Date: 4/27/25 2:53 pm From: <dpsiminski...> Subject: [AZNMbirds] Sierra Vista EOP Birding Walk
This morning, ten birders attended the birding walk at the Sierra Vista
Environmental Operations Park (EOP). The participants were from Arizona and
New York. We walked the dikes, and we saw 87 species of birds.
The bird of the day was a Zone-tailed Hawk, an uncommon visitor to the EOP. At
the EOP, they are most often seen during migration, March to May and August to
October, but sometimes in mid-summer. This bird appeared teetering in flight
as the Turkey Vulture mimic it is. However, we noticed the big head of a hawk
and finally in poor light we were able to see some light banding on the tail,
and the flight feathers of the wing were not the silvery of a Turkey Vulture
but vaguely patterned. The photos seem to show a bird in the early stages of
molt of its flight feathers. New central tail feathers and a slight gap in the
line of the wing feathers where the primary feathers meet the secondary
feathers. Not much is known about molt timing in this species. The group had
fun figuring out the ID details.
The other highlight was six Vaux’s Swifts. A regular but sparse spring and
fall passage migrant through the EOP. “V-oh” or “Vox”? This swift was named
by ornithologist John Townsend of warbler and solitaire fame for his college
at the American Academy of Science named William Vaux. Dr. Vaux pronounced his
own name as it rhymes with “fox”, not the French pronunciation. The swifts
were seen flying with six species of swallows (Barn, Northern Rough-winged,
Cliff, Bank, Tree and Violet-green). Only the barn swallow has regularly breed
at the EOP in recent years. In fact, we saw some barn swallows flying in and
out of a maintenance “barn” today apparently getting ready to nest.
Duck numbers and diversity have dropped dramatically. Nevertheless, the single
rare Greater White-fronted Goose continued in one of the water-filled
impoundments. We have never seen this goose fly. Waders were showing well with
19 White-faced Ibis, three Great Blue Herons and a Black-crowned Night-heron.
There was a good variety of shorebirds today with seven species noted (Least,
Western, Solitary, and Spotted Sandpipers plus Killdeer, Wilson’s Phalarope
and Long-billed Dowitcher). Some we observed in their colorful breeding
plumage in good light, e.g. Western Sandpiper, Wilson’s Phalaropes and Spotted
Sandpipers.
It is the time of the season when the granivore (sparrow) numbers decline and
the insectivore (flycatcher, swallow and warbler) numbers increase. The
variety of species, however, was high. We saw ten species of sparrows
(Chipping, Brewer’s, Lark, Lincoln’s, Song, White-crowned, Savannah plus Lark
Bunting, Canyon and Green-tailed Towhees), seven tyrant flycatcher species
(Hammond’s, Gray, Vermilion, and Ash-throated Flycatchers, Cassin’s and
Western Kingbirds, and Say’s Phoebe), eight warbler species (Lucy’s,
Virginia’s, MacGillivray’s, Yellow, Yellow-rumped, Townsend’s, Wilson’s and
Common Yellowthroat ) and the six species of swallows mentioned above.
Birding walks behind the locked gates of the Sierra Vista EOP occur every
Sunday morning. For the month of May, the walks start at 7:00am. Meet early at
the EOP Bird Viewing Platform to sign up with the guide. Late arrivals will
not have access behind the locked gates. Scopes are useful. A hat and water
are highly recommended.
The EOP is located just east (~ 3 miles) from Sierra Vista on AZ Hwy 90. Look
for the Brua Animal Care Center and the Wildlife Viewing signs on the
northside of Hwy 90. Turn left (north) and proceed to the bird viewing
platform. Note that Google Maps may direct you to the wrong entrance.
The next EOP Birding Walk is on Sunday, 4 May, at 7:00 am. Arrive early to
secure a spot. We have a limit of fifteen birders behind the locked gate.
