ARTICLES ON HAWAIIAN AND PACIFIC BIRDS, BIRDWATCHING AND WILDLIFE
Newly arrived Ibises on O'ahu and Kaua'i during September 2004 - migrants or
locally bred birds?
In September 2004 a "newly arrived" first-year Ibis arrived on O'ahu with another individual on Kaua'i, which would either mean they were locally bred birds or more likely are new arrivals from the mainland. However with the arrival last year of 11 birds on Kaua'i it is interesting to speculate whether we are witnessing a colonisation of the islands by the species.
An article has already appeared on the Birding Hawaii website with regard to the arrival of the birds on Kaua'i in 2003 and so only brief details are repeated here. On 16th September 2003 five immature White-faced Ibis (Plegadis chihi) arrived at Hanalei NWR, Kaua'i. 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. By the end of January 2004 none of the birds had shown any sign of plumage change, 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, secondly the lores and bare skin area in front of the eye had changed to a pale pink colour, the pale head streaking had decreased and the body feathers (particularly the breast and lower neck) had deepened in colour. To see the previous article, Click Here.
Peter Donaldson found a first-year Ibis at Honouliuli NWR, O'ahu on September 25th 2004 and on closer observation realised that it had a brown, not red eye. Peter realised that if it was one of the birds originally seen on Kaua'i in 2003-2004 it would almost certainly exhibit red eyes by now (being over a year old). The brown eye could only mean one of two things: either the bird was a new arrival from the American mainland, or less likely, was a bird produced by last year's Kaua'i flock.
Presumed White-faced Ibis, Honouliuli NWR, O'ahu, September 2004
Photograph © by Peter Donaldson
Brenda Zaun (biologist with the FWS on Kaua'i) commented just after the discovery of the O'ahu bird: "There are still 4 White-faced Ibises at Hanalei NWR. They have lost some of the luster and chestnut color they exhibited this summer. Their heads are again flecked with white as they were when they arrived. However, their eyes are clearly red. If the ibis you saw had brown eyes, I suspect it is a juvenile that wandered over recently. Fledging in SW Arizona and S California occurs the end of July." A couple of days later she added: "Just returned from the wetlands (Hanalei NWR, Kauai) and saw 5 ibises - 4 with red eyes, 1 with brown eyes (a new arrival apparently). I doubt that any of the 11 ibises that were HY last year bred this year. The Species Account states the earliest reported breeding at about 2 years of age. However, should these second year birds stay, I believe breeding could occur next year. I am most familiar with WFIB nesting in bulrush, however, they will nest in low trees/shrubs over water - hau flourishes along the rivers and irrigation ditches here and could provide potential nest sites."
Presumed White-faced Ibis, Honouliuli NWR, O'ahu, September 2004
Photograph © by Peter Donaldson
Doug Pratt later added: "Something very strange and interesting seems to be going on with these ibises. Any WFIB with brown eyes is a HY bird, so that one on Kauai must be a new immigrant like (apparently) the one on Oahu. Once adult eye color is attained, it doesn't change with the plumage. Both dark ibis species have been undergoing range expansions, so maybe these birds are just being pushed out by population pressure. If this colonization attempt is successful, it will not, of course, be the first ibis colonization of Hawaii. The flightless Apteribis inhabited Maui in prehuman times."
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White-faced Ibis at Hanalei NWR, Kaua'i, December 2003. Photograph © by Brenda Zaun |
White-faced Ibis at Hanalei NWR, Kaua'i, March 2004. Photograph © by Brenda Zaun |
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| Note the lack of chestnut feathers on the "shoulder" or bend of the wing. 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. 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. | 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. |
Peter Pyle commented on the O'ahu Ibis as follows: "I've looked at Plegadis specimens a lot lately to figure out molts and plumages. The O'ahu ibis is an HY (1st-fall) bird undergoing what we now call the "preformative" molt. The worn brown feathers left on the crown are juvenal, being replaced by formative streaked feathers in the head and neck. An SY (2nd-fall bird) would have some maroon lesser coverts and likely would still be completing the 2nd prebasic molt, appearing patchy in the back and wings. Some Glossy Ibis at this age can show slate-colored loral skin and two indistinct pale stripes within the skin, whereas White-faced Ibis show dull brown skin without pale stripes, similar to that of this bird, through the first year. As with all of these young ibis that reach Hawaii, we'll have to await eye-color change to reddish (or not) and facial-color change to confirm the species. On the mainland this occurs during the first fall but in Hawaii (where they are away from their natural cycles and food sources) it might take a bit longer."
Along with the 5 birds still present at Hanalei, Kaua'i up to three were regularly observed at Kealia Pond NWR, Maui from late September until at least mid-October and a further single individual was observed on one evening at Hanapepe Saltpond, Kaua'i.
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.
MELGAR, C.W. White-faced Ibis and Glossy Ibis: Hawai'i's largest ever flock with notes on Distribution and Identification. 2003. Birding Hawaii Website.
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.
