YELLOWSTONE NATIONAL PARK — On Monday, Sept. 9, eight young Trumpeter Swans known as “cygnets” were released at Alum Creek in Yellowstone National Park’s (YNP) Hayden Valley as part of an ongoing restoration project to increase territorial pairs of the species.
According to Bill Long, program coordinator for Wyoming Wetlands Society (WWS), Trumpeter Swans have been declining in YNP for roughly 50 years with the decline intensifying in recent years. Long tells Buckrail that the immediate goal of the release, which was facilitated by members of WWS, YNP and Yellowstone Forever, is to increase territorial pairs in the Park to avoid swan extirpation, or local extinction.
The eight cygnets released were 100 days old and came from WWS’ captive breeding program, which uses swans only with Greater Yellowstone Area (GYA) genetics. Long says staff checked on the swans on Sept. 15 and they were all doing well, observed doing practice flights in the area of release.
An adult white bird previously in the area, specific species unknown, has also been observed joining the group of cygnets, which Long emphasizes is noteworthy because the adult bird will act as a mentor for migration paths and wintering areas it’s used over the last several years as a wild bird.
Long says there are currently five established breeding pairs in YNP; this is a low number compared to over 18 established breeding pairs in the 1960s, but Long says restoring the swan population to its historic population high is not part of the goal. The cygnet releases are primarily helping to preserve the existing YNP Trumpeter Swan population.
Long says an original 10-year period of evaluation was established for the cygnet release program, primarily due to the fact that Trumpeter Swan pair-bonding and territory establishment can take four to five years. If, over a period of 10 years, it’s not possible to continue establishing more territories or existing territories become no longer sustainable, current swan management activity would halt; however, as of now the restoration effort is in its 11th year.
Long says Trumpeter Swan reproduction and breeding season in 2023 showed an increase in nesting pairs that hasn’t been seen since 2006. While only two cygnets fledged, or developed feathers for flight, in 2023, four of the five pairs that nested that year hatched a total of 12 cygnets; Long confirms this number is higher than anything that’s been observed since at least 1993.
According to YNP, as of 2023 these releases have bolstered the Trumpeter Swan population to over 26 birds and five or more territorial pairs in conjunction with additional restoration efforts. This population includes natural reproduction at multiple sites.
YNP’s Facebook page confirms that this September, the Park’s Trumpeter Swan population total will be assessed by staff during the annual swan count across the Greater Yellowstone Ecosystem. Long tells Buckrail that the autumn count over the last few years has varied between 20 to 26 birds, numbers that indicate cygnet releases, seasonal lake closures and nest platform installations can be considered successful so far.
As of now, WWS’ plan is to continue releasing swans for the foreseeable future.
