25 November 2014

Lincoln Birders Study Waterthrush at Platte Park

Nesting season activities of several waterthrushes were well studied at Platte River State Park by Shari Schwartz and John Carlini, Lincoln birders.

“Curiosity about the mysterious lives of several Louisiana Waterthrushes resident at Platte River State Park inspired a fun project during the 2014 breeding season that consisted of near weekly surveys along Stone Creek to see what would (and wouldn't) be revealed,” the birders said.

Surveys started April 15 and lasted through September 13 when the last bird was observed," the birders said. Their search was focused solely on Stone Creek where they observed four territories, two nests, and one or more fledglings on each of the four territories. Two of the territorial boundary lines were determined by locations where males had repeated disputes, both by aerial battles and sing-offs (like a version of dueling banjos but featuring waterthrushes instead.) The third boundary line was speculative because no disputes were observed so location was based on singing males, foraging adults, and foraging juveniles who were easily identified by different hatch months.

The two birders were familiar with waterthrushes at the park, having observed them in previous years. "Louisiana Waterthrushes in our region have a preference for clear moving water in deep shade where they nest in stream bank cavities, which explains why Stone Creek is such a unique and desirable nesting site.

“A few memorable encounters included epic battles between the first and second territory males earlier in the season, always in the same location,” birders Schwartz and Carlini said. “They would chase each other across a big bend, chittering and dramatically attacking in flight. Sometimes the Louies were conspicuous but other times they were as invisible as little ninjas. They were active in the morning but late afternoon and early evening were also a good time to detect the birds calling and foraging.”

“A surprising twist to this year's breeding season was the late timing of the juvenile sightings, about a month later than last year,” they said, adding that a “major highlight of the surveys was observing and becoming familiar with several juveniles. A lone juvenile on first territory consistently used a small side stream as its nursery. Two siblings on fourth territory who were always accompanied by one adult, appeared to have their favorite spots as well. A very late nest with parents feeding nestlings was photographed July 8 on third territory and surely had to be a renest.”

“Louies can be one of the first eastern warblers to depart after breeding, leaving as early as July, but this year's entire crew stayed on Stone Creek through most of August.”

“They're such fantastic birds to watch, they don't give you warbler neck, they choose scenic locations for nesting, and their compulsive u-shaped tail bobbing is so endearing. Sometimes the juveniles almost lose their balance when perching because they just can't stop bobbing! It was a challenge to get photographs in shady low light conditions,” the birders said, “but we were able to get shots of a fourth territory juvenile on different dates and then compare the plumage development, most noticeably the streaking on the flanks which is absent when they're younger."

“Hopefully the limited habitat will endure at the park,” the birders said in an email. “We try to impress upon park management how special this species is, but what is ultimately needed is a system of keeping information permanently and easily available that would describe special and unique bird species at each individual Nebraska Game and Parks Commission unit where unique species occur. The description could include habitat needs and be available at a glance to park managers, park naturalists, and the general public. When new park superintendents take over management responsibilities, they currently have no way of knowing that information about their unit, especially if they're not a birder.”

A map of nests found to date and 2014 territories has been attached to an ebird checklist and can be viewed at this link along with additional photographs.

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