Tracking Condors, One Day at a Time by Zeka Kuspa
It is the job of California condor release site managers to monitor the condor flock. What this means is that they must attempt to locate every condor in their region on a daily basis. This kind of monitoring is above and beyond what is done for other species. Can you imagine trying to locate every single bluebird or coyote on earth, every day of the year? Such a feat is made possible only by the year-round work of biologists and volunteers, technologies such as radio and satellite telemetry (a.k.a. GPS), the regular capture of individuals for wing-tagging and blood lead tests, and the restricted condor population and range. Even with these advantages, it is a rare day that every individual bird is contacted. Once a condor has been off the radar for more than three days, targeted attempts are made to get a “visual” (visual observation) or a “signal” (radio-transmitter signal). After 5-7 days flights are chartered to search the remote parts of the condor range for the missing bird. Finding missing condors is important whether they are living or dead. If a condor is sick or injured, then they can be captured and treated. If they have been killed, determining the causes of death is also vital to the success of the program.
As an intern for Ventana Wildlife Society and Pinnacles National Park, I got the opportunity to track these amazing birds in the wild. Here’s an abridged description of a tracking day, one of the essential management responsibilities of California condor recovery partners:
A day of tracking usually starts at 9 a.m. or later, when condors are up and moving. Thermal updrafts, which occur when the ground is warmed by the sun and the surrounding air rises, are a boon to a foraging condor. So condor watching doesn’t require the pre-dawn motivation that other bird watchers must muster. Once at the office, we look at our records for the previous day’s condor activity and set our game plan for the day based on specific individuals we are looking for, or where a wild carcass may have been spotted.
As we drive or hike through condor territory we stop often to “take signals.” We receive the signals emitted by radio-transmitters on the birds wings or tail feathers, using a directional antenna and handheld receiver (as pictured). Since each condor has its own unique frequencies, we can tell who we’re hearing, and in what direction they are from our location. Additionally, by listening closely to the intensity of the signal we can make some assumptions about distance from the observer, and whether the bird is perched or flying. Over the course of the day we may get multiple signals from the same bird that may indicate longer range movements within their range (between canyons or even between release sites). Over the course of a tracking day we will also make visual observations of the condors we come across. These observations may just be a flyby, but when we’re lucky we might get to see the birds feed, or display mating behavior. All of this information is recorded in order to document the relative health of the bird (e.g. no symptoms of lead poisoning), monitor breeding efforts, and provide insight into location of the bird if they do go missing.
A tracking day usually ends at about 4 when condors are starting to seek out their roost for the night. When we make it back to the office we input this data and eventually incorporate it with GPS data downloaded from satellites. Hopefully, we contacted all the birds we were looking for! If not, we will increase our efforts to contact missing birds the following day.
Meet the Science Team: Carolyn Kurle
I was brought onto the condor project by my collaborator and friend Dr. Myra Finkelstein to help decipher potential variations in California condor diets among the flocks in central and southern California. Up until then, I had only seen live California condors at the Santa Barbara Zoo and stuffed condors in a diorama at the Santa Barbara Natural History Museum. When the opportunity arose for me to join the US Fish and Wildlife Service for their summer condor round up and bird examination in summer 2011, I jumped at the chance.
My son Jeremiah was four years old at the time and he and my husband Christian had already accompanied me on several field excursions related to my other projects, so I invited them along for three days at the Bitter Creek National Wildlife Refuge. We drove to their field site and met with the scientists who would be rounding up the birds for health monitoring, testing for lead poisoning, and blood sampling and drove to the condor pen. It was over 100 degrees, so very hot and somewhat desolate, but beautiful.
My job was minimal – watch the USFWS personnel catch the condors from the capture pen, label the blood collection vials and hand them to the scientists drawing blood, and keep my blood samples cold in a small cooler I had brought along for sample transport. I would spin the blood in a centrifuge later, back at our hotel, to separate the red blood cells from the plasma portion of the blood. I would later prepare these samples for stable carbon and nitrogen isotope analysis in my lab at the University of California San Diego. I then combined these data with isotope data from blood samples previously collected from these southern California condors and from birds in the central California flock to better understand potential dietary differences between the flocks and how these diet differences affect the health and well-being of the condors.
The most amazing things about being up close to California condors were their incredible size and their overwhelmingly ugly-but-beautiful faces. It’s one thing to know that condors are the largest terrestrial bird in North America, with wingspans that range to three meters, but it’s another thing to actually see these birds up close and truly understand what such a large size really means. And, up close, their faces are so incredibly fierce and intimidating, that one can clearly see they share a common ancestor with dinosaurs. These birds look dangerous, but they were very mellow to handle and the USFWS personnel did an excellent job processing each bird. I have worked with many animals species in my work as a food web ecologist, but the condors are definitely one of my favorites. Especially because I got to share the experience with my young son.
Dr. Carolyn Kurle and her then 4 year old son Jeremiah getting their first glimpse of free-flying California condors at the USFWS capturing pen in summer 2011 at the Bitter Creek National Wildlife Refuge in Southern California.
The incredibly large wingspan of a California condor.
Dr. Kurle and her son organizing blood samples and preparing tubes for blood collection.
The beautifully “ugly” face of the California condor.