Point Blue Conservation Science: Monthly Banding Summary, July 2019
September 9, 2019
This summary was compiled by Point Blue’s Palomarin banding interns Olivia Wang and Sarah Mueller with help from Mark Dettling, Banding Supervisor.
About Point Blue: Our mission is to conserve birds, other wildlife, and ecosystems through science, partnerships, and outreach.
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Exciting Captures and Observations:
The interns kicked off the month with a different, more artistic project than usual – making a float for Bolinas’ annual 4th of July parade! We turned intern Sam Snowden’s car into a California Quail, and the crowds of Bolinas cheered as we drove him down the street and played their distinct “Chi-ca-go!” call from the speakers.
Art projects aside, July marks the tail end of the breeding season and the beginning of “molting season” for many birds. Birds molt (replace their feathers) at least once a year. Feathers are essential structures for thermoregulation (regulating body temperature) and flight, so keeping them in good condition is crucial to the bird’s survival. July is an optimal time for birds to molt since it is just after the breeding season but before fall migration, and there is plenty of food available. At this time of year, adult birds of most species go through a “complete molt”, replacing all of their flight and body feathers. Juvenile birds of most species go through a “partial molt”, only replacing their body feathers or a few wing and tail feathers. This difference in adult and juvenile molt patterns allows us to age many birds in fall through the next summer by comparing quality, color, and wear of retained juvenile feathers versus replaced adult feathers.
Though the breeding season is slowing down, we have still been capturing many juvenile birds. Many days seeming like an endless stream of young Swainson’s Thrushes, Wilson’s Warblers, and Song Sparrows in our nets. Other less common young bird captures include a Red-shafted Flicker, MacGillivray’s Warbler, and an American Robin.
We also closely monitored two nests on the side of our bunkhouse at Palomarin. One belonged to a Barn Swallow and contained five nestlings, all of whom fledged and stuck around the building in August. The other belonged to a Pacific-slope Flycatcher with two nestlings. By carefully tracking the nestlings’ development, we were able to determine when the birds had reached an appropriate size to be banded. Though they still look quite different from their fledgling state in these photos, their legs have reached full size and thus were safely banded.
Let’s Do the Numbers:
In 24 days (2850.66 net hours) of mist-netting at Palomarin in July, we captured 276 new birds and recaptured 172 previously banded birds. A total of 448 birds of 27 species were caught. Approximately 18 birds were caught per banding day.
At our other West Marin banding sites, we captured 312 new birds and recaptured 142 previously banded birds. A total of 454 birds of 29 species were caught over 14 banding days in July (716.5 net hours), an average of approximately 32 birds per day.
The highest capture rates at Palomarin and our other West Marin banding sites were on July 11th at Palomarin with 26 birds, and July 30th at Muddy Hollow (in Point Reyes National Seashore) with 67 birds!
At Palomarin, the following species were caught in the highest numbers: Swainson’s Thrush (100), Wilson’s Warbler (76), Bewick’s Wren (31), Song Sparrow (25), and Chestnut-backed Chickadee (23).
Across all off-sites, the highest numbers of captures by species were: Song Sparrow (110), Swainson’s Thrush (91), Wilson’s Warbler (87), and Wrentit (29).
About these Summaries:
Point Blue interns and staff at our Palomarin Field Station share these blog posts in an effort to further engage the public in our science. We are grateful to our partners at the Point Reyes National Seashore and to our surrounding Bolinas and West Marin County community for their support of our work.
Our Palomarin Field Station is open to the public. Consider visiting us! Learn how on our contact & visit us web page.