08-14-15 Bird Field Note

08-14-15 Bird Field Note

August 14, 2015

Debbie Leick bird field note shares updates on Barn Owl detection, Gray Catbird tracking, songbird banding, and a new acoustic monitoring station.

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New Acoustic Station, Barn Owl Detection, Gray Catbirds and Songbird Banding

In mid-July we established a new acoustic monitoring station east of the Continental Divide on private land near Red Lodge. We will analyze the acoustic data for differences in nocturnal passerine migration patterns east and west of the divide.

The new monitor is 250 air miles southeast of the ranch. At 5500 feet, it sits on a bench that rises 1700 feet above the Bighorn River Basin. The Beartooth and Pryor Mountains flank the monitor to the southwest and east, respectively. We hope the mountains will funnel migrants through the area.

We found our last Barn Owl audio detection on August 23, 2014. Using the automated Barn Owl detector we discovered calls at the Floodplain recording station on July 12 and July 28. We do not know if these sporadic calls indicate a local bird or a dispersing juvenile. The spectrograms below show one of the calls and the greater sensitivity of the 21c microphone from Old Bird, Inc.

For Barn Owl Audio Click Below

In July we deployed 30 radio transmitters on catbird nestlings. Nestlings are old enough to receive a transmitter eight days after hatching. We removed them from their nests, affixed the device, and returned them to the safety of their nest. The careful handling process minimized stress to the young birds. The red arrows in the photos point to the transmitter antennas.

Nestlings fledged from their respective nests about eleven days after hatching. The Northern Floodplain nest (above) successfully fledged its young. After leaving the nest, one fledgling hid in a hawthorn bush (below).

Busy adults fed the fledglings a variety of insects and berries for twelve days after the young fledged. In Woodchuck Draw an adult picked a ripe serviceberry for its young (below).

This hungry fledgling with a transmitter begged for food in Woodchuck Draw. It exhibited a crossed-bill deformity, but thrived despite the malformation.

We captured 84 birds of 16 species on our sixth day of summer banding. Forty-six of those birds were juveniles born this year. We also caught our first Yellow-rumped Warbler and House Finch of the season. Neither of these species breed within the banding site, though both breed on the floodplain.

We observed the feather molt progression of a recaptured male American Redstart. Between its capture on 7/14 (left) and 7/24 (right), its head and back darkened to black.