General

Peregrine falcons lose chicks again

For the second year in a row, falcon chicks born at OPPD’s North Omaha Station have died.

The cause is unknown. But Clark, their mother, is 13 years old now, and wildlife experts who have followed her life suspect she isn’t able to produce successful offspring as easily.

“After last year, I had a feeling that this could occur again,” said Jerry Toll, a licensed master raptor bander who has banded previous falcon chicks at North Omaha Station. “I’m disappointed, of course, because I really enjoy working with the falcons. I love climbing up the stack and going up to see them.”

Clark and her mate/brother, Lewis, have produced and raised at least nine surviving chicks since 2020: Storm, Flicker, Flash, Volta, Watt, Ohm, Ampere, Thunder and Lightning. Last year, however, Clark lost all four of her hatchlings. The cause of those deaths was never determined.

Clark and Lewis were born at the Nebraska State Capitol in 2012. Clark was so named because observers believed she was a male, based on her weight when she was banded. Both falcons settled into her box at North Omaha Station in 2015, on a stack overlooking the Missouri River. A video camera captures their moments in the nest and broadcasts them live on YouTube and Facebook.

Toll said he suspects Clark and Lewis will follow a pattern similar to that of their parents, who nested at the Nebraska State Capitol in Lincoln. As they aged, the mother falcon at the Capitol started producing eggs that weren’t viable. Chicks would hatch but die soon thereafter. Eventually, she stopped laying eggs altogether.

Possible factors

The latest falcon chicks – known as eyases – could have faced a variety of factors that contributed to their demise.

It’s possible, though unlikely, that the recent heavy rains soaked the nesting area, making it hard for the eyases to stay warm. The box has drainage holes designed to prevent water buildup.

“There are a lot of what-ifs,” said James Thiele, OPPD’s Wildlife and Natural Resources program manager. “Even if she was incubating them, that (cold) could zap a lot out of them.”

Some speculated last year that a food-borne parasite killed the 2023 falcon hatchlings, though that was never proven.

Thiele questions whether that would have been the case this year, since the chicks died so quickly. He said the first eyas hatched around 2:30 p.m. May 5 and was fed about 6:18 p.m.

The next two hatched sometime on May 6. At 3 p.m. that day, Thiele counted three eyases, but only one was active.

By the morning of May 7, all three had died. Clark removed all three from the nest around 6 a.m., leaving just one unhatched egg. Thiele and Toll said the egg, no longer visible in the nest, likely isn’t viable.

“It’s disappointing,” Thiele said. “I was really excited to watch the little guys grow and keep track of them.”

Thiele said aging birds tend to lay smaller eggs that don’t always contain enough nutrition to keep the offspring alive. He said Clark’s previous hatchlings appeared to be much more active than the latest group and seemed to be working harder to get food.

Ideally, Toll hoped to recover the last unhatched egg and send it to a lab for testing to try to determine a likely cause of death. Thiele checked with federal wildlife regulators and was told no one can take possession of the egg without a permit, and it appears one of the falcons removed the egg from the nest before a permit could be acquired.

Before next year’s nesting season, Theile said, the utility will either switch out the gravel in the box or clean the existing gravel, although the condition of the gravel is not likely to be the cause.

Other chicks possible

The other predator birds at OPPD sites appear to be doing well, with eggs waiting to hatch.

Ospreys at the now-shuttered Fort Calhoun Station have laid three eggs. They have their own live feed on YouTube that bird lovers can watch.

Down at OPPD’s Nebraska City Station, separate falcon parents are still incubating eggs laid in a new nesting box.

Thiele said he hopes to check the parents for banding information sometime soon, since it’s possible that one or both of the parents are Lewis and Clark’s offspring. All of Lewis and Clark’s surviving chicks have bands and tracking numbers to help follow them in the wild.

OPPD employees have kept their distance from the nesting box at Nebraska City to avoid disturbing the eggs, but there is hope. Clark may have lost her offspring this year, but she may now be a grandma.