Thursday, July 29, 2010

Jackson Bottom birds: July 23-29, 2010

Bald EagleJuvenile Bald Eagle, Jackson Bottom Wetlands, Hillsboro, Oregon on 28 July 2010 by Greg Gillson.


Even though it is still July, fall migration is picking up at Jackson Bottom Wetlands Preserve in Hillsboro, Oregon.

Shorebirds, gulls, and a few migrant songbirds that don't nest on the Preserve showed up this week. A BONAPARTE'S GULL and a SEMIPALMATED SANDPIPER were present on July 28, both annual but rather rare migrants inland in NW Oregon. In fact, this is the first known record for SEMIPALMATED SANDPIPER at the Preserve, though admittedly difficult to identify. After an absence of about 8 weeks migrant WESTERN TANAGERS have returned. They nest in conifer woods, mostly in the hills, but not on the Preserve.

But the event of the week was that not one, but two, juvenile BALD EAGLES were together back by the Experimental Wetlands on July 28. One bird about 15 feet up in an ash tree calmly allowed visitors on the trail to view it at a distance of about 35 feet (photo above).

The nest at Jackson Bottom has been under constant scrutiny for months. The adults began incubating on March 17. The first food was brought to the nest on April 25, indicating the hatching date. First flight was observed July 19. At no time was it suspected that there were two young.

Two possibilities exist. 1) There were two chicks present all along and no one ever saw more than one at a time. 2) A lone juvenile from somewhere else joined the local fledgling and its parents. Either option presents problems. It is hard to believe a second bird was not observed during all those weeks. It is hard to believe that the parent eagles would not attack and kill any interloper.

Here is this week's list of birds...

Blue-winged Teal
Green-winged Teal
Great Blue Heron
Great Egret
Green Heron
Turkey Vulture
Bald Eagle
Northern Harrier
Cooper's Hawk
Red-tailed Hawk
Spotted Sandpiper
Greater Yellowlegs
Lesser Yellowlegs
Western Sandpiper
Semipalmated Sandpiper
Least Sandpiper
Pectoral Sandpiper
Long-billed Dowitcher
Bonaparte's Gull
Ring-billed Gull
California Gull
Mourning Dove
Vaux's Swift
Belted Kingfisher
Downy Woodpecker
Northern Flicker
Western Wood-Pewee
Warbling Vireo
Western Scrub-Jay
American Crow
Tree Swallow
Cliff Swallow
Barn Swallow
Black-capped Chickadee
White-breasted Nuthatch
Bewick's Wren
Swainson's Thrush
American Robin
European Starling
Cedar Waxwing
Common Yellowthroat
Western Tanager
Spotted Towhee
Savannah Sparrow
Song Sparrow
Black-headed Grosbeak
Red-winged Blackbird
Brown-headed Cowbird
Bullock's Oriole
House Finch
Lesser Goldfinch
American Goldfinch
House Sparrow


  1. Great photo- even a juvenile's stare looks intimidating...