A USGS-permitted raptor biologist uses professional climbing gear to collect a Bald Eagle chick and places small bands on its legs, to aid with identification in the future.
In southern California, we are fortunate to be able to observe many different species of raptors, including both Bald and Golden Eagles. Through the efforts of raptor biologist/zoologist Dr. Peter Bloom (www.bloomresearch.org) and his colleagues, we are able to study movements in these birds of prey, answering questions such as where do these species go when they fledge from their nest, and where do they end up choosing to nest once they are mature? In order to find such answers, Pete Bloom is permitted by the United States Geological Survey (USGS) to place lightweight metal identification leg bands on nestlings while they are still in the nest. Since the 1970’s, Pete and his team of carefully trained volunteers and fellow biologists have banded over 21,000 raptor nestlings, including Red-tailed Hawks, Barn Owls, Swainson’s Hawks, Great Horned Owls, Bald and Golden Eagles, Red-shouldered Hawks and several other species, mostly in southern California. Since the mid 2010’s, many of these nestlings (except owls) also received a colored leg band. These color bands are used as a visual aid to make identification easier from a distance. From far away and in certain lighting conditions, it can be very difficult to read the 8 or 9-digit sequence of small numbers on the imprinted metal USGS bands, even with a high-powered scope or telescopic camera lens. The color bands have a larger and simpler 2- or 3-digit code, which often provide a quicker way to identify the raptor without the stress of recapturing it. These types of color bands require additional permitting from USGS and are included on Bloom’s federal master bander permit. Bird leg bands and wing tags that are resighted in the United States can be reported online at www.reportband.gov – This will submit your encounter data to the Bird Banding Lab, which is the centralized database maintained by the USGS for all permitted banders in the United States. By submitting your encounter details here, you will ensure the correct bander receives an official report of your sighting, and the data contained in your report will be protected for future research. You will also receive a certificate of appreciation for your efforts!
We get many emails from the public, curious and eager to learn more about an individual bird they have spotted, and we welcome these questions and comments – we would never be able to amass the large collection of data points provided by encounters, without help from the public. As such, we try to share as much data as we can for educational purposes and to advance conservation efforts. There are some details we can never disclose to the public, such as exact locations for either nests or resighted birds, in order to ensure their safety and well-being. We realize that some of the birds we have banded, such as bald eagle chicks from the 2018 and 2019 nesting seasons at Big Bear Lake, have very large followings on social media due to the webcams at the nest. In the past, we have shared short reports in response to individual requests for movement details on birds like these – the last report on our banded bald eagles was created in 2020. We have recently updated it with new movement details that we would like to share more broadly.
Two bald eagle chicks sit in their nest prior to being banded by a permitted raptor biologist.
In 2017, Bloom began adding color bands, made of a colored aluminum material for durability, in addition to the standard metal USGS bands on nestling bald eagles. Since 2017, twenty-five bald eagle nestlings from five different nests in southern California have been fitted with color bands. As bald eagles slowly make their comeback in southern California, these color bands have been very successful in allowing us to monitor the movements and status of this species, as we have done for other raptor species. Unfortunately, one of the bald eagle nestlings included in the color band group died during a late season snowstorm prior to fledging, leaving 24 color bands to monitor, up to and including the 2022 nesting season. Between January of 2018 and July of 2023, we have received thirty-three encounter reports for sixteen different individual bald eagle color bands, with several individuals being sighted on more than one occasion and/or over multiple years in multiple locations. The complete encounter data can be reviewed in a table at the end of this article.
Encounter data that we receive also contains details of the birds’ current status, i.e. alive, dead, injured, etc*. While we understand that learning of a bird’s injury or death can be upsetting and disheartening, it is important to remember that even these sad reports provide valuable information. We learn how far the bird traveled prior to injury or death, and if there were previous reports while it was healthy, we can begin to see patterns in their movements. Injury and death also often illuminate the troubling conservation issues these birds face, and allow us to provide evidence-based data to regulating authorities or conservation organizations, which will hopefully prevent other similar injuries or deaths in the future.
Some of the more common ways that bald (and golden) eagles suffer injuries, often resulting in death, is by vehicle strikes and electrocution from power lines. Many eagles will feed on roadkill (free food!), and an oncoming speeding car spells big trouble for these eagles (or any other scavenging animal). Even if the eagle is able to get off the road before being hit by the car, it might be frightened up into a power line, which can be just as deadly for these birds, especially if they are startled and disoriented. Bald eagles have a large wingspan of 5-7 feet which can unintentionally allow them to make contact between wires that are degraded or not properly retrofitted. We have worked with various power agencies over the years to make sure that power lines known to have caused death to any raptor are investigated and retrofitted properly to prevent another occurrence. But you can help too, by slowing down and watching for wildlife on the road. You can also help give eagles the best chance for long lives by using lead-free ammunition and non-lead fishing sinkers if you are a hunter or fisher, and by not using rodenticides and pesticides; poisoning in various forms are also an unfortunate cause of death for many top predators including eagles, and is also known to be a potential cause for non-viable eggs and nest failures.
The first few years of a young bald eagle’s life can be precarious – they are often nomadic, travelling long distances before settling on a territory. At least two bald eagles banded by Bloom are known to have had remarkable journeys documented by encounter reports; the first, a three-year old bald eagle, banded as an adult in 1986 near Clear Lake, CA in was found injured in Alberta (Canada) in 1987, approximately 1200 miles (~ 1900km) from the original banding location, and the second was a bald eagle banded in Orange County as a nestling in 2014 and found deceased in Klamath Falls (Oregon) in 2016, approximately 625 miles (~ 1005km) from the original banding location.
Bald eagles mature and develop the classic and easily recognizable white head between 4.5 – 5.5 years of age. The lifespan for wild bald eagles can be up to 20 years, if they make it through those first tough years. The oldest known bald eagle in the wild was 38 years old – that eagle was banded by other researchers as a nestling in Minnesota and transported to New York state to enhance the wild population in that area. Prior to our use of color bands on bald eagle chicks, the oldest bald eagle banded as a chick by Bloom was reported deceased in Oregon in 1993 at the age of 8 years (banded in 1985 at Eagle Lake, CA). Another potential long-lived individual was officially reported in 2017 at a nest in Los Angeles County. A photographer’s diligent efforts captured the entire sequence of the single USGS band which verified that this was an eagle banded by Bloom as a chick in 2012 at a nest in Orange County, making it five years old at the time. Unofficial reports have stated that one of the mated pair with a single metal band has returned in subsequent years to that same nest through at least 2022. Two of the bald eagles color banded by Bloom since 2017 have lived to be at least 4 years of age so far, based on official encounter reports through July of 2023.
To know with certainty that the same eagle is being seen in a particular location can be priceless for research. This was recently illustrated with three separate reports of a juvenile bald eagle at Big Bear Lake in 2020 – while most people initially assumed this must be one of the chicks from the Big Bear nest, the juvenile ended up being positively identified by its color band on each occasion as one of the bald eagles from a 2018 nest near Silverado, CA. We have also been able to determine that at least one bald eagle who was rehabilitated after sustaining injuries in the wild has survived for three years after being released back to the wild, based on official reports of the color band.
The photos below show one of Bloom’s color banded eagles, encountered in 2020 near Atascadero, CA* – the survival of this eagle is of special interest as a dangerous tangle of fishing line was removed from the chick’s legs when it was banded in 2017. We can see in the photos that the eagle appears healthy and was not suffering any long-term negative effects from what could have been a devastating injury. We have removed other types of fishing gear such as hooks from bald eagle chicks during our banding efforts; bald eagles, as well as other shorebirds, are especially vulnerable to waste left behind by recreational fishing, so if you enjoy fishing, please remember to take everything with you when you leave - hooks, lines, and sinkers!
Big Bear Lake in California’s San Bernardino Mountains is a very common stopover point for the bald eagles we have color-banded as chicks in southern California and, as you will see in the encounter table below, is one of the most common resight locations. Viewing wildlife such as bald eagles in a place like Big Bear is a wonderful privilege – please allow them the space they need to perform natural behaviors. These birds have to work hard just to stay alive, and it costs them precious amounts of energy to fly away from an unnecessary human-caused disturbance. The photo below was the result of an observer who patiently observed the hunting habits from a vantage point that would not disturb the eagle, and was also able to capture the color band in a series of other shots (color bands are obscured in photos).
A banded juvenile Bald Eagle flies over water with a large fish in its talons.
A banded adult Bald Eagle is seen vocalizing while perched on a power pole.
We are grateful for the many enthusiastic volunteers who spend a lot of time and effort searching for raptors with Bloom color bands. As a result we get valuable reports and photos, such as this color banded Bald Eagle (right) who, as we can see by the fully white head, has survived to adulthood, and has shown similar travel patterns over the years based on the observer’s official reports and many photos.
A banded juvenile Bald Eagle is seen perched on a power pole.
The same observer also provided us with the only official encounter of the 2018 Big Bear Lake chick after fledging (known as “Stormy” to fans online - see photo at right)*. Only a few months after that report was submitted, we were informed that this eagle had unfortunately been found deceased. But with this photo, we were able to see that it appeared healthy at that time, and we could track its progress northwards during its first exploratory year.
If in the past you happened to take a photo of a bald eagle (or any bird) with a color band, and did not yet report it to the Bird Banding Lab, it is not too late! As long as you know the location it was seen and the date the photo was taken (sometimes recorded in the photo metadata), you can still submit it to www.reportband.gov. We have received so many helpful photographs of color banded bald eagles over the years, but a photo is not always necessary to report a resight. If you are able to read the color band through binoculars or a spotting scope, you can also submit your report online at www.reportband.gov. We have banded several thousand adult raptors with just the single USGS metal band, so if you are lucky enough to be able to read the entire 8-or-9 digit number code, those reports are also of course incredibly valuable.
Typically, funding for Bloom’s bald eagle banding efforts are generously sponsored by local non-profits, and the cost of color bands can also be funded by donations collected from the public. We are hopeful that as bald eagles continue to re-establish populations throughout Southern California, we will continue to be invited to band chicks at new and existing nests. These birds still have a lot to teach us!
The encounters below are listed by a unique identifier for each color banded Bald Eagle – this identifier is NOT the code on either band (to prevent false reports). Some birds have more than one report, and those are listed in order by encounter date (which is the date provided on the report submitted online to the USGS Bird Banding Lab). The banding date is the date that bands were placed on the chicks prior to fledging. Raptor chicks are typically banded between 3-7 weeks of age. The banding location is the general area where the nest is located. The encounter location is the general area that was provided on the report where the bird was either found or seen. If the status is listed as “Alive”, this means the observer either stated the bird was alive at the time, or submitted photos which show the bird to be alive. Birds listed as “injured” were taken to California state licensed wildlife rehabilitators who maintain the necessary permits required for the treatment and transportation of federally protected species, with the intention of releasing the bird back to the wild if it survives.
This list is meant to show a general overview of the current movements for bald eagles color banded by Bloom from 2017 to present, and is not intended to provide details for specific individual eagles; if you have questions about a particular eagle that cannot be answered with the info presented below, please feel free to contact us. As a reminder, information regarding exact locations is not something we are able to provide to the public.
Thank you for your interest in the conservation of bald eagles and other raptors!
All photos used with permission of the photographer - our sincere gratitude goes to Nelson, Trisha, and Wendy for sharing these photos with us!
*ADDENDEM & CORRECTIONS:
The photo of the eagle who survived a tangle of fishing line on its legs was taken at a lake in Atascadero, CA (previously stated to have been at Big Bear Lake). Also, the photo of the juvenile eagle on a telephone pole was mistakenly identified as being named “Simba”, but “Stormy” was the name given to the chick from 2018 by local 3rd graders as part of the naming contest organized by a local non-profit Friends of Big Bear Valley (FOBBV), who also installed a popular live camera at the nest. Simba was the name given to the chick hatched at the nest in 2019.
We understand that learning of the death of a beloved bald eagle can be upsetting, but we can assure you that all reports submitted to the USGS Bird Banding Lab (a.k.a. the BBL) are investigated by USGS biologists not associated with the bander, and outcomes are not reported to the bander until they are sure the report is valid. In some cases this can take several months; in fact, one report of a banded Osprey took a couple years to be validated. Eagles are protected by federal law, so the reported death of any eagle requires more scrutiny, and their bodies may only be collected by individuals with certain required licenses and permits. We don't always learn the cause of death in these cases, and even if known, it is not pertinent for the purpose of this article.
The color band codes were not mentioned in the article, and images that may have shown the color bands were obscured - this was specifically done to prevent false reports being made. We cannot control if others choose to share the color band codes online, but we always do encourage anyone who informs us about a sighting to report it to the BBL. The BBL makes the final determination about each sighting which constitutes an official reported sighting. In the past we have been informed by the BBL about reports of other bands or tags that contained unusual or questionable details, and we assist them however we can.
Again, we want to remind everyone that each official re-sight is important, even ones that contain an unfortunate outcome. We are sorry that this might not answer everyone’s questions, but the most significant information to take away here is that sixteen of twenty-four bald eagles have provided us with valid and interesting data points, regardless of outcome. That is at least two-thirds of the chicks surviving long enough to be encountered in locations outside of their natal territory. While it would be wonderful and scientifically illuminating if all the bald eagles we’ve banded had encounters reported, we recognize the hardships these eagles face in their formative years, and we also realize that many eagles travel in areas less populated by humans, which is likely in their favor for survival at times. It's important that we continue to add individuals to this group, and we hope that as more people become interested in birding and/or conservation, reports of color banded eagles continue to be submitted to the BBL throughout North America.
Written by: Nicollet Overby