General

Falcons return to North Omaha Station, with a bit of a plot twist this year

The resident falcons at OPPD’s North Omaha Station are back for the season, but not without a little soap-opera drama.

Clark, a longtime tenant and mother of nine, returned to her summer home recently in a stack box overlooking the Missouri River. Another peregrine falcon – not her sibling and longtime mate, Lewis – joined her in the space, and the two appeared to be very friendly.

But the arrangement was short lived. Sometime on March 10, Lewis returned and reclaimed his spot in the box with Clark. It’s unclear where the new, younger suitor went, but any encounter with Lewis probably didn’t end well for him.

“It’s usually combat to the death or major injury,” said Jerry Toll, a seasoned falcon observer who has banded OPPD’s peregrines. “I’m really surprised that Lewis predominated. Lewis is 13 years old, and the new guy looked pretty spry. I’m thinking maybe Clark helped him out.”

A falcon courtship

The courtship between Clark and the younger male appeared to be strong before Lewis arrived, Toll said. The two talked and bowed their heads, a gesture of submission. Peregrines tend to be loners, so coming together in a shared space requires a degree of trust.

“They were definitely a pair,” said James Thiele, OPPD’s Wildlife and Natural Resources program manager.

Lewis and Clark were born at the Nebraska State Capitol in 2012. Clark was so named because observers at the time believed she was a male, based on her weight when she was banded. The two settled into the box at North Omaha Station in 2015, and produced and raised nine surviving chicks: Storm, Flicker, Flash, Volta, Watt, Ohm, Ampere, Thunder and Lightning.

Over the last two years, however, all of their offspring have died. Some of their eggs never hatched, and those that did barely ate and appeared to be sick and weak. The cause of the deaths is unknown, but Thiele, Toll and others have speculated that Clark’s advanced age may be a factor.

Housecleaning

Thiele cleaned the falcon box recently and replaced the gravel bed inside on the chance that the nest box itself could have contributed to the chicks’ demise. It’s possible that some pathogen inside the box played a role.

“It wasn’t horribly dirty in there, but there was plenty of dirt, dust and organic matter,” Thiele said. “Over time, you get dust blowing around, droppings and leftover prey items. The old gravel probably wasn’t the cause, but we cleaned it out anyway and added clean gravel as a precaution.”

Peregrine falcons tend to return to spots where they’ve previously stayed but will often create a new nest for themselves, Toll said. Falcons tend to accumulate mites and other parasites, such as flat flies, which feed on their blood. The parasites’ eggs can lay dormant in gravel for long stretches of time until their hosts return.

“If the parasite load is too high, the chicks can die from it,” Toll said. “It weakens them enough that they don’t survive.”

Winter homes

Over the winter, Clark likely ventured south to a place like Mexico or even as far as Peru, Toll said. One of Clark and Lewis’ offspring was spotted a few years ago in southern Mexico.

Lewis likely didn’t leave the continent. Males travel as well but tend to stay closer to their breeding grounds so they can be in place to attract a female. Toll said he spotted Lewis back at the OPPD nest once during the winter.

“He may not do the same thing every year,” Toll said. “Sometimes, he may try to stay close. That’s why I was surprised that he wasn’t there” when Clark returned to the nest.

As always, you can see the falcons for yourself on OPPD’s live falcon camera on YouTube and Facebook.