Bird banding with Tahoe science institute; 13 years of gathering data in the basin

Dusky Flycatcher
provided

Birds are an important part of the Lake Tahoe experience. Seeing an eagle soar over Lake Tahoe can be magical and visiting Chickadee Ridge is an annual occasion for many people. While those are well-known birds in the basin, there are many more unknown species that are just as important to the ecosystem.

Who is TINS?

The Tahoe Institute for Natural Science is a member-supported nonprofit advancing the natural history, conservation, and ecosystem knowledge of the Tahoe region through scientific research, education, and outreach. In short, we connect people to nature, but research forms the foundation for all of our public outreach and education. Bird banding is just one facet of the wildlife research TINS ​​conducts in the Tahoe region.



Nashville Warbler in Sarah Hockensmith’s hand.
Photo by Kendal Scott

What is Bird Banding?

Have you ever seen a bird with a bracelet on its leg? This jewelry isn’t placed by accident, but instead a method of learning more about birds via scientific research also known as bird banding. TINS uses a systematic sampling method known as constant-effort mist-netting to capture birds and collect data. Forty-foot long nylon nets are placed among the vegetation where birds forage and go about their daily movements. When birds hit the nets, they become entangled. At regular intervals, banders make their rounds to gently untangle and retrieve the birds, carrying them in soft cloth bags to an onsite banding station. There the researcher collects valuable information about each bird, such as species, age, sex, weight and fat deposition, wing length and other measures of size, patterns of molt, and overall health and condition. A small aluminum bracelet, each with a unique nine-digit number, is placed on the bird’s leg to identify the individual if it is recaptured, and it is released back into the wild.



Measuring a Dark-eyed Junco.
Photo by Sarah Hockensmith

Why is banding important?

Birds are widespread, diverse, and sensitive to habitat changes, making them important indicators of overall environmental health and stability. Bird banding data provide tremendous insights about the individual birds, their populations, the species involved, and the study sites. Furthermore, all of the data are electronically submitted to the USGS Bird Banding Lab, and by aggregating banding data across the continent, we achieve perspective at much larger scales. All of these data help scientists and land managers make informed management and conservation decisions, especially when they involve birds with declining populations or threatened birds in an ecosystem. For TINS, bird banding demonstrations are also an incredibly useful tool for conservation education. For all of these reasons, TINS ​​initiated its bird banding program in 2010, with a goal of creating a massive, long-term dataset of the birds migrating through Tahoe each fall.

MacGillivray’s Warbler caught in a net.
Photo by Sarah Hockensmith

Has TINS ​​had any recapture success?

Over the years, TINS ​​has banded over 6,500 birds, and we recapture many of our birds between days, seasons, and even sites. Although we haven’t had any of our banded birds recaptured by other banding projects outside of Tahoe yet, we have had our birds turn up in interesting places. These include a Steller’s Jay who moved from South Lake to Incline over a 5 year span, a Western Tanager that migrated to central America and was found the next spring near Fallen Leaf Lake, multiple Audubon’s Warblers that have been found in Southern California during the winter , and a Gambel’s White-crowned Sparrow found in central Oregon, returning to Tahoe from the arctic.

Has TINS ​​focused data collection on any specific species?

And it is. We have attached tiny tracking devices to our locally-breeding Swainson’s Thrush to find out where they winter, in an effort to determine why Sierra Swainson’s Thrush have declined so dramatically. We recaptured the birds to extract the data from these devices, which revealed that their wintering grounds are northern Colombia and Venezuela.

Have TINS ​​found birds from other banding projects?

We haven’t captured birds from other projects in our nets yet, but it is bound to happen eventually. We also see banded birds of all kinds at Tahoe, and on larger birds or color-banded birds, we often can read the band numbers or color combinations to identify the individuals. These have included everything from the many Canada Geese and California Gulls that show up from Stillwater or Mono Lake, Caspian Terns banded in northern Washington State, and quite a few songbirds and hawks from places unknown. Our most impressive banding resight has been a Western Sandpiper that spent several days at Lake Forest Beach and was originally banded on the Chukotka Peninsula in Siberia!

How have recent megafires affected birds migrating through the Tahoe Basin/Sierra Nevada?

As of now, we don’t have any sites directly impacted by fire, so it is difficult to draw inferences about the impacts of distant fires. However, the smoke does seem to affect migration patterns and habits, as the birds struggle with navigation, not to mention the physiological demands of migration, through thick smoke. Bird numbers can drop conspicuously when the smoke gets bad, and we suspect that many birds are adjusting their movements to avoid the smoke. Additionally, the birds do seem to suffer greater stress during days with unhealthy AQI; as a result, we have stopped banding during days where AQI is above 300.

How can we improve banding efforts in future years?

At present, TINS’ bird banding research is not supported by any discrete funding source. Unfortunately, this means we have to balance the demands of this project against other funded priorities within our organization, and occasionally this leads to our sampling effort being less systematic than we would like. We have a goal to find the funding to support a dedicated crew to run nets consistently at all three sites each week for the full fall season. Additionally, we have been actively exploring ways to expand our banding program to include hummingbird banding during the summer and owl banding during fall migration.

MacGillivray’s Warbler
provided

How can someone be more involved with TINS?

TINS provides banding demonstrations for school field trips and to members of TINS. We also lead bird tours each month in the Tahoe Basin and host a number of citizen science projects for the public to be involved in our research.

To learn more about TINS ​​and how to get involved, visit http://www.tinsweb.org

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