Bremer Wildlife's Bird Banding

Beginning in the summer of 2022, a special project was started at the Bremer Wildlife Sanctuary located in Hillsboro. The property has a 50-nest box trail that spans 2.3 miles and the boxes are primarily used by Eastern Bluebirds (target species), Tree Swallows, House Wrens, and occasionally a Black-capped Chickadee, Tufted Titmouse or Carolina Wren. Nancy Redman monitors the boxes during the breeding season, being April 1 through Aug. 31, and she also has a sub-permit for bird banding under Vern Kleen, Lincoln Land Association of Bird Banders.

Redman started banding the nestling Eastern Bluebirds and Tree Swallows in May of 22. A light-weight aluminum band was placed on the nestling’s left leg which identifies the bird by a unique 9-digit number. When both species are approximately 12-14 days old, their legs are the size they will be for the rest of their life so banding at that age is appropriate. However, no data can be collected on the nestlings, since they are just starting to produce flight feathers and cannot be sexed, measured, or weighed like adult birds. The only information recorded is their age which is hatch year.

Since 2022, 203 Eastern Bluebird nestlings have been banded, 72 in 2022 and 131 in 2023. Banded Tree Swallows for 2022 include 44 nestlings and one adult on nest and in 2023, 43 nestlings and five adults on nest for a total of 93 Tree Swallows. When monitoring boxes, occasionally the female will be persistent and not vacate the nest box, that is how females on the nest are captured, banded and processed.

This is where the science of bird banding comes into play. During a box monitoring on May 2, 2024, a female on eggs was discovered and quickly snatched for banding. Much to the surprise of the bander, the female Tree Swallow was already wearing a band. The band number was recorded and the bird was measured. Redman looked up the number and that female was banded by her on May 25, 2023 as an adult in the exact same nest box.

The following week during the monitoring on May 10, 2024 a different box contained a female on eggs that was also wearing a numbered band. The number was recorded and the Tree Swallow was measured. When this band number was researched, it was discovered that this female had been banded at the sanctuary on June 13, 2022 as a nestling in a nest box. Although the adult was not in the same nest box as when it was initially banded as a nestling, it was in the same proximity.

Tree Swallows are a migratory bird that use the Mississippi Flyway route to go to Mexico and Central America during the winter months and fly back in early spring. While we do not know the exact age of the first bird since it was an adult when branded, we do know the second bird is two-years of age and a female. Amazing to think that these two resilient birds have flown 1,200 to 3,500 miles, one-way, to their wintering grounds and back again the following spring returning to the exact same breeding area.

They are excited about the science of this and hope more banded species will be discovered in the nest boxes this year. All banding, marking and sampling is being conducted under a Federal Bird Banding Permit issued by the U.S. Geological Survey’s BBL.