ARTICLES ON HAWAIIAN AND PACIFIC BIRDS, BIRDWATCHING AND WILDLIFE



White-faced Ibis and Glossy Ibis: Hawai'i's largest ever flock with notes on Distribution and Identification



On 16th September 2003 five immature Ibis, presumed to be White-faced Ibis (Plegadis chihi) arrived at Hanalei NWR, Kaua'i. This is the second record for Hanalei NWR, and the fourth record for the island. This is also the largest flock ever recorded in the Hawaiian Islands, with most previous records being of either single birds or pairs, although a group of three was recorded in the 1930s. The birds were presumed to be White-faced Ibis, rather than the similar Glossy Ibis (P. falcinellus), as the latter has yet to be recorded in the Hawaiian Islands, however in immature plumage it is impossible to tell the two species apart, and it would only be possible for the birds to be fully identified to species once they had completed their first winter, when White-faced Ibis exhibits a red iris and Glossy Ibis a brown iris and pale face-lines. Once they attain adult plumage further differences become apparent, such as face, leg and bill colour. The flock increased to eight individuals on 6th October and then to an incredible ten birds on 13th October 2003. At the end of 2003 an eleventh bird was reported and this was confirmed on January 21st 2004 when 11 birds were seen and photographed at Waioli Taro Fields near Hanalei, and this then became the biggest flock ever recorded in the Hawaiian Islands. By the end of January 2004 none of the birds had shown any sign of plumage change, and so they could not be definitely assigned to species, although this in itself could indicate that the birds were White-faced. It was debated that as the birds were young and not in their usual habitat/location, that they would suspend moult until they left (see comments below), however in early March 2004 one bird was photographed at close range and a few small changes could be noted. Firstly the eye had changed from the ruddy-brown colour seen in December 2003 to a reddish colour (indicative of White-faced Ibis), secondly the lores and bare skin area in front of the eye had changed to a pale pink colour (again indicative of White-faced Ibis), the pale head streaking had decreased and the body feathers (particularly the breast and lower neck) had deepened in colour. With these changes occurring it seems that all eleven birds are indeed White-faced Ibis. In September 2004 a "newly arrived" first-year bird arrived on O'ahu with probably another on Kaua'i, which either means they are new arrivals from the mainland, or more unlikley, locally bred birds. A future article will discuss these new birds.



Distribution and Occurrence

White-faced Ibis is a North American species which occurs predominantly in the western half of the continent, with breeding taking place mainly in the Great Plains and wintering to coastal Louisiana, Texas, southern California and throughout northern Mexico. The species is being increasingly recorded from the Atlantic Coast of North America with records from the Delaware Estuary, New York, Massachusetts, Connecticut, New Hampshire and Maine. White-faced Ibis has yet to be recorded on the eastern side of the Atlantic Ocean.

The species is a rare but fairly regular visitor to the Hawaiian Islands with the first record probably in 1872 on Kaua'i, when a specimen was apparently obtained by Knudson. The specimen is in the U.S. National Museum (USNM 61258). The specimen tag says Plegadis guarauna and gives only Kaua'i as locality (Robert Pyle, pers. comm.), however at the time White-faced and Glossy Ibis were considered conspecific. [Note that the scientific name for Glossy Ibis is now P. falcinellus, not P. guarauna]. The 1872 record was quickly followed by one in 1873. An Ibis, probably this species, was collected on Kaua'i by G.P. Wilder sometime during this year. Munro's report on Wilder's 1873 bird doesn't give an island locality, but it is often attributed to Kaua'i because it follows immediately after his report of Knudsen's Kaua'i bird. Actually, Henshaw 1902, p. 104 reports (under P. falcinellus, Glossy Ibis) that Wilder "of Honolulu" shot his 1873 bird on Maui and gave it to Newell for preparation. Gerritt P. Wilder, son of Honolulu lumberman Samuel Wilder and a botanist in later years, was born in November 1863 adding more interest to the 1873 specimen. Perhaps the 1873 collector was another G. P.Wilder or just some other Wilder (Robert Pyle, pers. comm.). Since 1873 observations have been made on Kaua'i, O'ahu, Moloka'i, Maui and Hawai'i with some birds remaining for several years, e.g. a bird on O'ahu from 1976 - 1986, and some records relating to more than one individual e.g. three at Kahana Pond, Maui in 1937 and two at Kona STP, Hawai'i from 1997 - 1999.

Map A: North American distribution of White-faced Ibis ca. 2000. Orange indicates all-year occurrence, yellow indicates summer range and blue indicates winter range. Dotted line indicates extent of out-of-range records. Based on National Geographic Society's Birds of North America 1999.


Glossy Ibis is generally an Old World species which appears to have crossed the Atlantic Ocean in a similar way to the Cattle Egret, and was first recorded in North America in 1817, when a specimen was collected at Great Egg Harbour, New Jersey on 7th May. It remained very rare however and Audubon only encountered the species once (in Florida in 1832) and breeding records were not obtained until the 1880s. By the trun of the twentieth century it was rare and local along the Gulf of Mexico and in Florida, with perhaps only about 50 pairs by the mid-1930s. During the 1940s the species increased its North American range with breeding occurring north to Long island and west to Louisiana. By the 1980s the species was a bird of the southeastern United States and Atlantic Coast with local populations in the Greater Antilles, Costa Rica and northern Venezuela and a current breeding range which overlaps with White-faced Ibis in southern Louisiana and Alabama. Vagrants have been recorded regularly in eastern North America east of the Great Plians away from the breeding areas as well as increasingly in the western half of the continent, with some birds reaching the Pacific Coast.


Map B (below left): North American distribution of Glossy Ibis ca. 1960. Map C (below right): North American distribution of Glossy Ibis ca. 2000. The blue dots show recent vagrant occurrences outside the current "normal" range. Maps based on Patten and Lasley 2000.

















Identification

In adult breeding plumage White-faced Ibis can be identified by the extensive white feathering that borders pink facial skin, whereas in Glossy Ibis the white feathering to the face is lacking and they exhibit blue facial skin with whitish-blue stripes around the edge (not feathering but the actual skin). Both species show rich deeply-coloured heads and pink-reddish legs, however the legs of White-faced Ibis tend to be brighter and more obviously pink-red. In adult winter plumage the head becomes browner and is lightly streaked with white and the bare parts become duller. On both species the lesser coverts are maroon in colour in adult plumage in both winter and summer plumage. Adult Glossy Ibis tends to be about 10% larger than White-faced Ibis, although there is sexual variation within species, but this feature is only really of any use if both species are seen side-by-side.

In sub-adult plumage or in birds that have reached the winter of their first year White-faced Ibis almost always exhibits pink skin at the base of the bill and a red eye (from October onwards in the first year) whereas Glossy Ibis tends to show a blue-grey face with obvious pale stripes above and below the bare facial skin, as well as brown eyes (from September-January of the first year). Of course there do seem to be exceptions to this, and White-faced Ibis occurring in the Hawaiian Islands as vagrants have not developed plumage in the "normal" way and have remained in seemingly first-year plumage despite staying for several years. No adult-like plumaged White-faced Ibis have ever been recorded from Hawai'i. Birds in first-winter plumage do not show any summer plumage and have only a few, if any, maroon-coloured lesser coverts, thus a bird exhibiting a maroon shoulder (lesser coverts) can be aged as older than first-year on this alone. Juveniles before about October in the first year cannot be identified with certainty to either species until the eye-colour has developed.

The understanding of moult regimes and ageing of the Plegadis Ibis are still not fully understood but it appears that White-faced Ibis undergoes a series of protracted and variable moults to attain full adult plumage (Wilson et al. 2002).

Doug Pratt wrote in late 2003 (with reference to the 2003 Kaua'i White-faced Ibis): "I am in a good position to talk about separating the two dark ibis species because Louisiana is where the narrow contact zone between them is. Years ago, I wrote an article for Birding on the subject of identification, and I have done some subsequent research as to when the facial skin colors change. By this time of year, virtually all dark ibis are identifiable to species, even birds of the year, but you need a good, close look. First, you have to determine whether the bird is a hatching-year or older individual. That is determined by whether there are chestnut feathers on the "shoulder" or bend of the wing. Older birds retain some chestnut feathers from their alternate (spring, breeding) plumage when they molt into basic (winter, nonbreeding) plumage. First-year birds have the wing all glossy olive green with no chestnut. At least some of the Hanalei birds are first-year, but with 10 of them present, we might well have some older birds mixed in (which would make things easier). So check for those chestnut shoulders. Eye color is hard to see in the photos posted on our website.Usually by this time in the fall, young White-faced Ibis will have dark red eyes, which they then retain for life with no seasonal change. I could not make a call based on eye color as shown in the photos. Facial skin, however, is another matter.

Glossy Ibises develop a pale mark in the loral skin between the eye and the base of the bill very early. Even some birds that I observed on the East Coast in August that were young enough to retain a dark band on the bill had recognizable beginnings of this pale border. The border in this area is shaped like a very elongated triangle with the point at the bill base, so it is not hard to see. It is enhanced by the fact that it actually is a fold of skin which casts a shadow making it really stand out. As part of the molt into alternate plumage, this border becomes pale blue and a narrow one also develops below the eye (but not encircling the eye). Therefore they (the photographed Hanalei birds) have to be the more expected White-faced. Reggie David raises an interesting point about molts: Previous White-faced Ibis in Hawai'i have never molted into alternate plumage, even though one individual stayed on O'ahu for 9 years. This is very unusual (one would think that such things were automatic) in an otherwise seemingly healthy bird. One hypothesis has been that the hormonal changes that produce the molt are triggered by social activity, and thus isolated individuals (or pairs or triplets) cannot receive the needed stimulus. It could also be that the presence of the opposite sex is required as well. It would not be too far-fetched for previous pairs to have been single-sex just by chance. But a group of 10 birds is almost guaranteed to have both males and females present (unless there is some previously unknown tendency for males and females to migrate separately, which would be hard to determine because the sexes are not distinguishable in the field). Certainly, we should watch these birds carefully. If they are going to molt, they should begin to do so by March. I hope they do (see photos at foot of article). Alternate-plumage White-faced Ibis are quite stunning with their rich glossy chestnut plumage, white faces, and red eyes and facial skin." Above right: Immature presumed White-faced Ibis at Hanalei NWR, Kaua'i, 18th September 2003 © by Brenda Zaun/USFWS.


Left: Immature presumed White-faced Ibis at Hanalei NWR, Kaua'i, 18th September 2003 © by Jim Denny.

Note the lack of chestnut feathers on the "shoulder" or bend of the wing. Older birds retain some chestnut feathers from their alternate (spring, breeding) plumage when they moult into basic (winter, nonbreeding) plumage. First-year birds have the wing all glossy olive green with no chestnut. Older birds would also exhibit red/pink facial skin and a red eye. Although both White-faced and Glossy Ibis occur in North America there is only a narrow overlap zone in their ranges, which is in the Louisiana area.

Left: Immature Glossy Ibis at Budleigh Salterton, Devon, England, September 7th 2002 © Ian Barnard.

Note that the white lines of adult-like plumage above and below the bare skin at the base of the bill have already started to appear. Also note the green gloss to the wing and brown lesser coverts indicative of a first winter bird. The dark brown eye indicates that this bird is a Glossy Ibis, rather than White-faced. A small influx of Glossy Ibis occurred in September 2002 in southern England and this bird was part of a flock of eight birds which appeared in Devon, however only this bird remained for more than a couple of days. The birds probably originated in Spain, and in fact a flock of eight birds was seen flying north in the Bay of Biscay just a few days before.

Left: Immature presumed White-faced Ibis at Hanalei NWR, Kaua'i, 18th September 2003 © by Brenda Zaun/USFWS.

Although this shot is slightly out of focus it does illustrate well the salient identification features a juvenile Ibis. Note the dull brown-coloured shoulder, not bright chestnut as in adults or post first-summer. Also note the white flecking on the head, if this were an adult in winter plumage (and thus also showing white head flecks) the bird would almost certainly exhibit red facial skin and a red iris, as well as the aforementioned chestnut shoulder patch.


Left: First-year White-face Ibis at Hanalei NWR, Kaua'i, March 11th 2004 © by Brenda Zaun.

Note the eye has changed to a reddish colour and the skin on the lores/above and below the eye has changed to a pale pink colour. Compare this with the December photographs of a bird from the same group (above) and the similarly-aged Glossy Ibis in Devon, UK (above).





Eight immature White-faced Ibis in flight at Hanalei NWR, Kaua'i, 6th October 2003.

Part of the largest flock ever recorded in the Hawaiian Islands.

Photograph © by Brenda Zaun/USFWS


Eight immature White-faced Ibis amongst taro lo'i at Hanalei NWR, Kaua'i, 6th October 2003.

Part of the largest flock ever recorded in the Hawaiian Islands.

Photograph © by Brenda Zaun/USFWS


Eleven White-faced Ibis at Waioli, near Hanalei, Kaua'i, Hawai'i, January 21st 2004.

The Hawaiian Islands' biggest-ever Ibis flock.

Photograph © Brenda Zaun


Eleven White-faced Ibis at Waioli, near Hanalei, Kaua'i, Hawai'i, January 21st 2004.

The Hawaiian Islands' biggest-ever Ibis flock.

Photograph © Brenda Zaun


First-year White-face Ibis at Hanalei NWR, Kaua'i, March 11th 2004. Note the eye has changed to a reddish colour and the skin on the lores/above and below the eye has changed to a pale pink colour. Compare this with the December photographs of a bird from the same group and the similarly-aged Glossy Ibis in Devon, UK, above. Photograph © by Brenda Zaun

First-year White-face Ibis at Hanalei NWR, Kaua'i, March 11th 2004. Note the eye has changed to a reddish colour and the skin on the lores/above and below the eye has changed to a pale pink colour. Compare this with the December photographs of a bird from the same group and the similarly-aged Glossy Ibis in Devon, UK, above. Photograph © by Brenda Zaun


White-faced Ibis at Hanalei NWR, Kaua'i, December 2003

 

White-faced Ibis at Hanalei NWR, Kaua'i, March 2004

 

Note the dark-brown eye, brownish fore-face and profuse head streaking.   The eyes have become much redder and the facial area has become more pink, with very pale pink upper and lower borders, which will presumably turn to white in time. The head streaking has also become more sparse.

References

BEAMAN, M and MADGE, S. 1998. The Handbook of Bird Identification for Europe and the Western Palearctic. Christopher Helm. London.

CARMONA, R.; BRABATA, G. and GODINEZ, L. 1997. First observation of the Glossy Ibis (Plegadis falcinellus: Threskiornithidae) in the Peninsula of Baja California. Oceanoides 12: 127-128.

CRAMP, S. and SIMMONS, K.E.L. eds. 1977. The Handbook of the birds of Europe, the Middle East and North Africa - Birds of the Western Palearctic. Volume I. Ostrich - Ducks. Oxford University Press, U.K.

DAVID, R.E. 2003. Flock of ten Ibis at Hanalei NWR, Kaua'i. Message posted to the Hawaii Birding Chatlist Group, October 2003.

DEL HOYO, J.; ELLIOTT, A.; and SARGATAL, J. 1992. The Handbook of the Birds of the World, Volume 1: Ostrich to Ducks. Lynx Edicions, Barcelona.

MCALPINE, D.F.; FINNE, J.; MAKEPEACE, S.; GILLILAND, S. and PHINNEY, M. 1988. First nesting of the Glossy Ibis (Plegadis falcinellus) in Canada. Canadian Field-Naturalist 102: 536-537.

PATTEN, M.A. and LASLEY, G.W. 2000. Range expansion of the Glossy Ibis in North America. North American Birds Volume 54, Number 3: 241-247.

PRATT, H.D. 1976. Field identification of White-faced and Glossy Ibis. Birding 8: 1-5.

PRATT, H.D. 2003. Identification of the Hanalei Ibis. Message posted to the Hawaii Birding Chatlist Group, September 2003.

SHUFORD, W.D.; HICKEY, C.M.; SAFRAN, R.J. and PAGE, G.W. 1996. A review of the status of the White-faced Ibis in winter in California. Western Birds 27: 169-196.

SIBLEY, D. 2000. North American Bird Guide. Pica Press, U.K.

WILSON, A.; GUTHRIE, A. and PYLE, P. W. 2002. White-faced Ibis - Europe next? Birding World Vol.15, No. 8: 343-345.

ZAUN, B. 2003. Report of White-faced Ibis at Hanalei NWR, Kaua'i. Message posted to the Hawaii Birding Chatlist Group, September 2003.

ZAUN, B. 2003. White-faced Ibis flock at Hanalei NWR, Kaua'i increases to eight birds. Message posted to the Hawaii Birding Chatlist Group, October 2003.

ZAUN, B. 2004. White-faced Ibis flock at Hanalei NWR, Kaua'i increases to eleven birds. Message posted to the Hawaii Birding Chatlist Group, January 2004.


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