Second season: Dippers on Ashland Creek
Barbara W. Massey
The American Dipper is perceived as a bird of the clear, cold, fast-running streams and lakes of western mountains, and that is true picture for the most part. But here at the south end of the valley Ashland Creek meets all the bird’s criteria as it rushes down from a source high on Mt. Ashland to Bear Creek on the valley floor. For the past decade, Bob Quaccia has led a dipper walk up the creek every January, and seen the birds on almost every trip. This information, plus many other winter sightings, made us realize that a year-round observation of this unique bird was not only plausible but easy. So in the spring of 2010 a group of us decided to do a more comprehensive study. In late April we began walking the creek weekly to look for dippers. We found two nests during the season, both of which produced young, and I reported our adventures in The Chat last September.
This year Bob and I, along with Eric Setterberg, Larry Wright, Gwyneth Ragosine and Frank Lospalluto began our dipper watching in February. Bob built a nest box which was installed under a bridge just above park headquarters. (Alas, I twas never used, but we will relocate it this winter and perhaps build another of a different design.) Frank developed a website for us on which he posted events as they happened. Plus field notes from 2010. The first exciting event of late winter was the appearance of a bird with white edges on its primaries, a leutistic bird first seen on the annual January walk. We hoped it would stay and nest (and be readily identifiable without bands) but no such luck. Although it was interacting with another dipper below the Main Street bridge on 2/11, we did not see it again.
In early March a pair began building a nest high on a buttress of the reservoir dam at the top of Granite St. It was finished in a week, and we expected to watch the full breeding cycle. But there was never any sign that eggs were laid and attended. And although the pair stayed around for quite a while, and sometimes carried in more nesting material, they apparently went no farther with the breeding process, and had left the area by mid-May. The nest was totally inaccessible so we could not determine whether eggs had been laid. It also looked precarious to us, and might not have withstood the presence of 3-4 active chicks. But that was purely our perception.
In early May we spotted a pair carrying nesting material to the underside of the Water St. bridge in the center of Ashland. The nest was visible from the rocks below the bridge and we watched nest building, the long period of egg laying and incubation, and finally there were chicks being fed in the last week of May. The pre-fledging period is reported to be 25-28 days. This nest was accessible and we very much wanted to band the 4 chicks, but decided against doing so lest they try to leave the nest prematurely. But the parents can be banded safely while they are attending eggs or chicks, so we pursued that course. Both RVAS and KBO were very supportive, With funding from RVAS we hired David Hodkinson, a KBO intern who had banded many dippers in the United Kingdom and was not intimidated by the furiously rushing stream that Ashland Creek was this spring! KBO also contributed the banding equipment. On June 14 David and two helpers strung a net across the creek and caught both parents. It sound so simple, but was an amazing feat to observe. Eric took great photos of the whole procedure and they can be viewed on line at lithiadipperwatch. They were color banded and released, and back at the job of feeding their young within the hour. We watched them feeding for the next 3 days, and on the 4th day they fledged. We were able to follow the family for 2 weeks as they moved up- and down-stream and then disappeared from the area.
Color banding made a huge difference in our ability to understand the adults’ behavior, as there are no plumage differences to distinguish them from each other. We hope they will be back next spring, and since they were so successful, there seems to be a good chance. And next year perhaps there will be more nesting pairs and we can do more color banding, including chicks if a nest is accessible and it is safe to do so. Meantime we will be meeting once a month to walk Ashland Creek and keep abreast of dipper activity throughout the year.
If any reader(s) would like to join us on this study we would welcome your help. We will be walking the creek monthly until early spring (or whenever nesting behavior is seen). Then weekly during the breeding season. We could use more enthusiasts, and I guarantee that this adventure is fascinating and provides a unique learning experience to all participants from beginning birders to the most experienced among us. Our website has field notes from both seasons, photos of dippers, nests, and a great series on the color banding session. Most photos were taken by Eric and Larry. If you are interested in joining us, you can contact me at firstname.lastname@example.org or Bob Quaccia at email@example.com.