Canada goose release

An Update on Canada Geese from the Tanzanite Spill

The Importance of Citizen Science

One year ago, on November 14, 2022, the Oiled Wildlife Care Network was activated to respond after an estimated 6,000 gallons of red-dye diesel spilled from a fuel storage tank for a back-up generator system that flowed through stormwater infrastructure into a pond at Tanzanite Park near Sacramento, California. Along with various other species of birds and mammals, a total of 34 Canada Geese were captured alive, of which 24 were released back to the area after both the geese and Tanzanite Park pond were cleaned.

As part of OWCN’s mission to provide best-achievable capture and care of oil-affected animals, being able to monitor animals after they have been cleaned, rehabilitated, and released back to the wild is an important aspect of continual improvement in rehabilitating oiled wildlife. However, once the spill is over, monitoring the animals that have been released requires a tremendous amount of time and effort. Therefore, local citizen scientists can play a crucial role in helping collect data of survival, movement, and breeding behavior.

Tanzanite Pond at dusk

According to Wikipedia, “Citizen science” refers to “scientific research conducted with participation from the general public.” I think one reason it has become more popular recently is that the scientific community now realizes what an important role citizen scientists play in adding to the scientific body of knowledge. Trained scientists can’t be everywhere at once, so engaging the local populace in collecting data and sharing it can greatly contribute to science. The ease with which people can now collect and share data through phones and through online reporting opportunities has tremendously enhanced the feasibility and relevance of citizen science. In addition, involving the public in collecting and sharing data helps to increase their awareness and willingness to support conservation issues.

In early May 2023, I received a report from the Bird Banding Lab that several of the banded Tanzanite geese had been observed. I contacted the person that reported them, and that is how I “met” Karen Richardson, who is an avid birder and photographer (a great combination for our purposes!). In the months that followed, Karen amassed more than 100 individual observations of these geese, including seeing and reporting the same individuals multiple times. In addition, she has taken many wonderful photographs, not only of the adult geese and their bands, but also of their goslings. One story in particular that we want to highlight in this blog is the story of a pair of Canada Geese that was impacted by the Tanzanite spill and subsequently cleaned and rehabilitated at the San Francisco Oiled Wildlife Care & Education Center in Cordelia. Sam Christie (Wildlife Rehabilitator, OWCN) filled the role of Care Strike Team Leader during this time and had a chance to get to know the birds in her care, including the Canada Geese pair, “L-30 “and “L-46” (the birds’ log number when they were brought to the facility), whose story we highlight below.

canada goose being washed

In Sam’s words, “L-30 (later banded with the number 1068-04814) was a memorable bird for me. The bird was exceptionally feisty while in care and experienced several secondary issues during its 24 days in care. L-30 came in with severe 2nd degree chemical burns under its wings from the oil. So severe were the burns that we considered euthanasia but decided to give them a few days with antibiotics and pain medication. Fortunately, the burns improved quickly, but then the bird had other complications. This bird was very agitated while housed indoors. In between washing and transitioning to outside caging, L-30 sustained some nasty carpal “bumper” wounds from repeated attempts to escape its pen and had significant feather loss from the diesel exposure. Having done both the intake and release exams on L-30, this bird stands out to me as one that overcame a lot to survive.”

diesel burns
Left-right: L-30's diesel burn on day 1; L-30's burn site on release day

“L-46 (band # 1068-04813) had a less remarkable stay, but during its 19 days in care, it was placed into an outdoor enclosure together with L-30 on December 8th and they were released together on December 12th. A match made in rehab! I am very happy to hear that the birds are thriving back out in the wild where they belong!”

Continuation of the story of L-30 and L-46

by Karen Richardson, citizen scientist

My name is Karen Richardson and I have been tracking the Canada geese that were treated and released after the oil spill at Tanzanite Park in Sacramento in November 2022. In May 2023, I was at San Juan Reservoir Park in Sacramento taking photos of the baby geese there.  When I was looking through my photos later, I noticed that one of the parent geese had a metal band around its ankle.  So, I went back the next day and was able to get the number from taking zoomed in photos of each side of the band.  I reported it to the US Geological Society (USGS) site and found out that it was banded in December 2022 by UC Davis. Then I found out from Kyra Mills at OWCN that it was one of the geese rescued and rehabilitated from the Tanzanite Park oil spill!

geese sightings part 1

Since then, I have been on a mission to find and monitor the rest of the banded and released geese. I have found 20 of the remaining 23 geese that were released (one was reported deceased last April).  I’ve seen them at Tanzanite Park, San Juan Reservoir Park, Peregrine Park, and the nearby drainage canals. There are at least three couples in which both individuals have bands. There are several other geese that have a partner without a band.  Several of the banded geese are parents, which means they are healthy and thriving!

geese sightings part 2

One of the banded pairs I’m monitoring is L-30 and L-46, whom have two young. I first encountered them on May 30, 2023, and have seen them nine times, as recently as November 7, 2023.  When I first saw them, the babies were very young - still yellow and fuzzy. Now, the young are hard to tell apart from the adults (see photos below).  I can mostly tell they are the young by their behavior.  I'm excited to continue tracking them, especially into the next nesting season to see if they stay together and if they nest in the same place.

geese sighting part 3

I am grateful for those who rescued and cared for these geese, and I am thankful for the opportunity to participate in follow up research.


Karen Richardson holding binoculars

Karen Richardson is married with two grown children.  She has lived in the area since the late 1980’s, when she came to attend UC Davis. Karen works part-time and goes birding as often as possible.  She loves nature, photography, and contributing to citizen science, and regularly submits birding data to ebird. Karen has also done citizen science projects on butterflies, bumblebees, ladybugs, and plant phenology.  In the summer, she helps monitor a couple of nesting colonies of egrets and herons.

NOTE: As a citizen scientist, Karen’s work has allowed us to continue to monitor the Tanzanite Spill geese and her work has provided valuable information regarding their survival and reproduction. However, it is important to point out that even well-intentioned people can jeopardize the safety and well-being of animals (and themselves), if they try to capture or “help” them.

During active oil spills, the OWCN, along with partner organizations, broadcasts the message to not approach oiled wildlife but to instead call our hotline, (877-UCD-OWCN). The rationale is that a team of trained professionals, with the proper protective gear and training, capture and transport the affected animal(s) to a location where it/they can be cared for.

If you see a banded bird and have a suitable lens to do so, please attempt to read the number on the band, if possible. The next step is to report this number to the Bird Banding Lab (