ARGOS USER STORIES

California Condors

Thomas Gray1, Kristina Vanesky​2 and Rachel Wolstenholme2

CLS America, Inc.1

Pinnacles National Park2

There are not many places along the Central Coast of California where you can see condors in flight, and one of the two prime locations has recently been dubbed "Big Sur Island." Only 35+/- miles separate Pinnacles National Park and Big Sur; although, it is at least a two hour drive by car. 

Ventana Wildlife Society was the founder of the Pinnacles Condor Program which was transitioned over to National Park Service management through the years; however, both groups co-manage the Central Coast populations.

The Pinnacles staff tag every bird that they come in contact with using an identifier tag (plastic, numbered tags on the wings) and a VHF transmitter. Some select birds also receive an Argos transmitter with a GPS receiver in order to get precise, fine scale movement data. Pinnacles manages 39 birds, and Ventana manages 48 birds thus between the two they co-manage 87 total.

One of the major concerns for Condors is unnatural mortality due to contaminated food. Condors consume carrion (dead animals), and feed upon larger wild or domestic animals such as cattle, sheep, deer, or similar, as well as smaller species like rabbits or ground squirrels. 

Lead is still the primary choice for ammunition, and upon impact, it shatters leaving fragments within the dead animal. Even small fragments can cause poisoning when consumed, and because condors are communal scavengers several birds at a time may become poisoned when feeding at just one carcass that was shot with lead. 

Biologists actively monitor the data coming from the Argos satellite tags to determine whether animals are on the move or if they are otherwise still. If a condor has not moved in 2-3 days (based on the transmitted GPS data) they will put together a team to go check on the bird. If the biologists determine it is injured or sick they may capture the bird for rehabilitation at a clinic. Depending on the severity of lead poisoning, birds can often be returned to the wild.

The staff makes the pilgrimage up to the top of Pinnacles every day scanning the surrounding area to see which birds are nearby. Our Argos Goniometer and the VHF receiver both picked up five birds that day all within about 20 miles from our location.

 

The upper limit on range that we've seen, to-date, using the Goniometer has been just over 100 miles. (This was in Montana with someone on the ground tracking sage grouse; they picked up receptions from a golden eagle flying 106 miles away.)

The Argos Goniometer is a great tool for actively tracking animals for several reasons: 

     • It provides compass heading so you can follow your animal's movement in real-time.

     • Acting as a receiver, it will store all of the messages received by the transmitter.

     • In direct reception mode it can decode transmitted GPS data (on select transmitters).

     • It provides you with signal strength, an indicator of distance.

     • It allows you to track one individual at a time. (VHF does this as well through slightly different frequencies.)

You can learn more about the Condor program at Pinnacles N.P. through this link: https://www.nps.gov/pinn/learn/nature/updates.htm 

In addition, here is a link to Ventana Wildlife Society: http://www.ventanaws.org

Kristina Vanesky (Pinnacles N.P.) and Thomas Gray (CLS America) with their respective tag finding gear.

Rachel Wolstenholme (program manager for the condor program), Kristina, and Thomas. 

Image by Tim Huntington - webnectar photography