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Point Blue Conservation Science: Monthly Banding Summary, February 2020

This summary was compiled by Point Blue’s Palomarin banding interns Hannah Roodenrijs, Samantha Chavez, and Mary De Aquino 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.

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.

Explore Point Blue’s website to learn more.

Exciting Captures and Observations:

We had an interesting top capture this month at Palo, Pacific Wrens! Pacific Wrens are a very squirmy and feisty little brown wren with a very short tail. In January we started to hear Pacific Wrens in the area singing their little hearts out, but this month we had the honor of processing seven of those little cuties! The males have been busy singing in order to expand their territories so they can have more opportunities to find good nest locations. Males will build multiple nests on their territory and sing to lure females over to show off their craftsmanship. If a female Pacific Wren is impressed, she will select a nest and begin the hard work of laying and incubating a clutch of eggs.

Unknown sex Pacific Wren. These tiny wrens are busy singing and building nests, or if they’re female they are busy trying to select a mate. Photo by Samantha Chavez.


During one of our banding days this month, we discovered that an Allen’s Hummingbird had built a nest right along our net trail! We did not want to disturb her too much, so we built a new detoured trail that gave her a little more space so she can feel comfortable while incubating and taking care of her young. We first found the nest around February 19th so we are hoping that soon we’ll be able to spot some cute little nestlings! This female was also the first Allen’s Hummingbird we detected at Palomarin Field Station. Many Allen’s had been detected off of our study site such as at the Pacific Coast Learning Center and the nearby Coast Trail, but it took a few more weeks to actually detect one at Palomarin. Allen’s Hummingbirds are returning from Mexico and will be spending the spring and summer in California displaying, mating, nesting, and rearing young. The very similar looking Rufous Hummingbird moves through the California Coast from Mexico to its summer range between Oregon and British Columbia during late winter/early spring as well. While these two birds are almost impossible to distinguish in the field and even can be difficult to distinguish in the hand, a nesting hummingbird is guaranteed to be an Allen’s Hummingbird rather than a Rufous Hummingbird.

Female Allen’s Hummingbird. The female Allen’s is easily sexed by the small patch of orangey red iridescent feathers on the throat. Photo by Samantha Chavez.


Other fun captures in the month of February included a beautiful male Varied Thrush caught at Palo, and a Marsh Wren caught at Pine Gulch (Bolinas Lagoon Open Space Preserve). Varied Thrushes are a wintering species here at the field station, though they are not a very common capture. Marsh Wrens are a year round resident at our Pine Gulch site, though we don’t often catch them because our mist nets are not set up in the open, marshy areas where they most often reside.

A Male Varied Thrush. Males have deep blue steel colored backs and black bands across their breast. Photo by Hannah Roodenrijs.
An unknown sex Marsh Wren. Marsh Wrens have striking black and white feathers on their back. Photo by Samantha Chavez.


February was filled with a few field trips for the fall/winter banders. At UC Davis, we helped a PhD student use Potter Traps to capture Golden-crowned Sparrows to put GPS tags on them and track their migration before they take off for their summer grounds in Alaska. The Potter traps were a new way of capturing birds for us. A Potter trap consists of a small wire cage with a trap door that is triggered to drop once a bird has entered the cage and is safely away from the entrance.

The Palomarin crew also went on a trip to Cosumnes River Preserve, Woodbridge Ecological Preserve, and Staten Island Preserve. We birded our hearts out despite the high winds and we saw many waterfowl and Sandhill Cranes! The cranes are a big attraction in the fall and winter and February is one of the later months that they can still be seen in the Central Valley before they leave for more northern latitudes in the spring. As the sun sets, large flocks of cranes fly in to the preserves to settle down for the night in a beautiful display colloquially known as the “Fly In”.

Last but not least, both winter banders took separate trips out to the Southeast Farallon Islands! We rode along during a supply drop off for the biologists on the island and each had a quick tour of the area before getting back on a sailboat and sailing for San Francisco. The highlights of the Farallon trips were the Elephant Seal colonies, the Common Murre blinds, and the beautiful scenery of the islands.

A Common Murre colony on the Southeast Farallon Islands. Photo by Samantha Chavez.
Some scenery from the Farallon Islands. Photo by Hannah Roodenrijs

Let’s Do the Numbers:

In 17 days (1566.50 net hours) of mist-netting at Palomarin in February, we captured 16 new birds and recaptured 26 previously banded birds. A total of 42 birds of 15 species were caught. Approximately 3 birds were caught per banding day.

At Pine Gulch, our Bolinas Lagoon banding site, we captured 11 new birds and recaptured 5 previously banded birds. A total of 16 birds of 7 species were caught over 2 banding days in February (88.17 net hours), an average of approximately 8 birds per day.

The highest capture rates at Palomarin and our other West Marin banding sites were on February 25 at Palomarin with 8 birds, and February 11 at Pine Gulch (Bolinas Lagoon Open Space Preserve) with 11 birds.

At Palomarin, the following species were caught in the highest numbers: Pacific Wren (7), Varied Thrush (4), Oregon Junco (4), Fox Sparrow (4), and Anna’s Hummingbird (4).

At Pine Gulch, the following species were caught in the highest numbers: Yellow-rumped Warbler (9), Ruby-crowned Kinglet (2), and Marsh Wren (1).

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.