condor breeding season


Preparing for Condor Breeding Season

A California condor spreads it magnificent wings.

A California condor spreads it magnificent wings.

Even though there are currently no condor chicks to feed or eggs to care for, this is still a hectic time at the San Diego Zoo Safari Park’s condor breeding facility. In order to maximize success for the breeding pairs and their chicks, we try to conduct all of our maintenance work in the “off season,” which lasts from mid-October to the beginning of December. We don’t want to cause unnecessary disturbances during egg production, incubation, or chick-rearing. The chicks are usually moved from the parents’ pens by October, and the new courtship season is in full swing by December, so that short period is the time we are busy with a multitude of tasks, preparing for the next season.

We have been making our yearly repairs: replacing wood that may have been chewed by curious condors, securing perches, fixing leaky pool valves, repairing shift pen doors, and adding visual barriers to better hide human activity to newly fledged chicks that may be released to the wild someday. We also try to weed the majority of the flight pens, opening up area on the ground so the parents can forage for food and small bones in preparation for egg laying. The trees and shrubs also get pruned so video camera access does not become obscured, and our pen and nest cameras get serviced and cleaned. Lastly, and most importantly, the condors get their routine health exams.

Exams are conducted every three years. This year, 11 out of our 31 condors were due for exams. During these exams by our veterinary staff, a number of procedures are completed. Blood samples are taken to test for any potential diseases. A full body inspection is conducted, examining the tail, wings, feather condition, heart rate, respiration rate, eyes, ears, and mouth. If any wing tags need to be replaced, we do it at this time; the next time you see Sisquoc or Towich on camera, you may notice their nice, new wing tags! A fecal sample is submitted to the lab to test for any parasites. And finally, the birds are weighed before being released back into their flight pens.

Condor Cam viewers have noticed that the nest boxes have barriers preventing the condors from entering them. We have been changing the soiled substrate in the nests so that when the next breeding season begins, the nests are clean. Normally, in the wild, a condor pair can have several nest sites within its breeding territory, and the parents don’t always nest in the same cave every year. By changing nest sites, this allows the used nest to dry out and, hopefully, eliminate any nest hazards (insects, parasites, diseases, etc.) before the pair decides to nest in it again, preventing any potential health threats to a newly hatched chick. Since we only have one nesting cavity in our condor pens at the Safari Park, we clean the nests every year: we scrub and repaint the walls and change the sand.

The condors can now settle into the new season. Courtship displays should start occurring with more regularity throughout December. The male will display to the female with wings either partially or fully outstretched; his head will be arched, and his mouth will usually be open. Sometimes he may display with a feather or some food in his beak. He will sway back and forth and will walk toward or around the female, almost like he is in a trance. The female may tug at his feathers or the skin on his neck or face. Breeding can be observed throughout December and January. You can recognize this activity when the male is standing on the female’s back and he’s flapping his wings to keep his balance. This is usually very quick in smaller birds, but for condors, it can last for several minutes. Lastly, eggs are laid anytime between early January and mid-April. One of the females at the Safari Park has been laying her first egg of the season in late December for the past two years – very early for California condors!

Of course, we’ll keep you posted about any eggs as they are laid here at the Safari Park, so you can prepare to meet our next little Condor Cam superstar. Enjoy the season!

Ron Webb is a senior keeper at the San Diego Zoo Safari Park. Read his previous post, Saticoy Flies into the Wild!


Condors: Quest for the Egg

Female condor #284 enters her nest.

Female condor #284 enters her nest.

April has been a very busy and exciting month for the San Diego Zoo’s California condor project. Condor field managers and researchers have been using VHF and GPS telemetry to closely monitor the movement behaviors of the birds that have been reintroduced to Baja California, Mexico. Early spring is the condor breeding season, and we hope to observe breeding and nesting behaviors that will lead to successfully fledged chicks this year.

Condor Field Manager Juan Vargas rappels down the cliff face to a condor nest.

Program Field Manager Juan Vargas rappels down the cliff face to a condor nest.

Two pairs of condors are currently exhibiting breeding behaviors within the reintroduction site in Sierra de San Pedro Martir National Park in the northern Baja peninsula. The first condor pair, comprising birds #217 and #261, is nesting about 10 miles (16 kilometers) east of the reintroduction field station among the soaring, jagged peaks overlooking the desert toward the Gulf of California. The second pair, comprising birds #284 and #269, is guarding a nest site only a mile (1.6 kilometers) from the condor field station in the middle of a steep cliff face on the western, Pacific side of the Sierra ranges. These condors laid an egg in the same nest last year but, unfortunately, it was infertile. The field staff decided to conduct another inspection of this nest to determine whether the pair has laid a viable egg in the wild this year.

A condor egg in the nest.

A condor egg in the nest.

The nest site that condors #284 and #269 have chosen is isolated and well concealed from potential egg raiders such as bobcats and ravens. However, this meant that to access the nest we had to carry climbing equipment along the steep edge of a granite scree slope before program field manager Juan Vargas could make an extended 330-foot (100-meter) rappel in three stages from the top of the cliff down into the nest entrance. Juan found that these condors had indeed laid another egg within this nest. Using a powerful flashlight, Juan was able to candle the egg and determine that this time it was viable. During the candling process, the female condor #284 soared back and forth in front of the nest before landing on the ledge outside (see photo at top), entering and regurgitating her last meal all over Juan’s boots! This defensive, anti-predator behavior is actually an encouraging sign that the birds are determined to guard their nest and are therefore good breeders. Further nest entries will be conducted in the near future to determine the health of the condor chick once it hatches, inoculate it against avian viruses, and attach transmitters before it takes to the air for the first time.

After the western nest inspection, the field team traveled to the mountain ranges on the eastern side of the Sierras to search for the nest of condors #217 and #261. This trip took us across the parched lakebeds and deserts inland from the coastal tourist town of San Felipe toward the imposing mountains of Picacho del Diablo. At 10,000 feet (3,000 meters), these are the tallest peaks in Baja. Camped among the giant cardon cacti at the base of the mountains, the field team is now sweeping the area for the VHF signals broadcast by microtransmitters attached to the breeding pair. Once the location of the condor nest is confirmed, an expedition will be conducted to enter the site and inspect the (hopefully healthy) egg that lies within.

While based at the feet of the eastern ranges during the search for the second condor nest, we also installed the first of a series of meteorological stations on top of one of the nearby peaks. Hauling the station and the heavy equipment needed to install it up steep, spiny, cactus-covered slopes during 108 degree Fahrenheit (42 degrees Celsius) heat in the shade proved to be a challenging endeavor, and we greatly appreciate the assistance of the local Mexican neighborhood at Rancho Santa Clara. This meteorological station is currently transmitting data on wind speed and direction plus the temperature of the air at the eastern mountains for download via the Internet. These data on the climate conditions experienced by the condors in the region are providing valuable information on the environmental variables that determine the habitat preferences of the birds. Condors make extensive use of the strong winds and thermal updrafts that occur across the face of mountain ranges to make long-distance foraging flights without expending excessive energy. Enhanced understanding of how these winds shape condor movement behaviors will enable managers to better tailor the reintroduction program to the specific habitat requirements of the birds.

James Sheppard is a postdoctoral fellow for the San Diego Zoo’s Institute for Conservation Research.

Read more about his project
Read James’ previous post, Golden Eagle Helicopter Survey