Monthly Banding Summary, April-May 2025
November 9, 2025
This summary was compiled by Point Blue’s Palomarin Field Station banding apprentices Ren Chen, June Yost, Kyleigh Miklos, and Rosa Ponce Vargas, with help from banding supervisor Larissa Babicz.
Exciting Captures and Observations:
The arrival and passage of spring migrants at the Palomarin Field Station and other banding sites nearby began in full force in April. Two of the earliest migrants we caught were Allen’s and Rufous Hummingbirds. These two hummingbird species can look almost identical (for females and young birds). Upon closer inspection, however, their tail feathers can be an excellent clue. Banders at the Palomarin Field Station take note of the width and shape of the tail feathers of these birds, as there are some small differences that we can use to determine the species.
On May 5th at the Muddy Hollow Trailhead in Point Reyes National Seashore (one of our other Marin County banding sites, referred to as “off-sites”), banders captured a Swainson’s Thrush that already had a band on it. This is nothing unusual – in fact, roughly 30% of the birds caught by our banders are what we call “recaptures”. However, this particular individual’s band had an interesting mix of letters and numbers that was quite different from ours, which only have numbers. After some digging, we discovered that this Swainson’s Thrush was most likely banded in Mexico and traveled north to breed at Muddy Hollow this spring! (Check out one of our publications about where our Swainson’s Thrushes winter). Banders call these birds “foreign recaptures” – birds that were originally banded at a different site, and we are awaiting details from Mexican banders. This is a pretty unusual encounter!
Red-winged Blackbirds are common year-round birds found around Pine Gulch, one of our other West Marin off-sites located at the Bolinas Lagoon Preserve. Despite their abundance, they typically prefer the habitat just outside the area where we mist net, and only occasionally get caught there. Male birds of this species are typically glossy black with colorful shoulder patches, like the one pictured below. Female Red-winged Blackbirds are brown with streaky breasts.
About 47% of the birds we captured this spring were already banded. Data from these recaptured birds helps researchers at the Palomarin Field Station to understand the lifespans of the species we are studying. On April 27th, we recaptured a Western Flycatcher that was last caught when it was banded in 2016. This means that the bird was nearly 9 years old, setting the longevity record by two years!
Clearly there was no shortage of fun birds this spring. On May 13th at the Palomarin Field Station, we captured a Pileated Woodpecker, a species that is not often caught because of its large size. Our nets are designed for small songbirds, and large birds usually find it easy to escape.
Let’s Do the Numbers:
In 48 days (4864.02 net hours) of mist-netting at Palomarin in April-May, we captured 124 new birds and recaptured 156 previously banded birds. A total of 280 birds of 31 species were caught. Approximately 6 birds were caught per banding day.
At our other West Marin banding sites, we captured 149 new birds and recaptured 148 previously banded birds. A total of 297 birds of 37 species were caught over 21 banding days in April-May (974.56 net hours), an average of approximately 17 birds per day.
The highest capture rates at Palomarin and our other West Marin banding sites were on May 13th and May 6th at Palomarin with 13 birds, and May 18th at Redwood Creek with 38 birds.
At Palomarin, the following species were caught in the highest numbers: Wilson’s Warbler (58), Allen’s Hummingbird (35), Swainson’s Thrush (20), Dark-eyed Junco (18), Wrentit (13), and Song Sparrow (12).
Across all off-sites, the highest numbers of captures by species were: Song Sparrow (63), Swainson’s Thrush (52), Wilson’s Warbler (43), Common Yellowthroat (18), and Bewick’s Wren (15).
About these Summaries:
Point Blue apprentices 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 Marin County Parks, and to our surrounding Bolinas and West Marin County community and our funders for their support of our work.
Early-career bird banders are part of a rigorous training program at Point Blue’s Palomarin Field Station, where they learn to capture birds safely using mist nets and record data on each bird caught. The information collected allows us to better understand how populations of birds are doing and in turn gives us insight into the health of the systems we research. Learn more about our seasonal apprenticeships by visiting the careers page on our website.
All banding, marking, and sampling is being conducted under a federally authorized Bird Banding Permit issued by the U.S. Geological Survey’s Bird Banding Laboratory.
Our Palomarin Field Station is open to the public. Consider visiting us! Learn how on our contact & visit us web page.