Point Blue Conservation Science: Monthly Banding Summary, December 2017
By Palomarin Field Station
This summary was compiled by Point Blue’s Palomarin banding interns Krista Fanucchi, Nicole Gaudenti and Kimberly Navarro-Vélez with help from Hilary Allen, Banding Supervisor.
About Point Blue: Our mission is to conserve birds, other wildlife, and ecosystems through science, partnerships, and outreach.
Our Vision: Because of the collaborative climate-smart conservation work we do today, healthy ecosystems will continue to sustain thriving wildlife and human communities well into the future.
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Exciting Captures and Observations:
December was a very exciting month for the banders with new species encountered and high capture rates at our “offsites” (mist-netting sites around West Marin County).
Rare bird alert! We captured a Swainson’s Thrush at Pine Gulch in the Bolinas Lagoon Open Space Preserve on December 21st! Their close cousin, the Hermit Thrush, is a common wintering species in Marin County, however the Swainson’s Thrush is a long distance migrant whose winter range extends from Mexico into South America. Swainson’s Thrushes are common here in the breeding season but are typically all off to their winter grounds by October. This capture is particularly interesting to the greater Point Blue community, considering that this is the latest date we have ever captured this species in Palomarin’s 51 year history!
We were also thrilled to capture so many Yellow-rumped Warblers at our offsites this month. We catch both the Myrtle’s and Audubon’s subspecies of Yellow-rumped Warbler here in West Marin which are distinguished by different facial patterns and the presence or absence of yellow in their throat. We look at other plumage characteristics of the Yellow-rumped Warblers that we catch to try to determine their age and sex, though this often proves to be quite difficult.
On the winter solstice we captured a Gambel’s White-crowned Sparrow (Z. l. gambelii) at one of our west Marin off sites. In North America we have five subspecies of White-crowned Sparrows. The Nuttall’s White-crowned Sparrow (Z. l. nuttalli) is a non-migratory subspecies that occurs here in Marin County year-round. In the fall and winter we capture other migrant subspecies, most commonly the Puget Sound White-crowned Sparrow (Z. l. pugetensis) which winters along the coast from southern Washington to southern California. The Gambel’s subspecies usually winters further east from here, making this an unusual and exciting capture!
We caught two species of woodpecker in December. A Downy Woodpecker at Pine Gulch on December 12th and a Hairy Woodpecker at the Palomarin Field Station on December 24th.
Our last two birds captured and banded in 2017 were a Hutton’s Vireo and a Ruby-crowned Kinglet, which are very similar in appearance and often misidentified in the field. Examine the picture below, can you tell which one is which?
Let’s Do the Numbers:
In 16 days (1764.55 net hours) of mist-netting at Palomarin in December, we captured 40 new birds and recaptured 74 previously banded birds. A total of 114 birds of 18 species were caught. Approximately 7 birds were caught per banding day.
At our other West Marin banding sites, we captured 124 new birds and recaptured 74 previously banded birds. A total of 198 birds of 23 species were caught over 8 banding days in December (451 net hours), an average of approximately 24 birds per day.
The highest capture rates at Palomarin and our other West Marin banding sites were on December 2nd at Palomarin with 12 birds and December 21st at Pine Gulch with 62 birds.
At Palomarin the highest numbers were captured for the following species: Ruby-crowned Kinglet (28), Hermit Thrush (27), Song Sparrow (14), Wrentit (8), Spotted Towhee (8), and Fox Sparrow (6).
Across all off-sites, the highest numbers of captures by species were: Yellow-rumped Warbler (38), Song Sparrow (32), Ruby-crowned Kinglet (30), Hermit Thrush (22), and Fox Sparrow (21).
About these Summaries:
In an effort to share our science with the public, Point Blue interns and staff at our Palomarin Field Station (Palomarin or “Palo”) in Point Reyes National Seashore near Bolinas, CA produce these monthly bird-banding summaries. Our science interns create these summaries as part of their science outreach training.
Our Palomarin Field Station is open to the public. Consider visiting us! Learn how by visiting our mist-netting demonstrations web page.