Verification of Unusual
Rec. # 2008-14
|Scientific name:||Plegadis falcinellus|
|Date:||3 Jul 2008|
|Length of time observed:||10 minutes, then 5 minutes|
|Location:||Logan City Polishing Ponds, Benson|
|Distance to bird:||~30 m|
|Optical equipment:||Nikon Sky and Earth spotting scope, Pentax Optio W30 digital camera|
|Weather:||Sunny, hot, about 90 F.|
|Light Conditions:||Direct bright sunlight. Sun almost straight up, but just behind me in the first period of observation and just to the right of vertical in the second observation.|
|Description: Size of bird:||Dark ibis-sized|
|(Description:) Basic Shape:||Dark ibis: wading bird with long, downcurved bill.|
|(Description:) Overall Pattern:||Dark chestnut reddish brown from head to shoulders, including shoulders and breast. Dark iridescent greenish wings.|
|(Description:) Bill Type:||Long and down-curved.|
Field Marks and
(Please see photos and "Similar Species"
|Song or call & method of delivery:||None.|
|Behavior:||Standing. Preening in the first ten minutes of observation, not moving much. After about ten minutes of observation, the bird flew from the south edge of the pond to the northwest corner. When I relocated the bird at the northwest corner, it was foraging by walking around and probing the mud with its bill. The bird was alone both times. Killdeer were in the immediate vicinity, but this bird was not associating with any other ibis. There were many white-faced ibis seen in the Polishing Ponds that day, but none were within at least 50 yards or so of this individual.|
|Habitat:||Mudflats in the later stages of the wastewater treatment facility for the City of Logan.|
were they eliminated:
This bird was easily identified as a dark ibis (Glossy/White-faced) by its size
and shape. A young White Ibis can be eliminated by the dark (not white) belly
and drab grayish or brownish (not orange) bill. In determining whether this bird
is a Glossy or White-faced Ibis, it helps to first determine the age and plumage
of the bird. This bird was an adult in breeding plumage, as indicated by its
dark chestnut brown head, neck, shoulders, and breast, which would be dull dark
gray in a non-breeding bird. Also, this was an adult bird, as indicated by the
solid color of the bill (not banded as in a juvenile). The following traits
eliminate White-faced Ibis and support Glossy Ibis as an identification for the
bird I observed.
Head Feathering: This bird did not have the white feathering around the face that would normally be seen in a breeding-plumage White-faced Ibis. Rather, the head feathering was dark all the way up to the facial skin at all points of contact.
Facial Skin: The facial skin was dark slaty gray with a faint hint of blue at its center, becoming pale chalky blue around the edges where it met the dark head feathering. This facial skin was not as brilliant as is illustrated for some breeding plumage adult Glossy Ibis, and may indicate that the bird was entering non-breeding plumage or may indicate just a relatively dark-faced individual. An adult White-faced Ibis usually has pinkish or reddish facial skin in all plumages, (perhaps pinkish-gray in winter adults), and a White-faced x Glossy hybrid has purple facial skin.
Eye color: This bird had dark eyes that appeared black from most lighting angles. In certain light, the eyes appeared dark brown (the lightest extreme observed is shown in one of the photos). Adult White-faced Ibis have red eyes in all plumages, and hybrid Glossy x White-faced Ibis have eyes that are still visibly red, but darker than a pure White-faced.
Leg color: Because of the ovehead nature of the light, the birds legs were in its own shadow during most of the observation. They generally appeared dark gray. I did not notice any hint of red, which would indicate White-faced Ibis, but because of the shadows I put less weight in this character.
Bill color: This is mentioned as a diagnostic character by Sibley but not by Kaufmann. The bill of this bird was brownish, indicating Glossy Ibis, rather than cool gray, which would indicate White-faced Ibis.
Size: Size differences between these two species are very subtle. Because I did not see this bird next to any other ibis, I cannot judge its relative size.
this & similar species:
This is my first observation of a Glossy Ibis. I have seen thousands of
|References consulted:||Sibley's "The Sibley Guide to Birds," Kaufman's "Advanced Birding," and Kaufman's "Field Guide to Birds of North America," as well as many online photos of various plumages of both species.|
|Description from:||Notes taken at time of sighting|
|Observer:||Ryan P. O'Donnell|
|Observer's address:||1098 Crescent Drive.|
|Observer's e-mail address:||Ryan@biology.usu.edu|
|Other observers who independently identified this bird:||None in the field. Ron Ryel and Craig Fosdick confirmed my identification from photos, but have not seen the bird in the field.|
|Date prepared:||7 Jul 2008|
Notes were made into a digital voice recorder in the field, and this report is
based largely on those verbal notes with some details of weather conditions
taken from memory, and some of the description supplemented from the photos.