by Rachel Hutchison, Nestbox Monitoring Coordinator

This year has brought big changes in Evergreen Audubon’s Citizen Science Nestwatch Project. Most importantly we have greatly increased the number of nestboxes that we monitor thanks to Jefferson County Open Space. Evergreen Audubon was chosen to take over all of the Open Space nestboxes in the four Open Space Parks in the Bear Creek Watershed: Elk Meadow, Alderfer Three Sisters, Flying J and Meyer Ranch. Because of our many enthusiastic volunteers, Evergreen Audubon was a perfect match for assuming monitoring of these nestboxes.

To get an idea of how amazing our volunteers are here are some numbers: 154 nestboxes divided among 17 loops were monitored by 27 individuals going out an average of 8 times each. That is a lot of dedicated volunteers devoting an hour or two of their time weekly! They had a blast. Besides hundreds of baby birds, they saw a bear checking out the boxes, coyotes, foxes, elk, deer, and even fledgling Great Horned Owls. In addition to bird and animal sightings, we met a soccer team of deaf young ladies here from Australia and many park hikers who wondered what we were doing with the boxes.

Nesting activity varied among the parks. Meyer Ranch and Flying J had the most House Wrens and Mountain Chickadees. The other parks tended to have more bluebirds and swallows. In total 404 birds fledged from our nestboxes. Also of note is that 12 of the boxes had second broods. Perhaps the huge increase was due to fewer spring cold weather days allowing the birds to get started earlier without interruptions from late snowstorms. During the very hot spells in June and July we noticed that Tree Swallows and Mountain Bluebirds were leaving their eggs unattended to go out and catch insects. Since it was so warm the eggs didn’t need to be kept warm by the parents for so many hours in the day. This allowed the adult females to be healthy enough to attempt a second nesting.

There are many challenges facing our cavity nesting birds in our Open Space Parks. Western Bluebird numbers are still very low compared to six years ago. Forest fires and loss of habitat in both winter and summer are a huge factor. Increased foot traffic in the parks may intimidate cavity nesting birds as they tend to prefer more secluded areas. Wildfire mitigation activities in Alderfer Three Sisters may be contributing to decreased nesting there. Bears were a significant factor in the other three parks, destorying nestboxes to get to the tiny eggs and baby birds. A total of 12 boxes were taken down by bears, most destroyed beyond repair. These nestboxes will be replaced and relocated.

We look forward to next spring and hope that Evergreen Audubon can continue to do our part in allowing the bird population in the Bear Creek Watershed to increase and thrive.

below:

Table 1. Breeding success of birds using nestboxes in 2024 in Alderfer Three Sisters, Elk Meadow, Flying J Ranch and Meyer Ranch.

Table 2. Totals of each of the four Open Space Parks.