White-faced Ibis - Plegadis chihi

White-faced Ibises appeared at Ellis Creek recently, so Patti and I went to check on them. The Ellis Creek water treatment facility is in Petaluma, accessed from S. McDowell Blvd. 

The Ibises (9 in all) were foraging actively near the path. Light was from the right side, but sometimes one would turn just right to reveal the shimmering greens and related hues we all love. These birds were all in basic (winter) plumage, and Patti suggested they matched some photos of subadult birds, either hatch year or perhaps second winter. The adult White-faced Ibis has a red iris, whereas these appeared amber in color.

A crop of the above photo below shows the iris color better. The birds foraged for invertebrates much like a a godwit or curlew, probing vigorously in the moist brushy areas close to the trail, rather than in the water.

Another shot shows the sickle-shaped bill better, as well as the long toes that help in marshy areas. Plegadis translates as a sickle, or scythe.

One last shot of the iris, cropped and enhanced from another photo.

None of the birds we observed exhibited any of the rich chestnut hues seen in alternate plumage birds, and none showed any red in the iris. Opinions welcomed as to the age.

So, if a group of Emus is called a "mob", what would be the term for a group of Ibises?

White-faced Ibis - Plegadis chihi

The Central Valley is a great place to view wintering White-faced Ibises, although you're never quite sure where you'll run into them. They forage in agricultural lands, flooded fields, and a variety of wetlands and fresh-water marshes. The White-faced Ibis is similar to the Glossy Ibis of the Gulf Coast, but the 2 species don't often hybridize, even when on the same breeding grounds. They feed on a variety of animal prey, ranging from small insects and earthworms up through crustaceans, snails and even small fish.

While at the Colusa National Wildlife Refuge this past Wednesday, Patti and I were lucky to watch a lone White-faced Ibis foraging directly in front of the viewing platform. Dull afternoon light was not the most flattering for photos, but we got great looks of the bird probing deeply with its sensitive bill, feeling for prey items on the bottom of the pond or in the mud. The shots barely hint at the beautiful iridescent colors one might see in better light.

We watched the White-faced Ibis feeding actively for over 20 minutes. It likely found and consumed some aquatic insects during that period, and it eventually came up with what looked like a crayfish, which it promptly swallowed.

Thought it might be worth taking a video to show the active probing methods it used, similar to those of the longer-billed shorebirds. The videos were shot through the scope using my regular camera, the Nikon V1.

Longer video (15 sec.):http://youtu.be/dRuRy3ob1I0

Shorter video (6 sec.):http://youtu.be/QUhqoYHbYFI