Arturo Lopez Ornat). location and a single bird was still January 1987: one at small fresh­ present on April 10, 1986. Photo­ water pool on Cancún Golf Course, graphs taken of the birds (Fig. 2) Quintana Roo (per. Howell). clearly show the whitish-bordered lo­ July 1988: one at Rio Lagartos, Yu­ res characteristic of the Glossy Ibis. catán (Howell and S. Webb). The third record of Glossy Ibis is a small flock seen along the road to Status of Glossy Ibis in Middle Palizada in the Usumacinta marshes, America Campeche, in February 1988 (R. A. Behrstock and K. J. Zimmer, inde­ Russell (1964) mentioned no rec­ pendently). At the time of observa­ Figure 2. Glossy Ibis at Cancún, Mexico, ords of Plegadis ibises for Belize (Brit­ tion, not all ibises were specifically February 1986. Photograph / Barbara M. de Montes. ish Honduras) but, by 1985, the identified but the observers’ notes plus Glossy Ibis was considered a rare per­ photographs (Fig. 3) indicate that of manent resident in the northern half about 20 Plegadis ibises, most were was seen at Kilometer 172. The bright of that country (Wood et al., 1986). Glossy but at least three White-faced red irises and plain gray lores of the However, the identification of birds as Ibises were also present. White-faced were striking in contrast Glossy Ibis is by presumption only The fourth record of the Glossy Ibis to the Glossies. In addition, groups up and breeding has never been proven is of a basic-plumaged bird found on to four-five Plegadis were scattered in in Belize (D. Scott Wood and Dora Isla Cozumel, Quintana Roo, on June flooded fields from Kilometer 173 to Weyer pers. comm.). 4, 1988 by Andres M. Sada. The Kilometer 156 (Palizada junction) but Monroe (1968) reported a single brown irises and contrasting bluish- none was found along the road to Plegadis ibis seen in the lower Sula white line along the upper lores were Balancan in adjacent Tabasco where Valley of northwestern Honduras, on seen clearly at close range. Howell and similar conditions prevailed. The rel­ November 29, 1953. In December it Sophie Webb relocated the bird, July atively localized concentrations and was joined by “a few others” which all 12, 1988, and agreed with the identi­ high percentage of juveniles indicate remained until February 1954. A fication. that a breeding colony of Glossy Ibises “white feathered area on the sides of Following the above scattering of exists close to the sites of our obser­ the face” was noted and hence at least records Howell and S. Webb were vations. It is also not inconceivable one bird was suspected to have been amazed to encounter 500–700 Ple­ that more of the birds were White­ a White-faced Ibis. However, given gadis ibises along Route 186 in south­ faced Ibises and that both species the time of year, it seems likely that western Campeche, July 18–20, 1988. might be breeding in the area. the white observed was the bare loral At Kilometer post 172 flocks totalling The fact that few birders visit south­ border and that the birds were, in fact, 300–350 birds were present in flooded ern Mexico in summer helps explain Glossy Ibises. fields near the highway; about 50% the seemingly dramatic discovery; We are aware of no confirmed or were alternate-plumaged adults and later in the year, birds presumably possible records of the Glossy Ibis 50% juveniles, many with bills not disperse more widely although a few from Guatemala, El Salvador, or Nic­ fully grown. All adults seen at close may be encountered close to the high­ aragua. There are several reports of range (minimum nine to ten birds) way. Plegadis sp., including specifically were Glossy Ibises: the brown irises As well as the confirmed records identified Glossies, in northwest Costa and dark blue facial skin with con­ detailed above, and earlier reports of Rica (A.O.U. 1983, Howell pers. obs.) trasting bluish-white borders were Plegadis sp. from the Usumacinta and there are several records of Ple­ quite obvious. At least one-two juve­ Marshes, there are several records of gadis sp., including one specimen re­ niles showed traces of whitish loral unidentified Plegadis ibises in the Yu­ ported as a Glossy, in Panama (D. borders, indicating they were also catán Peninsula (Fig. 1): Engelman pers. comm.; J. Guarnaccia Glossy. At Kilometer post 164 up to June 1976: 1 in roadside marsh at pers. comm.; Ridgely 1981). Records 375 Plegadis ibises were seen with Tulum, Quintana Roo (Hector Cebal- from Costa Rica and Panama are 35% adults and 65% juveniles. All of los–Lascurain). mainly in the northern winter months 45 adults seen well were Glossy Ibises October 1977: one in mangroves at but there are also records during the as were at least three-four juveniles. Celestun, Yucatán (de Montes). northern summer. Most if not all juveniles at Kilometer May 1982: two in freshwater marsh 164 appeared to have fully grown bills north of Vigía Chico, Quintana Roo and a few had traces of white streaking (Arturo Lopez Ornat). A Note on Field Identification about the head. No immature (year- June 1983: one, possibly two, in old) Glossies were identified but at freshwater marsh near Vigía Chico, Criteria for distinguishing between least one immature White-faced Ibis Quintana Roo (Ingrid Olmstead). the Glossy and White-faced ibises are

44 American Birds, Spring 1989 and Kevin J. Zimmer for allowing us to include their unpublished observa­ tions; Robert A. Behrstock for per­ mission to include his photograph; and Dodge Engelman, John Guarnac- cia, Dora Weyer and D. Scott Wood for help in researching records in Cen­ Figure 3. Mixed flock, in­ tral America. Howell would very cluding White-faced Ibises much appreciate further information (top and right hand flying on the distribution of Plegadis ibises birds), Glossy Ibises (stand­ in Mexico and Central America, in­ ing birds), White Ibises, cluding comment on the breeding and Great and Snowy egrets along road to Palizada. winter ranges of the White-faced Ibis. Photograph / Robert A. Behr- This is publication number 380 of the stock. Point Reyes Bird Observatory. discussed below. The reader is also dark gray, at least from fall into mid­ referred to Pratt (1976). winter. However, adult White-faceds Separating the Glossy Ibis from the can show distinctly reddish lores by LITERATURE CITED extremely similar White-faced Ibis in early January (Howell pers. obs.), AMERICAN ORNITHOLOGISTS’ the field is difficult, and perhaps im­ when the loral borders may appear UNION. 1983. Check-list of North possible in some cases. The plumages distinctly paler, almost reminiscent of American Birds, 6th Edition. Allen of the two species are essentially iden­ the Glossy. However, the pale border­ Press, Lawrence, Kansas. tical for most of the year, the feathered ing is washed pinkish and much less CRAMP, S„ and K. E. L. SIMMONS. 1977. Handbook of the Birds of Eu­ white “face” of the latter species being distinct than on the Glossy — an ob­ rope, the Middle East and North Af­ apparent only in adults during the server able to see the pale borders rica. Vol I. Oxford Univ. Press, Oxford. breeding season. Migrant White-faced should easily be able to see the reddish CROSBY, G. T. 1972. Spread of the Cattle Ibises in Mexico often show no trace lores and bright red irises. Egret in the Western Hemisphere. Bird- of white facial feathering as late as Banding Ah'. 205-212. April and May (Howell pers. obs.) and Summary DeSANTE, D. F„ and P. PYLE. 1986. care has to be taken distinguishing Distributional checklist of North American birds, Vol. I: United States white feathering from whitish facial The above observations indicate and Canada. Artemesia Press, Lee Vin- skin. For most of the year, only close that the Glossy Ibis has spread into ing, California. and careful observation of the color­ southeastern Mexico during the last MONROE, B. L., Jr. 1968. A distribu­ ation of soft parts may give a clue as 20 years; however, the Plegadis sp. tional survey of the birds of Honduras. to the identity of a vagrant ibis. recorded in Honduras in 1953–1954 Ornith. Monogr. No. 7. The iris color of an adult White­ hint that Glossies may have appeared PALMER, R. S. (Ed.). 1962. Handbook of North American birds. Vol. 1. Yale faced is bright red, perhaps duller in in the region much earlier. Small Univ. Press, New Haven. winter, that of an adult Glossy dark numbers of non-breeding immature PRATT, H. D. 1976. Field identification brown. Immatures of both species Glossy Ibises probably now occur an­ of White-faced and Glossy Ibis. Birding have gray-brown irises although at nually in the Yucatán Peninsula and 8: 1- 5. least some immature White-faceds at­ have been recorded there between at RIDGELY, R. S. 1981. A guide to the tain red irises by their first winter. least January and July. Strong evi­ birds of Panama. Princeton Univ. dence of breeding by Glossies in Mex­ Press, Princeton. Note: Very good and clear views are RUSSELL, S. M. 1964. A distributional required to see the true iris color; red ico was obtained in July 1988, in the study of the birds of British Honduras. irises can often look simply dark un­ Usumacinta marshes following sev­ Ornith. Monogr. No. 1. less seen at the right angle. eral sightings of Plegadis ibises in that SPRUNT, A. and C. E. KNODER. 1980. The unfeathered lores, bill, and legs area since 1972. In addition, the first Populations of wading birds and other and feet of both species are dark gray­ records of the White-faced Ibis for the colonial nesting species on the Gulf and Yucatán Peninsula are documented, Caribbean coasts of Mexico. In Schaef- ish or pinkish-gray for most of the fer, P. P., and S. M. Ehlers (Eds.). The year. In breeding condition (at least at three birds on January 19, 1988 and birds of Mexico: Their ecology and the onset of the breeding season) the a single immature on July 18, 1988, conservation. Nat. Aud. Soc., Tiburon, lores of the White-faced flush bright all in the Usumacinta marshes of California. red while those of a Glossy flush co­ southwestern Campeche. WOOD, D. S„ R. C. LEBERMAN, and balt blue and show a bright whitish- D. WEYER. 1986. Checklist of the blue margin above and below. The birds of Belize. Carnegie Mus. Nat. ACKNOWLEDGMENTS Hist. Spec. Publ. 12. whitish loral borders are kept through­ out the year by many adult Glossies The authors wish to thank Sophie ——Point Reyes Bird Observatory, and some immatures show a clear in­ Webb and Richard Wilson for helpful 4990 Shoreline Highway, dication of the paler borders by as criticism of earlier drafts of this paper; Stinson Beach, CA 94970 early as August (Howell pers. obs.). Robert A. Behrstock, Hector Cebal- (Howell); Apdo. Postal #8, The lores of basic plumage and im­ los-Lascurain, Ingrid Olmstead, Ar­ Cancún, Quintana Roo, mature White-faceds appear uniform turo Lopez Ornat, Andres M. Sada Mexico (de Montes).

Volume 43, Number 1 45