Taking the Long View: An inside look at the goings-on at the longest running avian ecology field station west of the Mississippi.

Point Blue Conservation Science: Monthly Banding Summary, September 2018

This summary was compiled by Point Blue’s Palomarin banding interns Nicole Gaudenti and Mike Mahoney with help from Renée Cormier, 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.

Visit Point Blue’s website to learn more.

Exciting Captures and Observations:

Fall migration banding continued at the Palomarin Field Station, and this month, we began catching more migrant passerines moving through coastal central California on their way to their wintering grounds.

A Nashville Warbler banded at Palo on September 26. Photo by Nicole Gaudenti.


Exciting first-of-fall season captures at the station included a House Wren on 9/16, a Fox Sparrow on 9/19, a Yellow Warbler on 9/20, a Golden-crowned Sparrow on 9/22, a Black-throated Gray Warbler on 9/26, a Nashville Warbler on 9/26, a Ruby-crowned Kinglet on 9/27, and a Lincoln’s Sparrow on 9/28; House Wrens, Black-throated Gray Warblers, and a few Yellow Warblers breed in Marin County, but not at any of our banding stations.

A first-year (hatched in 2018) Yellow Warbler banded at Palo on September 20. Photo by Mike Mahoney.


A Black-throated Gray Warbler captured at Palo on September 30. Photo by Nicole Gaudenti.


This month we also caught high numbers of Pacific-slope Flycatchers (PSFL) moving through the region. Pacific-slope Flycatchers belong to the genus Empidonax, and a brief flip through a field guide shows that there are many different Empid species, each with slight differences in plumage, bill-shape, habitat, and region. While the birds can look very similar to one another, there are measureable differences between the species, and the fall banders became accustomed to diagnostic features associated with the commonly captured PSFL. However, their ID skills were put to the test when the banders caught a Willow Flycatcher (another Empidonax flycather) on 9/10 at Pine Gulch! Can you tell the differences between the birds?

Can you spot the differences between these closely related species? On the left is a first-year Pacific-slope Flycatcher caught at Palo on September 7 (Photo by Mike Mahoney) and on the right is a first-year Willow Flycatcher caught at Pine Gulch in the Bolinas Lagoon Open Space Preserve on September 10 (Photo by Nicole Gaudenti).


A Townsend’s Warbler banded at Palo on September 8. Photo by Nicole Gaudenti.


Fox Sparrows, Golden-crowned Sparrows, Ruby-crowned Kinglets, and Lincoln’s Sparrows comprise just a few of the wintering migrant community at the Palomarin Field Station. All of these species breed in more northern locales; some individuals pass through to winter farther south than Palo, and others spend their winters with us! Recent advances in technology have allowed researchers at Palo to study migratory connectivity of these birds using light-level geolocators and GPS tags. Both technologies are attached to individual birds, collect location data using different methods, and then once retrieved from the bird, they provide information about migration and summering locations (and for species that spend the summer at Palo, we can figure out where they spend their winters). Unlike a typical range map that would display where the species as a whole spend both their winters and summers, maps made with the information from the tags show us where our populations spend their summers before returning to Palo for the winter. Below are maps from two of the species whose migratory patterns were investigated at Palo.

Figure from: Cormier, R. L., D. L. Humple, T. Gardali, and N. E. Seavy. 2016. Migratory connectivity of Golden-crowned Sparrows from two wintering regions in California. Animal Migration 3: 48-56
Figure from: Fraser, K. C., A. Roberto-Charron, B. Cousens, M. Simmons, A. Nightingale, A. C. Shave, R. L. Cormier, and D. L. Humple. 2018. Classic pattern of leapfrog migration in Sooty Fox Sparrow (Passerella iliaca unalaschcensis) is not supported by direct migration tracking of individual birds. Auk 135: 572-582.

Let’s Do the Numbers:

In 26 days (2,864.7 net hours) of mist-netting at Palomarin in September, we captured 169 new birds and recaptured 63 previously banded birds. A total of 232 birds of 36 species were caught. Approximately 9 birds were caught per banding day.

At Pine Gulch, we captured 29 new birds and recaptured 48 previously banded birds. A total of 77 birds of 21 species were caught over 4 banding days in September (210 net hours), an average of approximately 19 birds per day.

The highest capture rates at Palomarin and Pine Gulch were on September 25th at Palomarin with 19 birds and September 10th at Pine Gulch with 26 birds.

At Palomarin, the highest number of captures were of the following species: Pacific-slope Flycatcher (40), Wrentit (34), Townsend’s Warbler (16), Swainson’s Thrush (12), and Yellow Warbler (11).

At Pine Gulch, the highest numbers of captures by species were: Song Sparrow (21), Common Yellowthroat (14), Wilson’s Warbler (6), and Pacific-slope Flycatcher (6).

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.