January 12, 2015  

Tres Rios Overflow Wetlands is located within the City of Tolleson, south of I-10 West, about half way between north/south routes I-17 and the 303 Loop.  Part of a waste-water treatment plant, the major ponds are enclosed behind chain link fencing but the overflow area is in front of the fence beside the flat dirt-road trail that extends 2.5 miles to its end.  A permit is required for the limited parking spots to visit this rich riparian area.

The permitted property is surrounded by agricultural fields and cattle feed lots which, on this day my birding friend, Susan Fishburn, and I chose to visit first before entering the controlled area. In a field of alfalfa, we found a large flock of Canada Geese within 50 yards of the rural road.  Among them were some white geese - that were NOT Snow Geese.  

For the past several years, I've gone out to local ponds to see a Ross's Goose that would hang out with a Snow Goose or two.  For my first sighting, it took me a long time to figure out the different identification marks; the obvious smaller size was not always apparent.

Today, seven Ross's Geese were among a flock of Canada Geese, so it was an easy call.  It was not a Snow Goose because of its shorter triangular bill that lacked the Snow Goose's "grin line; it had a shorter neck and its small black eye was set in its pure white round head.  We were excited about finding these rare transient birds especially in this habitat.  It's the first time I've seen them out of water and not in the company of Snow Geese.

Then we noticed another unusual goose - with only its head showing above the alfalfa.  It was a distant and dark photo on this overcast day, so I've posted a previous shot of a Greater White-fronted Goose. Note the white ring at the base of its bill.  This is also a rare transient through this part of our state.

Greater White-fronted Goose

Not every birding day begins so well!   But the good luck continued when we stopped at an agricultural pond.   Among more than 50 Black-necked Stilts, were a few large ducks with long necks and reddish bills.  Farther along the shore were several other small groups of them. Altogether, we counted twelve Black-bellied Whistling Ducks - a rare species in winter in our part of the country.

Close to where we were standing at that pond, a mixed flock of 30-75 blackbirds would intermittently fly down from the utility wires overhead.  Many of them were Yellow-headed Blackbirds, but also included Brown-headed Cowbirds and I spotted a few female Red-winged Blackbirds in the group, too.  What fun!

The duck in the photo below had us guessing for quite a while.  Sometimes, I bird by photograph as I did in this case to see how close we came to naming the duck correctly.  It's a juvenile Northern Shoveler.  The honkin' bill on it was a clue that put us on the right species.

Finally, we arrived at the Overflow Wetlands portion of Tres Rios where many cars were already parked.  After walking up on a high berm with my spotting scope to look into the fenced ponds where we found numerous waterfowl, we walked the dirt trail next to the riparian area.  With marsh on one side and desert habitat on the other, we decided to focus on the marsh side.  This Common Gallinule gathering nest material was fun to watch.

Many Black-crowned Night Herons reside or roost in the trees of the marsh.  Below is one of them looking for something good to eat.  

Before leaving, we enjoyed having two American White Pelicans (of 32 we saw) fly overhead.  This is one of them.

Except for the fact that Tres Rios is a good one-hour drive (1.5 hours in commuter traffic this morning) from my home, it is full of bird life and a choice spot to visit.  We enjoyed 59 species of birds in three hours.  It's best to set aside a full day to take advantage of the great variety of birds here!

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  1. Nice blog and posts, Babs! Tres Rios is an awesome area, glad you got to see the geese. I'm still searching for the Fulvous Whistling-Duck(s), still with no luck. The White Pelicans at Tres Rios sure are amazing!

  2. Thanks, Tommy. We had a great time there but missed seeing you. I think you arrived well ahead of us.

  3. Looks like a very good day with a lot of great waterfowl!