10-14-14 Bird Field Note

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10-14-14 Bird Field Note

October 14, 2014

Debbie Leick's Bird Field Note shows the results from banding efforts, nocturnal flight call data analysis, and shrubby draw surveys.

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Bird Field Note Nocturnal Flight Calls, Curlew Tracking, Raptor Counts, Songbird and Raptor Banding 10/12/14 Debbie Leick

Fall Migration Nocturnal Flight Calls September 2013 vs. September 2014

We used data from the Sanfoin Bench weather station to explore trends between barometric pressure, precipitation, and the number of nocturnal flights call (Figures 2 and 3). When we compared the dips and rises in pressure to the number of nocturnal flight calls, we could not find consistent patterns.

Large increases in nocturnal flight calls also did not coincide with precipitation events (Figures 4 and 5). This surprised us because we saw patterns in the August 2013 and August 2014 data. We plan to explore other weather variables such as wind speed, wind direction, and cloud ceiling height.

Long-billed Curlew Satellite Tracking Project Our Long-billed Curlew transmitters have sent few locations, suggesting the batteries are not charging well. A recent signal from one of our female curlews showed her wintering in northwestern Mexico, about 1,000 miles from the ranch.

Shrubby Draw Surveys 10/3/14 A shift in species composition occurred this week, with a marked increase in White-crowned Sparrows, American Robins, and Dark-eyed Juncos. We also saw a flock of Mountain Bluebirds in Tongue Creek.

Partridge Alley’s debris piles continued to provide shelter for a group of Rock Wrens. Kerr watched this Merlin hunt the White-crowned Sparrows, Horned Larks, and American Pipits foraging in Partridge Alley.

Avian Science Center: Fall Migration Highlights 9/29-10/3/14

On the floodplain, we finally captured a White-throated Sparrow; for the last three seasons, a single bird has been caught. The distinct facial markings (yellow lores, white throat, and dark eyeline) make this species one of the easier sparrows to identify. White-throated Sparrows breed in the forests of Canada, and northern parts of the Midwest and Eastern U.S. They spend winters throughout the eastern and southern U.S.

Most of our captures this week consisted of sparrows and kinglets, but we also caught warblers in low but consistent numbers. We captured Orange-crowned Warblers, Wilson’s Warblers, and MacGillivray’s Warbler, but the most common species was Audubon’s Warbler (below), a subspecies of Yellow-rumped Warbler. The presence of yellow in the throat distinguishes this subspecies from its eastern counterpart, the Myrtle Warbler.

Dark-eyed Juncos are one of our top 10 species captured each fall. Juncos display a huge range of geographic variation throughout the country, with 15 described races. Sometimes we can identify juncos to race. The majority of our captures are Oregon Juncos, but each season we capture a handful of Slate-colored Juncos (below). This bird’s flanks, which are gray rather than rufous or pink, and smooth gray upperparts, identify it as a male Slate-colored Junco.

We counted 914 raptors this week, including the season’s daily high of 338 birds from October 1. Turkey Vultures and Red-tailed Hawks dominated the count, though we also saw more Sharp-shinned Hawks than in previous weeks. Eagle numbers also increased. We counted more raptors in September 2014 than in any of our previous fall surveys.

We banded nine raptors of five different species. We focused trapping efforts at Indian Ridge because most raptors were flying at low elevations. Falcons made up the bulk of our captures at Indian Ridge, though we also captured the season’s first Rough-legged Hawk. On West Baldy Ridge, we also caught a Peregrine Falcon. A young Golden Eagle made a pass at our station at West Baldy Ridge. It struck our lure so powerfully that it broke the lines that tether the pigeon and escaped.

We banded nine raptors of five different species. We focused trapping efforts at Indian Ridge because most raptors were flying at low elevations. Falcons made up the bulk of our captures at Indian Ridge, though we also captured the season’s first Rough-legged Hawk. On West Baldy Ridge, we also caught a Peregrine Falcon. A young Golden Eagle made a pass at our station at West Baldy Ridge. It struck our lure so powerfully that it broke the lines that tether the pigeon and escaped.

Previous Field Note

10-07-14 Bird Field Note