Tree trunks recycled to provide new habitat for cormorants
April 19, 2023 - On your next visit to Lakewood’s Belmar Park, you’re likely to see (and hear) a lot more activity in the middle of Kountze Lake. That’s thanks to the new rookeries that city parks employees built for the double-crested cormorants that visit each year.
Double-crested cormorants are migratory waterfowl that tend to nest in one particular area for a period of several years, which is known as rookeries. Over time, their waste tends to kill the trees in which they place their nests, and that is what happened to the trees on the island in Kountze Lake. Several of the dead trees had fallen, leaving limited space for continued nesting.
With such trees suitable for nesting at a premium in Lakewood and along the Front Range, Lakewood’s Parks staff decided to take a proactive approach to keep as many of these birds returning here to nest as possible. Additionally, Lakewood has some resident cormorants that stay year-round, and the island provides a resting place for them.
“Because we’ve encroached on their alternative habitat in this area, they’ve had to really stay situated in this one spot,” said Lee Blair, a natural resources specialist for Lakewood’s Community Resources Department. “We thought we would help them out and enhance their habitat on the island that they have right here. They feel safe there.”
Blair and others procured some lodgepole pine trunks that had already been cut down from Jefferson County Open Space and dragged those out to the island when Kountze Lake was frozen over in February. They then assembled wooden platforms on the trunks that the cormorants need as frames for their nests and hoisted the poles up, each one anchored in a 5-foot hole for stability.
“It was awesome to be able to work with Jefferson County Open Space to source these trees, and it was also great to work with our parks staff. We had a really great group of people with various fields of expertise come out and work together to get these poles up and (in place for) how they are today,” Blair said. “Having the buy-in from upper management to allow this to happen was also important.”
As of mid-April, dozens of cormorants were using the replacement poles for the rookeries in numbers beyond Blair’s expectations.
“I’m surprised and happy by how many birds are taking advantage of this,” he said. “When we put the rookeries up, I said one bird nesting would be a success, but it’s awesome to see that there’s no vacancy on any of the platforms. We were hoping that some great blue herons would be able to use them too, but I don’t think they’ll be able to this year.”
Blair said the plan is to keep these rookeries up for several years and to make any necessary repairs in the fall after the birds have moved to other locations or migrated south. In the meantime, Blair said, “They’ll fledge out their young here and enjoy the summer.”
Watch a video of these rookeries in action